Long‐Term Serviceable Ionic Thermoelectric Hydrogel with Temperature and Moisture Dual‐Driven Waste Energy Harvesting Capability

Abstract Despite the substantial progress in developing high‐performance quasi‐solid hydrogels based on ionic thermophoretic migration, ionic thermoelectric materials (i‐TEs) show unsatisfactory long‐lasting stability caused by ionic migration failures and de‐electrolytes. In this work, by enriching oxygen‐containing functional groups in the gel network and constructing oriented ionic transport nanochannels, an innovative approach is presented to reach long‐term service and reusability for i‐TEs without sacrificing their TE properties. The as‐prepared hydrogel with thermopower of 17.0 ± 1.0 mV K −1 stables at 82% of its original performance when immersed in the electrolyte. Notably, even after being air‐dried for 135 days, its thermopower returns to 87% of the original value through replenishing electrolyte solution and its 3D shape fully recovers. Meanwhile, the dual‐driven nature for moisture and temperature as well as the pH sensitivity of this network is systematically investigated. The maximum output voltage of a single sample reaches 0.215 V at a Δ T of 3.7 K, and it works continuously for more than 26 h. This study offers a new approach to overcoming the short‐term service bottleneck of i‐TEs and provides a practical scheme for the multi‐source drive of self‐powered TE equipment.