Low Current‐Density Stable Zinc‐Metal Batteries Via Aqueous/Organic Hybrid Electrolyte

Abstract Zinc‐metal batteries (ZMBs) are promising for large‐scale energy storage devices due to their intrinsically safe, low‐cost and environmentally friendly nature. ZMBs with vanadium‐based cathodes have exhibited excellent performance, however, many side reactions due to the presence of innumerable water molecules in aqueous electrolyte hinder their commercialization. Herein, high‐proportioned polyethylene glycol was introduced as solvent to form an aqueous/organic hybrid electrolyte, which limits the activity of free water molecules and lowers the risk of side reactions, such as cathode dissolution, zinc dendrites and H 2 evolution. As a result, a good reversible zinc plating/stripping over 3000 h for zinc anode and an excellent cycle stability with 96 % retention after 50 cycles at low current density of 0.1 A g −1 for vanadium‐based cathode were obtained, respectively. Importantly, to simulate the stability in actual application environment, a test mode at low current density under both continuous and intermittent electrochemical charge/discharge was conducted, which further demonstrated the superiority of this hybrid electrolyte. Finally, as a practical illustration, the pouch cells of 3 cm×3 cm exhibit a high capacity of 300 mAh g −1 at 0.1 A g −1 with a good retention of 81.7 % after 200 cycles, and even up to 500 cycles at 0.5 A g −1 . This work is expected to provide new opportunities for high‐performance hybrid electrolyte for the practical ZMBs.