Inhibiting zinc dendrites and side reactions enabled by solvation structure regulation and facile de-solvation process

Abstract

Rechargeable aqueous zinc-ion batteries show great promise as next-generation energy storage devices given their advantages of low cost and high safety. However, dendrite growth and detrimental side reactions result in poor reversibility of Zn anodes. Here, TEG molecules were introduced as additives to regulate the solvation structure through occupying the position of water molecules in the solvation shell, which also further decreasing the de-solvation energy barrier. The lower de-solvation energy barrier is beneficial for the dissociation of solvation water molecules and help to restrain the water decomposition and the related by-products. Theoretical studies also reveal that TEG is more easily adsorbed on the surface of zinc than water molecules, electrons are more easily transferred from the TEG molecule to the zinc foil, thus promoting the uniform deposition of zinc atoms. Benefiting from the solvation structure regulation and facile de-solvation process of Zn2+, Zn/Zn symmetric cell achieve a long cycling life of 2000 h at the current density and capacity of 1 mA cm−2 and 1mAh cm−2, and a MnO2-Zn full cell reach a superior stability of 3000 cycles at the current density of 1000 mA g−1.