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All issues Volume 3 / No 6 (2024) Natl Sci Open, 3 6 (2024) 20240037 Full HTML
Issue
Natl Sci Open
Volume 3, Number 6, 2024
Special Topic: Key Materials for Carbon Neutrality
Article Number 20240037
Number of page(s) 26
Section Materials Science
DOI https://doi.org/10.1360/nso/20240037
Published online 09 October 2024

© The Author(s) 2024. Published by Science Press and EDP Sciences.

Licence Creative CommonsThis is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

INTRODUCTION

Nowadays, the primary energy source in the world is still fossil fuels, including coal, oil and natural gas. At present, the world is facing serious problems such as resource depletion and pollution, which are detrimental to the sustainable development of human society [1–7]. Thus, it is urgent to seek new, renewable and green energy sources [8]. The lead-acid batteries and nickel-cadmium batteries exhibit high safety level, but their energy density is too low (less than 70 Wh/kg), and these batteries contain heavy metal elements (lead and cadmium), which are harmful to the environment. Lithium-ion batteries are widely used in automobiles and portable devices due to their excellent power density and energy density [9–12]. However, safety problems (combustion, explosion) of the current commercial lithium-ion batteries are prominent, posing a great threat to personal safety, and their energy density is still unable to satisfy the escalating global demands. Therefore, it is urgent to develop a type of battery with higher energy density, safety and less pollution to cater to the diverse energy system needs of human society [13–23].

The metal-air battery is a system with high energy conversion efficiency, which typically consists of a metal cathode reacting with oxygen in the air [6,16,24–26]. Such batteries exhibit the advantages of high energy density, high energy conversion rate, non-pollution, high safety, low cost, simple structure and ease of operation, etc. [27–29]. The structure of the metal-air battery is shown in Fig.1. The metal-air battery comprises a metal anode (usually Mg, Al, Zn, Li, Fe, Ca, etc.), an air electrode supported by a catalyst, and an electrolyte. Its structure is simple and convenient for construction and subsequent maintenance [30–33].

thumbnail Figure 1

The structure of metal-air battery: (a) non-aqueous and (b) aqueous. Adapted with permission from Ref. [34]. Copyright 2019 MDPI.

As shown in Table 1, the theoretical energy density of metal-air batteries can reach up to 13124 Wh/kg [35–38], which is much higher than that of common lithium-ion batteries (100–200 Wh/kg), and holds great application potential. Among the various metal-air batteries, Al-air batteries (AABs) have obvious advantages over other similar batteries. AABs have extremely high theoretical energy density (8100 Wh/kgAl) and capacity density (2980 mAh/gAl), second only to lithium-air batteries with high risk factor and scarce anode resources [16]. At the same time, Al is abundant in resources, as the most abundant metal element in the earth’s crust. The discharge products of Al-air battery can be recycled; that is, when the discharge of the Al-air battery is completed, Al(OH)3 is formed in the alkaline electrolyte, and then Al2O3 obtained through treatment has a high utilization value. Furthermore, the Al recycled from the use of green energy (wind power, photoelectricity, etc.) can be used for AABs to achieve an environmentally friendly and pollution-free process throughout.

Table 1

Comparison of various metal–air batteries

However, severe hydrogen evolution reaction (HER) occurs, leading to a significant decrease in discharge voltage (less than 0.9 V), capacity density (less than 800 mAh/gAl), and anodic utilization efficiency (less than 30%) [39–41], limiting large-scale promotion and application of AABs. In recent years, treatments of the Al anode have been reported as promising approaches to inhibit the HER, including alloying, mechanical processing and surface modification [42,43]. The modification of Al anode could inhibit HER to some extent, but the process is complex and high-cost. Meanwhile, composition segregation would occur during smelting, which would enhance the surface energy of the Al anode and consequently the HER. On the contrary, electrolyte additives, as a simple and cheap method, have been explored to modify anode surface structure to inhibit HER [44–46]. Multiple types of additives have been proposed, including inorganic additives (ZnO, Na2SnO3, In(OH)3, etc.) and organic additives (ethylene diamine tetraacetic acid, cetyltrimethyl ammonium bromide, alkyl polyglucoside, etc.) [6,16,47–61]. Meanwhile, non-aqueous electrolyte and multiple electrolyte have been introduced into AAB to inhibit the HER, leading to a high battery capacity. However, the energy density of the battery was low, and its potential for application was insufficient. Thus, to address the issue of HER, it is important to consider the impacts of the intrinsic properties of anode and electrolyte materials, which are vital for obtaining high-capacity density and superior application potential [36,62].

This review begins with the reaction on the surface of Al anode in different electrolytes. The mechanism of the side reaction (HER) is discussed. Correspondingly, inhibition methods for HER were divided into two parts: anode and electrolyte. The mechanisms of improving anodic utilization and inhibiting HER are summarized respectively, which are crucial for promoting the progress of AABs in the future. The alloying elements can increase the HER overpotential of the Al anode, which can inhibit HER to some extent. The anodic processing could refine the structure and crystal orientation of Al anode to decrease the activity of HER on the anode. The additives could adsorb onto Al anode and block H2O molecules to inhibit HER. Meanwhile, organic additives could regulate the deposition of inorganic film on anode to block H2O molecules and increase HER overpotential. Finally, we outlined the remaining challenges and future perspectives. We hope this review could provide a deep insight into inhibiting side reaction in metal-air batteries and promoting the development of next-generation high-performance batteries.

INTERFACE REACTION IN Al-AIR BATTERIES

AAB consists of a metal Al anode, an air positive electrode, and an electrolyte, as shown in Fig. 2. The oxidation reaction occurs on the Al anode, and the reduction reaction takes place on the air cathode side.

thumbnail Figure 2

The structure of AAB [63].

Neutral electrolyte

The electrolyte of an AAB is usually alkaline or neutral. Among them, the surface of the Al anode of the neutral Al-air battery system (typically seawater or NaCl solution) is prone to forming a passivation film, and flocculent precipitation is formed in the solution, resulting in increased internal resistance of the battery and a significant decline in discharge performance. Thus, the discharge potential is only 0.5 V or even lower (at a current density of less than 5 mA/cm2), far lower than the theoretical value (2.70 V) [56–65]. The reaction process is as follows [66]:

Anodic reaction: Al+3H2O→Al(OH)3+3H++3e− (1)

Cathodic reaction: O2+2H2O+4e−→4OH− (2)

Total reaction: Al+3/4O2+3/2H2O→Al(OH)3 (3)

Alkaline electrolyte

Therefore, at present, the research of AABs mainly focused on alkaline system (where the electrolyte is usually NaOH or KOH solution). The surface of the Al anode is fully activated due to the dissolution of passivation film. Thus, the discharge voltage and current density are improved. The reaction process is shown in Equations (4)–(6) [5,67]. The Al anode oxidizes to Al(OH)3 in alkaline electrolyte, and then it is further dissolved to form Al(OH)4− [68]. Since Al3+ ions cannot be reduced to Al in aqueous solution, aqueous AABs are usually non-rechargeable.

Anodic reaction: Al+4OH−→Al(OH)4−+3e− (4)

Cathodic reaction: O2+2H2O+4e−→4OH− (5)

Total reaction: Al+3/4O2+3/2H2O+OH−→Al(OH)4− (6)

However, since Al is an amphoteric metal, severe HER can occur in alkaline solutions, as follows below [69]:

2Al+2OH−+2H2O→2AlO2−+3H2 (7)

Serious HER greatly reduces the utilization rate of the anode, resulting in a low discharge voltage (less than 0.90 V) and a low actual capacity density (less than 1000 mAh/gAl). Meanwhile, a large amount of hydrogen gas can also pose an explosion risk, resulting in significant safety hazards during the discharge process [47,70–73]. A large amount of hydrogen escapes with alkaline electrolyte, forming an alkaline atmosphere environment, which can cause damage to human skin and the respiratory tract. In addition, HER also causes significant thermal effects, resulting in excessively high electrolyte temperature, shell deformation, shortened battery life, and even a threat to personal safety [11]. Therefore, serious HER has become a primary problem limiting the promotion and application of AABs. In recent years, worldwide scholars have paid attention to solving the problem of HER during the discharge of AABs by modifying the anode and electrolyte. Addressing these issues will greatly promote the industrial application and promotion of AABs.

Al ANODE MODIFICATION

Anodic alloying

In the alkaline electrolyte without additives (NaOH or KOH aqueous solution), a serious HER would occur on an ultra-pure Al anode. Due to the competition between the normal discharge reaction and HER, the battery voltage and anode utilization rate decrease. On the contrary, some scholars use the method of increasing discharge current to suppress the rate of HER, which has a certain effect. However, serious anode polarization leads to a significant reduction in battery voltage and power [74–76]. In contrast, the introduction of alloying elements into the Al anode can inhibit HER to a certain extent while increasing the battery discharge voltage. Effective alloying elements should have the following characteristics [77]: (1) low melting point; (2) high solid solubility with Al anode; (3) lower activity than that of Al in Pourbaix plot; (4) higher hydrogen evolution overpotential than Al. At present, the widely used alloy elements include Sn, Zn, Ga, In, Mn, and Si.

Formation of solid solution with Al matrix is the main method by which alloying elements activate Al anode and inhibit HER simultaneously. Generally, alloying elements form precipitated phase within Al anode, which can greatly increase the surface energy of the Al anode and improve its activity, thereby increasing the discharge current density and inhibiting the competitive reaction (HER). On the other hand, alloying elements usually have higher hydrogen evolution overpotential than Al matrix, such as Sn, Zn, Mn, and Mg [78,79]. The introduction of such elements can effectively inhibit HER on the Al surface. At present, Al alloys applied in AABs have gradually developed from unit systems to binary systems, ternary systems and even more complex multi-component alloy systems. Multiple alloy elements can improve the activity of Al while inhibiting HER through synergistic effect [80,81]. For example, In, Ga, Sn, etc., can promote the formation of low temperature co-soluble mixtures, destroying the passivation film on the surface of the Al anode to achieve uniform activation. The parameters of common alloy elements in the Al matrix were shown in Table 2.

Table 2

Parameters of common alloy elements in Al

Among the above elements, the mechanism of alloying mainly includes the “solution-redeposition” and “eutectic” mechanisms.

