Modulating Photons and Phonons in Graphene‐Based Phase Change Materials for Solar‐Thermal‐Electrical Generation

ABSTRACT Solar‐thermal‐electrical generators offer a promising route for the conversion of solar energy into electricity. Their reliability can be enhanced by integrating phase change materials (PCMs) to buffer thermal fluctuations and ensure stable operation, yet conventional PCMs often suffer from low thermal conductivity and poor solar capture. Herein, photosensitive Co/C‐anchored reduced graphene oxide (rGO) conductive framework was fabricated via metal‐organic framework (MOF) pyrolysis‐assisted zinc volatilization strategy. This design enables the in situ formation of MOF‐derived uniformly dispersed cobalt nanoparticles within rGO framework. After the encapsulation of paraffin wax (PW), the resultant rGO@Co/C‐PW composite PCMs demonstrate a remarkable solar‐thermal conversion efficiency of 92.5% under 100 mW·cm −2 irradiation, attributed to the synergistic interplay between the broadband absorption and non‐radiative relaxation of graphitic carbon and the localized surface plasmon resonance of Co nanoparticles. rGO@Co/C‐PW also exhibits enhanced thermal conductivity, high phase change enthalpy, and excellent long‐term cycling stability, supported by regulated non‐isothermal phase transition kinetics via heterogeneous nucleation and spatial confinement. When integrated into a thermoelectric module, a sustained and stable power output of 8.82 mW under 100 mW·cm −2 is generated, capable of powering small electronic devices. This study provides valuable insights into developing next‐generation PCMs integrating solar‐thermal conversion, thermal energy storage, and thermoelectric output.