Al-air Battery Research Articles

Enhanced Electrochemical Performance of Aluminum-Air Batteries via Gallium Alloying

Enhanced Electrochemical Performance of Aluminum-Air Batteries via Gallium Alloying

Electrohydrodynamic Printing Grid-Structured Catalytic Layers with Excellent Bending Resistance for Flexible Al-air Batteries.

The catalytic film of a flexible Al-air battery is generally a brittle film formed by brushing a slurry onto the surface of carbon cloth. Fatigue bending can easily lead to cracking of the catalytic film and shedding of the active material. This study innovatively proposes a novel grid-structured catalytic layer prepared by electrohydrodynamic printing. Experiments have verified that, compared with traditional catalytic films, the grid-structured catalytic layer exhibits excellent bending resistance. After 10 000 fatigue bending cycles, its relative resistance is ≈1/9 that of the traditional catalytic film. The printed grid-structured catalytic layer is applied to a flexible Al-air battery, which maintains a power density retention rate as high as 92% after the same number of bending cycles. Compared to traditional catalytic films, the electrodynamically printed grid-structured catalytic layer proposed in this study demonstrates both excellent electrochemical performance and bending resistance. This advancement holds significant importance for the development and application of flexible metal-air batteries.

Nickel-Nitrogen Doped MnO2 as Oxygen Reduction Reaction Catalyst for Aluminum Air Batteries.

Aluminum-air battery has the advantages of high energy density, low cost and environmental protection, and is considered as an ideal next-generation energy storage conversion system. However, the slow oxygen reduction reaction (ORR) in air cathode leads toitsunsatisfactory performance. Here, we report an electrode made of N and Ni co-doped MnO2nanotubes. In alkaline solution, Ni/N-MnO2has higher oxygen reduction activity than undoped MnO2, with an initial potential of 1.00 V and a half-wave potential of 0.75 V. This is because it has abundant defects, high specific surface area and sufficient Mn3+active sites, which promote the transfer of electrons and oxygen-containing intermediates.Density functional theory (DFT) calculations show that MnO2doped with N and Ni atoms reduces the reaction overpotential and improves the ORR kinetics. The peak power density and energy density of the Ni/N-MnO2air electrodeincreased by 34.03 mW·cm-2and 316.41 mWh·g-1, respectively. The results show that N and Ni co-doped MnO2nanotubes are a promising air electrode, which can provide some ideas for the research of aluminum-air batteries.

Regulating the Helmholtz plane by trace ionic liquid additive for advanced Al-air battery

Al-air batteries (AABs) are the next generation of alternative energy sources due to their high theoretical energy density, low cost, and environmental friendliness. Researchers have been interested in AABs with stable discharge in alkaline solution, long discharge time, and high conductivity. However, the uncontrolled self-corrosion of the Al anode and the severe hydrogen evolution reaction in alkaline electrolytes have been two major drawbacks hindering the commercial development of AABs. These shortcomings reduce the Al anode's utilization and significantly shorten the battery's service life. Herein, the Helmholtz plane structure was reconstructed using an ionic liquid additive called 1-aminopropyl-3-methylimidazolium bromide (AMIB) to regulate the electrochemical interface between the electrolyte and the Al anode. Electrochemical tests found that when 3 mM AMIB was added, the corrosion inhibition efficiency could reach up to 60 %. Further surface analysis and theoretical calculations showed that AMIB can form a dense and uniform protective layer on the surface of the Al anode substrate, which reduces the anode corrosion, lowers the active centers for hydrogen evolution on the Al surface, and reduces the hydrogen evolution rate. The full-cell studies found that the specific capacity of the cell increased from 1227 to 2564 mAh g−1, the energy density increased from 1546 to 3359 Wh kg−1, and the Al anode utilization increased from 41.2 % to 86.1 % as the AMIB addition to the alkaline electrolyte risen from 0 to 3 mM. This method of electrolyte regulation provides an efficient strategy for the commercial development of AABs.

