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When chloroaluminate ( A l C l 4 − ) serves as the electrolyte, aluminum nitride (AlN) has shown promise as a cathode material in aluminum ion batteries. However, there is currently a lack of research on the mechanisms of charge transfer and cluster intercalation between AlCl4 and AlN cathode materials. Herein, first-principles calculations are employed to investigate the intercalation mechanism of AlCl4 within the AlN cathode. By calculating the formation energies of stage-1–5 AlN–AlCl4 intercalation compounds with the insertion of individual AlCl4 cluster, we found that the structure of the stage-4 intercalation compounds exhibits the highest stability, suggesting that when the clusters begin to intercalate, it is important to start with the formation of the stage-4 intercalation compounds. In the subsequent phases of the charging process (stages 1 and 2), the stabilized structure with four inserted clusters demonstrates two characteristics: the coexistence of standing and lying clusters and the insertion of two standing clusters in an upside-down doubly stacked configuration, which further improve the spatial utilization while maintaining the structural stability. In addition, we infer that a phenomenon of coexisting intercalation compounds with mixed stages will occur in the course of the charging and discharging processes. More importantly, the diffusion barrier of AlCl4 in AlN–AlCl4 intercalation compounds decreases with the reduction of stage number, ensuring the rate performance of batteries. Therefore, we expect that our work will contribute to comprehend the intercalation mechanism of AlCl4 into the AlN cathode materials of aluminum ion batteries, providing guidance for related experimental work. [ABSTRACT FROM AUTHOR]

The aluminum ion battery (AIB) is a promising technology, but there is a lack of understanding of the desired nature of the batteries' electrolytes. The ionic charge carriers in these batteries are not simply Al3+ ions but the anionic AlCl4− and Al2Cl7−, which form in the electrolyte. Using computational analysis, this study illustrates the effect of mole ratios and organic solvents to improve the AIB electrolytes. To this end, molecular dynamics simulations were conducted on varying ratios forming acidic, neutral, and basic mixtures of the AlCl3 salt with 1-ethyl-3-methylimidazolium chloride (EMImCl) ionic liquid (IL) and an organic solvent electrolyte [dichloromethane (DCM) or toluene]. The data obtained from diffusion calculations indicates that the solvents could improve the transport properties. Both DCM and toluene lead to higher diffusion coefficients, and higher conductivity. Detailed calculations demonstrated solvents can effectively improve the formation of AlCl3⋯Cl (AlCl4−) and AlCl4−···AlCl4− (Al2Cl7−) especially in acidic mixtures. The densities, around 1.25 g/cm3 for electrolyte mixtures of AlCl3-EMImCl, were consistent with experiment. These results, in agreement with experimental findings, strongly suggest that DCM in acidic media with AlCl3 and EMImCl might provide a promising basis for battery development. [ABSTRACT FROM AUTHOR]

High‐performance rechargeable aluminum‐sulfur batteries (RASB) have great potential for various applications owing to their high theoretical capacity, abundant sulfur resources, and good safety. Nevertheless, the practical application of RASB still faces several challenges, including the polysulfide shuttle phenomenon and low sulfur utilization efficiency. Here, we first developed a synergistic copper heterogeneous metal oxide MoO2 derived from polymolybdate‐based metal‐organic framework as an efficient catalyst for mitigating polysulfide diffusion. This composite enhances sulfur utilization and electrical conductivity of the cathode. DFT calculations and experimental results reveal the catalyst Cu/MoO2@C not only effectively anchors aluminum polysulfides (AlPSs) to mitigate the shuttle effect, but also significantly promotes the catalytic conversion of AlPSs on the sulfur cathode side during charging and discharging. The unique nanostructure contains abundant electrocatalytic active sites of oxide nanoparticles and Cu clusters, resulting in excellent electrochemical performance. Consequently, the established RASB exhibits an initial capacity of 875 mAh g−1 at 500 mA g−1 and maintains a capacity of 967 mAh g−1 even at a high temperature of 50 °C. [ABSTRACT FROM AUTHOR]

Aluminum‐ion batteries (AIBs) are promising electrochemical energy storage sources because of their high theoretical specific capacity, light weight, zero pollution, safety, inexpensiveness, and abundant resources. These theoretical advantages have recently made AIBs a research hotspot. However, electrolyte‐related issues significantly limit their commercialization. The electrolyte choices for AIBs are significantly limited, and most of the available options do not facilitate the Al3+/Al three‐electron transfer reaction. Thus, this review presents an overview of recent advances in electrolytes and modification strategies for AIBs to clarify the limitations of existing AIB electrolytes and offer guidance for improving their performance. Furthermore, herein, the advantages, limitations and possible solutions for each electrolyte are discussed, after which the future of AIB electrolytes is envisioned. [ABSTRACT FROM AUTHOR]

Gel lead‐acid batteries have the advantages of no acid leakage, no maintenance, and a long cycle life. In this article, it was found that Al3+ in the gel electrolyte can shorten the gel time and improve the stability of the gel. The battery test results show that the HRPSoC cycle life of the gel battery can be significantly improved by adding Al3+. In comparison to blank gel batteries without Al3+, HRPSoC cycle life is 8.2 times higher. Additionally, the gel battery with added Al3+ has a 0.5C discharge capacity of 1.8 Ah, which is 2.5 times that of the blank gel battery. The added Al3+ also demonstrates good capacity stability and still retains a capacity of 1.7 Ah after 150 discharge cycles. The kinetic simulation shows that Al3+ may participate in the formation of a silicon gel system and tend to gather around Si atoms to affect the properties of the gel electrolyte. [ABSTRACT FROM AUTHOR]

Cycling aging is the one of the main reasons affecting the lifetime of lithium‐ion batteries and the contribution of aluminum current collector corrosion to the ageing is not fully recognized. In general, aluminum is corrosion resistant to electrolyte since a non‐permeable surface film of alumina is naturally formed. However, corrosion of aluminum current collector can still occur under certain conditions such as lithium bis(fluorosulfonyl)imide (LiFSI)‐based electrolyte or high voltage. Herein, we investigates the corrosion of aluminum current collector in the electrolyte of 1.2 M LiFSI in ethylene carbonate (EC) and ethyl methyl carbonate (EMC) mixed solvents. The electrochemical results shows that the corrosion current of aluminum is enhanced by cycling time and potential, which is correlated with the surface species and morphology. The formation of AlF3, which is induced by deep penetration of F− anions through surface passivation film, leads to internal volume change and the surface crack in the end. Our work will be inspiring for future development of high‐energy‐density and high‐power‐density lithium‐ion batteries in which the LiFSI salt will be intensively used. [ABSTRACT FROM AUTHOR]

