Reinforcing Interfacial Molecular Dam through a Multifunctional Organic Electrolyte Additive for Stable Zn Anode

Abstract

The durability of aqueous zinc-ion batteries (AZIBs) is still impeded due to issues such as dendrite growth, byproducts formation and hydrogen evolution reactions in Zn metal anode. 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 mitigating corrosion via the H2O-deficient electric double-layer (EDL) but also facilitating uniform Zn deposition through their large conjugated planes and zincophilic properties. As a result, symmetrical cell with Ta additive harvests a highly reversible cycle life for 2200 h at 1 mA cm-2 with a capacity of 1 mAh cm-2. Notably, using 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 over 2000 cycles lifetime.