Recycling of spent heat pack towards Fe-Fe3O4@NC catalyst for ORR in direct methanol fuel cells and Al-air batteries

The effective repurposing of waste materials is crucial for sustainable development. The widespread use of disposable iron-based chemical warmers (IBCW) generates substantial solid waste annually. In this study, IBCWs were repurposed as raw materials to synthesize different electrocatalyst composites comprising metallic and oxide forms of iron embedded in nitrogen-doped carbon (NC). The composites were evaluated as oxygen reduction reaction (ORR) catalysts. The optimized Fe-Fe3O4@NC demonstrated enhanced ORR kinetics, with an onset potential of 0.92 V and a half-wave potential of 0.86 V vs. RHE. As an air cathode for direct methanol fuel cell (DMFC), Fe-Fe3O4@NC achieved a power density of 33.3 mW cm−2 at 88 mA cm−2, demonstrating its practical applicability. Additionally, a quasi solid-state aluminium-air battery (SAAB) was assembled using this catalyst as the air cathode with a PVA-KOH gel electrolyte and the separator. The quasi SAAB exhibited an open circuit voltage (OCV) of 1.46 V, a power density of 40 mW cm-2, and good rate capability compared to Pt/C. The combined effect of metallic and oxide iron with nitrogen doping enhances the overall catalytic activity. This study demonstrates that IBCWs can be effectively transformed into valuable catalysts for renewable energy applications, enabling clean and sustainable utilization of waste materials.

Mitigating anodic corrosion in aluminum–air batteries: Effects of alkali metal cation size on electrochemical performance

Anodic corrosion limits the performance of aluminum–air batteries (AABs) by reducing discharge capacity and hindering energy density. This study proposes a strategy to mitigate anodic corrosion by controlling electrolyte cations to decrease the activity of free water molecules in the anodic corrosion process. Alkali metal cations (Na+, K+, Rb+) are introduced into a 1mol dm−3 KOH solution to examine their solvation properties and effects on free water molecule activity. Results show that larger cations (Na+ < K+ < Rb+) enhance anode discharge capacity by promoting more stable discharge reactions. Raman spectroscopy reveals that as cation radius increases, free water molecule activity decreases due to increased hydration. X-ray photoelectron spectroscopy analysis shows that larger cations favor the formation of corrosion-resistant aluminum compounds like Al2O3 and Al(OH)3, due to their higher concentration in the electric double layer, inhibiting anodic corrosion. This study highlights the critical role of cation solvation in enhancing electrochemical performance and corrosion resistance of AAB anodes.

Oxophilic Low‐Coordination Gd‐N3 Single Atom Sites With P‐Enhanced Second Coordination for High‐Performance Al‐Air Batteries

AbstractThe development of efficient rare earth single‐atom (SA) catalysts for the oxygen reduction reaction (ORR) is essential yet challenging for high‐performance aluminum‐air batteries (AABs). This study introduces a concept‐to‐proof strategy for synthesizing a hollow carbon‐supported gadolinium (Gd) SA catalyst using low‐coordination and second‐coordination sphere engineering. In this design, Gd atoms are coordinated to three nitrogen (N) atoms in N‐doped carbon and surrounded by six phosphorus (P) atoms, forming Gd‐N3‐P6 sites. These catalysts demonstrated exceptional ORR performance, achieving a half‐wave potential of 0.895 V and superior durability compared to the commercial Pt/C benchmark. When integrated into AABs, they delivered impressive performance, with a peak power density of 257 mW/cm2 and an energy density of 2916 Wh/kg, alongside enhanced cycling stability. In situ characterization and theoretical calculations revealed that the strategic placement of P atoms in the second coordination sphere significantly enhanced the valence state of the Gd site. This enhancement improved the adsorption capacity for O2 and H2O while facilitating the rapid desorption of *OH intermediates during the ORR. This study offers valuable insights into the development of cost‐effective ORR catalysts, emphasizing the significance of modulating the local coordination environment of metal SA sites.