Nonaqueous organic aluminum batteries are considered as promising high‐safety energy storage devices due to stable ionic liquid electrolytes and Al metals. However, the stability and capacity of organic positive electrodes are limited by their inherent high solubility and low active organic molecules. To address such issues, here porphyrin compounds with rigid molecular structures present stable and reversible capability in electrochemically storing AlCl2+. Comparison between the porphyrin molecules with electron‐donating groups (TPP‐EDG) and with electron‐withdrawing groups (TPP‐EWG) suggests that EDG is responsible for increasing both highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, resulting in decreased redox potentials. On the other hand, EWG is associated with decreasing both HOMO and LUMO energy levels, leading to promoted redox potentials. EDG and EWG play critical roles in regulating electron density of porphyrin π bond and electrochemical energy storage kinetics behavior. The competitive mechanism between electrochemical redox reaction and de/adsorption processes suggests that TPP‐OCH3 delivers the highest specific capacity ~171.8 mAh g−1, approaching a record in the organic Al batteries. [ABSTRACT FROM AUTHOR]

Conventionally, rocking-chair batteries capacity primarily depends on cation shuttling. However, intrinsically high-charge-density metal-ions, such as Al3+, inevitably cause strong Coulombic ion-lattice interactions, resulting in low practical energy density and inferior long-term stability towards rechargeable aluminium batteries (RABs). Herein, we introduce tunable quantum confinement effects and tailor a family of anion/cation co-(de)intercalation superlattice cathodes, achieving high-voltage anion charge compensation, with extra-capacity, in RABs. The optimized superlattice cathode with adjustable van der Waals not only enables facile traditional cation (de)intercalation, but also activates O2– compensation with an extra anion reaction. Furthermore, the constructed cathode delivers high energy-density (466 Wh kg–1 at 107 W kg−1) and one of the best cycle stability (225 mAh g–1 over 3000 cycles at 2.0 A g–1) in RABs. Overall, the anion-involving redox mechanism overcomes the bottlenecks of conventional electrodes, thereby heralding a promising advance in energy-storage-systems. Here, the authors propose a superlattice cathode with co-(de)intercalation chemistry in a rechargeable aluminum ion battery. The proposed cathode exceeds the theoretical capacity for conventional oxide electrodes with single cation shuttling. [ABSTRACT FROM AUTHOR]

In the quest for sustainable energy storage technologies, lithium‐based batteries, despite their prominence, face limitations such as high costs, safety risks, and supply chain issues. This has propelled the exploration of alternative materials, with aqueous aluminum‐ion batteries (AAIBs) emerging as a promising candidate due to their high energy density, abundance, and cost‐effectiveness. However, the low equilibrium reduction potential of aluminum ions presents significant challenges, including hydrogen evolution and poor cyclability. Addressing these, the study pioneers the application of single‐atom catalysts (SACs) in AAIBs, leveraging their high atom utilization and stability to enhance aluminum deposition and suppress hydrogen evolution. Sn, In, Cu, and Ni SACs are evaluated through density functional theory analysis and experimental validation, with Sn SAC identified as the most effective. Subsequently, the Sn SAC based anode demonstrates enhanced performance, achieving stable cycling over 500 h at 0.5 mA cm−2, significantly improved capacity retention (60 mAh g−1@300 cycles), and rate performance (50 mAh g−1@1 A g−1) in full cell tests. This work underscores the potential of SACs in advancing AAIB technology and opens new pathways for energy storage solutions. [ABSTRACT FROM AUTHOR]

Among emerging rechargeable batteries, rechargeable aluminum‐ion batteries (AIBs) stand out for their high specific capacities and the abundance of aluminum, positioning them as an attractive electrochemical energy storage option. Despite the superior electrochemical performance of non‐aqueous AIBs, aqueous aluminum‐ion batteries (AAIBs) have garnered extensive research interest for their low cost and enhanced safety. Yet, realizing high energy density in AAIBs poses significant challenges. This article systematically reviews strategies and recent advancements in cathodes, anodes, and electrolytes aimed at achieving high energy density in AAIBs. It concludes with a forward‐looking perspective on the design of AAIBs with high energy density and prolonged cycle life, highlighting promising directions for future researches. [ABSTRACT FROM AUTHOR]

We report a facile synthesis of the metal–organic framework, MOF-199 (Cu-BTC) using a low-cost solution-processed method forming homogeneous crystals. The structural and electrochemical properties are determined by the implementation of applicable experimental techniques. The structure is determined by X-ray diffraction pattern simulation, and the X-ray diffraction pattern affirms the tetragonal MOF-199. Estimated parameters of the MOf-199 designate potential application in aluminum-ion batteries. Furthermore, ohmic and charge transfer resistances are evaluated for the aqueous Zn-Al/MOF-199 battery corresponding to charge carrier transfer rates by the use of electrochemical impedance spectroscopy (EIS). Trivalent Al3+ locally deposits on the Zinc anode during charging. The battery shows a high open-circuit voltage of 1.25 V, and the maximum specific capacity observed by galvanostatic charge–discharge is ~ 146 mAh/g at 55.5 mAh/g current density. Al/MOF-199 exhibited only around 4.5% degradation of the capacity for 100 cycles carried out at the current density of 55.5 mAh/g. The superior performance, scalable synthesis, and cost-effective approach to cell fabrication promote feasible applications. [ABSTRACT FROM AUTHOR]

Rechargeable aluminum ion batteries (AIBs) have recently gained widespread research concern as energy storage technologies because of their advantages of being safe, economical, environmentally friendly, sustainable, and displaying high performance. Nevertheless, the intense Coulombic interactions between the Al3+ ions with high charge density and the lattice of the electrode body lead to poor cathode kinetics and limited cycle life in AIBs. This paper reviews the recent advances in the cathode design of AIBs to gain a comprehensive understanding of the opportunities and challenges presented by current AIBs. In addition, the advantages, limitations, and possible solutions of each cathode material are discussed. Finally, the future development prospect of the cathode materials is presented. [ABSTRACT FROM AUTHOR]

Aluminum batteries have become the most attractive next-generation energy storage battery due to their advantages of high safety, high abundance, and low cost. However, the dendrite problem associated with inhomogeneous electrodeposition during cycling leads to low Coulombic efficiency and rapid short-circuit failure of the aluminum metal anode, which severely hampers the cycling stability of aluminum battery. Here we show an aluminum anode material that achieves high lattice matching between the substrate and the deposit, allowing the aluminum deposits to maintain preferred crystal plane growth on the substrate surface. It not only reduces the nucleation barrier of aluminum and decreases electrode polarization, but also enables uniform deposition of aluminum, improving the cycling stability of aluminum batteries. Aluminum anode with (111) preferred crystal plane can stably 25000 cycles at the current density of 5 A·g−1, with a capacity retention rate of over 80%. An aluminum anode is proposed to achieve high lattice matching between the aluminum anode and the aluminum deposit, allowing the aluminum deposits to maintain preferred crystal face growth on the aluminum anode surface. [ABSTRACT FROM AUTHOR]

