Gradient Desolvation-Diffusion Kinetic Layer Promoters for Low-Temperature Dendrite-Free Zn Metal Batteries.

Abstract

Aqueous zinc metal batteries have emerged as strong candidates for large-scale energy applications, but they are inhibited by significant dendrite growth resulting from corresponding depressive desolvation-diffusion kinetics. Herein, the strategy of gradient desolvation-diffusion kinetics is proposed by constructing an organic-inorganic layer on the zinc anode for increasing robust mechanical properties and strengthening ion/atom transport. The electron-insulative polymer layer effectively prevents interfacial electron contact from side reactions, and the phase-transformed Sn and ZnF₂ layer also promotes Zn²⁺ transport with lower barrier, as demonstrated by electrochemical and theoretical simulations. Consequently, the fabricated symmetric cell exhibits a surprisingly long-term life of 4000 h with low overpotentials (17 mV) and high average Coulombic efficiency under low-temperature surroundings. Coupled with MnO₂ and V₂O₅ cathodes, the full cells also show high-capacity retentions under a high rate of 3 A g^-1 or low-temperature surroundings, indicating the promising prospect of fast desolvation-diffusion modulation for practical applications.