Improved low-temperature performance of supercapacitors by black TiO2/EGO photothermal film

The performance decay of energy storage devices such as lithium batteries and supercapacitors in low-temperature environment has been a serious challenge for their practical applications. While great effort has been dedicated to develop low-temperature resistant electrolytes, it remains to be addressed. In present work, we have developed a composite film consisting of black TiO₂ and electrochemical graphene oxide (EGO), which enables localized high-temperature regions around energy storage devices in low-temperature environments through photothermal effects. The EGO is prepared by electrochemical oxidation of graphite foil. Black TiO₂, as a photothermal material, possesses excellent light absorption properties and stability. The resulted black TiO₂/EGO composites significantly improve the overall energy conversion efficiency at low temperatures. Supercapacitor encapsulated within black TiO₂/EGO demonstrates excellent low-temperature resistance, with specific capacitance increased by 351.12 % at −30 °C and by 283.34 % at −15 °C. The photothermal conversion material proposed in this study maintains high thermal conversion efficiency in low temperature environment, showing its considerable application potential.