Phase Change Composite with Core–Shell Structure for Photothermal Conversion and Thermal Energy Storage

The demand for a low-carbon lifestyle stimulates the high-efficiency utilization of solar energy despite its low conversion rate and intermittent nature. Based on this, a combined form of difunctional phase change composites (PCCs) integrated with phase change materials (PCMs) and photothermal conversion materials is put forward, which can simultaneously convert and store–release energy from the sunlight. First, CuS particles are in situ grown and deposited on the framework of a macroporous polyurethane foam (PUF) carrier to adsorb KAl(SO4)2·12H2O–C2H2O4·2H2O eutectic PCM and prepare semi-shape-stabilized PCM@PUF-CuS as the core. Second, a SiC–CuS modified silicone resin (MSR) thin layer is used as the shell that encapsulates PCM@PUF-CuS to construct a shape-stabilized PCM@PUF-CuS@MSR PCC. CuS can enhance the photothermal conversion and heat transfer abilities of the PCC. The photothermal conversion efficiency of the PCC reaches 51.25%, an increase of 279.35% compared with that without modification. The thermal conductivities of the core and shell of the PCC are 0.6682 and 0.5334 W m–1 K–1, respectively, an increase of 4.6 and 114.64% compared with those without modification. Meanwhile, thanks to the MSR thin layer, the PCC solves the leakage issue of the PCM under 60 °C and possesses outstanding thermal reliability displayed as consistent thermal properties, crystal phase, and composition after 100 heating-cooling cycles. This work proposes a novel assembly form of functional macroencapsulated PCCs, which uniformly distributes PCMs and photothermal conversion particles spatially.