“Solution-redeposition” mechanism [82]. As early as 1984, some scholars proposed the theory of “field promotion”. The elements in Al alloy oxidize with Al during the discharge process to form corresponding cations, which destroy the passivation film on the surface of Al. Then the cations deposited on the Al surface through a reduction reaction to form an inorganic film, as shown in Fig. 3. This theory applies to the elements Sn, In and Zn [83]. The Sn can destroy the passivation film on the surface of Al through the process of “solution-redeposition”. The Sn in the alloy is oxidized to SnO32−, which is usually rapidly reduced in the alkaline electrolyte due to the potential difference between Sn and Al. Sn finally deposited on the surface of Al and destroys the passive film, promoting the uniform dissolution of the Al anode [84]. Zn dissolved in Al alloy can inhibit HER on the surface of anode by increasing the overpotential of hydrogen evolution, thus improving the stability of the battery in alkaline electrolyte. However, the solubility of Zn in the anode is poor, and excessive Zn will cause segregation, leading to self-corrosion (HER) [85]. In element can also activate the Al anode by forming In-rich eutectic with Al to accelerate the local dissolution. However, the solubility of In in Al anode is limited, and the activation effect is far inferior to that of Ga element. Moreover, In2O3 will be generated in the electrolyte, covering the Al surface and hindering the continued dissolution of the Al anode [86].

thumbnail Figure 3

(a) Schematic diagram explaining the dissolution–redeposition mechanism in Al-alloys. (b) Schematic diagram showing the eutectic mechanism. Adapt with permission from Ref. [10]. Copyright 2024 Royal Society of Chemistry.

“Eutectic” mechanism [87]. This theory is applicable to the multicomponent Al alloys. The eutectic element becomes the cathodic site on the Al surface, enhancing the adsorption of anions in the electrolyte and destroying the passive film on the surface of Al. Mn can form compounds with impurity elements (such as Fe), eliminating the adverse effects of impurities and promoting the uniform dissolution of Al anode. Meanwhile, the electrochemical activity of the Al anode is not inhibited [40].

There are also elements that can react directly with Al anode. The reaction of alloying elements with the Al anode can promote the continuous dissolution in the alkaline electrolyte, such as the Ga element [88]. Ga can improve the overall activity of the Al anode through the Al-gallium amalgam reaction, as shown in Equation (8), which promotes the destruction of the passivation film and accelerates the adsorption of anions. Thus, the Al anode is uniformly activated. Meanwhile, the Al-gallium amalgam reaction promotes the continuous and rapid dissolution of the Al anode to achieve high-power density for the battery. However, the uncontrollable Al-gallium amalgam reaction causes unnecessary capacity loss of AABs [89,90].

Al+Ga→Al(Ga) (8)

Based on the aforementioned mechanism, some scholars have studied the effects of Zn and In as alloying elements (including Al-Zn alloy and Al-Zn-In alloy) on the discharge performance and HER inhibition of AABs and the corresponding mechanism (Fig. 4a) [89]. Compared with Al, Zn is more stable in the alkaline systems, and HER can be effectively inhibited by a higher hydrogen evolution overpotential. However, a ZnO passivation film forms when only the Zn element is excessively introduced, which seriously affects the discharge performance of batteries. Furthermore, the In element is introduced into the Al anode, and In can destroy the ZnO passivation film to increase the electrochemical activity. Moreover, the price of the Al-Zn-In ternary alloy anode is lower than that of 4N high-purity Al, which is more conducive to the large-scale promotion and application of AABs [89]. Sun et al. [90] introduced In element into Al anode to reveal its inhibitory effect on HER and the improvement effect of battery performance. The results show that after the introduction of In element, the discharge voltage of the battery in 4 M NaOH solution reached 1.30 V, and the anode utilization rate reached 75.2% (Fig. 4b) [90].

thumbnail Figure 4

(a) Hydrogen evolution volume of pure aluminum and Al-Mg-Ga-In alloys with different compositions in 4 M NaOH solution. Adapt with permission from Ref. [73]. Copyright 2019 Elsevier B.V. (b) Discharge behavior of pure Al, Al–Ga, Al–In and Al–Sn alloy as the anodes of Al-air batteries in 1 M KOH solutions at different current density. Adapt with permission from Ref. [73]. Copyright 2015 IOP Publishing. (c–e) The fracture surfaces of 6 wt% Al-Ga-In-Sn alloys with different Ti contents and relations of Al grain size with Ti contents: (c) Ti free, Ti 0.03 wt%, Ti 0.06 wt%; (d) Ti 0.09 wt%, Ti 0.12 wt%, Ti 0.15 wt%; (e) Ti 0.18 wt%, Ti 0.24 wt%; (f) relations of Al grain size with Ti contents. Adapt with permission from Ref. [76]. Copyright 2017 Elsevier B.V.

Furthermore, to more effectively inhibit HER during the discharge process, more diversified Al alloy systems have been studied and developed. Generally, the discharge performance and HER inhibition effect of multicomponent alloy systems (binary alloy, ternary alloy and even more multicomponent alloy systems) are mainly dominated by one of the elements. Du et al. [91] introduced Ga, In and Sn into Al anode, and prepared four Al alloys: A1-Ga-In, Al-Ga-Sn, A1-In-Sn and A1-Ga-In Sn. By analyzing the morphology, structure and electrochemical properties, the inhibition rate of the HER reaction and battery discharge performance were studied. The results (Fig. 4c–e) show that the alloy containing Ga is a single-phase solid solution. When In and Sn are introduced simultaneously, second-phase particles will precipitate on the surface of the Al alloy, which improves the surface energy and increases the electrochemical activity. The results of the electrochemical performance test of the Sn alloy show that the activity of Sn alloy is the same as that of the A1-Sn alloy, indicating that the Sn element has a significant effect on enhancing of Al anode activity. However, the performance of Al-In alloy did not improve after the introduction of the Ga element. Therefore, it is concluded that among the three elements, Sn plays a dominant role in improving the performance of Al anode, followed by In, while Ga element has the minimal effect. The main reason for this result is the difference in melting point among the alloying elements and their diffusion rate in the Al anode.

However, as shown in Table 3, the anodic utilization rate of the alloying method is usually 60–80% [80,85,92,93]. Although the aforementioned alloying control method has a certain effect on inhibiting HER in alkaline systems, the uncontrollable side reactions of the alloying elements often hinder the discharge process of the Al anode [92–94]. In addition, the process of preparing Al alloys by adjusting the ratio of alloying elements is complicated and costly. Furthermore, segregation during the preparation of large-size Al anodes would occur inevitably, which is not conducive to the large-scale production and application of AABs.

Table 3

Discharge performance of AABs using Al alloy as anode

Structural treatment of Al anode

The anode of Al alloy obtained by traditional casting means will inevitably produce element segregation, and the second phase particles will be enriched in the part with high surface energy, resulting in serious self-corrosion (HER) during discharge and uneven dissolution of Al anode. Meanwhile, failure of the battery and decrease of anode utilization occurs [100–102].

The heat treatment process can change the distribution of elements and grain size in Al alloy, simultaneously improve the internal stress distribution and microstructure of the matrix by restoring recrystallization, so as to reduce the element segregation and the number of defects (including dislocation, slip, etc.) during the preparation of Al alloy. Recently, some scholars have inhibited HER during the discharge of AABs and improved the discharge performance by adjusting the microstructure of the Al anode (including grain size and crystal orientation, etc.) [103]. Srinivas et al. [104] studied the electrochemical activity and HER rate of A1-0.5Mg-0.08Sn-0.08Ga (wt.%) Al alloy after heat treatment at 400–550 °C. The results showed that HER rate decreased due to the high hydrogen evolution overpotential of Sn element. After heat treatment, Sn element was more evenly distributed in Al anode, which is conducive to promoting uniform dissolution of Al anode. Multiple alloying elements improve battery discharge activity synergistically (Fig. 5a) [105].

thumbnail Figure 5

(a) X-ray elemental mapping of as-rolled and solutionized samples. Adapt with permission from Ref. [105]. Copyright 2016 Elsevier B.V. (b) Rolling process and discharge curves of pure Al and Al–Sb anodes for Al-air batteries at different current densities. Adapt with permission from Ref. [106]. Copyright 2020, Elsevier.

The mechanical processing of Al alloy can also improve its electrochemical properties. By common rolling (cold rolling, hot rolling, etc.) and extrusion, the grain size, crystal face orientation, internal stress, defect number and grain boundary distribution of Al alloy can be improved, and the surface energy of Al alloy can be reduced to increase the inhibition rate of HER. At present, there are few researches on preparing method and processing technology of Al anode. As Fig. 5 shows, Zhang et al. [106] carried out rolling treatment on pure Al, and the results of morphology and structure showed that the grain inside the Al anode was significantly refined, while the internal defects of the alloy material were effectively regulated (Fig. 5a). Meanwhile, the high-density dislocation structure generated by rolling significantly improved its electrochemical activity. The discharge voltage and capacity are increased from 1.47 V and 983 Ah·kg−1 to 1.53 V and 1524 Ah·kg−1 respectively (Fig. 5b).

In addition, emerging Al alloy preparation processes, such as directional solidification, 3D printing, friction stir welding, have gradually been applied to the preparation of high-performance Al alloy to improve the internal element distribution and structural properties. The battery achieved high power when the HER was inhibited. Ma et al. [98] prepared Al-0.5Mg-0.1Sn-0.05Ga (wt%) alloys with varying grain sizes using the directional solidification casting process, and found that the self-corrosion rate of the alloys in 4M NaOH decreased as the grain size increased. After annealing at 600 °C, the specific capacity and peak energy density of the Al anode produced through the combination of the directional solidification technology and the rolling process at 40 mA/cm2 are about 2529.7 Ah·kg−1 (23.4% higher than the as-cast sample) and 3743.9 Wh·kg−1 (33.2% higher than the as-cast sample), respectively.

The aforementioned treatment can activate the Al anode by improving material structure, grain size, grain orientation and other characteristics. However, the HER was still severe, resulting in limited improvement of the anodic utilization rate and low battery power density, capacity density and energy density [105,107–109]. Moreover, the energy loss during the mechanical processing is significant, the cost is excessively high, and the process is complex, which is not conducive to the promotion and application of AABs [19,110].

Surface modification of Al anode

Surface treatment is also an option to suppress HER and improve battery discharge performance. Some scholars have used electrochemical deposition to provide a protective copper layer for the 7075 Al alloy, which protects the Al anode from HER by forming a physical isolation film and improves the utilization rate of the battery anode [103]. Lee et al. [110] increased the specific surface area of the pure Al anode through a technique of micro-sandblasting (surface bombardment with metal oxides), giving an AAB an energy capacity of 4.5 mWh, which was 6.5 times higher than the basic Al anode. However, the current use of surface treatment methods exhibits poor long-term performance, greatly reducing the potential of AABs.

In summary, based on current studies, anode modification alone has been insufficient to promote Al anode activation and HER inhibition simultaneously. To address this issue, the types and contents of alloying elements need to be strictly controlled, the process of structural treatment and surface modification need to be refined, and the electrolyte and additives should be coupled for a synergistic effect [101]. Therefore, research on more effective method for activating the Al anode and inhibiting HER is crucial to advancing the application of AABs.

