Uniform redistribution of Zn2+ flux induced by remodeling the solvated structure to form zincophilic interfaces via sodium alginate electrolyte additive

Abstract

Irregular dendrites produced by zinc anodes and self-corrosion phenomena hinder the large-scale application of aqueous zinc-ion batteries. In this work, a natural polysaccharide sodium alginate molecule (SG) was introduced into the ZnSO4 electrolyte. Relying on the polar groups contained in the SG molecule, the coordination structure of anions and cations in the system is reshaped, and the hydrogen bonding is enhanced by a significant shift of the –OH bond, the reduction of H2 is reduced and the corrosion inhibition efficiency is 16 %. Moreover, the strong chelation between SG molecules and Zn anode prompted the formation of new interfaces, which limited the disordered two-dimensional diffusion of Zn2+, thus achieving the effect of inducing preferential transport and uniform redistribution deposition of Zn2+. Specifically, the Zn||Zn symmetric batteries survived for more than 2500 h for 2 mA cm−2 at 1 mAh cm−2, and survived for more than 1100 h under more severe conditions (10 mA cm−2, 2 mAh cm−2). The Zn||Cu half-cells still have high average Coulombic Efficiency (99.67 %) after 800 cycles, and the Zn||Na3VO4 (NVO) full-cells can stably run for 600 cycles with a remaining specific capacity above 150 mAh g−1. This strategy provides a new idea for the construction of aqueous batteries.