STEG devices coupled with circuit control achieving the conversion and storage regulation of solar thermal energy into electrical energy

A thermoelectric generator (TEG) device is capable of converting heat into electrical energy, the thermoelectric efficiency of which is primarily determined by the ZT value of the thermoelectric materials and the internal temperature difference. Consequently, for a constant ZT value, augmenting the thermal energy capture capacity of the TEG device to establish a significant internal temperature gradient emerges as a pivotal strategy for enhancing its thermoelectric efficiency. Spinel-type photothermal conversion (PTC) materials are capable of efficiently capturing solar irradiation and converting it into thermal energy, making them formidable candidates in the synthesis of PTC coatings and the enhancement of thermoelectric conversion efficiency of solar thermoelectric generators (STEG). However, the inherent defects of solar irradiation cause STEG devices to encounter output voltage instability, poor stability, and even insufficient output voltage, hindering efficient energy conversion and storage. Herein, the synthesized CuCr 2 O 4 spinel-type PTC material has been deposited onto the surface of the TEG device to construct the STEG device, which demonstrated a steady-state output voltage ( V opt ) of 133.9 mV and a maximum output power density ( P max ) of 68.8 μW cm -2 , exceeding 4.5 and 18.1 times that of the TEG device. Subsequently, a booster circuit was designed as the circuit control to stabilize and amplify V opt , thereby enabling the charging of lithium batteries and the powering of small sensors. This work elucidates the mechanisms of coupling STEG devices with circuit control to achieve the conversion and storage of solar thermal energy into electrical energy.