Self-powered wearable sensing devices based on a flexible ammonium-ion battery with fatigue resistance and frost resistance based on a strong and tough hydrogel

As a new type of flexible electronics, without an external power supply, wearable self-powered sensing devices have attracted more and more attention. However, poor flexibility, anti-fatigue and anti-freezing properties limit their applications. Hence, we synthesized a physically crosslinked poly(N-hydroxyethyl acrylamide)/ammonium sulfate/glycerol (PHEA/AS/Gly) ionic conductive hydrogel by means of photoinitiation and soaking, and the synthesized hydrogel exhibited high strength and toughness, good ionic conductivity, quick self-recovery, as well as excellent mechanical and sensing properties of fatigue and frost resistance. Based on the PHEA/AS/Gly hydrogel, a novel flexible ammonium-ion battery and a flexible sensor were designed and prepared to assemble self-powered wearable sensing devices, which exhibited highly sensitive, ambient-stable, long-term fatigue-resistant and frozen-resistant electrochemical/sensing performances, as well as deformation-insensitive electrochemical properties, and could detect different human movements sensitively and stably without an external power supply at room and low temperatures or after long-term storage. Therefore, this work will provide a simple strategy to fabricate a self-powered flexible sensing system with integrated high performances for wearable smart electronics.