Electrochemical Behaviour of Expanded Graphite for Thermogalvanic Cells and Thermally-Charged Supercapacitors Applications in Ionic Liquids

Abstract

In the present times of ever-increasing energy demands, escalating fuel prices and environmental concerns such as global warming, thermal energy harvesting emerges as a promising source of clean and sustainable energy. Thermogalvanic effect observed in liquid electrolyte-based thermoelectrochemical cells (TECs) offers direct heat to electricity conversion with zero gas emission. TECs in comparison to conventional solid-state thermoelectric materials are reliable, cost effective and require little maintenance, as they have no moving parts. Furthermore, these TECs can also serve as potential storage devices for waste-heat energy, which can be later recovered and converted into electrical energy. The objective of the present work is to study the combinations of different expanded graphite electrodes with different ionic liquid based electrolytes using traditional electrochemical methods such as open circuit potential, cyclic voltammetry and electrochemical impedance spectroscopy, coupled with the thermoelectric characterizations. The results allow a better understanding of the thermoelectrochemical energy conversion and stored charge efficiency in thermogalvanic cells and thermally-charged supercapacitors. This work is supported by European Union’s Horizon 2020 research and innovation programme under the grant agreement No 731976 (MAGENTA).