Exploiting High-Voltage Stability of Dual-Ion Aqueous Electrolyte Reinforced by Incorporation of Fiberglass into Zwitterionic Hydrogel Electrolyte

Rechargeable zinc aqueous batteries are key alternatives for replacing toxic, flammable, and expensive lithium-ion batteries in grid energy storage systems. However, these systems possess critical weaknesses, including the short electrochemical stability window of water and intrinsic fast zinc dendrite growth. Hydrogel electrolytes provide a possible solution, especially cross-linked zwitterionic polymers that possess strong water retention ability and high ionic conductivity. Herein, an in situ prepared fiberglass-incorporated dual-ion zwitterionic hydrogel electrolyte with an ionic conductivity of 24.32 mS cm(-1), electrochemical stability window up to 2.56 V, and high thermal stability is presented. By incorporating this hydrogel electrolyte of zinc and lithium triflate salts, a zinc//LiMn0.6Fe0.4PO4 pouch cell delivers a reversible capacity of 130 mAh g(-1) in the range of 1.0-2.2 V at 0.1C, and the test at 2C provides an initial capacity of 82.4 mAh g(-1) with 71.8% capacity retention after 1000 cycles with a coulombic efficiency of 97%. Additionally, the pouch cell is fire resistant and remains safe after cutting and piercing.

Automated summary

Rechargeable zinc aqueous batteries are potential substitutes for lithium-ion batteries in grid energy storage systems, but they face challenges such as the limited stability window of water and fast zinc dendrite growth. In this study, a fiberglass-incorporated dual-ion zwitterionic hydrogel electrolyte with high ionic conductivity and stability was developed. By using this electrolyte in a zinc//LiMn0.6Fe0.4PO4 pouch cell, excellent electrochemical performance was achieved with high capacity and retention after cycling, as well as fire resistance and safety even after cutting and piercing.