High-performance macro-encapsulated composite for photothermal conversion and latent heat storage

The request for green circular economy stimulates the use of solar energy. Capture and storage-release of solar energy can be simultaneously achieved by integrating photothermal conversion particles into phase change materials (PCMs) to obtain dual functional composites. Herein, a simple, cheap strategy for preparing 3D macro-encapsulated composite is proposed. Firstly, based on sizes difference, in situ grow nanoscale CuS coating on the surface of foamy Cu. The obtained CuS-Cu porous carrier adsorbs Na2S2O3·5H2O-CH3COONa·3H2O eutectic PCM to form semi-shape-stabilized PCM@CuS-Cu. Then, CuS-B4C modified epoxy resin (MEP) thin-layer macro-encapsulates PCM@CuS-Cu to fabricate PCM@CuS-Cu@MEP permanent shape-stabilized composite. The uniform distribution of CuS particles improves the heat transfer and photothermal conversion abilities of composite, as well as its exothermic accuracy shown as a low supercooling degree of only 0.740 °C. Photothermal conversion efficiency of PCM@CuS-Cu@MEP is 81.83 %, increased by 12.70 times compared with that of PCM (5.97 %). The MEP helps the composite to have leak-free performance under 60 °C for 72 h, and thermal reliability revealed as consistent thermal properties, crystal phase, composition after 100 heating-cooling cycles. The job provides a novel strategy to uniformly disperse PCM and photothermal conversion particles in space, ensuring the efficiently conversion and storage-release of energy. The preparative composite can capture solar energy and store-release thermal energy at the same time, which recycles the solar energy and conduces to green chemistry. It also has good photothermal conversion ability, heat transfer capacity, exothermic accuracy and thermal reliability, helping humans to seize renewable energy in the future. [Display omitted] •The macro-encapsulated PCM has high photothermal conversion of 81.83 %.•The macro-encapsulated PCM has simple, safe and economical preparation process.•The macro-encapsulated PCM has good heat transfer ability.•The macro-encapsulated PCM shows exothermic accuracy and thermal reliability.•The macro-encapsulated PCM uniformly disperses PCM and photothermal conversion particles.