Succinonitrile Electrolyte Additive for Stabilizing Aqueous Zinc Metal Batteries

The utilization of water electrolytes in zinc-ion batteries offers the advantages of enhanced safety, reduced cost, and improved environmental friendliness, rendering them an optimal choice for replacing lithium-ion batteries. Nevertheless, the conventional zinc sulfate electrolyte fails to meet stringent requirements. Therefore, developing electrolytes is crucial for addressing the low cycle life of zinc ions and suppressing the growth of zinc dendrites. So we proposed a strategy for engineering dilution of aqueous Zn(OTf)₂ solution with succinonitrile (SN) network electrolytes. The introduction of SN also disrupts the original hydrogen bonding network within the system and mitigates issues related to side reactions. Additionally, the inclusion of SN additives significantly diminishes the reactivity of water molecules and smoothing zinc deposition to form favorable two-component Zn₃N₂/ZnF₂ SEI. The results indicate that symmetric cells exhibit a remarkable cycling performance (877 h at current density and capacity of 1 mA cm^-2 and 1 mAh cm^-2, respectively). Furthermore, after 2000 cycles at a current density of 5 A g^-1, the full battery demonstrates an impressive capacity of 151.2 mAh g^-1. These results show that the electrolyte structure project provides a promising direction for the design of aqueous zinc-metal batteries, aiming to achieve high reversibility and long cycle life.