The ability to power sensors and other connected devices deployed in remote areas and throughout many internet of things (IoT) chains is challenging. University of Utah researchers have engineered a potential solution in the form of a self-charging pyroelectrochemical cell, which harvests thermal energy directly from the environment for conversion to stored electrochemical energy.

The device is charged by changing temperatures in the surrounding environment, whether inside a vehicle or under the soil. A pyroelectric material, such as porous polyvinylidene fluoride, serves as the separator of an electrochemical cell. When heated, the polarization of the pyroelectric separator decreases and produces a potential gradient that induces ion migration to charge the cell.

Under open circuit conditions, the cell charged by 0.65 mV after four applications of a 20° C–30° C–20° C thermal cycle. Laboratory testing demonstrated that the pyroelectrochemical cell could produce up to 100 microjoules per square centimeter from a single heating/cooling cycle. While this is not a large amount of energy, it should prove of value in powering IoT components.

Real-world field demonstrations are planned for the power harvesting system described in the journal Energy & Environmental Science.