Electrolyte Decoupling Strategy for Metal Oxide-Based Zinc-ion Batteries Free of Crosstalk Effect

Abstract

The crosstalk of transition metal ions between the metal oxide cathode and Zn anode restricts the practical applications of aqueous zinc-ion batteries (ZIBs). Herein, we propose a decoupled electrolyte (DCE) consisting of a nonaqueous-phase (N-phase) anolyte and an aqueous-phase (A-phase) catholyte to prevent the crosstalk of Mn2+, thus extending the lifespan of MnO2-based ZIBs. Experimental measurements and theoretical modelling verify that trimethyl phosphate (TMP) not only synergistically works with NH4Cl in the N-phase anolyte to enable fast Zn2+ conduction while block Mn2+ diffusion toward anode, but also modifies the Zn2+ solvation structure to suppress the dendrite formation and corrosion on Zn anode. Meanwhile, the A-phase catholyte effectively accelerates the cathode reaction kinetics. The as-developed Zn|DCE|MnO2 cell delivers 80.13% capacity retention after 900 cycles at 0.5 A g-1. This approach is applicable for other metal oxide cathode-based ZIBs, thereby opening a new avenue for developing ultrastable ZIBs.