Conductive Polymer/Multidimensional Carbon Composite on Graphite Felt Electrodes for Liquid Thermo-Electrochemical Cells

Thermo-electrochemical cells (TECs) are a promising technology that can convert waste heat into electrical energy, offering an effective way to improve energy efficiency and mitigate greenhouse gas emissions. However, the power generation of TECs is often limited by the inefficiency of the electrodes. In this article, we design a conductive polymer/multidimensional carbon composite on graphite felt electrodes for TECs. The conductive polymer and multidimensional carbon composite enhance the effective surface area and improve the accessibility of reactive sites for redox reactions, addressing the difficulties of electron transfer to the surface and interface from the electrode. In addition, the open porous structure of the graphite felt electrode helps overcome the diffusion limitation of redox ions. An electrocatalytic relationship between the electrode properties and the redox reaction activity was studied. The results indicate that the multidimensional carbon structure facilitates mass transport with an increased ion diffusion coefficient from 7.71 × 10–12 to 7.29 × 10–11 m2/s, while the deposition of polyaniline effectively improves the intrinsic activity of the electrode with a 1.6- to 1.7-fold increase in the apparent rate constant for the redox reaction. The TEC with the prepared electrode delivers a maximum power density of 1664 mW/m2 and a Carnot-relative efficiency of 1.97%, which are 9.2 and 8.9 times higher than that with the bare graphite felt electrode. In all, this work provides a strategy for the design of efficient electrodes in TECs, guiding future research on efficient systems for waste heat conversion.