Interface Engineering by Hydrophilic and Zincophilic Aluminum Hydroxide Fluoride for Anode-Free Zinc Metal Batteries at Low Temperature

Anode-free batteriesgreatly promote overall energy density, but they require an extremely high Coulombic efficiency (CE, >99.7%) to function normally. It becomes very challenging in aqueous batteries, because of water-related parasitic reactions and dendrite growth on Zn anodes. Herein, aluminum hydroxide fluoride coated on Cu foils (Cu@AOF) is used to realize the anode-free aqueous batteries. AOF exhibits a high adsorption affinity to H2O and a low diffusion energy barrier for Zn adatoms, promoting the desolvation process and surface migration. Meanwhile, the strong interaction between AOF and Zn2+ enables it to regulate the Zn2+ flux and benefit lateral growth. Then, the anode-free full cells of Cu@AOF||Zn0.5VO2 exhibit a record-high cycle life of 2000 cycles at 1 A g(-1) with an ultra-high average CE of 99.95%. More impressively, the full cell shows a long cycle life of 400 cycles with a high CE of 99.94% at -20 degrees C. This work provides sheds light on the rational engineering of the electrode interfaces to obtain excellent performance at low temperatures.

Automated summary

The use of aluminum hydroxide fluoride coated on Cu foils enables the realization of anode-free aqueous batteries, with high adsorption affinity to H2O and low diffusion energy barrier for Zn adatoms, resulting in improved cycle life and efficiency of the batteries.