CuS Nanoparticle-Based Microcapsules for Solar-Induced Phase-Change Energy Storage

Abstract

Phase-change microcapsules with photothermal conversion capabilities have been the focus of research in the energy storage field. In this study, a route is developed to prepare photothermal conversion and phase-change energy storage microcapsules by copper sulfide-stabilized Pickering emulsion with dodecanol tetradecyl ester as the phase-change material (PCM) and melamine formaldehyde resin (MF) as a shell. Spherical CuS particles with a diameter of approximately 10 nm are first synthesized by a facile hydrothermal reaction. The obtained CuS nanoparticles are used not only as a stabilizer but also as a photothermal conversion material in the preparation of the microcapsules. Then, the PCM microcapsules are prepared by a one-pot interfacial polymerization route and showed a well-defined core–shell structure with an average size of approximately 7 μm. The synthesized microcapsules have a latent heat of up to 180.3 J/g and an encapsulation efficiency of 81.36%. Meanwhile, the thermal conductivity of the microcapsules increased by 115–254% compared to the core material due to the hybrid shell filled with CuS nanoparticles. The photothermal conversion capacity of the synthesized microcapsules is measured and calculated to be up to 85.6%, achieving light-induced phase change and further inducing the passive thermal cycle. This study provides a potential candidate for the application of light-induced energy storage microcapsules in fabric insulation, solar hot water heating systems, and solar thermal power systems.