Boosting Performance of Quasi-solid-state Zinc Ion Batteries via Zincophilic Solubilization

Abstract

Hydrogel electrolytes hold great promise in tackling severe issues facing aqueous zinc-ion batteries (AZIBs). However, to satisfy the quest of flexible and eco-friendly batteries, developing low-cost and high mechanical durability hydrogel electrolyte remains a challenge. Here, employing the zincophilic solubilizer urea, we break the classical concentration limits of the low-cost Zn(Ac)2 salt and introduce it into the hydrogel skeleton. The “salting out” effect give the polymer chain sediments a tighter bundle and twist effect. The as-formed hydrogel electrolyte can endure 557% high elongation and 3.7 MPa compressive strength to resist repeated zinc plating/striping process and external physical stimuli. The in-situ polyurea solid electrolyte interphase (SEI) layer leads to thermodynamically stable anode/electrolyte interface. Utilizing the hydrogel electrolyte, the zinc anode shows high reversibility, leading to an average Coulombic efficiency (CE) of 99.93% for 150 cycles on the Zn//Cu battery. When assembled with NH4V4O10 cathode (NVO), the full battery delivers a high capacity of 253.8 mAh g-1 beyond 1000 cycles longevity at 1 A g-1. The pouch battery also shows a high capacity of 280.7 mAh g-1 at 500 mA g-1 and operate steadily for 90.13% retention after 200 cycles, and maintained a stable voltage even experienced bending and folding.