A Heteroanionic Zinc Ion Conductor for Dendrite-Free Zn Metal Anodes.

Although 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 Zn protection layer due to high zinc ion conductivity. However, the mixed-anion compounds have not been studied, which constrains the Zn 2+ diffusion in single-anion lattices to their own limits. We designed a heteroanionic zinc ion conductor (Zn y O 1 - x F x ) coating layer by in situ growth method with tunable F content and thickness. Strengthened by F aliovalent doping, the Zn 2+ conductivity is enhanced within wurtzite motif for rapid lattice Zn migration. Zn y O 1 - x F x also affords zincophilic sites for oriented superficial Zn plating to suppress dendrite growth. Therefore, Zn y O 1 - x F x -coated anode exhibits low overpotential of 20.4 mV for 1, 000 h cycle life at a plating capacity of 1.0 mA h cm -2 during symmetrical cell test. The MnO 2 //Zn full battery further proves high stability of 169.7 mA h g -1 for 1, 000 cycles. This work might enlighten the mixed-anion tuning for high-performance Zn-based energy storage devices. This article is protected by copyright. All rights reserved.