Al-air Battery Research Articles

Enabling a high-performance saltwater Al-air battery via ultrasonically driven electrolyte flow

As an emerging battery technology, the Al-air flow battery (AAFB) exhibits high energy density due to the recycling of electrolytes, thus showing great potential as a type of clean and sustainable energy storage system. Conventionally, it employs an external mechanical pump to recycle the electrolyte. In this work, the saltwater AAFB in which the electrolyte is recycled by the ultrasonic capillary effect (rather than a mechanical pump) and the reaction chamber is agitated by ultrasonic vibration, is proposed and investigated. Our numerical simulations show that a travelling ultrasonic wave in the electrolyte flow system causes the capillary flow and agitation. The experimental results show that the percentage increase of the peak power density (relative to that with static electrolyte) can be up to about 7.5 times of that with the electrolyte flow driven by a mechanical pump, under the same electrolyte flow rate and concentration (3.3 ml min−1 and 3 M NaCl). The optimal peak power density, which can be achieved by optimizing the reaction chamber thickness, electrolyte concentration and ultrasonic vibration velocity, is 43.88 mW cm−2. This work illustrates that the acoustofluidic method can not only improve the discharge performance of the saltwater AAFB effectively, but also greatly decrease the energy consumption, weight and volume of the electrolyte driving unit of the AAFB. In addition, analyses based on experimental results show that the energy gain of a series/parallel battery system formed by multiple identical cells can be larger than one, if the number of cells in the system is large enough.

Enhanced performance of Al-0.02Mg-0.01Sn-0.004Bi-0.003In alloy as novel anode for Al-air batteries in alkaline electrolyte

In this paper, aluminum alloy doped with Mg, In, Sn and Bi (Al-0.02Mg-0.01Sn-0.004Bi-0.003In) is prepared via melting and casting process. The influence of rare earth elements Bi and In on electrochemical performance of aluminum alloy anode is studied. The self-corrosion of hydrogen evolution and the electrochemical performance are investigated for the prepared alloy in 4 M NaOH electrolyte. The scanning electron microscope is used to study the surface morphology of the prepared alloy after discharge. It shows that synergistic effect between the alloy elements significantly reduces the self-corrosion rate of aluminum anode. Discharge experiments display that the prepared alloy outputs high capacity density and energy density of 2857.14 A h kg−1 and 4805.71 W h kg−1 at a high discharge rate (50 mA cm−2), respectively. It can also obtained considerable anodic utilization of 95.94 %. The prepared aluminum alloy is a desirable candidate anode material for the high-performance Al-air battery.

Enhanced electronic interaction between iron phthalocyanine and cobalt single atoms promoting oxygen reduction in alkaline and neutral aluminum-air batteries

Aluminum-air batteries (AABs) have received increasing interest for next-generation energy conversion systems. However, the development of AABs is hindered by the sluggish kinetics of cathodic oxygen reduction reaction (ORR). Iron phthalocyanine (FePc) is one of the active electrocatalysts for ORR but still far from Pt-based materials in terms of electrocatalytic performance. Herein, FePc molecules anchored on the Co single atoms/N-doped porous carbon nanofibers (denoted as FePc@Co-SAs/PCNF) with enhanced electronic interaction are prepared for the ORR. X-ray absorption spectra (XAS) analysis confirms the atomically dispersed Fe and Co sites and reveals the electronic interaction between FePc and Co-N3. The cobalt single atoms can break the electronic distribution symmetry of FePc and induce electronic localization to boost the ORR performance. As a result, the FePc@Co-SAs/PCNF electrocatalyst demonstrates a remarkable ORR activity in both alkaline and neutral electrolytes. The electrocatalytic ORR processes on the FePc@Co-SAs/PCNF are recorded by in-situ Raman spectra. Moreover, the ORR mechanism is discussed, which is supported by density functional theory (DFT) calculations. Furthermore, the AABs based on FePc@Co-SAs/PCNF exhibit remarkable discharge performance. This study offers a new strategy for rationally designing metallic macrocyclic compound electrocatalysts and promotes the development of metal-air batteries.

