Bamboo derived SiC ceramics-phase change composites for efficient, rapid, and compact solar thermal energy storage

Integrated solar thermal conversion and latent heat storage based on phase change materials (PCMs) has emerged as a promising way for improving solar thermal utilization by avoiding redundant energy transport processes. However, the poor solar absorptance and low thermal conductivity of PCMs prohibit achieving high solar thermal energy storage efficiency. Here, bamboo-derived silicon carbide (BSiC) eco-ceramics based phase change composites are proposed to realize efficient, rapid, and compact solar thermal energy storage. BSiC/paraffin demonstrates a high thermal conductivity of 40 W m⁻¹ K⁻¹ at the porosity of 66%, where 96% pores are filled with paraffin and no prominent deterioration is observed after 2500 cycles. By further loading TiN nanoparticles on BSiC skeletons, an ultrahigh solar absorptance of 96.23% is obtained due to exciting broadband plasmonic resonances. Subsequently, the solar-thermal energy storage efficiency achieves as high as 91.1% at 1.62 W cm⁻². The high-performance solar thermal energy storage benefits from continuous thermal conductive channels and excellent solar absorptance of BSiC/PCMs composites. For high temperature applications, BSiC/LiOH–LiF composites are developed and possess high thermal conductivity of 35.0 W m⁻¹·K⁻¹ and large latent heat of 309 kJ kg⁻¹ simultaneously, but corrosion problems need to be tackled before long-time utilization. This work paves the way for applying BSiC eco-ceramics in high-performance solar thermal energy conversion and storage.