Semi‐Solid Thermo‐Electrochemical Cell Based Wearable Power Generator for Body Heat Harvesting

A high‐performance TiO 2 /GO‐Fe 3+/2+ ‐based N‐type thermo‐electrochemical cell (TEC) is demonstrated and prepared P‐N combined power generator prototypes combining BST/FeCN 3‐/4− ‐based P‐type TEC that is reported in the previous work. The functional groups on the TiO 2 /GO in the electrolyte can adjust the solvation structure of Fe 3+/2+ to improve the S e value. In addition, TiO 2 acts as a relay reaction site to improve charge transport efficiency. The synergistic effect results in S e of 2.53 mV K −1 and a maximum output power density of 0.38 W m −2 . Besides, both flexible and rigid power generator prototypes are prepared. It is worth noting that the flexible prototype can generate an open‐circuit voltage of 1.27 V and power an electronic watch by using the temperature difference between the human body and the environment. This work demonstrates the potential of TEC for low‐grade heat energy recovery and powering wearable devices.