Rechargeable aluminum batteries (RABs) are a promising candidate for large‐scale energy storage, attributing to the abundant reserves, low cost, intrinsic safety, and high theoretical capacity of Al. However, the cathode materials reported thus far still face challenges such as limited capacity, sluggish kinetics, and undesirable cycle life. Herein, we propose an organic cathode benzo[i] benzo[6,7] quinoxalino [2,3‐a] benzo [6,7] quinoxalino [2,3‐c] phenazine‐5,8,13,16,21,24‐hexaone (BQQPH) for RABs. The six C=O and six C=N redox active sites in each molecule enable BQQPH to deliver a record ultra‐high capacity of 413 mAh g−1 at 0.2 A g−1. Encouragingly, the intermolecular hydrogen bonding network and π–π stacking interactions endow BQQPH with robust structural stability and minimal solubility, enabling an ultra‐long lifetime of 100,000 cycles. Moreover, the electron‐withdrawing carbonyl group induces a reduction in the energy level of the lowest unoccupied molecular orbital and expands the π‐conjugated system, which considerably enhances both the discharge voltage and redox kinetics of BQQPH. In situ and ex situ characterizations combined with theoretical calculations unveil that the charge storage mechanism is reversible coordination/dissociation of AlCl2+ with the N and O sites in BQQPH accompanied by 12‐electron transfer. This work provides valuable insights into the design of high‐performance organic cathode materials for RABs. [ABSTRACT FROM AUTHOR]

The high energy density and cost‐effectiveness of chloride‐ion batteries (CIBs) make them promising alternatives to lithium‐ion batteries. However, the development of CIBs is greatly restricted by the lack of compatible electrolytes to support cost‐effective anodes. Herein, we present a rationally designed solid polycationic electrolyte (SPE) to enable room‐temperature chloride‐ion batteries utilizing aluminum (Al) metal as an anode. This SPE endows the CIB configuration with improved air stability and safety (i.e. free of flammability and liquid leakage). A high ionic conductivity (1.3×10−2 S cm−1 at 25 °C) has been achieved by the well‐tailored coordination structure of the SPE. Meanwhile, the solid polycationic electrolyte ensures stable electrodes|electrolyte interfaces, which effectively inhibit the growth of dendrites on the Al anodes and degradation of the FeOCl cathodes. The Al|SPE|FeOCl chloride‐ion batteries showcased a high discharge capacity around 250 mAh g−1 (based on the cathodes) and extended lifespan. Our electrolyte design opens a new avenue for developing low‐cost chloride‐ion batteries. [ABSTRACT FROM AUTHOR]

The main drawback of seawater batteries that use the aluminum (Al)–air system is their susceptibility to anode self-corrosion during the oxygen evolution reaction, which, in turn, affects their discharge performance. This study consist of an electrochemical investigation of pure Al, 6061 Al alloy, and both types coated with zinc as an anode in a 3.5% sodium chloride (NaCl) electrolyte. The electrolyte solution used for the deposition of zinc metal contained citrate, with and without EDTA as a complexing agent. Subsequently, the performance of the anode was tested in a seawater battery, using a carbon@MnO2 cathode and a 3.5% NaCl electrolyte. The performance of Al–air batteries has been significantly enhanced by applying a process of electrodepositing zinc (Zn) with a citrate deposition electrolyte solution in both pure aluminum and alloy 6061. The performance of the battery was further enhanced by adding EDTA as a chelating agent to the citrate-based electrolyte solution. The Al–air battery with aluminum alloy 6061 with Zn electrodeposition with an additional EDTA as the anode, carbon@MnO2 as the cathode, and NaCl 3.5% solution as the electrolyte has the highest battery performance, with a specific discharge capacity reaching 414.561 mAh. g − 1 and a specific energy density reaching 0.255 mWh. g − 1 , with stable voltage at 0.55 V for 207 h. [ABSTRACT FROM AUTHOR]

In aqueous aluminum‐ion batteries (AAIBs), the insertion/extraction chemistry of Al3+ often leads to poor kinetics, whereas the rapid diffusion kinetics of hydronium ions (H3O+) may offer the solution. However, the presence of considerable Al3+ in the electrolyte hinders the insertion reaction of H3O+. Herein, we report how oxygen‐deficient α‐MoO3 nanosheets unlock selective H3O+ insertion in a mild aluminum‐ion electrolyte. The abundant oxygen defects impede the insertion of Al3+ due to excessively strong adsorption, while allowing H3O+ to be inserted/diffused through the Grotthuss proton conduction mechanism. This research advances our understanding of the mechanism behind selective H3O+ insertion in mild electrolytes. [ABSTRACT FROM AUTHOR]

Aluminum batteries employing organic electrode materials present an appealing avenue for sustainable and large‐scale energy storage. Nevertheless, conventional organic materials encounter limitations due to their restricted active sites, known instability, and sluggish redox kinetics. In this study, a redox‐active covalent organic framework supported by CNT is reported, enriched with substantial C═O groups, as an advanced cathode material for Al‐organic batteries. Theoretical simulation and ex situ analysis unveil the pivotal roles of C═O groups in effectively storing AlCl2+. As a result, Al batteries with the organic cathode exhibit a specific capacity of 290 mAh g−1 at 0.2 A g−1 and outstanding rate performance. Furthermore, it retains a reversible capacity of 170 mAh g−1 even after 32 000 cycles at 10 A g−1 and attains an energy density of 389 Wh kg−1. The remarkable performance stems not only from the abundant C═O and C─N groups enabling the storage of multiple AlCl2+ by the favorable pseudocapacitive process, but also from the synergistic interplay between the robust COF network and the conductive CNT channels that significantly enhances structural stability and accelerates ion/electron diffusion. This work stands to inspire further research in the pursuit of stable organic cathodes, fostering designs with plentiful accessible redox‐active sites to boost energy storage capabilities. [ABSTRACT FROM AUTHOR]

Aqueous aluminum metal batteries (AMBs) have attracted numerous attention because of the abundant reserves, low cost, high theoretical capacity, and high safety. Nevertheless, the poor thermodynamics stability of metallic Al anode in aqueous solution, which is caused by the self‐corrosion, surface passivation, or hydrogen evolution reaction, dramatically limits the electrochemical performance and hampers the further development of AMBs. In this comprehensive review, the key scientific challenges of Al anode/electrolyte interface (AEI) are highlighted. A systematic overview is also provided about the recent progress on the rational interface engineering principles toward a relatively stable AEI. Finally, suggestions and perspectives for future research are offered on the optimization of Al anode and aqueous electrolytes to enable a stable and durable AEI, which may pave the way for developing high‐performance AMBs. [ABSTRACT FROM AUTHOR]

