Promoting Preferential Zn (002) Deposition with a Low-Concentration Electrolyte Additive for Highly Reversible Zn-Ion Batteries

Abstract

Aqueous zinc-ion batteries have promising potential as energy storage devices due to their low cost and environmental friendliness. However, their development has been hindered by zinc dendrite formation and parasitic side reactions. Herein, we introduce a low-concentration sodium benzoate (NaBZ) electrolyte additive to stabilize the electrode-electrolyte interface and promote deposition on the Zn (002) crystal plane. From experimental characterization and computational analyses, NaBZ was found to adsorb on the Zn surface and inhibit side reactions while guiding homogeneous Zn deposition on the (002) plane. Consequently, Zn|Zn symmetric cells with the NaBZ additive cycled stably for over 1000 h at a current density of 0.5 mA cm^-2 and an areal capacity of 0.5 mAh cm^-2, while Zn|Cu cells showed excellent reversibility with a Coulombic efficiency of 99.05%. Moreover, Zn|Na_0.33V₂O₅ full cells achieve a high specific capacity of 124 mAh g^-1 while cycling for 600 h at 2 A g^-1. These findings present a low-cost electrolyte modification strategy for reversible zinc-ion batteries.