Efficient-thermal conductivity, storage and application of bionic tree-ring composite phase change materials based on freeze casting

Thermal energy storage, management, and utilization with phase change materials have received increasing attention in industrial fields such as photo-thermal-electric conversion and integrated circuit cooling. However, the inherent low thermal conductivity and melting leakage are long-term bottlenecks that prevent their widespread commercial application. Herein, a novel composite phase change material (CPCM) with high-thermal conductivity and stability based on bionic porous SiC skeleton is proposed, which is oriented by optimized freeze casting to design vertical tree-ring porous structure for fast photo-thermal conversion and storage. The results demonstrate the novel bionic SiC skeleton can regulate the porosity (50%–70%) by changing the slurry solid content, which also exhibits good anisotropic thermal conductivity. SiC/paraffin CPCM's mass and latent enthalpy of attenuated merely by 0.87% and 1.5% after 200 repeated heat storage/exhaustion cycles, confirming its excellent longevity and stability. The high-temperature SiC/NaCl-MgCl₂-KCl CPCM has a thermal conductivity of 12.54 W‧m⁻¹‧K⁻¹, an effective thermal-storage density per production cost of 74.5 kJ‧CNY^-1, and a high photo-thermal storage efficiency of 91.8%. Finally, a variable-power chip dissipation experimental system was built to verify the thermal performance of the CPCM module in the paper. It could dissipate heat rapidly and maintain a lower temperature. This work provides a promising strategy for photo-thermal utilization and thermal management of electronic devices.