An Ionic Hydrogel-Based Antifreezing Triboelectric Nanogenerator

Abstract

The rapid development of stretchable electronics and soft robotics requires a sustainable power source that can match their mechanical stretchability in various working environments. Ionic hydrogel-based soft triboelectric nanogenerators (TENGs) show great promise for those application scenarios. However, ionic hydrogel-based TENGs suffer from the freezing issue under subzero temperatures. In this study, a low-cost, highly stretchable, and antifreezing ionic triboelectric nanogenerator (iTENG) is designed to involve a dielectric elastomer and a freeze-tolerant ionic hydrogel as the electrification layer and the electrode, respectively. The iTENG design achieves a unique combination of merits such as robust hydrogel–elastomer bonding, high stretchability (300%), and excellent tolerance of extremely low temperature (down to −53 °C). Because of the reliable interfacial bonding, the iTENG shows a good mechanical durability under different stretching conditions. The iTENG can harvest mechanical energies from various human motions and can also serve as a self-powered wearable sensor in both regular and extremely cold environments. The stretchable iTENG overcomes the strain-induced performance degradation of existing stretchable materials with percolated conductive fillers and the water freezing-induced degradation of conductive ionic hydrogels, providing a feasible design of stretchable and sustainable power sources for stretchable electronics and soft robotics operating in harsh environments.