In-situ cobalt-nickel alloy catalyzed nitrogen-doped carbon nanotube arrays as superior freestanding air electrodes for flexible zinc-air and aluminum-air batteries

A flexible air electrode with excellent activity and outstanding stability is highly desirable for metal-air batteries. Herein, the rational design of CoNi alloys derived intertwined N-doped carbon nanotube arrays onto carbon cloth (CoNi@NCNTs/CC) is reported, as self-supported air electrodes for flexible zinc-air and aluminum-air batteries. CoNi@NCNTs/CC exhibits a low potential of 1.56 V at 10 mA cm−2 in OER, along with a half-wave potential of 0.82 V in ORR, which is attributed to abundant active sites including CoNi alloys with optimized adsorption energy, Co/Ni-Nx and N-doped CNTs. The well-designed nanotube array construction with substantial channels on carbon cloth facilitates the mass diffusion and electron delivery, and improves mechanical flexibility. Combining excellent activity and promising flexibility, CoNi@NCNTs/CC based liquid- and all-solid-state zinc-air batteries exhibit excellent charge/discharge capability and long-term stability. And the liquid- and all-solid-state aluminum-air batteries deliver promising discharge property with a high open circuit voltage as well as commendable flexibility.

Synergistic construction of bifunctional interface film on anode via a novel hybrid additive for enhanced alkaline Al-air battery performance

Aluminum-air battery is considered to be a hopeful source of clean energy. However, the serious self-corrosion of Al anode hinders its commercial application. Herein, we propose an original hybrid additive consisting of 4-amino-6-hydroxy-2-mercaptopyrimidine (AHMP) and zinc oxide (ZnO) to inhibit self-corrosion of Al-6061 in alkaline Al-air battery. It induces a dense bifunctional film formed on the anode. The anode utilization rate reaches 60%, and the mass capacity of full cell increases from 879 mAh g−1 (blank) to 1785 mAh g−1 (with the hybrid additive). Surprisingly, this film simultaneously functions to activate the anode, boosting the discharge voltage of full cell. Experiments and theoretical calculations jointly reveal the mechanism formation of this unique bifunctional interface film: “site-directed bridging” of double metals (Al, Zn) to distinct adsorption sites on AHMP molecules. Our work investigates the origin of the synergistic effect for hybrid additives and provides a new strategy for screening functionalized additives to construct characteristic aluminum/electrolyte interface film for Al-air battery.

Corrosion inhibition of hybrid H2QS/CaO additives for AA5052 alloy in alkaline solution

AbstractBACKGROUNDThe parasitic H2 evolution reaction (HER) is the main problem preventing the development of the commercial Al‐air battery (AAB) in alkaline solution. The purpose of this study is to investigate a hybrid additive for alkaline AAB. The inhibition effect of the additives for HER is studied by hydrogen evolution test, electrochemical measurements, and scanning electron microscope (SEM). The stability of the battery and the anode utilization rate in alkaline solution are also investigated.RESULTSResults showed that the maximum inhibition efficiency was 86.52% for 0.08 g L−1 CaO + 0.5 mmol L−1 H2QS, and that the anode utilization rate increased to 90.7%. A spectrum analysis, including infrared, ultraviolet, and fluorescence, was conducted to analyze the corrosion inhibition mechanism. The chelation of the quinoline ring with Al3+ ions and the electrostatic interaction of sulfonic groups with Ca2+ ions produce a strong synergistic effect.CONCLUSIONThe hybrid H2QS/CaO additive has synergistic effects to help form a stable composite film that significantly retards the hydrogen evolution reaction of the Al alloy anode for the alkaline AAB. © 2022 Society of Chemical Industry (SCI).

