Highly flexible and harsh temperature-tolerant single-electrode mode triboelectric nanogenerators via biocompatible ionic liquid electrolytes for wearable electronic applications

Conductive ionic liquid electrolytes have attracted increasing attention because of their remarkable energy harvesting and storage characteristics for utilization in triboelectric nanogenerators and energy storage devices, respectively. Especially, the ionic conductive liquid electrolyte-based energy harvesting device that can operate with high efficiency and stability in harsh temperature conditions is greatly needed for urgent rescue and wilderness exploration. Herein, the dual-function nature of carboxymethyl cellulose (CMC), water, and glycerol was employed as an electrolyte as well as an electrical conductor for single-electrode triboelectric nanogenerator (TENG) and supercapacitor applications. The biocompatible ionic liquid electrode-based single-electrode TENG (LSE-TENG) exhibits superior performance with an optimized CMC concentration of 3 wt%. Furthermore, by incorporating an additional ionic compound (NaCl) in the optimized CMC-based ionic liquid solutions, the performance of the LSE-TENG and the electrochemical properties are largely enhanced. With the anti-freezing and anti-dehydration properties of glycerol, the fabricated LSE-TENG delivers stable electrical output performance in the low temperature (−20 °C) to high temperature (70 °C) range. The power density of the 3 wt% NaCl-based LSE-TENG increases by 11 folds as compared to the CMC-based LSE-TENG. In addition, the LSE-TENG is integrated with a sensor for anti-theft applications. The present study demonstrates an innovative engineering technology for fabricating high-performance TENGs that can prove enormous interest in flexible and wearable applications.