ELECTROLYTE

Single electrolyte

Aqueous electrolyte

Electrolyte additives offers the advantages of low cost, simplicity in operation and effectiveness, capable of inhibiting the HER of Al anode through the deposition of inorganic films or the adsorption of organic molecules. This enhances the discharge performance of alkaline AABs [36,50,54,58,111–114]. At present, it is the most widely used and efficient method for HER inhibition. Notably, effective method of inhibiting HER through the deposition of inorganic film layers or the adsorption of organic additives, without compromising anode activity, have been extensively studied [115].

Inorganic additives

Inorganic additives were the first HER inhibitors used in AABs. The most prevalent inorganic additives in alkaline AABs include zinc oxide (ZnO), sodium stannate (Na2SnO3) and indium hydroxide (In(OH)3). Typically, inorganic additives form a protective film on the Al anode surface, isolating the metal from the alkaline electrolyte, and simultaneously increasing the hydrogen evolution overpotential to effectively inhibit HER on the Al surface and improving the anodic utilization rate of batteries [63,116].

(1) ZnO

Recent studies have shown that ZnO is a cathodic inhibitor, meaning it can inhibit HER on the Al anode surface without affecting the anodic reaction (discharge process) of the battery [114,117]. ZnO exhibits a very high inhibition rate of HER on both pure Al and Al alloy, reaching over 90% [111]. ZnO dissolves in aqueous solutions of KOH or NaOH to form Zn2+ ions, which undergo a reduction reaction on the surface of Al to deposit a Zn film, as shown in equations (8) and (9). The Zn film can be deposited because the electrode potential of Zn (−0.76 V vs. SHE) is higher than that of Al (−1.66 V vs. SHE), and it increases the hydrogen evolution overpotential of the Al anode. The deposited Zn film is relatively dense and adheres to the Al anode surface, functioning as a barrier to protect the Al anode from HER (Fig. 6a). This enhances the utilization rate of Al anode.

thumbnail Figure 6

(a) Cross-section view of Zn film deposited on Al anode. Adapt with permission from Ref. [111]. Copyright 2019 Springer Nature B.V. (b) SEM micrographs of the Al alloy anode surface at different resolutions after soaking in different electrolyte with 12 g/L K2SnO3. (c) Electrochemical of Al anode in electrolyte with different concentrations of K2SnO3. Adapt with permission from Ref. [116]. Copyright 2024 American Chemical Society. (d) SEM image of Al anode in electrolyte with In3+ ions. (e) Current- time plot of Al anode in electrolyte with In3+ ions after passivation. Adapt with permission from Ref. [118]. Copyright 1969 Kluwer Academic Publishers.

ZnO+2OH−+H2O→Zn(OH)42− (9)

2Al+3Zn(OH)42−→2Al(OH)42−+4OH−+3Zn (10)

(2) Na2SnO3

Na2SnO3 is also a commonly used inorganic additive that can significantly inhibit HER on the Al anode surface. Studies have shown that the addition of Na2SnO3 in NaOH or KOH solutions can significantly reduce the electrode potential of the Al anode, thereby activating it [61]. After adding 1×10−3 M Na2SnO3 into the electrolyte, the anodic utilization rate of the AAB reached 95% [61]. In the reaction process, SnO32− is reduced to Sn (Equation (10)), akin to the “solution-redeposition” process of Sn element in Al alloy (Fig. 6b). The Sn film inhibits HER by increasing the hydrogen evolution overpotential of the Al anode. Simultaneously, the deposition of the Sn film disrupts the passivation film on the Al anode surface, significantly enhancing its activity, as shown in the electrochemical test in Fig. 6c. However, excessive deposition of Sn on the Al anode can easily lead to dendrite growth, causing short circuit of the battery. Studies have shown that Na2SnO3 can inhibit 95% of HER on surface of Al-2Mg alloy anode. However, excessively high stannate concentration can result in short circuit of the battery or damage to the electrolyte circulation system [116].

6Al+3Na2SnO3+3H2O=3Sn+6NaAlO2+3H2 (11)

(3) In(OH)3

The In(OH)3 additive can also deposit an inorganic film on the Al anode surface to inhibit HER. Studies have shown that the introduction of In(OH)3 effectively reduces the electrode potential on the Al anode surface, enabling uniform activation during discharge [118]. Similar to Sn, In3+ ions can be deposited on the Al anode surface to form an In film, disrupting the passive film (Fig. 6d and e; Equation (11)). Notably, In(OH)3 can synergize with a variety of additives. It has been proved that introducing both Na2SnO3 and In(OH)3 into the electrolyte significantly inhibit HER on the Al anode surface. Meanwhile, the results of constant current discharge tests showed that the mixed additive greatly improves the discharge potential of the battery. Additionally, the anodic utilization rate of the battery reached 96% [118].

Al+In3+→Al3++In (12)

Organic additives

Organic additives, another type of additive in alkaline electrolyte, are widely used in AABs. They typically contain nucleophilic and electrophilic groups within their molecular structure. Nucleophilic groups can be several heteroatoms (N, S, O, and P, etc.) or functional groups (hydroxyl, carboxyl, benzyl, etc.), while electrophilic groups are usually hydrocarbon groups (-(CH2)nCH3) [119–123]. The nucleophilic functional groups in organic molecules are the primary sites for adsorption. The adsorption strength depends on the electron density and the polarizability of the functional groups; stronger molecular polarity facilitates easier adsorption on the Al anode surface, thereby shielding the active site for HER [124]. The electrophilic groups form a hydrophobic layer on the Al anode surface, blocking H2O molecules and inhibit HER. In addition, organic additives can adsorb H2O molecules in the electrolyte, forming strong hydrogen bonds that reduce the activity of free water, further inhibiting HER [125–128].

As mentioned above, the nucleophilic groups of the organic additives preferentially generate electrostatic adsorption with the Al anode compared with H2O molecules, while the electrophilic groups form a hydrophobic film that repels H2O molecules, effectively inhibiting HER. At present, a large number of researches focus on the application of quaternary ammonium salts (QASs) as additives in AABs [51,58,129]. Some researchers have revealed that introducing alkyl dimethyl benzyl ammonium chloride as an electrolyte additive causes the nucleophilic functional group (-N) to adsorb on the Al anode surface, occupying the active site for H2O molecules and inhibiting HER. Introducing 1.8×10−4 M cetyltrimethyl ammonium bromide into the alkaline electrolyte provided a high HER inhibition efficiency of 84.6% for pure Al [129]. It has also been reported that the length and type of functional groups in QASs affects the inhibition rate of HER and battery performance of AABs. Optimal lengths of electrophilic and nucleophilic groups promote higher inhibition rates and capacity densities. However, excessively long electrophilic groups decrease water activity, leading to HER recovered (Fig. 7a) [129].

thumbnail Figure 7

(a) HER inhibition mechanism of QASs with different electrophilic and nucleophilic groups (the additives was denoted as C1-C8 depending on the length of electrophilic groups). Adapt with permission from Ref. [127]. Copyright 2024 Wiley-VCH GmbH. (b) Destroy mechanism of h- bonds in electrolyte containing DSMO. (c) FTIR spectra of electrolyte with DSMO. Adapt with permission from Ref. [129]. Copyright 2021 American Chemical Society.

In addition to QASs, other organic additives containing nucleophilic and electrophilic groups have also been applied to AABs. Verma et al. [121] reported that a dimethyl nitrile exhibited a high inhibitory efficiency (94.7%) towards HER in 0.5 M NaOH. Wu et al. [68] added high concentration potassium acetate (HCPA) to KOH. When introducing 24 M HCPA, the adsorption of the affinity functional carboxyl group (-COOH) provided excellent HER inhibition efficiency (93.6%). Furthermore, HCPA is also conducive to the uniform dissolution of the Al anode. The AAB with 16 M HCPA has a high discharge capacity of 2324 mAh·g−1. Current studies have also shown that other organic additives, such as carboxylic acids, amine and amino acids, urea and thiourea, azo Schiff bases, and 6-thiguanine, can inhibit HER by adsorbing nucleophilic groups abundant in their molecular structures (-NH2, -C=O, -S, -C6H5, etc.) onto the Al anode surface, thus improving the anodic utilization rate of Al anode [120,121].

In addition, plant extracts can also be used to inhibit HER on the surfaces of Al and Al alloys. Halambek et al. [125] extracted vegetable oil from narrow-leaf lavender and laurel and then introduced it into the electrolyte as an additive to inhibit HER. The results of weight loss tests and electrochemical experiments show that the extract can significantly inhibit HER on the surface of Al alloy and prevent pitting corrosion. Abiola and Otaigbe [126] studied the inhibitory effect of Amaranthus oleracea leaf extract on HER on the Al surface. The results of electrochemical tests and morphology observations showed that the inhibition rate of the extract on HER on the Al anode surface reached 76%. Leaf and seed extracts of upland cotton are also used as HER inhibitors for Al metal in alkaline electrolytes. The results showed that the leaf extract was more effective than the seed extract, with HER inhibition rates of 97% and 94%, respectively.

Nian [127] proposed introducing an organic additive containing nucleophilic groups to regulate the hydrogen bond network of aqueous electrolytes and adjust the activity of water molecules to inhibit HER on the Al anode surface (Fig. 7b). After introducing dimethyl sulfoxide (DMSO) with high donor number, results from infrared spectroscopy and Raman spectroscopy showed that the nucleophilic group in DMSO can effectively regulate the number of hydrogen bonds in the electrolyte. Combined with the simulation results of molecular dynamics, it can be concluded that DMSO can effectively reduce the activity of water molecules while improving the hydrogen bond network. Consequently, HER was effectively inhibited. This study provides a new idea for the selection of additives for aqueous electrolyte in the future.

In published work, single corrosion inhibitors tend to be insufficient for inhibiting HER, while synergistic effect may occur when two (or more) additives are introduced. At present, inorganic additives inhibit HER due to the deposition of an inorganic film. However, this film is often loose and porous, resulting in insufficient inhibition of HER. Hybrid additives (combinations of organic and inorganic additives) can promote the even and uniform deposition of the film. Meanwhile, organic additives can be adsorbed onto the active sites of the Al anode (including impurities, defects, and other sites with high surface energy) to avoid excessive local current, which can lead to too fast deposition rates. Thus, the organic additives prevent the “tip effect” on the Al anode and promote two-dimensional growth to form a uniform, dense, and flat inorganic film [36,57,130–137]. This can improve the hydrogen evolution overpotential on the surface of the Al anode and form a physical barrier against H2O molecules, leading to a more effective HER inhibition on the Al anode. Currently, the most studied hybrid additives are ZnO or Na2SnO3 combined with other organic additives, which have achieved high inhibition efficiency of HER [58,138–141].