Development of Cathodes for Aluminum-Ion and Aluminum-Air Batteries Using Pulsed Electrodeposition

Electrical energy storage has emerged as a critical component in North America’s clean energy transformation. Vehicle electrification and integration of renewables such as wind and solar power into the grid have further underlined the importance of affordable, environmentally friendly energy storage platforms. Rechargeable batteries are now considered to be viable options for large-scale energy storage with lithium-ion and redox flow batteries leading the charge. Over the past decades, aluminum-ion batteries have experienced a renaissance on account of their high volumetric energy density, superior cycleability, enhanced stability and significant cost benefits compared with other commercially available secondary batteries. Aluminum-air batteries also hold significant promise as primary energy storage platforms, but they suffer from thermodynamics and kinetics hurdles, leading to inferior performance. To address these issues, researchers have focused on optimizing different cell components, including anodes, cathodes, and electrolytes.It is well established that nano-structuring battery components would markedly improve their short- and long-term performance by enhancing reaction kinetics. One of the major impediments to wide-scale commercialization of Al-ion batteries continues to be its inferior capacity and cycle stability compared with commercially available secondary batteries. Part of these issues can be ascribed to the failure of cathode materials currently being investigated and used. As for primary Al-air batteries, conventional air cathodes do not perform very well either; and there are many reasons as to why the incorporation of such air cathodes into Al-air batteries would lead to inferior performance or premature failure; the most important of which is low catalytic activity.To address a number of these issues, pulsed current electrodeposition was employed to deposit nano-catalysts such nickel, silver, platinum and oxides of manganese on different support materials, including carbon paper and cloth, titania nanotubes, and stainless steel and nickel meshes. The influence of various electrodeposition parameters, including peak current density, duty cycle, type of waveform and pulse frequency, on resulting layers were systematically investigated. In most cases, nanocatalysts about 2-40 nm in diameter were obtained. Various electrochemical tests were utilized to characterize the resulting layers. A simple mathematical model based on progressive nucleation also was developed to predict the influence of the aforementioned electrodeposition parameters on the resulting nano-catalyst layers. The model was further refined by considering all contributing factors towards growth current, including diffusion, ohmic and charge transfer phenomena as well as changing diffusion coefficients, during electrodeposition. According to the model, at high peak deposition current densities and low duty cycles (5% or less), the ramp-down waveform yielded the highest nucleation rates, confirming the experimental findings in which nanoparticles generated with the above waveform produced the smallest average grain size, ranging from 2-10 nanometer in diameter for platinum and silver nanocatalysts on carbon cloths and titania nanotubes, and 10-50 nm in diameter for nickel nanoparticles deposited on stainless steel and nickel meshes and titania nanotubes.

Localizing Tungsten Single Atoms around Tungsten Nitride Nanoparticles for Efficient Oxygen Reduction Electrocatalysis in Metal-Air Batteries.

Combining isolated atomic active sites with those in nanoparticles for synergizing complex multistep catalysis is being actively pursued in the design of new electrocatalyst systems. However, these novel systems have been rarely studied due to the challenges with synthesis and analysis. Herein, a synergistically catalytic performance is demonstrated with a 0.89 V (vs reversible hydrogen electrode) onset potential in the four‐step oxygen reduction reaction (ORR) by localizing tungsten single atoms around tungsten nitride nanoparticles confined into nitrogen‐doped carbon (W SAs/WNNC). Through density functional theory calculations, it is shown that each of the active centers in the synergistic entity feature a specific potential‐determining step in their respective reaction pathway that can be merged to optimize the intermediate steps involving scaling relations on individual active centers. Impressively, the W SAs/WNNC as the air cathode in all‐solid‐state Zn‐air and Al‐air batteries demonstrate competitive durability and reversibility, despite the acknowledged low activity of W‐based catalyst toward the ORR.

Constructing thinner micropore-enriched carbon skeleton through molecular configuration transformation of hexose isomers to boost oxygen reduction reaction in Al-air battery

Oxygen reduction reaction (ORR) is the core process of metal-air battery. Glucose and fructose are the primary monomers in biomass. In this work, the molecular configuration transformation between pyranose (glucose) and furanose (fructose) is selected as an entry point to construct thinner micropore-riched carbon skeleton with high amount of active sites. The molecular configuration transformation from furanose to pyranose increases the activation barrier associated with the molecular conversion, self-assembly, and aromatization reaction. The higher activation barrier slows the dynamic pyrolysis process, which favors the pore-forming and graphitization of precursors. The Glu-SSC-950–1 (derived from pyranose) exhibits a larger electrochemical active surface area (ECSA) and faster electron transfer, concretely, double-layer capacitance increases from 7.4 to 14.9 mF cm−2. And the Glu-SSC-950–1 exhibits a higher half-wave potential (0.847 V) and kinetic current density at half-wave potential (3.91 mA cm−2) than Fru-SSC-950–1 (derived from furanose, 0.801 V, 2.92 mA cm−2). In practical application, the Al-air battery with Glu-SSC-950–1 exhibits a superior peak power density (467.8 mW cm−2) than Fru-SSC-950–1 (400.7 mW cm−2). In general, we present an approach for the preparation of highly active ORR biomass-derived carbon.

