A high power density photoactive thermal energy storage material for rapid heat release at low temperatures

Abstract

Developing of photoactive chemical heat storage materials with high power density and rapid heat release ability at low temperatures is a key challenge for efficient utilize of solar thermal energy. Herein, a photoactive chemical heat storage material is presented which fluorinated azobenzene (AzoF) is covalently attached onto reduced graphene oxide (rGO). The AzoF-rGO complex exhibits excellent heat storage density up to 364.4 kJ kg−1, maximum power density of 2419.7 W kg−1 and good storage half-life of 55.6 h because of the intermolecular hydrogen bond and the intermolecular interactions between azobenzene as a result of high attachment density. This AzoF-rGO complex also shows remarkable cycle performance through green light for 50 cycles without degradation and rapid heat release ability at low temperatures, which realizes high rate heat release for short-term rapid and concentrated heating. This work develops a promising AzoF-rGO photoactive chemical heat storage material, which not only has high heat storage density and power density but also realize the rapid heat release of stored solar energy at low temperatures, shows that it has great practical application potential in making full use of solar thermal energy in the future.