Stable quasi-solid-state zinc-ion battery based on the hydrated vanadium oxide cathode and polyacrylamide-organohydrogel electrolyte

Aqueous zinc-ion batteries are promising owing their low cost and high safety. However, their development is inhibited by the adverse side reactions that occur during battery operation, which result in unsatisfactory battery performance and by-product formation on the zinc anode. Here, dimethyl sulfoxide (DMSO) was combined with H2O to prepare a gel electrolyte (PAM-DMSO/H2O) to address this issue. The as-prepared gel electrolyte revealed that the introduction of DMSO reduces water activity and enhances the ionic conductivity (31.2 mS cm−1, at room temperature) and promotes zinc-ion transference number (tzn2+= 0.69). The durability of the electrolyte was tested in a symmetrical Zn//Zn cell, and the result revealed that the Zn anode could sustain long-term stability (over 2000 h) at a current density of 0.5 mA cm−1. Furthermore, the electrochemical performance of the as-prepared electrolyte and pre-intercalated Hydrated Vanadium Oxide (VOH) cathode exhibited a high reversible capacity of 559.0 mAh g−1 at a current density of 50 mA g−1 and robust cycling stability over 2000 cycles. The proposed electrolyte development strategy can open a new door to the development of flexible yet highly durable zinc-ion batteries for broad applications.