Thermal transport in nanostructured porous silicon composites with phase change materials

This study evaluates the thermal transport in mesoporous silicon (pSi, 45–65% porosity) infiltrated with hexadecane and docosane phase change materials (PCMs). Using gas-microphone photoacoustics, we demonstrate that PCM infiltration significantly enhances the matrix's thermal conductivity. Notably, 65% porous samples exhibited a 5.3-fold conductivity increase with solid docosane, compared to a 2.6-fold increase with liquid hexadecane. We attribute this enhancement, which depends on porosity and filler phase, to reduced phonon mean free paths and the formation of efficient thermal percolation networks within the nanostructured silicon. These pSi/PCM composites are highly promising for advanced thermal energy storage and management applications.