Synergistic regulating the aluminum corrosion by ellagic acid and sodium stannate hybrid additives for advanced aluminum-air battery

Enhancing Al-Air Battery Performance with Beta-d-Glucose and Adonite Additives: A Combined Electrochemical and Theoretical Study

Al-air batteries are distinguished by their high theoretical energy density, yet their broader application is hindered by hydrogen evolution corrosion. This research focuses Beta (+) d-glucose (S1) and Adonite (S2) as potential corrosion inhibitors for the Al-5052 alloy within a 4 M NaOH solution. Utilizing electrochemical techniques, hydrogen evolution assessments, and surface analyses, our findings indicate enhancements in anode utilization by 21.9% for S1 and 21.1% for S2. Inhibition efficiency reached 65.5% for S1 and 65.1% for both additives at a concentration of 10-3 M. Additionally, the introduction of S1 and S2 markedly increased the nominal specific capacity (654 mA h g-1 for S1 and 629 mA h g-1 for S2) and energy density (1922 W h kg-1 for S1 and 1849 W h kg-1 for S2) of the batteries. These results suggest that managing the electrolyte composition with these additives can significantly enhance battery performance in alkaline environments. Supporting our experimental findings, density functional theory (DFT) and molecular dynamics (MD) analyses confirmed improved anode passivation and beneficial molecular interactions, contributing to the reduction of corrosion in the Al-5052 alloy.

Improvement of Electrochemical Performance with Cetylpyridinium Chloride for the Al Anode of Alkaline Al-Air Batteries

Aluminum-air batteries (AABs) are considered among high-power battery systems with various potential applications. However, the strong self-corrosion of Al in alkaline electrolytes negatively affects its Coulombic efficiency and significantly limits their large-scale application. This work presents the use of cetylpyridinium chloride (CPC) as an inexpensive and environmentally benign electrolyte additive in alkaline AABs. Hydrogen evolution test, electrochemical measurement, and surface analysis techniques were used to investigate the inhibition effects of CPC additive for the Al anode. The potentiodynamic polarization data indicated that the effectiveness of the CPC in inhibiting corrosion increased proportionally with higher CPC concentration. The maximum inhibition efficiency of 53.6% was achieved at a CPC dosage of 5 mM. The hydrogen evolution experiment revealed that the rate of hydrogen evolution decreased from 0.789 mL cm-2 min-1 for the pristine NaOH solution to 0.415 mL cm-2 min-1. The combination of X-ray photoelectron spectroscopy (XPS) and ab initio molecular dynamics (AIMD) provides conclusive evidence that CPC may adhere to the surface of Al and create a protective film. These findings indicate that CPC is successful in preventing the self-corrosion of the Al anode. Additionally, the Al anode has improved electrochemical characteristics, including a high specific capacity of 2041 mAh g-1 and a high energy density of 2874 Wh kg-1. This work focuses on the inhibition of self-corrosion of Al and provides novel insights for the design and development of effective additives for AABs.

Boosting the Performance of Aluminum-Air Batteries by Interface Modification

The large-scale application of aqueous Al-air batteries is highly restricted by the performance of Al anodes. The severe self-corrosion and hydrogen evolution of the Al anode in a concentrated alkaline electrolyte are the main reason. Here, aimed at relieving side reactions and enhancing the utilization of metal Al, we propose a hybrid electrolyte additive of 2-mercaptobenzothiazole (MBT) and ZnO to form a protective film at the anode/electrolyte interface and to decrease the hydrogen evolution active site. The strong absorption capability of MBT on the metal surface, along with the reduced Zn-containing layer, enables a compact protective film with high hydrogen evolution potential on the Al surface. With this benefit, the hydrogen evolution reaction (HER) inhibition efficiency is up to 83.58%, endowing a superior Al-air battery with an energy density of 2376.71 Wh kgAl-1 under a current density of 25 mA cm-2. The conception of constructing a hybrid protective film on the metal surface not only favors the development of metal-air batteries but also facilitates metal corrosion protection.

