An Intelligent, Solar‐Responsive, and Thermally Conductive Phase‐Change System Toward Solar‐Thermal‐Electrical Conversion Featuring Daytime Blooming for Solar Energy Harvesting and Nighttime Closing for Thermal Preservation

Abstract To alleviate resource shortage and environmental pollution, solar energy can be converted into thermal energy stored in phase change materials and in turn generate electrical energy. To enhance the solar energy utilization efficiency of solar‐thermal‐electrical conversion devices and prevent the heat loss to the environment at night, an intelligent solar‐responsive phase‐change system is innovatively designed consisting of a graphene aerogel film/paraffin wax stamen with an ultra‐high thermal conductivity of 46.7 W m⁻¹ K⁻¹, and thermally preserving aerogel film/liquid crystal elastomer bilayer petals that can bend solar‐responsively by the synergistic effect of solar‐thermal energy conversion and heat‐induced contraction. The solar‐responsive phase‐change system achieves daytime blooming for solar‐thermal conversion with simultaneous energy storage and nighttime closing for minimizing heat loss to the environment, exhibiting a high solar‐thermal conversion and energy storage efficiency of 89.4% and delaying its temperature drop by the thermal preservation effect of the petals. The assembled solar‐responsive solar‐thermal‐electric generator can reach an output voltage of 1033.8 mV at a light intensity of 500 mW cm⁻² and continue to generate electrical energy during nighttime, holding tremendous promise in efficient solar energy conversion, storage, and utilization.