Exploring the influence of bismuth content on the electrochemical performance of aluminum anodes in Aluminum-air battery

Abstract Bi is one of important alloying elements in aluminum anode of alkaline battery. In this work, Al-Bi alloy used as anode material.And how to optimize the addition amount of Bi in aluminum anode was studied to improve the discharge performance of aluminum anode. Using 4 mol/L−1 NaOH solution as electrolyte, the electrochemical properties of Aluminum anode Al-xBi (x=0, 0.2, 0.4, 0.6, 0.8, 1.0wt%) with different Bi content were studied. The results show that the addition of Bi will destroy the passivation film on the surface of aluminum alloy, making the reaction further. The addition of Bi element has the effect of refining grain and homogenizing microstructure, and reduces the solution resistance and polarization resistance during discharge to a certain extent. Under the condition of 4 mol/L-1 NaOH solution as the electrolyte, Al-0.8Bi anode plate has better corrosion resistance and electrode activity compatibility.

Ultrathin Al–air batteries by reducing the thickness of solid electrolyte using aerosol jet printing

Flexible Al–air batteries have great potential in the field of wearable electronic devices. However, how to reduce the thickness of the battery and improve their applicability in wearable applications is still an unresolved thorny problem. Therefore, this article focuses on the strategies to minimize the thickness of the solid electrolyte for flexible Al–air batteries. In this paper, an innovative aerosol jet printing method is used to prepare the ultrathin neutral electrolyte with a thickness of 18.3–74.5 μm. This study discusses the influence of the thickness and ion concentration on the conductance of the electrolyte in detail. The ultrathin electrolyte has been applied to the flexible Al–air battery, and the battery performance has been explored. The cell pack composed of single cells is light and thin, and can successfully drive small electrical equipment. This study provided new ideas for the preparation of ultrathin electrolyte for flexible energy products.

Study on Electrical Characteristics of Flexible Textile Aluminium-Air Battery/Wetness Sensor and their Applications

The field of smart textiles has been steadily growing throughout the last decades. Wearables and garments with integrated electronics being one of the major sections of this area. One of the components that virtually any such product has is a power source. This paper focuses on one such option, which employs only non-toxic materials, which can be safely used in close proximity to human body. The paper builds on previously developed flexible textile aluminium-air battery prototype. New electrical measurements are provided, which show possibilities and limitations of the developed primary battery, as well as niches, where it can be used. This paper focuses on testing the battery in real-world application conditions, by repeatedly activating and deactivating it for short periods of time in order to test its useful life period. From that point useful practical applications can be determined, which take into account limitations of the battery. The measurements show that the battery is best suited for use in emergency and alarm systems, where the system is activated for relatively short period of time in order to change system’s state or transmit an alarm message. Some examples are smart diapers with smart monitoring capabilities and anti-drowning safety bracelets.

Reversible passivation in primary aluminum-air batteries via composite anodes

Despite the fact that primary aluminum-air have extraordinary theoretical energy densities, their shelf life is irreversibly restricted by anodic hydrogen evolution corrosion. However, current corrosion-suppression solutions usually make significant sacrifices in terms of energy and power density. We prepared carbonaceous nanomaterial-reinforced aluminum matrix composites as anodes for reversible passivation, preventing self-corrosion in an open-circuit state. Homogeneous microstructures of the composites induced by severe plastic deformation allow for the formation of passivation films against hydrogen evolution reactions. The strong bonds between magnesium-containing aluminum hydroxides and fluorinated graphene nanoplatelet enhance the stability of the nanosphere-structured passivation layer. The fluorinated nano-reinforcements enable reversible adsorption and exfoliation induced by the discharge process to realize reversible passivation mechanisms. This composite anode in aluminum-air cells achieves a 424% increase in effective energy density during intermittent discharge, which possesses a considerable anode energy utilization of 37.5% and an intermittent discharge efficiency of 95.3 ± 3.1%.

