Thermoelectric ink paves way to battery-free IoT devices

Thermoelectricity is the direct conversion of heat to electricity. It’s possible to capture the heat that a device generates and convert to power that can be used by the same device, or another device. 

Researchers from KTH Royal Institute of Technology in Stockholm report that they have developed a promising blend of thermoelectric coating for devices that generate heat. 

When one end of a thermoelectric material is heated up, charge carriers (electrons and holes) move away from the hot end towards the cold end, resulting in an electric current.  

Researcher Muhammet Toprak said his team focused on the design and development of hybrid thermoelectric materials for room-temperature operations, which integrates solid-state semiconductors with flexible materials such as polymers, to formulate inks. 

The coating can be applied to any surface that dissipates heat, to generate electrical power. The research also makes headway in gaining better understanding of the capabilities and limitations of materials used for hybrid thermoelectric material design. 

“These results open a new low-cost and sustainable way of producing and implementing thermoelectric coatings on a large scale,” Toprak added. “In the short term, this is expected to make an impact for IoT and other low-power applications. It could replace batteries by being integrated as a coating in the form of wearable electronics. 

“In the long run, with the use of more sustainable inorganic thermoelectric materials compositions and sustainable biopolymers, such as cellulose and lignocellulose (or plant matter), the use of this technology on large areas will impact the adaptation of thermoelectric technology for efficient heat-to-power energy harvesting, as a complementary means to green transition.” 

Earlier this week, another team demonstrated a system that simultaneously broadcasts 5G signals and wireless power for IoT devices.