Dual-additive-based electrolyte design for aqueous zinc ion batteries with high plating/stripping efficiency

Abstract

A dual-additive-based aqueous electrolyte was designed with a pH-buffering additive (Zn(OAc)₂) and an electrostatic shielding additive (TMAOAc) for high Zn plating/stripping efficiency. The buffering pair, OAc⁻/HOAc, can stabilize the pH value to suppress side hydrogen evolution reactions. Meanwhile, TMA⁺ acts as a competitive cation being preferentially adsorbed on the uneven surface of the Zn anode and exerts an electrostatic shielding effect to facilitate flat Zn deposition. Such a dual-additive-based electrolyte promotes an ultra-high Zn plating/stripping efficiency of 99.9% at 1 mA cm⁻² and long-term cycling stability for 3600 h at 0.5 mA cm⁻², offering valuable insights for advanced aqueous batteries.