Corrosion behaviour improvement from the ultrafine-grained Al–Zn–In​ alloys in Al–air battery

Corrosion of aluminium anode in alkaline solution is a challenging matter for the development of a long-life aluminium anode in Al–air battery. This research focuses on grain size reduction by equal channel angular pressing (ECAP) of Al, Al–Zn, and Al–Zn–In samples. The average grain size of all samples after ECAP is lower than 1μm. Open circuit potential, potentiodynamic polarisation, electrochemical impedance spectroscopy, and self-corrosion test were carried out to study the effects of alloying elements (Zn, In) and grain size reduction by ECAP on the electrochemical behaviours of aluminium alloy anodes. The results show that alloying element, zinc, can improve the stability of ion dissolution by porous Al2ZnO4 film formation. Indium can activate ion dissolution that causes enhanced electrochemical activities for Al–Zn–In sample. Moreover, increasing grain boundaries through grain size reduction can enhance more negative potential and cause a uniformly corroded surface of Al–Zn–In sample, leading to a longer anode life in alkaline solution.

Improving Discharge Voltage of Al-Air Batteries by Ga3+ Additives in NaCl-Based Electrolyte.

The application of NaCl-based aluminum-air batteries is limited due to the passivation of the aluminum anode. In an effort to solve this problem, this work studied the influence of different concentrations of Ga3+ additives on the discharge behavior of Al in the NaCl electrolyte. The results of both experiments and theoretical calculations have shown that commercial purity aluminum could be significantly activated by Ga3+. Based on microstructure observations and electrochemical impedance spectroscopy, the influence activation mechanism of Ga3+ on the discharge behavior of commercial purity Al is clarified. The addition of Ga3+ biased the surface charge of aluminum along the activation direction, forming activation sites, and then destroyed the surface passivation film. Due to the formation of a gallium–aluminum amalgam, the Al-air battery had the best discharge characteristics in the electrolyte with 0.2 M Ga3+, and its discharge voltage reached 0.9734 V with a remarkable increase compared with that of NaCl solution (0.4228 V). Therefore, Ga3+ additive is a promising choice for NaCl-based Al-air batteries to improve their discharge voltage.

Photo-assisted Al-air batteries based on gel-state electrolyte

The use of new concept electrochemical devices to store and release solar energy has always been a research hotspot in the society of resource shortage. In this work, we firstly introduce sunlight into the Al-air battery by CuO and Cu2O semiconductor electrode materials to improve the discharge voltage under illumination and the calcium alginate hydrogel-based electrolyte is also applied to the Al-air battery. The calcium alginate hydrogel-based electrolyte can greatly inhibit the self-corrosion of aluminum, resulting in the specific capacity of Al-air battery being significantly increased. At the current density of 1 mA cm−2, the CuO air cathode shows better performance, the maximum discharge voltage is 1.37 V and 1.23 V under illumination in aqueous sodium hydroxide solution and hydrogel, respectively, while the maximum discharge is 0.9 V and 0.78 V in the darkness. And the specific capacity in the hydrogel is about 20 times that of the aqueous sodium hydroxide solution. In addition, the semiconductor energy band structure and the discharge mechanism of the photo-assisted Al-air battery under illumination are also studied. This study provides a prospect for the conversion and application of solar energy in the photo-assisted Al-air battery.

Inhibition of Hydrogen Evolution by a Bifunctional Membrane between Anode and Electrolyte of Aluminum-Air Battery.