Nie et al. [113] proposed a hybrid additive strategy combining Na2SnO3 and casein, subsequently introducing into alkaline AABs. The results show that the hybrid additive not only inhibits HER by isolating water molecules through the adsorption of organic additives, but also improves the deposition morphology of the Sn film (Fig. 8a). Morphological component analysis and simulation results of the Al surface show the strong adsorption of nucleophilic functional groups (-NH2, -COOH) and hydrophobicity of electrophilic functional groups (-(CH2)n) in casein. Consequently, the deposition of Sn film on the Al anode surface becomes more uniform and stable, further inhibiting HER. Ultimately, the HER inhibition rate reached 83.1%, and the anodic utilization rate of the battery improved by approximately 90%.

thumbnail Figure 8

(a) Deposition morphology of Sn film in absence and presence of casein. Adapt with permission from Ref. [51]. Copyright 2017 Elsevier Ltd. (b) Constant current and intermittent discharge test of battery with and without organic additive. Adapt with permission from Ref. [113]. Copyright 2015 IOP Publishing.

Researchers have also introduced ZnO and cetyltrimethyl ammonium bromide as a hybrid additive to study the performance of AABs and their inhibition effect on HER [51]. The results show that Zn has a higher electrode potential than Al, which inhibits HER on the Al surface. Cetyltrimethyl ammonium bromide occupies the cathode active site on the Al anode surface through the adsorption of nucleophilic groups (-N), further inhibiting HER. Thus, the discharge potential increases and stabilizes after introducing the hybrid additives (Fig. 8b). Additionally, the electrophilic group (-(CH2)15CH3) of cetyltrimethyl ammonium bromide significantly improves the deposition morphology of Zn film, further increasing the electrode potential on the electrode surface and inhibiting HER.

Some researchers have also utilized organic acid additives (including acetic acid, citric acid, ethylenediamine tetraacetic acid, etc.) to regulate the deposition behavior of inorganic Zn film on the Al surface [57,114,]. As shown in Fig. 9a, a Zn film is deposited on the Al anode by introducing ZnO additive into the electrolyte. The film is loose and porous, leading to severe HER. However, as shown in Fig. 9c, after introducing organic acid, organic molecules are first adsorbed on the Al anode surface to inhibit HER, while electrophilic functional groups are distributed on the other side to slow down the migration rate of Zn2+ ions, promoting the uniform deposition of the Zn film. Consequently, HER on the Al anode surface is significantly reduced. As a result, the discharge voltage increases to 1.13 V, and the capacity density increases to 2902 mAh/gAl (Fig. 9d).

thumbnail Figure 9

(a) Schematic diagram for constructing the ZnO + organic acid hybrid inhibitors system; corrosion inhibition mechanism for (b) ZnO inhibitor and (c) ZnO + organic acid hybrid inhibitors. (d and e) Discharge performance of Al-air battery based on Al foam anode in NaOH electrolyte (4 M) with different inhibitors: (d) single inhibitor, (e) ZnO + organic acid hybrid inhibitors. Adapt with permission from Ref. [57]. Copyright 2019 Elsevier B.V.

The battery performance of published works on electrolyte additives is shown in Table 4. Although hybrid additives in aqueous electrolyte are currently the best and simplest means to inhibit HER in alkaline electrolyte and have great potential for industrial application, there are still some issues to be addressed. Firstly, the capacity density and discharge current are still not high enough (Table 4), indicating that the inhibition rate of HER is insufficient and anodic dissolution is hindered after introducing additives. Secondly, the effect of the proportion, structure and type of nucleophilic and electrophilic groups of organic additives on battery performance and HER inhibition effect has not been studied sufficiently. Additionally, the interaction between functional groups and molecular polarity, and their further relationship with water activity and deposition behavior of inorganic films, need to be revealed in detail. Thirdly, the introduction of additives should not affect the dissolution process of the anode. At the same time, the long-term stability of additives is crucial for the battery. In the process of continuous dissolution of the Al anode, the dynamic balance of the inorganic film layer and the timely adsorption of organic additives are significant for the long-term inhibition of HER.

Table 4

Discharge performance and capacity of AAB with different additives

Non-aqueous electrolyte

Due to the severe HER of the Al anode in the aqueous electrolyte, some scholars have introduced non-aqueous electrolytes to AABs, which can be divided into two categories: ionic liquids (Ils) and gel polymer electrolytes (GPE) [23,110,146–150].

Ionic liquids are usually salts that remain liquid at or near room temperature, composed generally of organic cations and inorganic anions. The common cations include quaternary ammonium salt ions, pyrrole salt ions, and imidazole salt ions; the anions include tetrafluoroborate ions, halogen ions, hexafluorophosphate ions. etc. Revel et al. [151] developed an AAB based on AICl3/EMImCl ionic liquid electrolyte to avoid HER on the anode surface during discharge. The results show that HER is completely suppressed. The capacity density can reach 71 mAh/cm2, which is similar to the capacity density of lithium-air battery and 5 to 10 times that of lithium-ion batteries. However, due to the excessively low conductivity, the current density of this battery was only 0.1 mA/cm2. Meanwhile, the discharge voltage fluctuated significantly due to the poor chemical stability of the ionic liquid, which is also an issue that needs to be addressed during the application of ionic liquid electrolytes.

The polymer electrolyte typically includes the polymer in the solvent, the solvent in the polymer and the liquid crystal polymer electrolytes, which have good conductivity, good interface performance, and strong electrochemical stability. However, their dimensional stability and safety remain urgent problems to be addressed. Dipalma et al. [148] developed an AAB with a polymer electrolyte prepared from xanthan gum and K-carrageenan. The electrochemical test results show that the electrolyte has good ionic conductivity, with conductivity increasing in the order of xanthan gum + 1 M KOH < Xanthan gum + 8 M KOH GPE < K-carrageenan + 8 M KOH GPE. The polymer gel electrolyte inhibited HER of the Al anode and improved the discharge stability. Simultaneously, the electrolyte also exhibited good toughness and structural strength. Zhang et al. [152] prepared an alkaline gel electrolyte based on polyacrylic acid (PAA). The results show that HER on the anode surface of the Al anode is effectively suppressed, and the battery capacity density is increased to 1166 mAh/gAl, with an energy density of 1230 Wh/kgAl. However, the ion conductivity of the electrolyte is too low, resulting in insufficient current density of the battery.

Multi-electrolyte

The single-phase electrolyte can effectively inhibit HER on the anode surface, but it also inhibits the catalytic reaction on the positive electrode side to a certain extent. Therefore, some researchers introduce a biphase electrolyte to promote the reaction kinetics of the battery. Different electrolytes are used on both sides of the cathode and anode to inhibit HER on the Al surface and enhance the oxygen reduction reaction (ORR) activity of the air cathode. Wang et al. [153] introduced an organic electrolyte (a methanol solution of KOH) to the side of the Al anode and an aqueous electrolyte (KOH aqueous solution) to the side of the air cathode. The two electrolytes were separated by an anion exchange membrane, as shown in Fig. 10a, b. The results show that the energy density of the battery can reach 2081 Wh/kg (or 5819 Wh/L) when discharging at a current density of 30 mA/cm2. Simultaneously, HER on the surface of the Al anode can be effectively inhibited.

thumbnail Figure 10

(a) Schematic of the hybrid electrolyte AAB built on a non-direct counter-flow microfluidic platform. (b) Photograph of a hybrid electrolyte AAB. (c and d) Specific capacities of Al foil in the hybrid electrolyte Al-air cells with (c) anolyte: neat methanol-based KOH solutions with KOH concentrations of 1 M, 2 M, 3 M and 4 M; catholyte: aqueous KOH solution with KOH concentrations of 1 M, 2 M, 3 M and 4 M. (d) Anolyte: 1 M KOH methanol-based solution with various water contents of 0 vol%, 20 vol%, 40 vol% and 60 vol%; catholyte: 1 M KOH aqueous solution. Adapt with permission from Ref. [153]. Copyright 2016 Elsevier B.V. (e and f) Schematics and experimental setups of (e) traditional AAB and (f) double electrolyte AAB. (g and h) Typical discharge curves at different current densities: (g) traditional AAB, (h) double electrolyte AAB [153,154]. Adapt with permission from Ref. [154]. Copyright 2014 Royal Society of Chemistry.

Chen et al. [154] developed a new battery structure that coupled acidic and alkaline electrolyte systems (Fig. 10e, f). The alkaline KOH aqueous solution was used on the Al anode side to remove the surface passivation film and improve the activity of Al anode, while an acidic solution (H2SO4) was introduced on the air cathode side to enhance the activity of ORR. The results show that this electrolyte configuration can significantly improve the discharge voltage and power of the battery. The peak power density reaches 175 mW/cm2, which is much higher than that of AABs with a single-phase electrolyte system (20 mW/cm2) (Fig. 10g, h).

CONCLUSIONS AND FUTURE PROSPECTS

The wide range of applications (from vehicles to marine systems), environmentally benign reactions, use of ambient air and the abundance of Al in the Earth’s crust make AABs a promising energy source for the future. The methods mentioned in this review, including Al anode and electrolyte modification, have the potential to satisfy consumer needs. Among them, the most efficient and simple method for inhibiting HER is the use of electrolyte additives, which provide almost 80% inhibition rate of HER. However, anodic modification (including alloying, processing, surface modification. etc.) is complicated and high-cost, which is not conducive to the development of AABs. There are still some issues need to be addressed to improve the application potential of AABs.

Present methods of Al anode modification for HER inhibition include Alloying, mechanical processing, and surface modification. However, the high cost and complex process limited the development of AABs. To promote the application of AABs, it is crucial to develop the low-cost, simple and efficient technologies for Al anode processing. Non-aqueous electrolyte and multi electrolyte systems prevent HER but decrease energy density of the battery and increase safety risks. Introducing additives into electrolyte is a simple and efficient method to inhibit HER, but anodic dissolution of the Al anode is always suppressed. Meanwhile, the inhibition efficiency of HER has been insufficient to date. Thus, the selection of appropriate additives in AABs is crucial for inhibiting HER.

