Fast Zn2+ mobility enabled by sucrose modified Zn2+ solvation structure for dendrite-free aqueous zinc battery

Aqueous zinc battery has been regarded as one of the most promising energy storage systems due to its low cost and environmental benignity. However, the safety concern on Zn anodes caused by uncontrolled Zn dendrite growth in aqueous electrolyte hinders their application. Herein, sucrose with multi-hydroxyl groups has been introduced into aqueous electrolyte to modify Zn2+ solvation environment and create a protection layer on Zn anode, thus effectively retarding the growth of zinc dendrites. Atomistic simulations and experiments confirm that sucrose molecules can enter into the solvation sheath of Zn2+, and the as-formed unique solvation structure enhances the mobility of Zn2+. Such fast Zn2+ kinetics in sucrose-modified electrolyte can successfully suppress the dendrite growth. With this sucrose-modified aqueous electrolyte, Zn/Zn symmetric cells present more stable cycle performance than those using pure aqueous electrolyte; Zn/C cells also deliver an impressive higher energy density of 129.7 Wh·kg−1 and improved stability, suggesting a great potential application of sucrose-modified electrolytes for future Zn batteries.