• Sarma, Rajkumar
• Hardt, Steffen

Abstract

number of thermoelectric materials that show a very pronounced thermoelectric response have been reported in the literature. The Seebeck coefficient, a measure of the thermovoltage generated per temperature difference applied across a layer of material, is often higher for electrolyte-filled nano-confinements than for solid-state thermoelectric devices. Recently, it was reported that room-temperature ionic liquids (RTILs) and highly concentrated aqueous electrolytes, despite having large ion concentrations, yield electric double layers with a thickness of some nanometers [1]. This can be explained by the fact that the charge carriers in these electrolytes are not the elementary ionic constituents but are pseudoparticles, i.e. clusters of many ions which can partially dissociate in a thermally activated process. The number density of the effective charge carriers in such thermally activated electrolytes (TAEs) is, therefore, a function of temperature and is usually described by an Arrhenius equation. We study the thermovoltage generation in such TAEs using a theoretical framework based on the coupled Poisson-Nernst-Planck and heat transport equations. The results indicate that a TAE yields a significantly higher Seebeck coefficient than a dilute electrolyte. This can be explained by the charge carrier concentration gradients that form due to the thermally activated charge carrier formation. The study reveals that confined TAEs bear a significant potential for thermoelectric energy conversion. Additional information: This presentation was delivered online by Dr. Rajkumar Sarma at the International Workshop on Thermo-electrochemical Devices 2023 (IWTED 2023). The International Workshop on Thermo-electrochemical Devices (IWTED) 2023 was held in the serene coastal town of Benicàssim, Spain, from September 7th to 8th, 2023. It marked a significant milestone in the realm of renewable energy generation and storage. This event was a unique platform dedicated entirely to thermo-electrochemical systems, including thermo-electrochemical cells, ionic thermoelectric supercapacitors, and other devices that harness the synergy of electrochemical and thermal processes. TRANSLATE is a €3.4 million EU-funded research project that aims to develop a new nanofluidic platform technology to effectively convert waste heat to electricity. This technology has the potential to improve the energy efficiency of many devices and systems, and provide a radically new zero-emission power source. The TRANSLATE project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement number 964251, for the action of 'The Recycling of waste heat through the Application of Nanofluidic ChannelS: Advances in the Conversion of Thermal to Electrical energy'. More information can be be found on the TRANSLATE project website: https://translate-energy.eu/

Topics

• density
• impedance spectroscopy
• cluster