A Superior Flame‐Resistant and Wide‐Temperature Adaptable Yarn Lithium‐Ion Battery with a Highly Conductive Ionogel Electrolyte

Abstract Yarn batteries are extensively used in portable, flexible and wearable electronics due to their tiny volume, good flexibility and maximum compatibility with textiles. However, both the flammable organic electrolyte and the hydrogel electrolyte are not capable of solving safety issues. In this work, a poly(ionic liquid)(PIL)‐based ionogel was synthesized as an electrolyte with both superior flame resistance and high ionic conductivity. The flexible Li 4 Ti 5 O 12 //LiFePO 4 yarn battery based on the ionogel not only has the safety characteristic of incombustibility, but also guarantees stable electrochemical properties under cold and hot weather conditions.