In-situ physical/chemical cross-linked hydrogel electrolyte achieving ultra-stable zinc anode-electrolyte interface towards dendrite-free zinc ion battery

Hydrogen evolution reaction (HER), zinc corrosion, and dendrites growth on zinc metal anode are the major issues limiting the practical applications of zinc-ion batteries. Herein, an in-situ physical/chemical cross-linked hydrogel electrolyte (carrageenan/polyacrylamide/ZnSO4, denoted as CPZ) has been developed to stabilize the zinc anode-electrolyte interface, which can eliminate side reactions and prevent dendrites growth. The in-situ CPZ hydrogel electrolyte improves the reversibility of zinc anode due to eliminating side reactions caused by active water molecules. Furthermore, the electrostatic interaction between the SO4−· groups in CPZ and Zn2+ can encourage the preferential deposition of zinc atoms on (002) crystal plane, which achieve dendrite-free and homogeneous zinc deposition. The in-situ hydrogel electrolyte offers a streamlined approach to battery manufacturing by allowing for direct integration into the battery. Subsequently, the Zn//Zn half battery with CPZ hydrogel electrolyte can enable an ultra-long cycle over 5500 h at a current density of 0.5 mA cm−2, and the Zn//Cu half battery reach an average coulombic efficiency of 99.37%. The Zn//V2O5-GO full battery with CPZ hydrogel electrolyte demonstrates 94.5% of capacity retention after 2100 cycles. This study is expected to open new thought for the development of commercial hydrogel electrolytes for low-cost and long-life zinc-ion batteries.