Rechargeable aluminum battery (RAB) is expected to be a promising energy storage technique for grid‐scale energy storage. However, the development of RABs is seriously plagued by the lack of suitable cathode materials. Herein, we report two p‐type conjugated polymers of L‐PBPz and C‐PBPz with the same building blocks of diphenylphenazine but different linkage patterns of linear and crosslinked structures as the cathode materials for Al dual‐ion batteries. Compared to the linear polymer skeleton in L‐PBPz, the crosslinked structure endows C‐PBPz with amorphous nature and low dihedral angles of the polymer chains, which severally contribute to the fast diffusion of AlCl4− with large size and the electron transfer during the redox reaction of diphenylphenazine. As a result, C‐PBPz delivers a much better rate performance than L‐PBPz. The crosslinked structure also leads to a stable cyclability with over 80000 cycles for C‐PBPz. Benefiting from the fast kinetics, meanwhile, the C‐PBPz cathode could realize a high redox activity of 117 mAh g−1, corresponding to an areal capacity of 2.30 mAh cm−2, even under a high mass loading of 19.7 mg cm−2 and a low content of 10 wt% conductive agent. These results might boost the development of polymer cathodes for RABs. [ABSTRACT FROM AUTHOR]

Aqueous aluminum ion batteries (AAIBs) have drawn considerable attention due to their intrinsic safety, cost‐effectiveness, eco‐friendliness, and high theoretical capacity of aluminum. Currently, suitable anode materials are crucial for the development of high‐performance AAIBs. For the first time, a hydrophilic (ZnCr2O4) and hydrophobic (PVDF) layer modified zinc anode paired with an aluminum‐based aqueous electrolyte to construct a high‐performance aluminum–zinc hybrid ion battery. The Hydrophilic ZnCr2O4 layer of anode endows the battery with low polarization by boosting the pre‐desolvation and deposition kinetics of aluminum/zinc ions. Meanwhile, the hydrophobic PVDF layer suppresses water‐induced corrosion of the anode. The synergistic effect of the hydrophilic and hydrophobic layers of the anode stimulates the battery to exhibit unprecedented cycle life (> 6000 cycles) and considerable discharge capacity (280 mAh g−1), compared to the batteries proposed in previous works paired with aluminum alloy anodes and aluminum‐based aqueous electrolytes. This novel anode provides powerful backing for the development of long‐life and high‐capacity aqueous polyvalent ion batteries due to its low cost and simple fabrication process. [ABSTRACT FROM AUTHOR]

Rechargeable aluminium ion batteries (AIBs) are one of the potential metal battery alternatives to Li-ion batteries. A perfect pair of cathode and electrolyte is a key factor in developing a grid-scale Al ion battery. In this context, we evaluated a prototypical MWCNT and β-MnO2-20% composite (MWCNT/β-MnO2), in which β-MnO2 nanoparticles were grown on the surface of the MWCNT matrix by an ultra-sonication method followed by calcination at 400 °C and tested as a cathode system. The as-synthesized MWCNT/β-MnO2-20% cathode material was completely characterized by techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS) and thermo gravimetric analysis (TGA) to assess its composition and morphology. Its electrochemical performance was evaluated with the aid of various electroanalytical techniques, such as cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). MWCNT/β-MnO2-20% as a cathode system in AlCl3/Et3NHCl ionic liquid electrolyte showed a current density of 100 mA g−1 and a discharge capacity of 269 mA h g−1, and the resultant aluminium storage was around 60 cycles with a coulombic efficiency of 90%. Interestingly, this superior rate capability of the composite is due to the interdependent interaction between the β-MnO2 particles and MWCNTs as revealed by XPS, FT-IR, XRD and EDS techniques, which provided evidence for an intercalation and de-intercalation of the AlCl4− ions into the cathode material during charge–discharge. [ABSTRACT FROM AUTHOR]

Ancillary service provision and peak shaving (PS) play essential roles in the current day‐to‐day power system operation, which is challenged by the increasing renewable generation penetration. Providing these critical services using classical approaches such as peak load generators has been limited due to high operational costs and environmental impacts. The use of battery energy storage systems (BESS) is another popular method that is limited by high initial investment costs and high degradation rates. In this work, a novel approach to utilize industrial loads and BESS to provide multiple power system services in different stages is proposed. Industrial loads such as aluminium crushers are known for their intensive electricity consumption. Nevertheless, when applied in frequency regulation (FR), they perform poorly due to their discrete nature in operation. This drawback and the aforementioned BESS shortcomings are addressed by combining on‐site BESS with plant machinery to provide FR services and recover BESS related costs. Later, depending on the optimal capacity distribution, BESS usage is extended into the energy arbitrage market to provide PS services. This approach resulted in higher earnings for participating customers and network operators, as well as in less CO2${\rm {CO}}_{2}$ emissions, and minimal BESS degradations. An Australian case study of the South West Interconnected System, along with Worsley Alumina refinery data of Western Australia has been used to showcase the model performances. [ABSTRACT FROM AUTHOR]

As multivalent ion batteries, aluminum ion batteries (AIBs) have broad application prospects. In addition, with the further development of new electrolytes, deep eutectic electrolytes are expected to become a green, inexpensive, safe, and ideal electrolytic liquid system to replace traditional ionic liquid electrolytic systems commonly used in AIBs. Herein, we prepared an AlCl3–acetamide (AcAm) electrolyte and systematically analyzed its ion transport capacity at different molar ratios of its components. Consequently, a compositional ratio of 1 : 1.4 of AcAm : AlCl3 provided the best ion transport capacity, exhibiting an exceptional electrochemical performance with high reversible capacity, excellent rate performance, and excellent cycling performance. The graphite material in the electrolytic liquid system showed a typical charge storage mechanism dominated by diffusion-controlled processes, indicating that the charge storage behavior of the graphite electrode in this type of electrolyte battery is dependent on ion intercalation. Additionally, the main structure of the graphite material showed little to no change during a long electrochemical test cycle, suggesting its high structural stability. This research shows that the amide electrolyte has great potential for electrochemical application and broad application prospect. [ABSTRACT FROM AUTHOR]

