Rechargeable quasi-solid-state aqueous hybrid Al³⁺/H⁺ battery with 10, 000 ultralong cycle stability and smart switching capability

Safe and long lifespan batteries facilitate the development of portable electronics and electric vehicles. Owing to the low-cost, naturally abundance, and trivalent charge carrier of aluminum with the highest theoretical volumetric capacity, rechargeable aqueous aluminum-ion-based batteries are considered as promising next-generation secondary batteries. However, traditional electrolytes and frequent collapse of the host structure of electrode materials greatly jeopardize the cycle stability of the batteries. Here, we develop a novel hydrogel-based electrolyte coupled with stable layered intercalation electrodes for the first time to fabricate a highly safe and flexible rechargeable hybrid Al³⁺/H⁺ battery. The as-fabricated hybrid-ion battery (HIB) delivers a high specific capacity of 125 mAh∙g⁻¹ at 0.1 A∙g⁻¹ and exhibits an unprecedented super long-term cycling stability with no capacity fading over 10, 000 cycles at 2 A∙g⁻¹. In addition, the hydrogel-based electrolyte possesses smart function of thermoresponsive switching, which can effectively prevent thermal runaway for the batteries. The unprecedented long cycle stability, highly intrinsic safety as well as low-cost indicate that the flexible aqueous HIBs are promising for applications.