Biomacromolecule guiding construction of effective interface layer for ultra-stable zinc anode

Liquid systems in living organisms stabilize colloidal particles and prevent the aggregation of ions by forming an efficient interface. This allows for the uniform migration of ions in a directed manner. Inspired by the interface optimization in the biological realm, herein we have attempted to incorporate a biomaterial, chondroitin sulfate (CS), into the electrolyte of aqueous zinc ion batteries, which enables the construction of an effective interface layer at the zinc anode side. The presence of this effective interface layer guiding the uniform migration to mitigate the "tip effect", leading to the deposition of zinc ions in a flat manner, which in turn serves a protective function for the metal anode. This interface layer also effectively shields against direct contact between the zinc anode and hydrate, thereby preventing the occurrence of any unwanted side reactions. Benefiting from these characteristics, our cell with CS additive achieves an ultra-stable zinc plating/stripping performance for 4000 h at 1 mA cm⁻²/1 mAh cm⁻² in Zn//Zn cell, with an ultra-high service capacity of 4 Ah cm⁻². The assembled Zn//MnO₂ full cell with CS additive also achieves a stable cycling performance with a capacity retention of 75.0% after 10,000 cycles. We believe that our bio-inspired design approach provides a feasible strategy for the optimization of metal anode in the battery field.