A robust TPU/PVA semi-interpenetrating polymer network gel electrolyte enabling high-performance zinc-ion batteries

Stretchable wearable electronics urgently require safe, flexible, and high-energy–density storage solutions. Aqueous zinc-ion batteries (AZIBs) show great promise due to their inherent safety, low cost, and environmental friendliness. Nevertheless, their large-scale practical implementation is hindered by unconstrained Zn dendrite growth and undesirable parasitic reactions occurring on Zn anodes. To mitigate these limitations, we developed a composite gel electrolyte based on thermoplastic polyurethane and polyvinyl alcohol (TPU/PVA). The semi-interpenetrating polymer network (semi-IPN) formed between TPU and PVA synergistically enhances both mechanical robustness and ionic transport. The electrolyte exhibits high ionic conductivity (42.7 mS cm −1 ) and Zn 2+ transference number (0.83). Its mechanical toughness suppresses dendrite growth, while polar groups promote uniform Zn deposition via solvation regulation. The Zn//Zn symmetric cell achieves stable cycling for more than 2500 h at 0.5  mA cm −2 , and runs for 2400 h at −20 °C. For the Zn//MnO 2 full cell, it delivers a specific capacity of 172  mAh g −1 at 5 A g −1 , and retains 95.8% of its initial capacity after 2000 cycles. Flexible pouch cells based on TPU/PVA also display stable performance under bending, highlighting their potential for flexible electronics. This work offers a viable electrolyte design strategy for high-performance, safe, and flexible zinc-ion batteries.