Flexible thermo-electrochemical cells using Iodolyte HI-30 for conversion of low-grade heat to electrical energy

Abstract

In this research work, we investigated the flexible thermo-electro chemical cells (TECs) for the conversion of low-grade heat into electrical energy in the temperature range of 20–70 °C. The TECs were fabricated using 30 mM iodide/tri-iodide (Iodolyte HI-30) in acetonitrile as a redox couple. A TEC consists of a carbon/Iodolyte HI-30/carbon structure. The cell contains a flexible polymer tube, filled with the electrolyte, whereas the openings of the tube have been sealed using carbon electrodes. Gradients of temperature (ΔT) up to 50 °C have been created. The Seebeck voltages and short-circuit currents (I_sc) were found to be 8–17 mV and 100–425 μA, respectively, in the 20–70 °C temperature range. It was found that the TECs could provide sufficient power to drive low-power electronic devices and could be used for measurement of temperature gradients as well. Furthermore, this work identifies the directions for realizing flexible thermo-electric cells that can be potentially used for several applications in the medical segment where, besides electrical and mechanical stability, flexibility is paramount.