Recently, hybrid additives in electrolyte have become the main method to inhibit HER in AABs. The study of constructing an even and dense protective inorganic film on the Al anode through the synergistic effect of inorganic and organic additives will be the focus of future investigation. By balancing the electrophilicity and nucleophilicity of organic molecules, HER can be effectively inhibited. Meanwhile, the appropriate organic additive can promote the uniform distribution of metal ions on the surface of the Al anode. The nucleophilic groups can adsorb onto the Al anode, and the nucleophilic groups can block H2O molecules. Additionally, the deposition of the inorganic film can be regulated, and the activity of free water will be decreased, thereby inhibiting HER. As a result, the space between the anode and cathode can be smaller, leading to a high ion exchange rate and large current density of the battery. Notably, the types and quantities of functional groups in organic additives will be vital for inhibiting HER in AABs. Furthermore, this could provide guidance on additive selection in other aqueous metal-air batteries and metal ion batteries.

In the future, extensive research on anode and electrolyte modification should be conducted to efficiently inhibit HER. The Al anode can be independently designed and optimized in terms of the material, alloying element, specific surface area optimization, and stereochemical structure (porosity, effective discharge area, etc.) design. Therefore, the discharge voltage and current density will increase when HER is inhibited. Meanwhile, organic molecules with diverse functional groups can be independently designed and synthesized, thereby promoting the homogeneous deposition of inorganic materials and effective adsorption properties of organic molecules simultaneously. As a result, HER will be efficiently inhibited, and the power density of AAB will be increased.

Funding

This work was supported by the National Natural Science Foundation of China (52171078 and 52371072), the Natural Science Foundation of Tianjin (22JCQNJC00950), and the Open Project of Yunnan Precious Metals Laboratory Co., Ltd (YPML-2023050275).

Conflict of interest

The authors declare that they have no conflict of interest.

