Harvesting Low-Grade Waste Heat to Electrical Power Using a Thermoelectrochemical Cell Based on a Titanium Carbide Electrode

Thermoelectrochemical cells (TECs) are efficient energy harvesting devices that convert low-grade waste heat into electricity. However, TECs based on hexacyanoferrate (Fe(CN)64–/Fe(CN)63–, HCF) require high-cost metal electrodes such as platinum (Pt), hindering their commercialization. Herein, we introduce titanium carbide (TiC) electrodes formed via the thermal decomposition of CH4 as an alternative to Pt electrodes for TECs. Titanium is difficult to be used in TECs, whereas TiC is a promising non-noble metal electrode that can be used in various electrochemical systems because of its excellent stability and reaction kinetics. In this study, the power output of TiC-based TECs was measured to be 397.20 mW·m–2, which was almost the same as that achieved with Pt. Furthermore, we confirmed that TiC demonstrated long-term stability in the electrolyte under operation conditions. The results strongly indicate that TiC can replace Pt as an electrode, paving the way for the commercialization of TECs.