Loofah-derived eco-friendly SiC ceramics for high-performance sunlight capture, thermal transport, and energy storage

Emerging integrated solar thermal conversion and latent heat storage has a great potential in harvesting solar energy continuously and efficiently by avoiding redundant energy transfer processes. However, the energy harvesting performance is limited by weak solar absorption and low thermal conductivity of phase change materials (PCMs). Here, loofah-derived eco-friendly SiC ceramics is proposed for fast, efficient, and compact solar thermal energy storage beyond state-of-the-art. We design a facile way to fabricate eco-friendly porous SiC ceramics with robust structure and tunable porosity by impregnating flour paste into loofah followed by carbonization and molten silicon reaction processes. After impregnation with NaCl-NaF eutectics, broadband sunlight capture with average solar absorptance of 95.25%, rapid thermal transport with thermal conductivity of 20.7 W/mK, and compact latent heat storage with energy storage density of up to 424 kJ/kg are demonstrated simultaneously. Highly conductive light SiC materials, hierarchical continuous loofah skeleton structure, and high energy density eutectics are attributed to this superior performance. This work opens new routes for efficient harvesting solar thermal energy based on biomimetic eco-friendly ceramics.