Promoting Migration Kinetic of Desolvated Zn2+ by Functional Interlayer Toward Superior Zn Metal Anode

Abstract

The development of Zn metal anodes is challenged by non-uniformity of ion flux causing inhomogeneous deposition and strong solvation of Zn(H₂O)₆²⁺ resulting in adverse side reactions. Applying intermediate protecting layers with high affinity to Zn²⁺ is a popular and effective solution, but it also limits the ion migration. A functional MXene-based interlayer is designed in this work to modify the glass fiber separator achieving balanced adsorption energy and ion migration. By coating porous silica on the MXene surface, the instinct advanatges of MXene are mostly reserved while the adsorption energy to Zn²⁺ is optimized. Such an interlayer enables high flux and uniformity of desolvated Zn²⁺, contributing to rapid deposition kinetic for excellent rate performance and inhibited side reactions for long-term cycling stability. As a result, the functionalized Zn metal anode delivers steady plating/stripping cycles for more than 5000 h at 0.1 mA cm⁻² and 700 h at 5.0 mA cm⁻². The Zn||MnO₂ full cells with this separator also exhibit superior rate capabilities (173 mAh g⁻¹ at 2.0 A g⁻¹) and excellent cycle performance (254.7 mAh g⁻¹ after 1000 cycles at 0.5 A g⁻¹). This work provides a feasible strategy for preparing functional interlayers toward superior Zn or other metal anodes.