The hydrogen evolution reaction of the anode is a severe barrier that limits the further commercial application of Al–air batteries. Therefore, this study introduces a bifunctional membrane for the inhibition of hydrogen evolution in Al–air batteries. The reference to Al2O3@PAN as “bifunctional” means that it has both hydrophobic and anti-corrosion functions. Al2O3 can effectively inhibit the migration of hydroxide ions, and PAN is an excellent hydrophobic material. The bifunctional membrane is placed between the aluminum anode and the electrolyte, which can prevent the invasion of excess water and hydroxide ions, thereby inhibiting the hydrogen evolution corrosion of the anode. Electrochemical tests have confirmed that the corrosion inhibition rate of a bifunctional membrane containing 1.82 wt. % Al2O3@PAN is as high as 89.24%. The specific capacity of Al–air batteries containing this membrane can reach 1950 mAh/g, and the utilization rate of the aluminum anode has reached 61.2%, which is helpful in reducing the waste of aluminum resources. The results prove that the bifunctional membrane has excellent anti-corrosion properties. Bifunctional membranes can also be used to prevent the corrosion of metals in other fields.

Improving energy efficiency of commercial aluminum alloy as anodes for Al-air battery through introducing micro-nanoscale AlSb precipitates

The micro-nanoscale AlSb precipitates are introduced into selected commercial aluminum alloys as anode material for alkaline Al–air battery, and their corrosion behaviors, microstructure and discharge properties are investigated in details. It is found that such Sb addition can coexist in harmonization with already added other alloying elements in the Al alloys, and further bring out the improved microstructure and the electrochemical performance as the Al anodes. The energy density of 1080 alloy with Sb (1544 Wh•kg−1) is 30.9% higher than that without Sb at 10 mA•cm−2. The resulting electrochemical impedance spectroscopy (EIS) with Sb addition demonstrates that the diffusion resistance (RC) and inductance (L) reduce with decreasing thickness of passive film on the anode surface while increasing its discharge voltage. The improved refinement in microstructure can also restrain hydrogen evolution from the Al-based anode. The fundamental information obtained is useful for designing and fabricating the Al anode products from low-cost commercial alloys with added-on electrochemical performance.

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

Aqueous aluminum-air batteries have attracted tremendous interest because of their inherent safety and low cost. However, their lifespan is limited by the severe self-corrosion at aluminum anode. Herein, a design strategy is presented to suppress the corrosion by modifying the aluminum/electrolyte interface. Adding hybrid additives (ellagic acid and sodium stannate) can significantly reduce the corrosion rate of aluminum anode (0.7667 mg cm−2 min−1 in the blank electrolyte and 0.3662 mg cm−2 min−1 in the electrolyte with hybrid additives). The aluminum-air full battery can achieve a higher discharge specific capacity of 2439 mAh g−1. Spectral characterization and theoretical calculation confirm that the corrosion inhibition is attributed to a composite protective film formed on the aluminum surface. This strategy has proven to be general in preventing metal corrosion.

High-performance solid-state metal-air batteries with an innovative dual-gel electrolyte

An innovative dual-gel electrolyte design is proposed in this work for solid-state metal-air batteries, which utilizes the acid-alkaline dual-gel for the Al-air and Zn-air batteries, and the acid-salt dual-gel for the Mg-air battery. During battery storage, a plastic thin-film can be used for dual-gel separation, which can be removed before battery usage. And during battery working, benefited from the higher ionic diffusion resistance of gel electrolytes, the mixing of different electrolytes is significantly reduced without using complex flowing system or expensive bipolar membrane separator, ensuring a pseudo-stable battery system. The acid-alkaline dual-gel Al-air and Zn-air batteries can provide ∼0.5 V higher voltage output than the corresponding alkaline single-gel batteries, and the discharge lifetime is not compromised too much due to the effective suppression of acid-alkaline neutralization. As for the acid-salt dual-gel Mg-air battery, attributed to the Mg(OH)2 dissolution by crossovered acid, both a 0.65 V higher discharge voltage and a 5.5 times longer discharge lifetime are achieved compared with the salt single-gel battery. By simulating the variation of ion concentration inside gels during battery discharge, it is found that the effective ion diffusivity in gel plays a vital role in the battery stability. In general, a moderate value is favored to avoid both the ion shortage at the electrode-electrolyte interface and the vigorous neutralization at the gel-gel contact surface. Furthermore, a flexible version of the dual-gel metal-air battery is demonstrated by using paper-based gel electrolytes.