Nowadays, Al (dual) batteries are mainly based on graphite cathode materials. Besides this material, the limited life cycle and the rate performance of other possible cathode materials have hampered the development of practical and sustainable rechargeable aluminium batteries (RABs). Herein, we report an organic A4‐metal‐free porphyrin system bearing diphenylamimo‐phenyl functional units as an Al‐storage cathode material, which is capable of delivering a reversible capacity of 83 mAh g−1 at 1 A g−1 after 200 cycles and displays a good cycling stability. Achieving such high rate performance opens a pathway to developing practical sustainable cathodes for aluminium batteries. [ABSTRACT FROM AUTHOR]

Al metal possesses ultrahigh theoretical volumetric capacity of 8,040 mAh cm−3, and gravimetric capacity of 2,980 mAh g−1, and thus is highly attractive for electrochemical energy storage. However, it suffers from several issues, such as the dendrite formation, during Al stripping–deposition cycling, which has been verified to account for the short circuit and limited cyclic performance. Herein, we use a facile and applicable method to in-situ reconstruct the Al anode surface with F-Al-O chemical bonds, which could preferentially induce the planar growth of Al along the interface plane, thus leading to the dendrite-free morphology evolution during the cycling. Benefiting from F-Al-O chemical bonds on the surface of Al anodes, long lifespan of symmetric cells can be realized even under 1 mA cm−2 and 1 mAh cm−2. Coupling the F-Al anode with graphite-based cathodes, high-voltage dual-ion Al metal batteries can be achieved with long-term cycle stability up to 1,200 cycles (at 0.5 mA cm−2), surpassing the counterparts using pristine Al metal anode. Furthermore, the effectiveness of this surficial modification strategy is also elucidated with the aid of theoretical calculation. This work provides novel insights on low-cost and facile strategies against the Al dendrite growth in aluminum batteries. [ABSTRACT FROM AUTHOR]

The aggravation of energy problems and the scarcity of lithium resources have forced us to look for new energy storage systems. Aluminum ion batteries, as a promising energy storage system, have the advantages of environmental friendliness and abundant aluminum resources, and have the potential for application in large‐scale energy storage and personal portable electronic devices. To solve the stability problem of aluminum ion batteries during cycling for large‐scale energy storage needs, we report a polythiophene‐based conductive polymer, poly(3,4‐dimethylthiophene) (PDMT), as a high performance cathode material for aluminum ion batteries. By introducing two methyl groups on the thiophene ring, we successfully adjust the local charge density of the heterocyclic thiophene, thus changing the electron delocalization characteristics, and improving the electrochemical reaction activity of the polythiophene (PTH) material as a redox electrode material. This also maintains the symmetry and regularity of the polymer structure, giving the material better cycling stability. The discharge specific capacity reaches 110 mAh g−1 at a current density of 200 mA g−1, far exceeding conventional PTH cathodes (~70 mAh g−1), and the capacity retention rate is 92.7 % after 1000 cycles. It also shows excellent rate performance due to the flexible structure of the conductive polymer. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) are a class of metal alloys consisting of four or more molar equal or near-equal elements. HEA nanomaterials have garnered significant interest due to their wide range of applications, such as electrocatalysis, welding, and brazing. Their unique multi-principle high-entropy effect allows for the tailoring of the alloy composition to facilitate specific electrochemical reactions. This study focuses on the synthesis of high-purity HEA nanoparticles using the method of femtosecond laser ablation synthesis in liquid. The use of ultrashort energy pulses in femtosecond lasers enables uniform ablation of materials at significantly lower power levels compared to longer pulse or continuous pulse lasers. We investigate how various femtosecond laser parameters affect the morphology, phase, and other characteristics of the synthesized nanoparticles. An innovative aspect of our solution is its ability to rapidly generate multi-component nanoparticles with a high fidelity as the input multi-component target material at a significant yielding rate. Our research thus focuses on a novel synthesis of high-entropy alloying CuCoMn1.75NiFe0.25 nanoparticles. We explore the characterization and unique properties of the nanoparticles and consider their electrocatalytic applications, including high power density aluminum air batteries, as well as their efficacy in the oxygen reduction reaction (ORR). Additionally, we report a unique nanowire fabrication phenomenon achieved through nanojoining. The findings from this study shed light on the potential of femtosecond laser ablation synthesis in liquid (FLASiL) as a promising technique for producing high-purity HEA nanoparticles. [ABSTRACT FROM AUTHOR]

Amorphous Al2O3 film that naturally exists on any Al substrate is a critical bottleneck for the cyclic performance of metallic Al in rechargeable Al batteries. The so‐called electron/ion insulator Al oxide slows down the anode's activation and hinders Al plating/stripping. The Al2O3 film induces different surface properties (roughness and microstructure) on the metal. Al foils present two optically different sides (shiny and non‐shiny), but their surface properties and influence on plating and stripping have not been studied so far. Compared to the shiny side, the non‐shiny one has a higher (~28 %) surface roughness, and its greater concentration of active sites (for Al plating and stripping) yields higher current densities. Immersion pretreatments in Ionic‐Liquid/AlCl3‐based electrolyte with various durations modify the surface properties of each side, forming an electrode‐electrolyte interphase layer rich in Al, Cl, and N. The created interphase layer provides more tunneling paths for better Al diffusion upon plating and stripping. After 500 cycles, dendritic Al deposition, generated active sites, and the continuous removal of the Al metal and oxide cause accelerated local corrosion and electrode pulverization. We highlight the mechanical surface properties of cycled Al foil, considering the role of immersion pretreatment and the differences between the two sides. [ABSTRACT FROM AUTHOR]

Chloroaluminate ionic liquids are commonly used electrolytes in rechargeable aluminum batteries due to their ability to reversibly electrodeposit aluminum at room temperature. Progress in aluminum batteries is currently hindered by the limited electrochemical stability, corrosivity, and moisture sensitivity of these ionic liquids. Here, a solid polymer electrolyte based on 1‐ethyl‐3‐methylimidazolium chloride‐aluminum chloride, polyethylene oxide, and fumed silica is developed, exhibiting increased electrochemical stability over the ionic liquid while maintaining a high ionic conductivity of ≈13 mS cm−1. In aluminum–graphite cells, the solid polymer electrolytes enable charging to 2.8 V, achieving a maximum specific capacity of 194 mA h g−1 at 66 mA g−1. Long‐term cycling at 2.7 V showed a reversible capacity of 123 mA h g−1 at 360 mA g−1 and 98.4% coulombic efficiency after 1000 cycles. Solid‐state nuclear magnetic resonance spectroscopy measurements reveal the formation of five‐coordinate aluminum species that crosslink the polymer network to enable a high ionic liquid loading in the solid electrolyte. This study provides new insights into the molecular‐level design and understanding of polymer electrolytes for high‐capacity aluminum batteries with extended potential limits. [ABSTRACT FROM AUTHOR]

