Diatomite porous ceramic-based phase change materials with Ti3C2Tx coating for efficient solar-thermal energy conversion

Based on the thermal energy storage and solar-thermal conversion of solid-liquid phase change materials (PCMs), they feature exceptional potential for energy-saving thermal insulation and solar energy utilization in buildings. However, the inherent low thermal conductivity, susceptibility to leakage and poor solar absorption of PCMs seriously restrict their practical applications. In this work, composite PCMs were fabricated by encapsulating paraffin with diatomite porous ceramics (DC) featuring hierarchical pore structures prepared by foaming and freeze-drying. Excellent sunlight absorption and solar-thermal conversion were achieved by spraying a Ti3C2Tx coating on the DC-paraffin surface. The as-prepared DC3-PA with 55.85 % loading on paraffin possessed a satisfactory thermal storage capacity of 112.1 J/g, maintained excellent stability, and improved the thermal conductivity by 107.25 %. The solar-thermal conversion and storage efficiency of DC3/T-PA is as high as 95.24 % under 200 mW/cm2 light intensity attributed to the large broad-band solar absorption and strong localized surface plasmon resonance (LSPR) effect of the Ti3C2Tx coating. This strategy combining hierarchical porous structured ceramic encapsulation and Ti3C2Tx coating surface modification was employed for obtaining highperformance shape-stable composite PCMs, which was expected to achieve potential applications in building energy efficiency, solar energy utilization, and thermal management.