In situ construction of solid-electrolyte interfaces for metallic Zn anodes in aqueous zinc batteries

Abstract

Zn–metal batteries (ZMBs) have attracted significant attention due to their high safety, cost-effectiveness, environmental friendliness, and promising electrochemical properties. However, ZMBs suffer from the stubborn irreversibility of Zn stripping/plating since their invention. To address this challenge, constructing a robust electrolyte–Zn interface is one of the major strategies. Importantly, an in situ solid-electrolyte interface (SEI) possesses the advantages of regulating the interfacial reactions and suppressing the side reactions. Thus far, the formation mechanisms of the in situ SEI have been intensely elaborated, which requires a concurrent summary. Herein, we aim to discuss the roles of the in situ SEI in rationalizing the interfacial reactions from the aspects of modulating the solvation structures, guiding zinc ion fluxes, modifying the nucleation sites, and inducing a uniform deposition and crystal orientation. The formation mechanisms of SEIs on Zn, including replacement, precipitation, decomposition, polymerization, combination, and adsorption/self-assembly, are summarized, along with the surface material characteristics and corresponding functions. Further, perspectives on understanding the SEI formation mechanisms with ideal intrinsic properties are provided. We anticipate this minireview can motivate in comprehending the underlying chemistry for novel SEI designs.