In recent years, silicon–air batteries have been recognized as a new type of air battery. However, it has been observed that an air battery with a pure silicon anode tends to passivate during discharge, leading to a decreased discharge potential and unstable discharging. In our study, aluminum was doped at different levels into silicon to improve the electrochemical activity of the electrode materials. The change in the constant current discharge, corrosion, and passivation of the full cell after aluminum doping were studied in a 5 mol KOH solution as an electrolyte. It was demonstrated that aluminum-doped silicon–air batteries exhibited a marked enhancement in their electrochemical activity, electrochemical impedance, and discharge performance. One of the cells with Si-1.5 wt% Al as the composite anode exhibited higher, smoother discharge potentials and lower corrosion rates. [ABSTRACT FROM AUTHOR]

The temperature of a lithium-ion battery is a crucial parameter for understanding the internal processes during various operating and failure scenarios, including thermal runaway. However, the internal temperature is comparatively higher than the surface temperature. This particularly affects cells with a large cross-section, which is due to heat development within the cell and lower heat dissipation due to a poorer ratio of volume to surface area. This paper presents an approach that enables real-time monitoring of the behavior of a commercial prismatic high-energy battery cell (NMC811/C, 95 Ah, Contemporary Amperex Technology Co., Limited (Ningde, China)) in the event of thermal runaway induced by overcharging. The internal cell temperature is investigated by the subsequent integration of two hard sensors between the two jelly rolls and additional sensors on the surface of the aluminum housing of the battery cell. The sensor's signals show a significant increase in the temperature gradient between the temperature in the core of the cell and the cell casing surface until the onset of venting and thermal runaway of the battery. The data enable a detailed investigation of the behavior of the battery cell and the comparatively earlier detection of the point of no return in the event of thermal runaway. [ABSTRACT FROM AUTHOR]

Aluminum metal batteries are considered to be promising secondary batteries due to their high theoretical specific capacity. However, metallic aluminum suffers from corrosion, pulverization, and crushing problems in nonaqueous electrolytes. Constructing a solid‐electrolyte interphase layer on the anode electrode has been confirmed to be the key to improving the cycling performance of rechargeable batteries. Herein, we demonstrate an Al metal anode with a physical protective layer achieved by a simple blade coating method. This modified Al metal anode demonstrates ultra‐low voltage hysteresis (~25 mV at 0.1 mA cm−2 and ~30 mV at 1 mA cm−2), and superior stability (630 h at 0.1 mA cm−2 and 580 h at 1 mA cm−2). When coupling this anode with flake graphite cathode, the assembled full cells exhibit superior cycling stability (92 mAh g−1 maintained after 740 cycles at 0.1 A g−1). The current work presents a promising approach to stabilize Al metal anodes for next‐generation rechargeable aluminum batteries. [ABSTRACT FROM AUTHOR]

Aluminum air batteries (AABs) are a desirable option for portable electronic devices and electric vehicles (EVs) due to their high theoretical energy density (8100 Wh K−1), low cost, and high safety compared to state‐of‐the‐art lithium‐ion batteries (LIBs). However, numerous unresolved technological and scientific issues are preventing AABs from expanding further. One of the key issues is the catalytic reaction kinetics of the air cathode as the fuel (oxygen) for AAB is reduced there. Additionally, the performance and price of an AAB are directly influenced by an air electrode integrated with an oxygen electrocatalyst, which is thought to be the most crucial element. In this study, we covered the oxygen chemistry of the air cathode as well as a brief discussion of the mechanistic insights of active catalysts and how they catalyze and enhance oxygen chemistry reactions. There is also extensive discussion of research into electrocatalytic materials that outperform Pt/C such as nonprecious metal catalysts, metal oxide, perovskites, metal‐organic framework, carbonaceous materials, and their composites. Finally, we provide an overview of the present state, and possible future direction for air cathodes in AABs. [ABSTRACT FROM AUTHOR]

Due to their high power density and availability, aluminum batteries consisting of graphite positive electrode and ionic liquid electrolytes are promising candidates for post‐lithium‐ion batteries. However, the effect of the various electrode design parameters on their electrochemical performance is not well understood. Herein, a high‐fidelity physics‐based model validated with experimental data obtained from a Swagelok cell consisting of an aluminum metal negative electrode, imidazolium ionic liquid electrolyte, and graphite positive electrode is used to study the effects of various electrode design parameters on the discharge capacity. The model is used to optimize the design of the electrodes by generating several Ragone plots, estimating the optimum current density for a given cell design, and explaining the limitations of the cells based on the transport of the electroactive species. An optimum graphite thickness of 50 μm is obtained for all the discharge times considered in this study. Determining the ideal electrode configuration for Al‐graphite batteries using different ionic liquid electrolytes and considering various discharge durations could provide a reference point for evaluating the suitability of a specific ionic liquid electrolyte in a particular use case. [ABSTRACT FROM AUTHOR]

Owing to their high volumetric capacity, low cost and high safety, rechargeable aluminum batteries have become promising candidates for energy applications. However, the high charge density of Al3+ leads to strong coulombic interactions between anions and the cathode, resulting in sluggish diffusion kinetics and irreversible collapse of the cathode structure. Furthermore, AlCl3-based ionic liquids, which are commonly used as electrolytes in such batteries, corrode battery components and are prone to side reactions. The above problems lead to low capacity and poor cycling stability. Herein, we propose a reduced graphene oxide (rGO) cathode with a three-dimensional porous structure prepared using a simple and scalable method. The lamellar edges and oxygen-containing group defects of rGO synergistically provide abundant ion storage sites and enhance ion transfer kinetics. We matched the prepared rGO cathode with noncorrosive electrolyte 0.5 mol·L−1 Al(OTF)3/[BMIM]OTF and Al metal to construct a high-performance battery, Al||rGO-150, with good cycling stability for 2700 cycles. Quasi-in-situ physicochemical characterization results show that the ion storage mechanism is codominated by diffusion and capacitance. The capacity consists of the insertion of Al-based species cations as well as synergistic adsorption of Al(OTF)x(3−x)+ (x < 3) and [BMIM]+. The present study promotes the fundamental and applied research on rechargeable aluminum batteries.