References

  • Zhu Z, Jiang T, Ali M, et al. Rechargeable batteries for grid scale energy storage. Chem Rev 2022; 122: 16610-16751. [Article] [CrossRef] [PubMed] [Google Scholar]
  • Ye Z, Jiang Y, Li L, et al. Rational design of MOF-based materials for next-generation rechargeable batteries. Nano-Micro Lett 2021; 13: 203. [Article] [NASA ADS] [CrossRef] [PubMed] [Google Scholar]
  • Bhushan N, Mekhilef S, Tey KS, et al. Overview of model- and non-model-based online battery management systems for electric vehicle applications: A comprehensive review of experimental and simulation studies. Sustainability 2022; 14: 15912. [Article] [CrossRef] [Google Scholar]
  • Zhang Y, Lv C, Zhu Y, et al. Challenges and strategies of aluminum anodes for high-performance aluminum-air batteries. Small Methods 2024; 8: 2300911. [Article] [CrossRef] [PubMed] [Google Scholar]
  • Ryu J, Park M, Cho J. Advanced technologies for high-energy aluminum-air batteries. Adv Mater 2019; 31: 1804784. [Article] [CrossRef] [PubMed] [Google Scholar]
  • Egan DR, Ponce de León C, Wood RJK, et al. Developments in electrode materials and electrolytes for aluminium–air batteries. J Power Sources 2013; 236: 293-310. [Article] [CrossRef] [Google Scholar]
  • Mokhtar M, Talib MZM, Majlan EH, et al. Recent developments in materials for aluminum–air batteries: A review. J Industrial Eng Chem 2015; 32: 1-20. [Article] [CrossRef] [Google Scholar]
  • Liu K, Li K, Peng Q, et al. A brief review on key technologies in the battery management system of electric vehicles. Front Mech Eng 2019; 14: 47-64. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Zhang L, Li X, Yang M, et al. High-safety separators for lithium-ion batteries and sodium-ion batteries: Advances and perspective. Energy Storage Mater 2021; 41: 522-545. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Rani B, Yadav JK, Saini P, et al. Aluminum–air batteries: Current advances and promises with future directions. RSC Adv 2024; 14: 17628-17663. [Article] [NASA ADS] [CrossRef] [PubMed] [Google Scholar]
  • Goel P, Dobhal D, Sharma RC. Aluminum–air batteries: A viability review. J Energy Storage 2020; 28: 101287. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Ipadeola AK, Eid K, Abdullah AM. Porous transition metal-based nanostructures as efficient cathodes for aluminium-air batteries. Curr Opin Electrochem 2023; 37: 101198. [Article] [CrossRef] [Google Scholar]
  • Lu L, Han X, Li J, et al. A review on the key issues for lithium-ion battery management in electric vehicles. J Power Sources 2013; 226: 272-288. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Miao Y, Hynan P, von Jouanne A, et al. Current Li-ion battery technologies in electric vehicles and opportunities for advancements. Energies 2019; 12: 1074. [Article] [CrossRef] [Google Scholar]
  • Xiong R, Sun F, Chen Z, et al. A data-driven multi-scale extended Kalman filtering based parameter and state estimation approach of lithium-ion polymer battery in electric vehicles. Appl Energy 2014; 113: 463-476. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Liu Y, Sun Q, Li W, et al. A comprehensive review on recent progress in aluminum–air batteries. Green Energy Environ 2017; 2: 246-277. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Ye L, Hong Y, Liao M, et al. Recent advances in flexible fiber-shaped metal-air batteries. Energy Storage Mater 2020; 28: 364-374. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Liu Q, Chang Z, Li Z, et al. Flexible metal–air batteries: Progress, challenges, and perspectives. Small Methods 2018; 2: 1700231. [Article] [CrossRef] [Google Scholar]
  • Nayem SMA, Islam S, Mohamed M, et al. A mechanistic overview of the current status and future challenges of aluminum anode and electrolyte in aluminum-air batteries. Chem Rec 2023; 24: e202300005 [Google Scholar]
  • Zhao Q, Yu H, Fu L, et al. Electrolytes for aluminum–air batteries: Advances, challenges, and applications. Sustain Energy Fuels 2023; 7: 1353-1370. [Article] [CrossRef] [MathSciNet] [Google Scholar]
  • Li Q, Bjerrum NJ. Aluminum as anode for energy storage and conversion: A review. J Power Sources 2002; 110: 1-10. [Article] [Google Scholar]
  • Alva S, Sundari R, Wijaya HF, et al. Preliminary study on aluminum-air battery applying disposable soft drink cans and arabic gum polymer. 1st Nommensen International Conference on Technology and Engineering, 11–12 July 2017, Medan, Indonesia, 237: 012039 [Google Scholar]
  • Ambroz F, Macdonald TJ, Nann T. Trends in aluminium‐based intercalation batteries. Adv Energy Mater 2017; 7: 1602093. [Article] [CrossRef] [PubMed] [Google Scholar]
  • Xia C, Kwok CY, Nazar LF. A high-energy-density lithium-oxygen battery based on a reversible four-electron conversion to lithium oxide. Science 2018; 361: 777-781. [Article] [NASA ADS] [CrossRef] [PubMed] [Google Scholar]
  • Wang HF, Xu Q. Materials design for rechargeable metal-air batteries. Matter 2019; 1: 565-595. [Article] [CrossRef] [Google Scholar]
  • Rahman MA, Wang X, Wen C. High energy density metal-air batteries: A review. J Electrochem Soc 2013; 160: A1759-A1771. [Article] [CrossRef] [Google Scholar]
  • Pramuanjaroenkij A, Kakaç S. The fuel cell electric vehicles: The highlight review. Int J Hydrogen Energy 2023; 48: 9401-9425. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Xu Q, Guo Z, Xia L, et al. A comprehensive review of solid oxide fuel cells operating on various promising alternative fuels. Energy Convers Manage 2022; 253: 115175. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Zhao J, Liu H, Li X. Structure, property, and performance of catalyst layers in proton exchange membrane fuel cells. Electrochem Energy Rev 2023; 6: 13. [Article] [CrossRef] [Google Scholar]
  • Zhang X, Wang XG, Xie Z, et al. Recent progress in rechargeable alkali metal–air batteries. Green Energy Environ 2016; 1: 4-17. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Huang Y, Wang Y, Tang C, et al. Atomic modulation and structure design of carbons for bifunctional electrocatalysis in metal–air batteries. Adv Mater 2019; 31: 1803800. [Article] [CrossRef] [PubMed] [Google Scholar]
  • Buckingham R, Asset T, Atanassov P. Aluminum-air batteries: A review of alloys, electrolytes and design. J Power Sources 2021; 498: 229762. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Liu X, Jiao H, Wang M, et al. Current progresses and future prospects on aluminium–air batteries. Int Mater Rev 2022; 67: 734-764. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Wang C, Yu Y, Niu J, et al. Recent progress of metal–air batteries—A mini review. Appl Sci 2019; 9: 2787. [Article] [CrossRef] [Google Scholar]
  • Liu Q, Pan Z, Wang E, et al. Aqueous metal-air batteries: Fundamentals and applications. Energy Storage Mater 2020; 27: 478-505. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Sun W, Wang F, Zhang B, et al. A rechargeable zinc-air battery based on zinc peroxide chemistry. Science 2021; 371: 46-51. [Article] [NASA ADS] [CrossRef] [PubMed] [Google Scholar]
  • Tan P, Chen B, Xu H, et al. Flexible Zn– and Li–air batteries: Recent advances, challenges, and future perspectives. Energy Environ Sci 2017; 10: 2056-2080. [Article] [CrossRef] [Google Scholar]
  • Li G, Wang X, Fu J, et al. Pomegranate‐inspired design of highly active and durable bifunctional electrocatalysts for rechargeable metal–air batteries. Angew Chem Int Ed 2016; 55: 4977-4982. [Article] [CrossRef] [PubMed] [Google Scholar]
  • Hu T, Fang Y, Su L, et al. A novel experimental study on discharge characteristics of an aluminum-air battery. Int J Energy Res 2019; 43: 1839-1847. [Article] [CrossRef] [Google Scholar]
  • Wu P, Wu S, Sun D, et al. A review of Al alloy anodes for Al–air batteries in neutral and alkaline aqueous electrolytes. Acta Metall Sin (Engl Lett) 2021; 34: 309-320. [Article] [Google Scholar]
  • Xue Y, Sun S, Wang Q, et al. Transition metal oxide-based oxygen reduction reaction electrocatalysts for energy conversion systems with aqueous electrolytes. J Mater Chem A 2018; 6: 10595-10626. [Article] [CrossRef] [Google Scholar]
  • Lv C, Zhu Y, Li Y, et al. Hydrogen-bonds reconstructing electrolyte enabling low-temperature aluminum-air batteries. Energy Storage Mater 2023; 59: 102756. [Article] [CrossRef] [Google Scholar]
  • Chawla N. Recent advances in air-battery chemistries. Mater Today Chem 2019; 12: 324-331 [NASA ADS] [CrossRef] [Google Scholar]
  • Cho YJ, Park IJ, Lee HJ, et al. Aluminum anode for aluminum–air battery—Part I: Influence of aluminum purity. J Power Sources 2015; 277: 370-378. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Tang Y, Lu L, Roesky HW, et al. The effect of zinc on the aluminum anode of the aluminum–air battery. J Power Sources 2004; 138: 313-318. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Tan WC, Saw LH, Yew MC, et al. Analysis of the polypropylene-based aluminium-air battery. Front Energy Res 2021; 9: 599846. [Article] [CrossRef] [Google Scholar]
  • Gelman D, Lasman I, Elfimchev S, et al. Aluminum corrosion mitigation in alkaline electrolytes containing hybrid inorganic/organic inhibitor system for power sources applications. J Power Sources 2015; 285: 100-108. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Hou C, Chen S, Wang Z, et al. Effect of 6‐thioguanine, as an electrolyte additive, on the electrochemical behavior of an Al-air battery. MaterCorros 2020; 71: 1480-1487 [Google Scholar]
  • Sovizi MR, Abbasi R. The effect of gum arabic and zinc oxide hybrid inhibitor on the performance of aluminium as galvanic anode in alkaline batteries. J Adh Sci Tech 2018; 32: 2590-2603. [Article] [CrossRef] [Google Scholar]
  • Deyab MA. Effect of nonionic surfactant as an electrolyte additive on the performance of aluminum-air battery. J Power Sources 2019; 412: 520-526 [NASA ADS] [CrossRef] [Google Scholar]
  • Sun Z, Lu H, Hong Q, et al. Evaluation of an alkaline electrolyte system for Al-air battery. ECS Electrochem Lett 2015; 4: A133-A136. [Article] [CrossRef] [Google Scholar]
  • Kang QX, Wang Y, Zhang XY. Experimental and theoretical investigation on calcium oxide and L-aspartic as an effective hybrid inhibitor for aluminum-air batteries. J Alloys Compd 2019; 774: 1069-1080. [Article] [CrossRef] [Google Scholar]
  • Teabnamang P, Kao-ian W, Nguyen MT, et al. High-capacity dual-electrolyte aluminum–air battery with circulating methanol anolyte. Energies 2020; 13: 2275. [Article] [CrossRef] [Google Scholar]
  • Grishina E, Gelman D, Belopukhov S, et al. Improvement of aluminum–air battery performances by the application of flax straw extract. ChemSusChem 2016; 9: 2103-2111. [Article] [NASA ADS] [CrossRef] [PubMed] [Google Scholar]
  • Faegh E, Shrestha S, Zhao X, et al. In-depth structural understanding of zinc oxide addition to alkaline electrolytes to protect aluminum against corrosion and gassing. J Appl Electrochem 2019; 49: 895-907. [Article] [Google Scholar]
  • Ma J, Li W, Wang G, et al. Influences of L-cysteine/zinc oxide additive on the electrochemical behavior of pure aluminum in alkaline solution. J Electrochem Soc 2018; 165: A266-A272. [Article] [CrossRef] [MathSciNet] [Google Scholar]
  • Jiang H, Yu S, Li W, et al. Inhibition effect and mechanism of inorganic-organic hybrid additives on three-dimension porous aluminum foam in alkaline Al-air battery. J Power Sources 2020; 448: 227460. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Liu Y, Zhang H, Liu Y, et al. Inhibitive effect of quaternary ammonium-type surfactants on the self-corrosion of the anode in alkaline aluminium-air battery. J Power Sources 2019; 434: 226723. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Zhu C, Yang H, Wu A, et al. Modified alkaline electrolyte with 8-hydroxyquinoline and ZnO complex additives to improve Al-air battery. J Power Sources 2019; 432: 55-64. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Liu J, Wang D, Zhang D, et al. Synergistic effects of carboxymethyl cellulose and ZnO as alkaline electrolyte additives for aluminium anodes with a view towards Al-air batteries. J Power Sources 2016; 335: 1-11. [Article] [CrossRef] [MathSciNet] [Google Scholar]
  • Wu S, Zhang Q, Sun D, et al. Understanding the synergistic effect of alkyl polyglucoside and potassium stannate as advanced hybrid corrosion inhibitor for alkaline aluminum-air battery. Chem Eng J 2020; 383: 123162. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Melzack N, Wills RGA. A review of energy storage mechanisms in aqueous aluminium technology. Front Chem Eng 2022; 4: 778265. [Article] [CrossRef] [Google Scholar]
  • Gu Y, Liu Y, Tong Y, et al. Improving discharge voltage of Al-air batteries by Ga3+ additives in NaCl-based electrolyte. Nanomaterials 2022; 12: 1336. [Article] [CrossRef] [PubMed] [Google Scholar]
  • Mori R. A novel aluminium-air rechargeable battery with Al2O3 as the buffer to suppress byproduct accumulation directly onto an aluminium anode and air cathode. RSC Adv 2014; 4: 30346-30351 [NASA ADS] [CrossRef] [Google Scholar]
  • Han B, Liang G. Neutral electrolyte aluminum air battery with open configuration. Rare Met 2006; 25: 360-363. [Article] [CrossRef] [Google Scholar]
  • Mori R. Addition of ceramic barriers to aluminum–air batteries to suppress by-product formation on electrodes. J Electrochem Soc 2015; 162: A288-A294. [Article] [CrossRef] [Google Scholar]
  • Yang L, Wu Y, Chen S, et al. A promising hybrid additive for enhancing the performance of alkaline aluminum-air batteries. Mater Chem Phys 2021; 257: 123787. [Article] [CrossRef] [Google Scholar]
  • Wu S, Hu S, Zhang Q, et al. Hybrid high-concentration electrolyte significantly strengthens the practicability of alkaline aluminum-air battery. Energy Storage Mater 2020; 31: 310-317. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Wang H, Leung DYC, Leung MKH, et al. Modeling of parasitic hydrogen evolution effects in an aluminum−air cell. Energy Fuels 2010; 24: 3748-3753. [Article] [CrossRef] [Google Scholar]
  • Fan L, Lu H, Leng J, et al. The study of industrial aluminum alloy as anodes for aluminum-air batteries in alkaline electrolytes. J Electrochem Soc 2016; 163: A8-A12. [Article] [CrossRef] [Google Scholar]
  • Haleem SMA, Wanees SA, Farouk A. Hydrogen production on aluminum in alkaline media. Prot Met Phys Chem 2021; 57: 906-916 [Google Scholar]
  • Irankhah A, Seyed Fattahi SM, Salem M. Hydrogen generation using activated aluminum/water reaction. Int J Hydrogen Energy 2018; 43: 15739-15748. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Cai Y, Tong Y, Liu Y, et al. Study on thermal effect of aluminum-air battery. Nanomaterials 2023; 13: 646. [Article] [CrossRef] [PubMed] [Google Scholar]
  • Fan L, Lu H. The effect of grain size on aluminum anodes for Al–air batteries in alkaline electrolytes. J Power Sources 2015; 284: 409-415. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Li L, Ban C, Shi X, et al. Influence of a high magnetic field on the solidification structures of ternary Al–Fe–Zr alloy. J Mater Res 2017; 32: 2035-2044. [Article] [CrossRef] [Google Scholar]
  • Fan L, Lu H, Leng J, et al. The effect of crystal orientation on the aluminum anodes of the aluminum–air batteries in alkaline electrolytes. J Power Sources 2015; 299: 66-69. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Kumar Y, Mooste M, Tammeveski K. Recent progress of transition metal-based bifunctional electrocatalysts for rechargeable zinc–air battery application. Curr Opin Electrochem 2023; 38: 101229. [Article] [CrossRef] [Google Scholar]
  • Gao J, Li Y, Yan Z, et al. Effects of solid-solute magnesium and stannate ion on the electrochemical characteristics of a high-performance aluminum anode/electrolyte system. J Power Sources 2019; 412: 63-70. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Wang Q, Miao H, Xue Y, et al. Performances of an Al–0.15 Bi–0.15 Pb–0.035 Ga alloy as an anode for Al–air batteries in neutral and alkaline electrolytes. RSC Adv 2017; 7: 25838-25847. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Wu Z, Zhang H, Yang D, et al. Electrochemical behaviour and discharge characteristics of an Al–Zn–In–Sn anode for Al-air batteries in an alkaline electrolyte. J Alloys Compd 2020; 837: 155599. [Article] [CrossRef] [Google Scholar]
