3D reduced graphene oxide aerogel supported TiO2-x for shape-stable phase change composites with high photothermal efficiency and thermal conductivity

Photothermal conversion, thermal energy transportation and storage are crucial in solar energy utilization. Due to the complexity of synthesis technology, it remains a hot issue to achieve the integration of high photothermal conversion, thermal conductivity and energy storage for phase change materials (PCMs) in recent years. As a typical carbon aerogel, reduced graphene oxide (RGO) aerogel exhibits the porous structure and outstanding properties, which makes RGO aerogel an attractive material for compounding with phase change materials. In this work, RGO aerogel is prepared by the hydrothermal-freeze drying method, which can effectively solve the issue of PCMs leakage. Oxygen-deficient TiO2 (TiO2-x) can further enhance the optical performance and improve the thermal conductivity of composite materials to 1.22 W/(m.K). The optimum TiO2-x content is 80%, which can obtain 89.9% photothermal conversion efficiency for TiO2-x/RGO@PW. TiO2-x/RGO aerogel will bring a new paradigm for PCMs as the working medium in absorption solar energy.