Full-spectrum light-driven phase change microcapsules modified by CuS-GO nanoconverter for enhancing solar energy conversion and storage capability

Due to the low direct thermal effect of solar irradiation, conventional phase-change microcapsules have poor solar energy utilization capability. To increase the solar-to-thermal energy storage efficiency, in this work, we reported a light-driven microencapsulated n-eicosane based on a crystalline TiO2 shell coated by graphene oxide (GO)-based copper monosulfide (CuS) (CuS-GO) nanoconverter. Due to the combination of local surface plasma resonance (LSPR), semiconductor and synergetic effects, the CuS-GO nanoconverter conferred full-spectrum solar light-to-thermal conversion capability on the microcapsule system. The resultant n-eicosane@TiO2@CuS-GO microcapsules achieved high full-spectrum solar-to-thermal storage efficiency (97.1%) under stimulated solar light with no compromise of the latent heat density (212.0 ± 1.2 J/g). Furthermore, the thermal conductivity of n-eicosane@TiO2@CuS-GO (0.985 ± 0.004 W/(m·K)) significantly increased by 39.9% compared with that of n-eicosane@TiO2. These results indicate that this light-driven microcapsule with superior properties is advantageous for direct solar-to-thermal energy utilization applications. [Display omitted] •CuS-GO nanoconverter encapsulated the microcapsules uniformly like a second shell.•The light-driven microcapsules exhibited full-spectrum absorption and conversion capability.•The solar energy storage efficiency was improved up to 97.1%.•The thermal energy storage capability of the microcapsules was 212.0 ± 1.2 J/g with high encapsulation ration (86.5%).