Three-center-four-electron hydrogen bond bridged by fluorine enables advanced electrolyte for aluminum air batteries

Aluminum air batteries have great potential as a state-of-the-art energy storage device due to their high capacity, energy density and fascinating safety. However, the disturbing hydrogen evolution reaction (HER) of the Al anode increase the gap between practical application and theoretical level. Electrolyte engineering with organic additives has been the spotlight to address the problem of HER. The polar functional group of organic molecules could bound with the water via the hydrogen bond to drop the activity of water. Unfortunately, the basic physicochemical properties of electrolyte would be deteriorated due to the organic matter, which has a negative impact on the electrochemical performance of batteries. Herein, an inorganic additive was adopted to regulate the hydrogen bond network and anode interface. The activity of H2O could be obviously suppressed by the stronger three-center-four-electron hydrogen bonds bridged by fluoride ions. And the water molecules are kept away from the anode surface due to the protective layer caused by the adsorption of fluoride ions. The HER could be greatly inhibited by both pathways, which reaches an inhibition efficiency of 55% in the electrolyte with 5 M KF. Correspondingly, the Al air battery exhibits a high discharge specific capacity of 1552.8 mAh g−1 and an energy density of 1829.51 Wh kg−1 at a current density of 25 mA cm−2. This work showcases a promising inorganic additive to suppress the HER for high-performance Al air battery.

The Effect of Hatch Spacing on the Electrochemistry and Discharge Performance of a CeO2/Al6061 Anode for an Al-Air Battery via Selective Laser Melting

To improve the electrochemical activity and discharge performance of an aluminum-air (Al-air) battery, a commercial 6061 alloy (Al6061) was selected as the anode, and CeO2 was also added inside the anode to enhance its performance. The CeO2/Al6061 composite was prepared using selective laser melting (SLM) technology. The influence of hatch spacing on the forming quality, corrosion resistance, and discharge performance of the anode was studied in detail. The results showed that with an increase in hatch spacing, the density, corrosion resistance, and discharge performance of the anode first increased and then decreased. When the hatch spacing is 0.13 mm, the anode has the best forming quality. At this point, the density reaches 98.39%, and the self-corrosion rate (SCR) decreases to 2.596 × 10−4 g·cm−2·min−1. Meanwhile, the anode exhibits its highest electrochemical activity and discharge voltage, which is up to −1.570 V. The change in anode performance is related to the defects generated during the SLM forming process. For samples with fewer defects, the anode can dissolve uniformly, while for samples with more defects, the electrode solution is prone to penetrate the defects, causing uneven corrosion and reducing electrochemical and discharge activity.

Interfacial activation of anode in aluminum-air battery through incorporating 5-carboxyl benzotriazole@β-cyclodextrin assembly in synthetic seawater electrolyte

Neutral electrolyte, such as synthetic seawater (SW), is a promising candidate for aluminum-air (Al-air) battery due to the alleviated hydrogen evolution along with anode self-corrosion. However, aluminum surface passivation in SW poses a serious challenge for battery's power generation. Following molecular self-assembly theory, 5-carboxylate benzotriazole (CB) was incorporated into β-cyclodextrin (β-CD), which (CB@β-CD) was utilized as an interfacial activator for aluminum anode in SW. CB could be released from β-CD, and activated aluminum surface, facilitating anode discharge. The specific capacity and energy density of Al-air battery were achieved as 2607.4 mAh/gAl and 2.37 kWh/kgAl, respectively, at an optimal CB@β-CD concentration of 120 mg/L. Density functional theory calculations revealed that the overwhelming adsorption energy of guest molecule (CB) on Al (111) plane over its binding energy inside host (β-CD) accounted for the release of CB on anode surface, and the ensuing interfacial activation effect.

