Bifunctional biomorphic SiC ceramics embedded molten salts for ultrafast thermal and solar energy storage

Abstract

Abstract Phase change materials (PCMs) are regarded as one of the most promising candidates for thermal energy storage due to possessing large energy storage densities and maintaining nearly a constant temperature during charging/discharging processes. However, the intrinsically low thermal conductivity of PCMs has become a bottleneck for rapid energy transport and storage. Here, we present a strategy to achieve ultrafast solar and thermal energy storage based on biomorphic SiC skeletons embedded NaCl-KCl molten salts. A record-high thermal conductivity of 116 W/mK is achieved by replicating cellular structure of oak wood, leading to an ultrafast thermal energy storage rate compared with molten salts alone. By further decorating TiN nanoparticles on SiC skeletons, the solar absorptance is enhanced to be as high as 95.63 % via exciting broadband plasmonic resonances. Excellent thermal transport and solar absorption properties enable designed composites to have bifunctional capabilities of harvesting both thermal energy and solar energy very rapidly. This work opens a new route for the design of bifunctional energy storage materials for ultrafast solar and thermal energy storage.