Inhibition of dendrite growth and side reactions using histidine as electrolyte additive for aqueous Zn-ion batteries

Aqueous Zn-ion batteries have attracted wide attention in the field of energy storage due to their low cost and high safety. However, the problems of dendrite growth and side reactions of Zn anode have been puzzling them and become the main factors limiting their development and application. Herein, we introduce histidine additive into the ZnSO4 electrolyte to inhibit dendrite growth and side reactions. The histidine is preferentially adsorbed on the surface of Zn anode to form a shield molecular layer, guiding the uniform deposition of Zn ions and inhibiting the side reactions. Consequently, an long cycle life of 4180 h for Zn||Zn symmetric battery can be achieved at 2 mA cm-2 (1 mAh cm-2), and even at the ultra-high current density of 10 mA cm-2 (5 mAh cm-2) for more than 1000 h. The capacity retention of Zn-MnO2 full battery with His/ZnSO4 retains 64% after 800 cycles of charge/discharge at 0.5 A g-1, while 47% for the full battery with pure ZnSO4 electrolyte. This work provides an effective electrolyte additive to address the dendrite growth and side reactions in Zn-ion batteries.