Multi-Objective Optimization for the Forming Quality of a CeO2/Al6061 Alloy as an Aluminum–Air Battery Anode Manufactured via Selective Laser Melting

To improve the discharge performance of aluminum–air batteries, CeO2/Al6061 composites were prepared as an anode using selective laser melting (SLM). Response surface methodology (RSM) was employed, and the test results were linearly fitted. A prediction model for the forming quality of the composite anode was established, and the reliability of the model and the interaction between process parameters were explored based on variance analysis and significance testing. On this basis, with corrosion potential, self-corrosion rate, and discharge voltage as optimization objectives, the optimal solution set of the SLM forming CeO2/Al6061 anode process parameter was solved through a genetic algorithm, and experimental verification was conducted. The results indicate that the optimal process range for the forming quality and various properties of composite materials is laser power of 265~285 W, scanning speed of 985~1025 mm/s, and scanning spacing of 0.116~0.140 mm. The optimized process parameters were selected for reliability testing, and the errors were all within 3.0%, verifying the accuracy and reliability of the model.

Beyond Barrier Function: Exploring the Potential of Polymer Coatings for High-Performance Aluminum–Air Batteries

Beyond Barrier Function: Exploring the Potential of Polymer Coatings for High-Performance Aluminum–Air Batteries

Building aluminium-air battery on waste paper for DIY learning

Abstract Environmental sustainability and the effective use of renewable resources are critical subjects that need to be integrated into our educational systems through practical, hands-on learning. This paper focuses on the fabrication of aluminium-air batteries using waste materials, providing an innovative and cost-effective DIY approach to energy storage education. Utilizing aluminium from food packaging and graphite from pencils, this study demonstrates the construction and functionality of an aluminium-air battery to run an LED, highlighting its potential applications in educational settings and low-cost energy solutions. The paper aims to inspire the adoption of environmentally friendly practices and enhance students’ understanding of electrochemical energy conversion through accessible and engaging DIY projects.

Regulating H-bonded network of aqueous electrolytes for stable and energy-dense Al-air batteries

Aluminum-air batteries offer unique advantages over other aqueous batteries in terms of environmental friendliness, energy density, resource abundance, and cost-effectiveness. Nevertheless, the parasitic hydrogen evolution reaction (HER) of anode presents severe challenges for stable and long-term operation of batteries. Here we found that the mixed solution with strong H-bond network has a significant inhibitory effect on the self-discharge and HER of Al anode in alkaline electrolyte. And establishing the relationship between the molecular structure of the cosolvent (carbon chain lengths and hydrogen bond acceptors) and the strength of the hydrogen bonding network of the electrolyte. The as-constructed Al-air battery with ethylene glycol (EG) cosolvent demonstrates a remarkable increased discharge specific capacity of 2725 mAh g-1, corresponding to the Al anode utilization of 91.4%. The operation time also extends to 160 hours at 5 mA cm-2. This work provides new avenues to understand the role of H2O in aqueous electrolytes and explore low-cost and effective approaches for the development of next-generation aqueous Al-air batteries.

Recent progress in inhibition of hydrogen evolution reaction in alkaline Al-air batteries

Recent progress in inhibition of hydrogen evolution reaction in alkaline Al-air batteries

The effect of Artemisia capillaris leaf extract as a benign corrosion inhibitor on the performance of Al–air batteries

The self-corrosion of the aluminum anode reduces largely the performance of Al-air batteries. Herein, we report on the effect of Artemisia capillaris leaf extract (ACLE) as a benign corrosion inhibitor on the performance of Al-air batteries in 4 M NaOH electrolyte. The hydrogen evolution tests, electrochemical measurements, and surface analysis show that ACLE can markedly reduce the corrosion current density of the Al electrode in 4 M NaOH, which is due to the adsorption of the active components in ACLE inhibitor on the Al electrode surface. The presence of ACLE in 4 M NaOH greatly reduces the self-corrosion of the Al anode, and thus improves the utilization rate of the Al electrode. Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) are employed to determine the chemical composition of the adsorption layers on the surface of the Al electrode. When the concentration of ACLE in 4 M NaOH is 5 g/L, the Al-air battery has a high practical capacity density of 3545 Wh kg−1, and the fuel efficiency also increases to a high value of 44 % from 14 % without ACLE. This work presents a novel approach to enhance the performance of Al-air batteries through the utilization of natural product extracts as corrosion inhibitors.

