Stabilizing water and regulating interfacial electrostatic interaction with economical supporting salt for stable Zn metal anode

Developing rechargeable aqueous Zn batteries for large-scale energy storage is impeded by inadequate reversibility and stability of the Zn anode, primarily caused by parasitic reactions and heterogeneous deposition. This study proposes an economical electrolyte strategy to address these Zn-related issues. The addition of a supporting salt enhances the thermodynamic stability of water, reduces the number of highly reactive water molecules, and modulates the interfacial electrostatic interaction. This approach effectively suppresses hydrogen evolution reaction and uncontrolled deposition. Remarkably, the rationally proportioned electrolyte allows a high average Coulombic efficiency of 99.93% for 1000 cycles in a Zn||Cu battery and a prolonged lifespan exceeding 4800 h in Zn||Zn cells. The knock-on effect is that Zn||MnO₂ pouch cells deliver stable cycling performance, demonstrating the viability of this approach for practical applications.