Anhydrous Thermogalvanic Gel for Simultaneous Waste Heat Recovery and Thermal Management of Electronics

Due to their distinctive characteristics of adequate flexibility, stability, and functional diversity, thermogalvanic gels have demonstrated tremendous promise in the area of renewable energy sources. However, their inability to adapt to low or high temperature environments greatly limits their practical applications. In this work, an anhydrous thermogalvanic gel prepared from dimethyl sulfoxide (DMSO)/ethylene glycol (EG) binary organic solvent is developed with Fe3+/2+ as a redox pair, which displays an exceptional temperature tolerance (−80 to 80 °C) and remarkable antidrying property (80% weight retention at 70 °C after 12 h), while maintaining stable mechanical flexibility and electrical conductivity over a wide temperature range. These merits result from the formation of numerous hydrogen bonds between DMSO and EG molecules, which prevent crystallization and hinder evaporation of the solvent simultaneously. As an applicative demonstration, by placing the thermogalvanic gel on the surface of a charging battery/charger/chip, it acts as a thermal-conductive network while performing the thermal-electric conversion, revealing a viable strategy for simultaneous waste heat recovery and thermal management. This research provides new insight into the creation of flexible thermoelectric materials for energy recovery and self-powered wearable electronics.