Inhibited Passivation by Bioinspired Cell Membrane Zn Interface for Zn-Air Batteries with Extended Temperature Adaptability.

Due to the slow dynamics of mass and charge transfer at Zn|electrolyte interface, the stable operation of Zn-air batteries (ZABs) is challenging, especially at low temperature. Herein, inspired by cell membrane, a hydrophilic-hydrophobic dual modulated Zn|electrolyte interface is constructed. This amphiphilic design enables the quasi-solid-state (QSS) ZABs to display a long-term cyclability of 180 h@50mAcm-2 at 25°C. Moreover, a record-long time of 173 h@4mAcm-2 at -60°C is also achieved, which is almost threefolds of untreated QSS ZABs. Control experiments and (in situ) characterization reveal that the growth of insulating ZnO passivation layers is largely inhibited by tuned hydrophilic-hydrophobic behavior. Thus, the enhanced transfer dynamic of Zn2+ at Zn|electrolyte interface from 25 to -60°C is attained. As an extension, the QSS Al-air batteries (AABs) with bioinspired interface also show unprecedented discharge stability of 420 h@1mAcm-2 at -40°C, which is about two times of untreated QSS AABs. This bioinspired-hydrophilic-hydrophobic dual modulation strategy may provide a reference for energy transform and storage devices with broad temperature adaptability.

Beyond Catalysts: Pioneering a New Era in Aluminum‐Based Electrochemical Energy Systems

AbstractAqueous Aluminum‐air batteries (AABs) hold promise for advancing high‐energy density storage systems in future technologies. However, their widespread practical deployment is limited by the inherent hydrogen side reactions in Aluminum (Al) and incomplete cathodic reactions. To address these challenges, the Al‐sodium persulfate (Na2S2O8) system is introduced as an alternative to traditional AABs. Utilizing Na2S2O8 allows to simultaneously achieve three critical objectives, namely, eliminating the need for a cathode catalyst, increasing the system voltage from 1.4 to 2 V, and reducing the hydrogen evolution reaction (HER). Three distinct configurations of the Aluminum electrochemical energy system (Al‐EES) using Na2S2O8: static, flow, and gel are developed. The static configuration demonstrates a performance 1.7 times superior to that of traditional AABs. The flow configuration of Al‐EES achieves a discharge duration of 77 h, which is three to four times longer than that of AABs and exhibits an energy density of 2,650 Wh kgAl−1. This emerging technology has the potential to significantly enhance electric vehicles by providing powerful, efficient, cost‐effective, and durable power‐generation devices.

High-Energy-Density High-Power-Density Micro Aluminum-Air Batteries for Small Scale Quadcopters

