Sr²⁺ and choline chloride cointercalation in V₂O₅ for aqueous zinc-ion batteries

V₂O₅·nH₂O has been widely studied for aqueous zinc-ion batteries. The intercalation of inorganic ions has been used as a feasible method to improve the capacity of vanadium pentoxide. To further improve the stability, organic small molecule choline chloride intercalation is used to expand the spacing of the vanadium pentoxide layers and increase the cycling stability. Therefore, we consider the introduction of Sr²⁺ to cointercalate with choline chloride. Here, we synthesized vanadium pentoxide cointercalated with Sr²⁺ and choline ions (Ch⁺) via a simple hydrothermal method. The electrochemical performance shows an enhanced cathode capacitance contribution of Sr&Ch-V₂O₅, with a discharge capacity of 526 mAh·g⁻¹ at 0.1 A·g⁻¹ and a retention rate of 78.9% after 2000 cycles at 5 A·g⁻¹. This work offers a novel strategy for the design of organic‒inorganic hybrid materials for use as cathodes in aqueous zinc-ion batteries.