A Heteroanionic Zinc Ion Conductor for Dendrite‐Free Zn Metal Anodes

Abstract

AbstractAlthough zinc‐based batteries are promising candidates for eco‐friendly and cost‐effective energy storage devices, their performance is severely retarded by dendrite formation. As the simplest zinc compounds, zinc chalcogenides, and halides are individually applied as a Zn protection layer due to high zinc ion conductivity. However, the mixed‐anion compounds are not studied, which constrains the Zn2+ diffusion in single‐anion lattices to their own limits. A heteroanionic zinc ion conductor (ZnyO1−xFx) coating layer is designed by in situ growth method with tunable F content and thickness. Strengthened by F aliovalent doping, the Zn2+ conductivity is enhanced within the wurtzite motif for rapid lattice Zn migration. ZnyO1−xFx also affords zincophilic sites for oriented superficial Zn plating to suppress dendrite growth. Therefore, ZnyO1−xFx‐coated anode exhibits a low overpotential of 20.4 mV for 1000 h cycle life at a plating capacity of 1.0 mA h cm−2 during symmetrical cell test. The MnO2//Zn full battery further proves high stability of 169.7 mA h g−1 for 1000 cycles. This work may enlighten the mixed‐anion tuning for high‐performance Zn‐based energy storage devices.