Temperature gradient independent thermoelectric conversion based on asymmetric interfacial ion rearrangement

Ionic thermoelectric conversion based on Soret effect, a phenomenon of converting heat into electricity, has been popularized in establishing self-powering systems where thermal exchange is associated. It works in the presence of a temperature gradient, but becomes invalid if there is no significant temperature difference between two electrodes, especially in miniaturized devices and large thermal field. Herein, we break this cognition by discovering thermoelectric conversion in isothermal environments resulting from a heterogeneous system consisting of Metal A/Ionic liquid/Metal B. Asymmetric ion rearrangement is proposed on two ionic liquid/electrode interfaces when temperature varies, accounting for the generation of thermoelectric voltage. This principle can be applied to many electrodes/ionic liquids groups. The advantages of temperature gradient independence lay the ground for the creation of powerless thermometers to alarm large area of fire.