Inhibition of zinc dendrites by dopamine modified hexagonal boron nitride electrolyte additive for zinc-ion batteries

Abstract

Aqueous zinc ion batteries (AZIBs) have attracted much attention due to their safety, reliability, low cost, simple operation and environmental friendliness. However, the stability and safety of AZIBs are seriously affected by uncontrolled hazardous zinc dendrite growth and adverse side reactions of the zinc anode. To address these problems, we present a strategy of adding polydopamine (PDA) modified h-BN (h-BN@PDA) additive into 1 M ZnSO4 electrolyte to inhibit Zn dendrites and construct safe batteries. The h-BN@PDA additive endows a dendrite-free electrodeposition behavior by regulating the concentration gradient of Zn2+, redistributing the uneven Zn2+ flux, and covering the formation sites of dendrites. This is mainly attributed to the combined action of redistribution of Zn2+ by h-BN and the immobilization of electrolyte anions by the catechol functional groups of PDA. Consequently, the Zn||Zn cell with h-BN@PDA additive can be cycled for more than 1700h at 0.5 mA cm−2 with a small plating/stripping overpotential of around 0.03 mV, and more than 1000h even at 1 mA cm−2. Additionally, the Zn||ZnSO4+h-BN@PDA||V2O5 battery can render excellent stability for 1500 cycles at 10 A g−1. These results open up an opportunity for h-BN@PDA and other solid electrolyte additives in the design of advanced and durable AZIBs.