Exploring the Mechanism, Advancements, and Application of Thermogalvanic Effect in Hydrogels

Comprehensive Summary The issue of energy consumption has garnered significant interest due to its excessive usage. Recently, thermoelectric devices have been getting increased attention, as they can harness waste heat from various sources, such as solar radiation, human body, and industrial processes. Traditionally, the recovery of low‐grade heat has been a challenge, resulting in unsustainable energy use and significant losses. While considerable advances have been made in thermoelectric materials in recent decades, the majority of these devices still primarily employ semiconductors. Nevertheless, the emergence of quasi‐solid‐state thermoelectric materials represents a novel development with profound promise for the environment and society. These materials offer several advantages, such as improved energy conversion capacities, cost‐effectiveness, versatility, and scalability, to support increased usage. Additionally, this review explores the application of thermoelectric materials in self‐powered sensors, integrated modules, and heat harvesting management. Lastly, the potential of high‐performance thermocouples based on thermogalvanic effects is assessed, along with the challenges that must be overcome to realize this goal.