A High-Strength Ionic Conductive Hydrogel with Antifreezing and Moisturizing Properties for Flexible Strain Sensors and Triboelectric Nanogenerator

Conductive hydrogels, due to their exceptional stretchability, flexibility, and conductivity, exhibit promising potential for a wide range of applications in the field of flexible electronic devices such as wearable electronics, biosensors, and flexible energy harvesting devices. In this study, we employed a one-pot approach to incorporate tannic acid (TA) into a polyacrylamide/carboxymethyl cellulose sodium (PAM/CMC) semi-interpenetrating polymer network hydrogel and supplemented it with lithium chloride (LiCl). This approach led to the development of a physically cross-linked ionic conductive hydrogel (PCTL) demonstrating viscoelastic properties, outstanding tensile strength (534.07 kPa), remarkable antifreezing performance (nonfreezing below −20 °C), and superior moisturizing capabilities. The strain sensor fabricated from PCTL hydrogels exhibits an exceptionally broad detection range (0–400%) and high sensitivity (GF = 5.10), along with a response time (220 ms) and recovery time (160 ms), capable of monitoring rapid motions. Furthermore, the PCTL hydrogel-assembled triboelectric nanogenerator (PCTL-TENG) demonstrates an exceptional electrical output performance with an open-circuit voltage of approximately 70 V. This device has the capacity to power small electronic devices and facilitate information transmission. Therefore, the high-performance flexible strain sensor and TENG presented in this paper hold broad application prospects in man–machine interface systems, intelligent recognition systems, auxiliary control systems, and other fields owing to their excellent stretchable nature and high conductivity performance.