MXene Ti3C2Tx for phase change composite with superior photothermal storage capability

The latent heat storage of PCMs has gained increasing attention in the solar energy application field due to their high thermal energy storage density. However, the lack of energy conversion ability of the organic PCMs results in the low utilization efficiency of solar energy. Herein, we report a novel PEG/Ti3C2Tx layered composite PCM with superior photothermal storage capability, which consists of stacked Ti3C2Tx nanosheets and PEG filled within the spaces between the flakes. The resulting composites exhibited a strong absorption capacity for electromagnetic waves at the UV-Vis-NIR region. Notably, there are two enhanced absorption bands at the visible and near-infrared regions due to the localized surface plasmon resonance (LSPR) effect of the Ti3C2Tx nanosheets, which endows the composite PCM with excellent photo-to-thermal storage efficiencies (up to 94.5%) under actual solar light irradiation. In addition, the composite PCM also possesses a high energy storage density and form-stable property before and after the phase transition. These results indicate that the synthesized composite presents superior comprehensive properties suitable for solar energy storage applications.