Rechargeable aluminum batteries (RABs) are attractive cadidates for next-generation energy storage and conversion, due to the low cost and high safety of Al resources, and high capacity of metal Al based on the three-electrons reaction mechanism. However, the development of RABs is greatly limited, because of the lack of advanced cathode materials, and their complicated and unclear reaction mechanisms. Exploring the novel nanostructured transition metal and carbon composites is an effective route for obtaining ideal cathode materials. In this work, we synthesize porous CoSnO3/C nanocubes with oxygen vacancies for utilizing as cathodes in RABs for the first time. The intrinsic structure stability of the mixed metal cations and carbon coating can improve the cycling performance of cathodes by regulating the internal strains of the electrodes during volume expansion. The nanocubes with porous structures contribute to fast mass transportation which improves the rate capability. In addition to this, abundant oxygen vacancies promote the adsorption affinity of cathodes, which improves storage capacity. As a result, the CoSnO3/C cathodes display an excellent reversible capacity of 292.1 mAh g−1 at 0.1 A g−1, a good rate performance with 109 mAh g−1 that is maintained even at 1 A g−1 and the provided stable cycling behavior for 500 cycles. Besides, a mechanism of intercalation of Al3+ within CoSnO3/C cathode is proposed for the electrochemical process. Overall, this work provides a step toward the development of advanced cathode materials for RABs by engineering novel nanostructured mixed transition-metal oxides with carbon composite and proposes novel insights into chemistry for RABs.

Self‐discharge, which is associated with energy efficiency loss, is a critical issue that hinders practical applications of rechargeable aluminum batteries (RABs). The self‐discharge properties of two commonly‐used RAB positive electrode materials, namely natural graphite (NG) and expanded graphite (EG), are investigated in this work. EG, which has a wider spacing between graphitic layers and a larger surface area, has a higher self‐discharge rate than that of NG. After 12 h of rest, NG and EG electrodes retain 74% and 63% of their initial capacities, respectively, after charging up to 2.4 V at 0.3 A g−1. Operando X‐ray diffraction, X‐ray photoelectron spectroscopy, and energy‐dispersive X‐ray spectroscopy are employed to study the self‐discharge mechanism. The self‐discharge loss is related to the spontaneous deintercalation of AlCl4− anions from the graphite lattice charge‐compensated by Cl2 gas evolution at the same electrode and can be restored (i.e., no permanent damage is caused to the electrodes) in the next charge‐discharge cycle. It is found that the charging rate and depth of charge also affect the self‐discharge properties. In addition, the self‐discharge rates of NG in 1‐ethyl‐3‐methylimidazolium chloride–AlCl3 and urea–AlCl3 electrolytes are compared. [ABSTRACT FROM AUTHOR]

Rechargeable aluminum batteries with aluminum metal as a negative electrode have attracted wide attention due to the aluminum abundance, its high theoretical capacity and stability under ambient conditions. Understanding and ultimately screening the impact of the initial surface properties of aluminum negative electrodes on the performance and lifetime of the battery cell are of great significance. The purity, surface finishing and degree of hardness of aluminum metal may strongly impact the device's performance, but these properties have not been systematically studied so far. Here, we present an investigation of the underestimated but crucial role of the aluminum foil surface properties on its electrochemical behavior in aluminum battery half‐cells. The results show that commercial aluminum foils with the same purity and degree of hardness but with different thicknesses (from 0.025 to 0.1 mm) exhibit different microstructure and surface roughness, which in turn have an impact on the cyclability. Atomic force microscopy studies show that the aluminum foil is corroded after repeated electrochemical cycling, thus leading to cell failure. The sample with 0.075 mm thickness exhibits the best cycling stability. [ABSTRACT FROM AUTHOR]

Aluminum ion batteries (AIBs) are widely regarded as the most potential large‐scale metal ion battery because of its high safety and environment‐friendly characteristics. To solve the problem of weak electrical conductivity of organic materials, different structures of cyano organic molecules with electrophilic properties are selected as the cathode materials of aluminum batteries. Through experimental characterization and density functional theory theoretical calculation, Phthalonitrile is the best cathode material among the five organic molecules and proved that the C≡N group is the active site for insertion/extraction of AlCl2+ ions. The first cycle‐specific capacity of the assembled flexible package battery is as high as 191.92 mAh g−1, the discharge‐specific capacity is 112.67 mAh g−1 after 1000 cycles, and the coulombic efficiency is ≈97%. At the same time, the influences of different molecular structures and functional groups on the battery are also proved. These research results lay a foundation for selecting safe and stable organic aluminum batteries and provide a new reference for developing high‐performance AIBs. [ABSTRACT FROM AUTHOR]

Herein, a self‐charging mechanism of rechargeable aluminum (Al) batteries with Chevrel phase molybdenum sulfide (Mo6S8) cathode is reported. The results unambiguously reveal that the self‐charging is a spontaneous disproportionation of Al intercalated Mo6S8 originated from the dynamic shift of Al between occupied sites during Al intercalating and resting. The theoretical study indicates that the fully Al intercalated Mo6S8 in the format of Al4/3Mo6S8 is kinetically accessible driven by electrochemical overpotential but thermodynamically unstable due to the repulsion between Al3+ cations. This mechanism is a true self‐charging with no input of any form of energy, thus distinctly superior to the previously reported self‐charging mechanisms. Based on this discovery, a semi‐flow AlMo6S8 battery is designed and demonstrated with long‐lasting discharge capability and high capacity. [ABSTRACT FROM AUTHOR]

Solid‐state zinc ion batteries (ZIBs) and aluminum‐ion batteries (AIBs) are deemed as promising candidates for supplying power in wearable devices due to merits of low cost, high safety, and tunable flexibility. However, their wide‐scale practical application is limited by various challenges, down to the material level. This Review begins with elaboration of the root causes and their detrimental effect for four main limitations: electrode‐electrolyte interface contact, electrolyte ionic conductivity, mechanical strength, and electrochemical stability window of the electrolyte. Thereafter, various strategies to mitigate each of the described limitation are discussed along with future research direction perspectives. Finally, to estimate the viability of these technologies for wearable applications, economic‐performance metrics are compared against Li‐ion batteries. [ABSTRACT FROM AUTHOR]

Metallic aluminum is an attractive anode owing to its high specific capacity, earth abundance, and low cost. However, the poor reversibility of Al deposition/dissolution and Al dendrites have impeded its deployment. Herein, a strategy for constructing a lattice‐matching layer (LML) to regulate the behavior of Al deposition/dissolution is demonstrated. Various experiments and theoretical calculations validate that gold LML as an example can significantly enhance the nucleation density and reduce average particle size, which achieve highly reversible, dendrite‐free, durable, and anode‐free Al anodes. The metallic Al shows stable Al deposition/dissolution on Au@Ti substrate for more than 4500 h with an average Coulombic efficiency of 99.92%, which is a record‐high reported value. Furthermore, the anode‐free full cell based on Au@Ti anode and expanded graphite cathode exhibits outstanding long‐term stability for 900 cycles with the capacity retention rate of 80%. This study provides an effective strategy to enhance the reversibility and utilization of the Al anode, which provides inspiration for advanced Al batteries. [ABSTRACT FROM AUTHOR]

