Interface engineering enables stable and reversible zinc anode for high-performance Zn–I2 battery

Abstract

Aqueous Zn-based batteries have been regarded as a promising energy storage system due to their high energy/power density, safety, and cost-effectiveness. However, their performance have been severely hindered by the dendrite growth of zinc and water-induced side reactions. Herein, a facial strategy of electrolyte modification with a high concentration of zinc sulfate and lithium iodide (LiI) as additives is proposed to guide the preferential growth along with the Zn (002) plane for the smooth Zn deposition. Compared to the pure zinc sulfate electrolyte, the Zn anode in the modified electrolyte exhibited the ultralong cycling stability for 3000 h at a capacity of 1 mAh cm−2 and 400 h at a higher capacity of 5 mAh cm−2, with low reversible deposition potentials of around 30 and 40 mV, respectively, demonstrating the stable plating/stripping behaviors. More importantly, the cycling stability of the Zn–I2 battery with the modified electrolyte can still deliver a large specific capacity after 5000 cycles. The strategy presented that the LiI as additive could not only provide an iodine-rich environment to induce the preferential growth of Zn (002) plane, but also eliminate the side corrosion reactions with the help of additional Li-ions, thus leading to the high-performing Zn–I2 battery.