At the KTH Royal Institute of Technology, scientists report that they are close to developing a method to substitute batteries for low-power applications and wearables in the internet of things (IoT).
A piece of film is coated in thermoelectric ink. Image Credit: KTH Royal Institute of Technology.
The answer comes in the form of an ink coating allowing low-grade heat, produced by devices, to be transformed into electrical power.
As published in the journal American Chemical Society Applied Materials & Interfaces, the scientists from KTH in Stockholm reported that they have come up with a useful blend of thermoelectric coating for devices that have the potential to produce heat amounting to below 100 oC.
Thermoelectricity is known as the direct conversion of heat to electricity. It is feasible to capture the heat that a device produces and transform it into power that could be utilized by the same device, or another device. What is needed are uniquely-designed thermoelectric materials.
When one end of a thermoelectric material tends to heat up, charge carriers (electrons and holes) tend to shift from the hot end to the cold end, thereby leading to an electric current. One difficulty is in regulating the resistance and thermal conductivity with materials that could be employed in a huge area without lacking their performance over time.
Muhammet Toprak, Professor of Materials Chemistry at KTH, states that the study his team performed concentrated on the design and development of hybrid thermoelectric materials for room-temperature operations. This combines the solid-state semiconductors with adaptable materials like polymers, to devise inks.
Toprak states that the coating could be employed on any surface that dissipates heat, to produce electrical power. Also, the study makes progress in gaining better insights into the limitations and abilities of materials that have been utilized 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. 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.
Muhammet Toprak, Professor, Materials Chemistry, KTH Royal Institute of Technology
Toprak added, “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.”
The study was performed in collaboration with the University of Valencia, Spain, and the University of Warwick, UK.
This study received financial support from the Swedish Energy Agency (43521-1), the Swedish Research Council (VR, 2018-03462), and, in part, the European Union’s Horizon 2020 research and innovation program under the grant agreement No. 863222 (UncorrelaTEd).
Journal Reference:
Serrano-Claumarchirant, J. F., et al. (2022) Thermoelectric Inks and Power Factor Tunability in Hybrid Films through All Solution Process. ACS Applied Materials Interfaces. doi.org/10.1021/acsami.1c24392.