  • Wu Z, Zhang H, Zou J, et al. Enhancement of the discharge performance of Al-0.5Mg-0.1Sn-0.05Ga (wt.%) anode for Al-air battery by directional solidification technique and subsequent rolling process. J Alloys Compd 2020; 827: 154272. [Article] [CrossRef] [Google Scholar]
  • Tu J, Wang S, Li S, et al. The effects of anions behaviors on electrochemical properties of Al/graphite rechargeable aluminum-ion battery via molten AlCl3-NaCl liquid electrolyte. J Electrochem Soc 2017; 164: A3292-A3302. [Article] [CrossRef] [Google Scholar]
  • Yang M, Liu Y, Shi Z, et al. Study on the electrochemical behavior of Al-6Zn-0.02In-1Mg-0.03Ti sacrificial anodes for long-term corrosion protection in the ocean. Corrosion 2020; 76: 366-372. [Article] [CrossRef] [Google Scholar]
  • Okobira T, Nguyen DT, Taguchi K. Effectiveness of doping zinc to the aluminum anode on aluminum-air battery performance. Int J Appl Electrom 2020; 64: 57-64 [Google Scholar]
  • Vu TN, Mokaddem M, Volovitch P, et al. The anodic dissolution of zinc and zinc alloys in alkaline solution. II. Al and Zn partial dissolution from 5% Al–Zn coatings. Electrochim Acta 2012; 74: 130-138. [Article] [CrossRef] [Google Scholar]
  • Zhao R, He P, Yu F, et al. Performance improvement for aluminum-air battery by using alloying anodes prepared from commercially pure aluminum. J Energy Storage 2023; 73: 108985. [Article] [CrossRef] [Google Scholar]
  • Xie Y, Meng X, Mao D, et al. Deformation-driven modification of Al-Li-Mg-Zn-Cu high-alloy aluminum as anodes for primary aluminum-air batteries. Scripta Mater 2022; 212: 114551. [Article] [CrossRef] [Google Scholar]
  • Liang R, Su Y, Sui XL, et al. Effect of Mg content on discharge behavior of Al-0.05Ga-0.05Sn-0.05Pb-xMg alloy anode for aluminum-air battery. J Solid State Electrochem 2019; 23: 53-62. [Article] [CrossRef] [Google Scholar]
  • Li L, Liu H, Yan Y, et al. Effects of alloying elements on the electrochemical behaviors of Al-Mg-Ga-In based anode alloys. Int J Hydrogen Energy 2019; 44: 12073-12084. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Sun Z, Lu H, Fan L, et al. Performance of Al-air batteries based on Al–Ga, Al–In and Al–Sn alloy electrodes. J Electrochem Soc 2015; 162: A2116-A2122. [Article] [CrossRef] [Google Scholar]
  • Du BD, Wang W, Chen W, et al. Grain refinement and Al-water reactivity of Al-Ga-In-Sn alloys. Int J Hydrogen Energy 2017; 42: 21586-21596. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Park IJ, Choi SR, Kim JG. Aluminum anode for aluminum-air battery—Part II: Influence of In addition on the electrochemical characteristics of Al-Zn alloy in alkaline solution. J Power Sources 2017; 357: 47-55. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Ma J, Zhang Y, Ma M, et al. Corrosion and discharge performance of a magnesium aluminum eutectic alloy as anode for magnesium–air batteries. Corrosion Sci 2020; 170: 108695. [Article] [CrossRef] [Google Scholar]
  • Zhou YJ, Xiong CH, Lu CB, et al. Design of 1 kw Al-air battery. AMM 2014; 535: 22-25. [Article] [CrossRef] [Google Scholar]
  • Zhang W, Hu T, Chen T, et al. Electrochemical performance of Al-1Zn-0.1In-0.1Sn-0.5Mg-xMn (x = 0, 0.1, 0.2, 0.3) alloys used as the anode of an Al-air battery. Processes 2022; 10: 420. [Article] [CrossRef] [Google Scholar]
  • Rani B, Yadav JK, Saini P, et al. Impact of aluminum alloy grade as anode on electrochemical performance for Al-air cell in alkaline electrolyte. Energy Storage 2024; 6: e586. [Article] [CrossRef] [Google Scholar]
  • Liu X, Zhang P, Xue J, et al. High energy efficiency of Al-based anodes for Al-air battery by simultaneous addition of Mn and Sb. Chem Eng J 2021; 417: 128006. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Jingling M, Jiuba W, Hongxi Z, et al. Electrochemical performances of Al–0.5Mg–0.1Sn–0.02In alloy in different solutions for Al–air battery. J Power Sources 2015; 293: 592-598. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Wu Z, Zhang H, Tang S, et al. Effect of calcium on the electrochemical behaviors and discharge performance of Al–Sn alloy as anodes for Al–air batteries. Electrochim Acta 2021; 370: 137833. [Article] [CrossRef] [Google Scholar]
  • Ren J, Fu C, Dong Q, et al. Evaluation of impurities in aluminum anodes for Al-air batteries. ACS Sustain Chem Eng 2021; 9: 2300-2308. [Article] [CrossRef] [Google Scholar]
  • Ran Q, Shi H, Meng H, et al. Aluminum-copper alloy anode materials for high-energy aqueous aluminum batteries. Nat Commun 2022; 13: 576. [Article] [CrossRef] [PubMed] [Google Scholar]
  • Martin JH, Yahata BD, Hundley JM, et al. 3D printing of high-strength aluminium alloys. Nature 2017; 549: 365-369. [Article] [CrossRef] [Google Scholar]
  • Xiao R, Zhang X. Problems and issues in laser beam welding of aluminum–lithium alloys. J Manufacturing Processes 2014; 16: 166-175. [Article] [CrossRef] [Google Scholar]
  • Maárif MS, Fanani AZ, Oerbandono T, et al. Performance of Al-air battery with different electrolytes. Int J Integr Eng 2021; 13: 281-287 [Google Scholar]
  • Srinivas M, Adapaka SK, Neelakantan L. Solubility effects of Sn and Ga on the microstructure and corrosion behavior of Al-Mg-Sn-Ga alloy anodes. J Alloys Compd 2016; 683: 647-653. [Article] [CrossRef] [Google Scholar]
  • Zhang P, Liu X, Xue J, et al. The role of microstructural evolution in improving energy conversion of Al-based anodes for metal-air batteries. J Power Sources 2020; 451: 227806. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Galy C, Le Guen E, Lacoste E, et al. Main defects observed in aluminum alloy parts produced by SLM: From causes to consequences. Addit Manuf 2018;22: 165-175 [Google Scholar]
  • Azarniya A, Taheri AK, Taheri KK. Recent advances in ageing of 7xxx series aluminum alloys: A physical metallurgy perspective. J AlloyCompd 2019;781: 945-983 [Google Scholar]
  • Zhang P, Gao Y, Liu Z, et al. Effect of cutting parameters on the corrosion resistance of 7A04 aluminum alloy in high speed cutting. Vacuum 2023; 212: 111968. [Article] [CrossRef] [Google Scholar]
  • Lee J, Yim CY, Lee DW, et al. Manufacturing and characterization of physically modified aluminum anodes based air battery with electrolyte circulation. Int J Pr Eng Man-Gt 2017; 4: 53-57 [Google Scholar]
  • Faegh E, Shrestha S, Zhao X, et al. In-depth structural understanding of zinc oxide addition to alkaline electrolytes to protect aluminum against corrosion and gassing. J Appl Electrochem 2019; 49: 895-907. [Article] [Google Scholar]
  • Cai S, Pan C, Li J, et al. Effect of Tween 85 and calcium malate as hybrid inhibitors on the performance of alkaline aluminum-air batteries. J Energy Storage 2024; 79: 110136. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Nie Y, Gao J, Wang E, et al. An effective hybrid organic/inorganic inhibitor for alkaline aluminum-air fuel cells. Electrochim Acta 2017; 248: 478-485. [Article] [CrossRef] [Google Scholar]
  • Rashvand avei M, Jafarian M, Moghanni Bavil Olyaei H, et al. Study of the alloying additives and alkaline zincate solution effects on the commercial aluminum as galvanic anode for use in alkaline batteries. Mater Chem Phys 2013; 143: 133-142. [Article] [CrossRef] [Google Scholar]
  • Choi SR, Kim KM, Kim JG. Organic corrosion inhibitor without discharge retardation of aluminum-air batteries. J Mol Liquids 2022; 365: 120104. [Article] [CrossRef] [Google Scholar]
  • Zhu R, Xu G, Shao G, et al. Synergistic regulation of Al alloy anode/electrolyte interface layer in Al-air battery by composite inhibitor HEC-K2 SnO3. ACS Appl Energy Mater 2024; 7: 2120-2128. [Article] [CrossRef] [Google Scholar]
  • Choi SR, Song SJ, Kim JG. Hydrogen evolution inorganic inhibitors in alkaline electrolyte for aluminum-air battery. Int J Electrochem Sci 2020; 15: 8928-8942. [Article] [CrossRef] [Google Scholar]
  • Shayeb HAE, Wahab FMAE, Abedin SZE. Role of indium ions on the activation of aluminium. J Appl Electrochem 1999; 29: 601-609. [Article] [Google Scholar]
  • Hou C, Chen S, Wang Z, et al. Effect of 6-thioguanine, as an electrolyte additive, on the electrochemical behavior of an Al-air battery. Mater Corrosion 2020; 71: 1480-1487. [Article] [CrossRef] [Google Scholar]
  • Al‐Rawashdeh NAF, Maayta AK. Cationic surfactant as corrosion inhibitor for aluminum in acidic and basic solutions. Anti-Corrosion Methods Mater 2005; 52: 160-166. [Article] [CrossRef] [Google Scholar]
  • Verma C, Singh P, Bahadur I, et al. Electrochemical, thermodynamic, surface and theoretical investigation of 2-aminobenzene-1,3-dicarbonitriles as green corrosion inhibitor for aluminum in 0.5M NaOH. J Mol Liquids 2015; 209: 767-778. [Article] [CrossRef] [Google Scholar]
  • Brito PSD, Sequeira CAC. Organic inhibitors of the anode self-corrosion in aluminum-air batteries. J Fuel Cell Sci Tech 2014; 11: 011008. [Article] [CrossRef] [Google Scholar]
  • Moghadam Z, Shabani-Nooshabadi M, Behpour M. Electrochemical performance of aluminium alloy in strong alkaline media by urea and thiourea as inhibitor for aluminium-air batteries. J Mol Liquids 2017; 242: 971-978. [Article] [CrossRef] [Google Scholar]
  • Arjomandi J, Moghanni-Bavil-Olyaei H, Parvin MH, et al. Inhibition of corrosion of aluminum in alkaline solution by a novel azo-schiff base: Experiment and theory. J Alloys Compd 2018; 746: 185-193. [Article] [CrossRef] [Google Scholar]
  • Halambek J, Jukić M, Berković K, et al. Investigation of novel heterocyclic compounds as inhibitors of Al-3Mg alloy corrosion in hydrochloric acid solutions. Int J Electrochem Sci 2012; 7: 1580-1601. [Article] [CrossRef] [Google Scholar]
  • Abiola OK, Otaigbe JOE. The effects of Phyllanthus amarus extract on corrosion and kinetics of corrosion process of aluminum in alkaline solution. Corrosion Sci 2009; 51: 2790-2793. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Nian Q, Zhang X, Feng Y, et al. Designing electrolyte structure to suppress hydrogen evolution reaction in aqueous batteries. ACS Energy Lett 2021; 6: 2174-2180. [Article] [CrossRef] [Google Scholar]
  • Wan S, Zhang T, Chen H, et al. Kapok leaves extract and synergistic iodide as novel effective corrosion inhibitors for Q235 carbon steel in H2SO4 medium. Industrial Crops Products 2022; 178: 114649. [Article] [CrossRef] [Google Scholar]
  • Liu Y, Gao Z, Li Z, et al. Tailoring non‐polar groups of quaternary ammonium salts for inhibiting hydrogen evolution reaction of aluminum‐air battery. Adv Funct Mater 2024; 34: 2315747. [Article] [CrossRef] [Google Scholar]
  • Sun KEK, Hoang TKA, Doan TNL, et al. Suppression of dendrite formation and corrosion on zinc anode of secondary aqueous batteries. ACS Appl Mater Interfaces 2017; 9: 9681-9687. [Article] [CrossRef] [PubMed] [Google Scholar]
  • Lin MH, Huang CJ, Cheng PH, et al. Revealing the effect of polyethylenimine on zinc metal anodes in alkaline electrolyte solution for zinc–air batteries: Mechanism studies of dendrite suppression and corrosion inhibition. J Mater Chem A 2020; 8: 20637-20649. [Article] [CrossRef] [Google Scholar]
  • Zhang Y, Han X, Liu R, et al. Manipulating the zinc deposition behavior in hexagonal patterns at the preferential Zn (100) crystal plane to construct surficial dendrite‐free zinc metal anode. Small 2022; 18: 2105978. [Article] [CrossRef] [Google Scholar]
  • Bu YF, Jiang WY, Liu HT, et al. Hydrogen bond interaction in the trade-off between electrolyte voltage window and supercapacitor low-temperature performances. ChemSusChem 2022; 15: e202200539 [CrossRef] [Google Scholar]
  • Meng Q, Bai Q, Zhao R, et al. Attenuating water activity through impeded proton transfer resulting from hydrogen bond enhancement effect for fast and ultra‐stable Zn metal anode. Adv Energy Mater 2023; 13: 2302828. [Article] [CrossRef] [Google Scholar]
  • Xu J, Li H, Jin Y, et al. Understanding the electrical mechanisms in aqueous zinc metal batteries: From electrostatic interactions to electric field regulation. Adv Mater 2024; 36: 2309726. [Article] [CrossRef] [Google Scholar]
  • Yan T, Tao M, Liang J, et al. Refining the inner Helmholtz plane adsorption for achieving a stable solid-electrolyte interphase in reversible aqueous Zn-ion pouch cells. Energy Storage Mater 2024; 65: 103190. [Article] [CrossRef] [Google Scholar]
  • Hao Y, Feng D, Hou L, et al. Gel electrolyte constructing Zn (002) deposition crystal plane toward highly stable Zn anode. Adv Sci 2022; 9: 2104832. [Article] [CrossRef] [Google Scholar]
  • Wang X, Meng J, Lin X, et al. Stable zinc metal anodes with textured crystal faces and functional zinc compound coatings. Adv Funct Mater 2021; 31: 2106114. [Article] [CrossRef] [Google Scholar]
  • Zeng YX, Pei ZH, Guo Y, et al. Zincophilic interfacial manipulation against dendrite growth and side reactions for stable Zn metal anodes. Angew Chem Int Ed 2023; 62: e202312145 [CrossRef] [Google Scholar]
  • Feng DD, Jiao YC, Wu PY. Guiding Zn uniform deposition with polymer additives for long-lasting and highly utilized Zn metal anodes. Angew Chem Int Ed 2023; 62: e202314456 [CrossRef] [Google Scholar]
  • Su T‐T, Wang K, Chi B‐Y, et al. Stripy zinc array with preferential crystal plane for the ultra-long lifespan of zinc metal anodes for zinc ion batteries. EcoMat 2022; 4: e12219. [Article] [CrossRef] [Google Scholar]
  • Cheng H, Wang T, Li Z, et al. Anode interfacial layer construction via hybrid inhibitors for high-performance Al–air batteries. ACS Appl Mater Interfaces 2021; 13: 51726-51735. [Article] [CrossRef] [PubMed] [Google Scholar]
  • Lee W, Choi SR, Kim JG. Spent coffee grounds as eco-friendly additives for aluminum–air batteries. ACS Omega 2021; 6: 25529-25538. [Article] [CrossRef] [PubMed] [Google Scholar]
  • Wu P, Zhao Q, Yu H, et al. Modification on water electrochemical environment for durable Al-air battery: Achieved by a low-cost sucrose additive. Chem Eng J 2022; 438: 135538. [Article] [CrossRef] [Google Scholar]
  • Wang T, Cheng H, Tian Z, et al. Simultaneous regulation on electrolyte structure and electrode interface with glucose additive for high-energy aluminum metal-air batteries. Energy Storage Mater 2022; 53: 371-380. [Article] [CrossRef] [Google Scholar]
  • Gelman D, Shvartsev B, Ein-Eli Y. Aluminum–air battery based on an ionic liquid electrolyte. J Mater Chem A 2014; 2: 20237-20242. [Article] [CrossRef] [Google Scholar]
  • Levy NR, Auinat M, Ein-Eli Y. Tetra-butyl ammonium fluoride—An advanced activator of aluminum surfaces in organic electrolytes for aluminum-air batteries. Energy Storage Mater 2018; 15: 465-474. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Di Palma TM, Migliardini F, Caputo D, et al. Xanthan and κ-carrageenan based alkaline hydrogels as electrolytes for Al/air batteries. Carbohydrate Polyms 2017; 157: 122-127. [Article] [CrossRef] [Google Scholar]
  • Gelman D, Shvartsev B, Ein-Eli Y. Challenges and prospect of non-aqueous non-alkali (NANA) metal–air batteries. Top Curr Chem (Z) 2016; 374: 82. [Article] [CrossRef] [PubMed] [Google Scholar]
  • Wang T, Yang T, Luo D, et al. High‐energy‐density solid‐state metal–air batteries: Progress, challenges, and perspectives. Small 2024; 20: 2309306. [Article] [CrossRef] [Google Scholar]
  • Revel R, Audichon T, Gonzalez S. Non-aqueous aluminium–air battery based on ionic liquid electrolyte. J Power Sources 2014; 272: 415-421. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Zhang Z, Zuo C, Liu Z, et al. All-solid-state Al–air batteries with polymer alkaline gel electrolyte. J Power Sources 2014; 251: 470-475. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Wang L, Liu F, Wang W, et al. A high-capacity dual-electrolyte aluminum/air electrochemical cell. RSC Adv 2014; 4: 30857-30863. [Article] [NASA ADS] [CrossRef] [Google Scholar]
  • Chen B, Leung DYC, Xuan J, et al. A high specific capacity membraneless aluminum-air cell operated with an inorganic/organic hybrid electrolyte. J Power Sources 2016; 336: 19-26. [Article] [NASA ADS] [CrossRef] [Google Scholar]

