Reinforcing an interfacial molecular dam through a multifunctional organic electrolyte additive for stable Zn anodes

Abstract

The durability of aqueous zinc-ion batteries (AZIBs) is still impeded due to issues such as dendrite growth, byproduct formation and hydrogen evolution reactions in Zn metal anodes. Herein, we proposed a polydentate ligand, triazole (Ta), as an effective electrolyte additive to prolong the anode stability by its selective adsorption preference and enhanced zinc ion coordination and proton buffering ability. Specifically, Ta induces the formation of an interfacial molecular dam that not only mitigates corrosion via the H₂O-deficient electric double-layer (EDL) but also facilitates uniform Zn deposition through its large conjugated planes and zincophilic properties. As a result, a symmetrical cell with the Ta additive exhibits a highly reversible cycle life for 2200 h at 1 mA cm⁻² with a capacity of 1 mA h cm⁻². Notably, using the Ta/ZnSO₄ electrolyte enables stable cycling for 400 h at a high depth-of-discharge (DOD) level of 85%, leading to improved performance in the Zn//α-MnO₂ full cell with a lifetime of over 2000 cycles.