Tuning Desolvation Kinetics with Perovskite-Type Ion-Conductive Modulators toward Low-Temperature Zn Metal Batteries

Aqueous zinc metal batteries (AZMBs) are regarded as the promising candidates for low-cost, sustainable, but safe energy storage systems. Unfortunately, Zn metal anodes suffer from incomplete desolvation and random dendrite formation, which is attributed to sluggish diffusion kinetics resulted from the strong ion (Zn²⁺)-dipole (H₂O) interactions. Herein, to promote the Zn²⁺ desolvation and diffusion kinetics, the strategy of constructing perovskite-type ion-conductive kinetic modulators of ZnSn(OH)₆ is initially designed and coated on the Zn metal anode (PIC-ZSH@Zn), regulating ion behaviors against dendrite growth and side reactions of active water. As confirmed by theoretical simulations, COMSOL, time-of-flight second-ionic mass spectroscopy, Raman and various electrochemical analyses, the abundant active sites synergistically weaken Zn²⁺-H₂O interactions to accelerate desolvation to release free Zn²⁺, effectively homogenizing the Zn²⁺ flux distribution to preferentially nucleate and plate metallic Zn. Consequently, the as-fabricated cell maintains reversible stability of 800 h at 10 mA cm^-2 with high Coulombic efficiency over 99% under low temperature of 0°C. The paired full cell with PIC-ZSH@Zn presents a high-capacity retention of nearly 80% after 1000 cycles at 1.0 A g^-1 at 0°C, reinforcing the operation robustness of AZMBs under low temperature environments.