Aluminum-air batteries: current advances and promises with future directions

Owing to their attractive energy density of about 8.1 kW h kg-1 and specific capacity of about 2.9 A h g-1, aluminum-air (Al-air) batteries have become the focus of research. Al-air batteries offer significant advantages in terms of high energy and power density, which can be applied in electric vehicles; however, there are limitations in their design and aluminum corrosion is a main bottleneck. Herein, we aim to provide a detailed overview of Al-air batteries and their reaction mechanism and electrochemical characteristics. This review emphasizes each component/sub-component including the anode, electrolyte, and air cathode together with strategies to modify the electrolyte, air-cathode, and even anode for enhanced performance. The latest advancements focusing on the specific design of Al-air batteries and their rechargeability characteristics are discussed. Finally, the constraints and prospects of their use in mobility applications are also covered in depth. Thus, the present review may pave the way for researchers and developers working in energy storage solutions to look beyond lithium/sodium ion-based storage solutions.

A Mechanistic Overview of the Current Status and Future Challenges of Aluminum Anode and Electrolyte in Aluminum-Air Batteries

Aluminum-air batteries (AABs) are regarded as attractive candidates for usage as an electric vehicle power source due to their high theoretical energy density (8100 Wh kg-1 ), which is considerably higher than that of lithium-ion batteries. However, AABs have several issues with commercial applications. In this review, we outline the difficulties and most recent developments in AABs technology, including electrolytes and aluminum anodes, as well as their mechanistic understanding. First, the impact of the Al anode and alloying on battery performance is discussed. Then we focus on the impact of electrolytes on battery performances. The possibility of enhancing electrochemical performances by adding inhibitors to electrolytes is also investigated. Additionally, the use of aqueous and non-aqueous electrolytes in AABs is also discussed. Finally, the challenges and potential future research areas for the advancement of AABs are suggested.

Quasi-Solid-State Aluminum-Air Batteries with Ultra-high Energy Density and Uniform Aluminum Stripping Behavior

Aqueous aluminum-air batteries are attracting considerable attention with high theoretical capacity, low-cost and high safety. However, lifespan and safety of the battery are still limited by the inevitable hydrogen evolution reaction on the metal aluminum anode and electrolyte leakage. Herein, for the first time, a clay-based quasi-solid-state electrolyte is proposed to address such issues, which has excellent compatibility and a liquid-like ionic conductivity. The clay with uniform pore channels facilitates aluminum ions uniform stripping and reduces the activity of free H2 O molecules by reconstructing hydrogen bonds network, thus suppressing the self-corrosion of aluminum anode. As a result, the fabricated aluminum-air battery achieves the highest energy density of 4.56 KWh kg-1 with liquid-like operating voltage of 1.65 V and outstanding specific capacity of 2765 mAh g-1 , superior to those reported aluminum-air batteries. The principle of constructing quasi-solid-state electrolyte using low-cost clay may further promote the commercialization of aluminum-air batteries and provide a new insight into electrolyte design for aqueous energy storage system.

Regulating the Anode Corrosion by a Tryptophan Derivative for Alkaline Al-Air Batteries

Screening a green corrosion inhibitor that can prevent Al anode corrosion and enhance the battery performance is highly significant for developing next-generation Al-air batteries. This work explores the non-toxic, environmentally safe, and nitrogen-rich amino acid derivative, N(α)-Boc-l-tryptophan (BCTO), as a green corrosion inhibitor for Al anodes. Our results confirm that BCTO has an excellent corrosion inhibition effect for the Al-5052 alloy in 4 M NaOH solution. An optimum inhibitor addition (2 mM) has increased the Al-air battery performance; the corrosion inhibition efficiency was 68.2%, and the anode utilization efficiency reached 92.0%. The capacity and energy density values increased from 990.10 mA h g^-1 and 1317.23 W h kg^-1 of the uninhibited system to 2739.70 mA h g^-1 and 3723.53 W h kg^-1 for the 2 mM BCTO added system. The adsorption behavior of BCTO on the Al-5052 surface was further explored by theoretical calculations. This work paves the way for constructing durable Al-air batteries through an electrolyte regulation strategy.

Regulating solvation and interface chemistry enables advanced aluminum-air batteries

The main challenge for developing aqueous aluminum-air batteries with high mass-specific capacity depends on the inhibition of the parasitic hydrogen evolution reaction. Herein, a regulation strategy of solvation and interface chemistry has been proposed by introducing organic methylurea (MU) and inorganic stannous chloride (SnCl₂) to the alkaline electrolyte, which can modulate the solvent structure and electrode/electrolyte interface and endow the aqueous aluminum-air battery with an outstanding mass-specific capacity of 2625 mA h g^-1 at 50 mA cm^-2.