All Tables

Table 1

Comparison of various metal–air batteries

In the text
Table 2

Parameters of common alloy elements in Al

In the text
Table 3

Discharge performance of AABs using Al alloy as anode

In the text
Table 4

Discharge performance and capacity of AAB with different additives

In the text

All Figures

thumbnail Figure 1

The structure of metal-air battery: (a) non-aqueous and (b) aqueous. Adapted with permission from Ref. [34]. Copyright 2019 MDPI.
In the text
thumbnail Figure 2

The structure of AAB [63].
In the text
thumbnail Figure 3

(a) Schematic diagram explaining the dissolution–redeposition mechanism in Al-alloys. (b) Schematic diagram showing the eutectic mechanism. Adapt with permission from Ref. [10]. Copyright 2024 Royal Society of Chemistry.
In the text
thumbnail Figure 4

(a) Hydrogen evolution volume of pure aluminum and Al-Mg-Ga-In alloys with different compositions in 4 M NaOH solution. Adapt with permission from Ref. [73]. Copyright 2019 Elsevier B.V. (b) Discharge behavior of pure Al, Al–Ga, Al–In and Al–Sn alloy as the anodes of Al-air batteries in 1 M KOH solutions at different current density. Adapt with permission from Ref. [73]. Copyright 2015 IOP Publishing. (c–e) The fracture surfaces of 6 wt% Al-Ga-In-Sn alloys with different Ti contents and relations of Al grain size with Ti contents: (c) Ti free, Ti 0.03 wt%, Ti 0.06 wt%; (d) Ti 0.09 wt%, Ti 0.12 wt%, Ti 0.15 wt%; (e) Ti 0.18 wt%, Ti 0.24 wt%; (f) relations of Al grain size with Ti contents. Adapt with permission from Ref. [76]. Copyright 2017 Elsevier B.V.
In the text
thumbnail Figure 5

(a) X-ray elemental mapping of as-rolled and solutionized samples. Adapt with permission from Ref. [105]. Copyright 2016 Elsevier B.V. (b) Rolling process and discharge curves of pure Al and Al–Sb anodes for Al-air batteries at different current densities. Adapt with permission from Ref. [106]. Copyright 2020, Elsevier.
In the text
thumbnail Figure 6

(a) Cross-section view of Zn film deposited on Al anode. Adapt with permission from Ref. [111]. Copyright 2019 Springer Nature B.V. (b) SEM micrographs of the Al alloy anode surface at different resolutions after soaking in different electrolyte with 12 g/L K2SnO3. (c) Electrochemical of Al anode in electrolyte with different concentrations of K2SnO3. Adapt with permission from Ref. [116]. Copyright 2024 American Chemical Society. (d) SEM image of Al anode in electrolyte with In3+ ions. (e) Current- time plot of Al anode in electrolyte with In3+ ions after passivation. Adapt with permission from Ref. [118]. Copyright 1969 Kluwer Academic Publishers.
In the text
thumbnail Figure 7

(a) HER inhibition mechanism of QASs with different electrophilic and nucleophilic groups (the additives was denoted as C1-C8 depending on the length of electrophilic groups). Adapt with permission from Ref. [127]. Copyright 2024 Wiley-VCH GmbH. (b) Destroy mechanism of h- bonds in electrolyte containing DSMO. (c) FTIR spectra of electrolyte with DSMO. Adapt with permission from Ref. [129]. Copyright 2021 American Chemical Society.
In the text
thumbnail Figure 8

(a) Deposition morphology of Sn film in absence and presence of casein. Adapt with permission from Ref. [51]. Copyright 2017 Elsevier Ltd. (b) Constant current and intermittent discharge test of battery with and without organic additive. Adapt with permission from Ref. [113]. Copyright 2015 IOP Publishing.
In the text
thumbnail Figure 9

(a) Schematic diagram for constructing the ZnO + organic acid hybrid inhibitors system; corrosion inhibition mechanism for (b) ZnO inhibitor and (c) ZnO + organic acid hybrid inhibitors. (d and e) Discharge performance of Al-air battery based on Al foam anode in NaOH electrolyte (4 M) with different inhibitors: (d) single inhibitor, (e) ZnO + organic acid hybrid inhibitors. Adapt with permission from Ref. [57]. Copyright 2019 Elsevier B.V.
In the text
thumbnail Figure 10

(a) Schematic of the hybrid electrolyte AAB built on a non-direct counter-flow microfluidic platform. (b) Photograph of a hybrid electrolyte AAB. (c and d) Specific capacities of Al foil in the hybrid electrolyte Al-air cells with (c) anolyte: neat methanol-based KOH solutions with KOH concentrations of 1 M, 2 M, 3 M and 4 M; catholyte: aqueous KOH solution with KOH concentrations of 1 M, 2 M, 3 M and 4 M. (d) Anolyte: 1 M KOH methanol-based solution with various water contents of 0 vol%, 20 vol%, 40 vol% and 60 vol%; catholyte: 1 M KOH aqueous solution. Adapt with permission from Ref. [153]. Copyright 2016 Elsevier B.V. (e and f) Schematics and experimental setups of (e) traditional AAB and (f) double electrolyte AAB. (g and h) Typical discharge curves at different current densities: (g) traditional AAB, (h) double electrolyte AAB [153,154]. Adapt with permission from Ref. [154]. Copyright 2014 Royal Society of Chemistry.
In the text

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