Recently, anion storage materials have gained significant attention owing to the widened cell voltage and additional anion storing capacity for a large energy density. MXenes are considered as the emerging anion storing materials owing to their sufficient interlayer spacing, rich surface chemistries, tunable structures, remarkable electrochemical properties, and mechanical integrity. Herein, a comprehensive review on the anion storage of MXenes covering their anion storage mechanism and state‐of‐the‐art chemical strategies for the improved anion storage performances is reported. The recent progress of MXenes on aluminum ion batteries, metal halogen batteries, halogen ion batteries, and electrochemical electrode deionization is addressed. The scientific and technical challenges and the research direction into the anion storage of MXenes are also addressed and finally the authors' perspective on anion storage of MXenes is provided. Therefore, this review offers an insight into the rational design of MXenes for anion storage materials and the correlation of surface chemistries and structural modifications with anion storage properties for the applications into electrochemical energy storage and water purification. [ABSTRACT FROM AUTHOR]

The development of high-performance two-dimensional anode materials is the key to the application of rechargeable ion batteries. Based on first-principles calculations, the interaction of Mg and Al ions with two-dimensional Nb2N was systematically studied in this work, including its geometric configuration, electronic structure, ion diffusion characteristics, open-circuit voltage, and theoretical capacity. Both Mg and Al ions can be adsorbed on two-dimensional Nb2N, and the adsorption energy is negative, indicating that metal ions have strong binding effect with two-dimensional Nb2N, which is conducive to the application in rechargeable ion batteries. The metallic properties of two-dimensional Nb2N ensure that the ion batteries maintain good conductivity. The diffusion barrier of the two ions is less than 0. 2 eV, indicating that they have good charge and discharge rates. In addition, both magnesium ion and aluminum ion batteries have relatively low open-circuit voltage and high theoretical capacity. These results show that two-dimensional Nb2N is suitable for the use of magnesium ion and aluminum ion batteries as high-performance anode materials. [ABSTRACT FROM AUTHOR]

Emerging rechargeable aluminium batteries (RABs) offer a sustainable option for next‐generation energy storage technologies with low cost and exemplary safety. However, the development of RABs is restricted by the limited availability of high‐performance cathode materials. Herein, we report two polyimide two‐dimensional covalent organic frameworks (2D‐COFs) cathodes with redox‐bipolar capability in RAB. The optimal 2D‐COF electrode achieves a high specific capacity of 132 mAh g−1. Notably, the electrode presents long‐term cycling stability (with a negligible ≈0.0007 % capacity decay per cycle), outperforming early reported organic RAB cathodes. 2D‐COFs integrate n‐type imide and p‐type triazine active centres into the periodic porous polymer skeleton. With multiple characterizations, we elucidate the unique Faradaic reaction of the 2D‐COF electrode, which involves AlCl2+ and AlCl4− dual‐ions as charge carriers. This work paves the avenue toward novel organic cathodes in RABs. [ABSTRACT FROM AUTHOR]

Conventional solid-to-solid conversion-type cathodes in batteries suffer from poor diffusion/reaction kinetics, large volume changes and aggressive structural degradation, particularly for rechargeable aluminium batteries (RABs). Here we report a class of high-capacity redox couples featuring a solution-to-solid conversion chemistry with well-manipulated solubility as cathodes—uniquely allowed by using molten salt electrolytes—that enable fast-charging and long-lived RABs. As a proof-of-concept, we demonstrate a highly reversible redox couple—the highly soluble InCl and the sparingly soluble InCl3—that exhibits a high capacity of about 327 mAh g−1 with negligible cell overpotential of only 35 mV at 1 C rate and 150 °C. The cells show almost no capacity fade over 500 cycles at a 20 C charging rate and can sustain 100 mAh g−1 at 50 C. The fast oxidation kinetics of the solution phase upon initiating the charge enables the cell with ultrafast charging capability, whereas the structure self-healing via re-forming the solution phase at the end of discharge endows the long-term cycling stability. This solution-to-solid mechanism will unlock more multivalent battery cathodes that are attractive in cost but plagued by poor reaction kinetics and short cycle life. Conventional solid-to-solid conversion cathodes in rechargeable aluminium batteries suffer from sluggish reaction kinetics and cumulative structural degradation. Here the authors disclose a solution-to-solid conversion chemistry using molten salt electrolytes to achieve fast-charging capability and good cycling stability. [ABSTRACT FROM AUTHOR]

The operating temperature of a battery energy storage system (BESS) has a significant impact on battery performance, such as safety, state of charge (SOC), and cycle life. For weather-resistant aluminum batteries (AlBs), the precision of the SOC is sensitive to temperature variation, and errors in the SOC of AlBs may occur. In this study, a combination of the experimental charge/discharge data and a 3D anisotropic homogeneous (Ani-hom) transient heat transfer simulation is performed to understand the thermal effect of a novel battery system, say an aluminum-ion battery. The study conducts a turbulence fluid dynamics method to solve the temperature distribution of the battery rack, and the entropy generation method analyzes the heat generation of AlB during the charging/discharging process. The AlB is modeled by a second-order Thevenin equivalent circuit to estimate the status of the battery. An extended Kalman filter is applied to obtain the accurate SOC for monitoring the battery cell. The current study conducts the Galvanostatic Intermittent Titration Technique (GITT) on aluminum-ion batteries under different operation temperatures: 25 °C, 40 °C, 60 °C, and 80 °C. According to the sensitivity analysis of the SOC, the temperature sensitivity tends to or greater than one, S T ≥ 1 , while the operation temperature is above 40 °C, and the SOC modification of EKFtmep estimator improves the battery state of charge in the error range below 1%. [ABSTRACT FROM AUTHOR]

Using three-dimensional (3D) metal foams as current collectors is considered to be a promising approach to improve the areal specific capacity and meet the demand for increased energy density of lithium-ion batteries. Electrodes with an open-porous metal foam as current collector exhibit a 3D connected electronic network within the active mass, shortening the electron transport pathways and lowering the electrodes' intrinsic electronic resistance. In this study, NMC622 cathodes using an aluminium foam as current collector with a measured areal capacity of up to 7.6 mAh cm−2 were investigated. To this end, the infiltrated foams were densified to various thicknesses between 200 µm and 400 µm corresponding to an electrode porosity between 65% and 30%. The microstructural analysis reveals (i) the elimination of shrinking cavities and a decrease in the porosity of the infiltrated active mass, (ii) an improved contact of active mass to the current collector structure and (iii) a pronounced clogging of the surface pores. The electrochemical properties such as capacity and rate capability are correlated to the electrode's microstructure, demonstrating that densification is necessary to improve active material utilization and volumetric capacity. However, strong densification impairs the rate capability caused by increased pore resistance and hindered electrolyte accessibility. [ABSTRACT FROM AUTHOR]