A low concentration electrolyte additive for constructing solid-electrolyte interphase on a Zn metal anode for aqueous batteries

Zn metal anodes in aqueous batteries experience inhomogeneous deposition and corrosion issues. Herein, we introduced, at a low concentration, dioxane (DX) as an electrolyte additive to stabilize a Zn anode. The oxygen sites of DX endowed it with a strong affinity for Zn and Zn2+, resulting in its adsorption onto the Zn electrode surface and its coordination with Zn2+ locally. The Zn2+-DX species exhibited a decreased lowest unoccupied molecular orbital energy level relative to those of water-involved components. The DX additive not only inhibited side reactions but also generated a stable solid-electrolyte interphase on the Zn electrode, ensuring a uniform Zn deposition. As a result of including the additive, the cycle life of the Zn symmetric cell was extended from 99 h to 2100 h, and the coulombic efficiency in Zn//Cu cell reached 99.5%. A 1% dioxane electrolyte additive was introduced into aqueous Zn batteries, which adsorbed onto the Zn surface, coordinated with Zn2+ locally and generated a solid-electrolyte interphase on Zn. It enhanced the stability of Zn electrode.