Extreme condition-resistant flexible triboelectric nanogenerator and sensor based on swollen-yet-enhanced and self-healing deep eutectic gel

Abstract

Triboelectric nanogenerator (TENG) and sensor based on conductive gel have captured more and more attention, while they usually possess poor properties, limiting their wide applications in wearable flexible electronics, especially under extreme conditions (e. g., large force, damage and low temperatures) and long-term use. Herein, inspired by the simultaneous enlargement and enhancement of organisms, we propose a simple method of hydrogen bond self-crosslinking and metal salt-based deep eutectic solvent replacement to synthesize multiple hydrogen bonds-reinforced poly(N-hydroxyethyl acrylamide)/lithium chloride/ethylene glycol (PHEA/LiCl/EG) deep eutectic gel with a swelling yet mechanical and electrical enhancing behaviors, which has high transparency, high toughness and strength, quick self-recovery, good self-healing, environmental stability, low temperatures resistance and low friction. The PHEA/LiCl/EG deep eutectic gel-based TENG possesses excellent energy collection performance to supply power, and has good self-powered sensing performance based on energy harvesting. The PHEA/LiCl/EG deep eutectic gel-based sensor exhibits highly sensitive, long-term stable and fatigue-resistant sensing performances, and can monitor various human movements. Even if they are damaged, or placed for a long time or at low temperatures, the flexible TENG and sensor still have excellent energy harvesting or sensing performance. Therefore, this work presents a novel and simple method to design extreme condition-resistant and environment-stable wearable flexible electronics.