Biocrust-Inspired Interface Layer with Dual Functions towards Highly Reversible Zinc Metal Anode

Abstract

The commercialization of aqueous zinc-ion batteries is still challenging due to the terrible dendrite growth and serious side reactions occurring at anode surface. In-situ construction of solid electrolyte interfaces (SEI) can effectively improve the stability of zinc anode. Herein, a bioinspired crust strategy implemented by eflornithine (DFMO) electrolyte additive is proposed to construct ZnF2-rich SEI, which can adjust the interfacial chemistry of zinc anode. Such functional SEI, akin to biological crust, can not only suppress side reactions by blocking direct contact between anode and electrolyte, but also enhance anode stability at high current via its high ionic conductivity and excellent mechanical properties. Additionally, the carbonyl group participates in regulating the solvated structure of Zn2+ and reconstructing hydrogen bond networks. Accordingly, with the existence of DFMO, a prolonged cycling lifespan and an ultrahigh average coulombic efficiency (CE) of 99.87% at 5 mA cm–2 and 1 mAh cm–2 are realized for zinc anodes. Furthermore, the DFMO-based Zn//NVO pouch cell achieves excellent cycle stability, verifying the feasibility and superiority of bioinspired crust strategy. This work offers valuable insights into the construction of ZnF2-rich SEI by electrolyte additive and provides a novel perspective for the protection of zinc anodes.