Small-scale quadcopters are increasingly used in various fields, including rescue, surveillance and precision agriculture. The predominant energy storage system for such quadcopters has been the micro lithium-ion battery (mLIB). Two of the most important design metrics for power sources used in quadcopters are specific power and specific energy. The specific energy determines the flight duration of the quadcopters, while specific power is necessary for maneuverability and takeoff. The mLIB can easily meet the power requirement of small scale quadcopters; however, the limited energy density of mLIBs (exacerbated by the packaging overhead of these batteries as scales shrink) constrains their flight duration. To increase the flight time, aluminum-air batteries (AABs), with a theoretical energy density twenty times greater than conventional lithium-ion batteries, are being explored. [1] Despite AAB’s high theoretical energy density, the conventional AAB lacks the high-power performance of LIBs. [2] To fulfill the demanding power requirements of small scale quadcopters, the AAB cell has been re-engineered to enhance power capability while maintaining high energy density.To maximize AAB energy and power density at the cell level, it is imperative to address the issue of battery packages that add weight without contributing to electrochemical performance. A light-weight battery packaging approach is developed for the micro-AAB (mAAB). In the context of AABs, the primary function of the battery package is to retain the aqueous electrolyte within the cell. Typically, the cathode of an AAB is constructed using a carbon cloth, doped with a layer of polytetrafluoroethylene (PTFE). This hydrophobic carbon cloth cathode effectively retains the aqueous electrolyte. In order to increase the mechanical integrity of mAAB pouch cells, 3D printed polypropylene is utilized as the body frame of mAABs, providing a robust and lightweight structure. The carbon cloth cathode is affixed to the 3D printed polypropylene using epoxy, as shown in Figure 1A. An image of an assembled 2-gram mAAB pouch cell is shown in Fig 1B. Remarkably, the electrochemically inactive packaging materials contribute to less than 13% of the total cell weight, achieving the goal of minimizing packaging material to enhance battery performance. As a comparison, the packaging material of gram-scale mLIBs can contribute to over 30% of total cell weight. Furthermore, in contrast to traditional aluminum-air battery designs, the pouch cell architecture optimizes cathode area exposure, which is advantageous for high-power applications.The anode structure is also engineered for high power capability. Figure 2A shows that increasing the anode/cathode area ratio can augment areal power density. Therefore, a multi-layer anode structure, supported by 3D printed polypropylene, is developed for mAAB pouch cells. This design effectively increases the anode/cathode surface area ratio and enables rapid ion and electron transport within the multi-layer anode, optimizing power performance. A schematic of a 3D printed polypropylene supported multi-layer anode structure is shown in Figure 2B.The electrochemical performance of assembled mAAB pouch cells is evaluated to assess their suitability for the demanding requirements of small scale quadcopter applications. Figure 3A provides a comparative analysis of power densities between mAABs and commercial micro-quadcopter mLIBs. Notably, mAABs exhibit a peak power density exceeding 1500 Wh/kgbattery at 4 Amp, surpassing that of mLIBs. Battery weight encompasses anode, cathode, electrolyte and all necessary battery packaging, confirming that mAABs can meet the power demands of micro-quadcopters. In Figure 3B, the energy density of mAABs is compared to commercial mLIBs. When the power density is above 500 W/kgbattery, a threshold sufficient to lift a quadrotor drone, mAABs exhibit an energy density of 320 Wh/kgbattery, which is multiple times higher than that of mLIBs. [3] Notably, the anode utilization of the mAAB exceeds 85%, underscoring the effectiveness of the multi-layer anode design. This superior electrochemical performance emphasizes the superior capability of mAABs, indicating their potential as an advanced power source for long flight duration small scale quadcopters.

Flexible Aluminum-Air Batteries

Wearable and flexible electronics have a wide range of applications. Making a flexible power source for them is essential. Aluminum-air batteries are attractive for powering portable, lightweight devices due to their inexpensive, light, and powerful energy source. In this project, the Al-air battery was made using activated carbon and aluminum electrodes, chloride-based electrolytes with ionic liquid additives. Various mixtures of 1-ethyl-3-methylimidazolium chloride, aluminum chloride, sodium hydroxide, and sodium chloride were studied. Fundamental properties of room-temperature ionic liquids, such as lower conductivity and density, improved the performance of aluminum-air batteries. Cell capacity, cyclic voltammetry behavior, and cell interfacial impedance with various electrolytes were optimized using the design of experiments. The battery's electrical power output and cell capacity were lower than those obtained using an activated carbon air cathode. The cell capacity over repeated electrochemical reactions was stable. The Al-air battery had regular cyclic voltammetry behavior. Aluminum hydroxide was not found on the anode electrode when an ionic liquid electrolyte was used. The interfacial cell impedance did not decrease after electrochemical reactions over a long time.