Aqueous Biphasic Electrolyte Enabling Self-Adaptation of Mutually Exclusive Electrolyte Requirements for a Zn Anode and a Cathode

Aqueous Zn-based batteries, the coupling of a zinc anode and a cathode in aqueous electrolytes, are promising for large-scale energy storage. However, the preference of these two electrodes in aqueous zinc sulfate electrolytes with different concentrations exhibits inherent contradictions, which are enhanced rapidly at increased temperatures, impeding their sustainable applications. Herein, we took a zinc metal anode and a vanadium-based cathode as an example and developed an aqueous biphasic electrolyte (ABE) that utilized the distinct ion concentration contrast characteristics between the two phases to simultaneously fulfill the mutually exclusive environmental requirements for cathodes and anodes. The ABE substantially improved the stability of the full battery, which demonstrated a stable cycling performance for up to 1000 cycles at a current density of 5 A g^-1 at an increased temperature of 60 °C. A battery prototype with high-voltage output and energy expandability was also developed, providing a promising model for future large-scale applications of ABEs.