Cost-efficient nickel-based thermo-electrochemical cells for utilizing low-grade thermal energy

Abstract Utilizing low-grade waste heat by thermo-electrochemical cells (TECs) has recently attracted considerable attention. TECs are easily maintained and exhibit simple structures and flexibility; therefore, they have been proposed as an alternative to thermoelectric devices for utilizing thermal energy harvesting. Nonetheless, TECs use costly platinum (Pt) or nanostructured carbon electrodes, which limits their widespread applications. In this study, a cost-effective nickel-based TEC is developed by controlling the pH of an electrolyte in the immunity or passivation window of nickel (Ni). Notably, our Ni-based TECs have displayed similar performance comparable to that of a Pt electrode. Moreover, the performance and corrosion tolerance of the Ni-based TEC system is higher than that of a carbon electrode. Considering economic aspects, Ni ($15 per kg) costs January 2000 of Pt ($29,700 per kg) and 1/10 of multiwalled nanotubes (MWNTs). The cost per power of the Ni-based TEC ($0.36 W−1) is calculated nearly 1/3500 of that of the state-of-the-art carbon nanotube aerogel sheet electrode. We demonstrate that Ni electrodes operating under alkaline conditions is proposed as a promising alternative to Pt or nanostructured carbon electrodes, possibly facilitating to the commercialization of TECs.