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In recent years, there have been significant advancements in Al‐ion battery development, resulting in high voltage and capacity. Traditionally, only carbon‐based materials with layered structures and strong bonding capabilities can deliver superior performance. However, most other materials exhibited low discharge voltages of 1.4 V, especially in aqueous Al‐ion battery systems lacking anion intercalation. Thus, the development of high‐voltage cathode materials has become crucial. This study introduces 2D MoS2 as a high‐performance cathode for aqueous Al‐ion batteries. The material's interlayer structure enables the intercalation of AlCl4− anions, resulting in high‐voltage intercalation. The resulting battery achieved a high voltage of 1.8 V with a capacity of 750 mAh g−1, contributing to a high energy density of 890 Wh kg−1 and an impressive retention rate of ≈100% after 200 cycles. This research not only sheds light on the high‐voltage anion‐intercalation mechanism of MoS2 but also paves the way for the further development of advanced cathode materials in the field of Al‐ion batteries. By demonstrating the potential of using 2D MoS2 as a cathode material, this finding can lead to the development of more efficient and innovative energy storage technologies, ultimately contributing to a sustainable and green energy future. [ABSTRACT FROM AUTHOR]

The practical application of rechargeable aqueous zinc batteries is impeded by dendrite growth, especially at high areal capacities and high current densities. Here, this challenge is addressed by proposing zinc perfluoro(2‐ethoxyethane)sulfonic (Zn(PES)2) as a zinc battery electrolyte. This new amphipathic zinc salt, with a hydrophobic perfluorinated tail, can form an anode protecting layer, in situ, with a biomimetic lipid‐bilayer structure. The layer limits the anode contact with free H2O and offers fast Zn2+ transport pathways, thereby effectively suppressing dendrite growth while maintaining high rate capability. A stable, Zn2+‐conductive fluorinated solid electrolyte interphase (SEI) is also formed, further enhancing zinc reversibility. The electrolyte enables unprecedented cycling stability with dendrite‐free zinc plating/stripping over 1600 h at 1 mA cm−2 at 2 mAh cm−2, and over 380 h under an even harsher condition of 2.5 mA cm−2 and 5 mAh cm−2. Full cell tests with a high‐loading VS2 cathode demonstrate good capacity retention of 78% after 1000 cycles at 1.5 mA cm−2. The idea of in situ formation of a biomimetic lipid‐bilayer anode protecting layer and fluorinated SEI opens a new route for engineering the electrode–electrolyte interface toward next‐generation aqueous zinc batteries with long lifetime and high areal capacities. [ABSTRACT FROM AUTHOR]

The aqueous Al‐ion battery has achieved great progress in recent years. It now shows comparable performance to that of even non‐aqueous Al‐ion batteries. However, it also shows relatively low energy output and there is limited general understanding of the mechanism behind this restriction to its practical application. Thus, the development of a high‐performance cathode material is in great demand. Herein, a high‐capacity single‐walled carbon nanotube (SWCNT) is developed as a cathode for the water‐in‐salt electrolyte‐based aqueous Al‐ion battery, which provides an ultra‐high specific capacity of 790 mAh g–1 (based on the mass of SWCNT) at a high current density of 5 A g–1 even after 1000 cycles. Moreover, the SWCNT/Al battery shows a complicated multi‐ion intercalation mechanism, where AlCl4–, Cl–, Al3+, and H+ can function at the same time, improving the battery output. Beyond recently revealed H+ and metal ion co‐intercalation, the Cl‐assisted intercalation of Al3+ ions mechanism is also studied by experimental characterization and modeling for the first time, which significantly boosts the Al3+ storage capacity. This multi‐ion intercalation mechanism combines the high‐voltage anion deintercalation and the high‐capacity cation intercalation, and thus, benefits the development and application of high‐energy Al‐ion batteries in the future. [ABSTRACT FROM AUTHOR]

Aqueous Al–ion battery (AAIB) is regarded as a promising candidate for large‐scale energy storage systems due to its high capacity, high safety, and low cost, with MnO2 proved to be a high‐performance cathode. However, the potential commercial application of this type of battery is plagued by the frequent structural collapse of MnO2. Herein, an in situ, electrochemically reformed, urchin‐like AlxMnO2 cathode is developed for water‐in‐salt electrolyte‐based AAIBs. Benefiting from its unique α‐MnO2 coated Mn2AlO4 structure, a high Al ion storage capacity is achieved together with a high discharge voltage plateau of 1.9 V by reversible MnO2 electrolysis. Consequently, the battery exhibits a high specific capacity of 285 mAh g–1 and a high energy density of 370 Wh kg–1 at a high current density of 500 mA g–1. Improved stability with record capacity retention is also obtained at an ultrahigh current density of 5 A g–1 after 500 cycles. Such a high‐capacity and high‐stability AlxMnO2 cathode would pave the way for in situ electrochemical transformation of cathode design and thus boost the practical application of AAIBs. [ABSTRACT FROM AUTHOR]

Aqueous hybrid Na–Zn ion batteries (ASZIBs) are promising for large‐scale energy storage due to their low cost and potential for high output voltage. However, most ASZIBs show limited discharge voltage (<2.0 V) and capacity (<100 mAh g–1) due to inefficient usage of the dual ions. In this study, a novel large‐electrochemical‐window "water‐in‐gel" electrolyte based CuHCF‐CNT/Zn Na–Zn hybrid battery is proposed, which achieves a high extraction voltage of Na ion (2.1 V vs Zn/Zn2+), together with a large discharge specific capacity (260 mAh g–1) thanks to the Zn‐ion insertion, delivering a superior energy density of 440 Wh kg–1. The hybrid battery also shows a high capacity retention of 96.8% after 450 cycles. Moreover, an ultrahigh discharge capacity of 1250 mAh g–1 is achieved when further coupled with the Zn‐O2 reaction, delivering the promising application of ion intercalation and metal–air hybrid battery. [ABSTRACT FROM AUTHOR]