A promising solution for highly reversible zinc metal anode chemistry: Functional gradient interphase

Rechargeable zinc (Zn) metal batteries have long been plagued by dendrite growth and parasitic reactions due to the absence of a stable Zn-ion conductive solid-electrolyte interphase (SEI). Although the current strategies assist in suppressing dendritic Zn growth, it is still a challenge to obtain the operation-stability of Zn anode with high Coulombic efficiency (CE) required to implement a sustainable and long-cycling life of Zn metal batteries. In this perspective, we summarize the advantages of the functional gradient interphase (FGI) and try to fundamentally understand the transport behaviors of Zn ions, based on recently an article understanding Zn chemistry. The correlation between the function-orientated design of gradient interphase and key challenges of Zn metal anodes in accelerating Zn²⁺ transport kinetics, improving electrode reversibility, and inhibiting Zn dendrite growth and side reactions was particularly emphasized. Finally, the rational design and innovative directions are provided for the development and application of functional gradient interphase in rechargeable Zn metal battery systems.