Hybrid electrodes exhibit intriguing properties due to the synergetic effect of different components that are propitious for the practical applications of thermo-cells (TECs). In this study, Ag–carbon nanotube (CNT) hybrid electrodes were prepared using two simple and effective steps, involving the direct growth of CNTs on stainless steel substrates without any external catalyst, followed by decorating the CNTs with Ag nanoparticles. Ag–CNT electrodes were characterized via scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy and were applied in TECs for the first time. The TEC performances of the Ag–CNT electrodes were significantly enhanced compared to that of the pristine CNT electrode due to their better conductivity and thermal conductivity, as well as more activation sites. The results show that the construction of Ag–CNT hybrid electrodes can effectively improve the TEC performances of CNT electrodes, which is promising for heat energy harvesting by CNT-based electrodes.