Structurally Tunable High‐Thermal‐Conductivity Silicon Carbide Composites for Thermal Energy Storage

Abstract

In this study, silicon carbide foam ceramics (SFCs) were fabricated by a foaming method and subsequently infiltrated with molten NaCl to obtain SFC/NaCl composites. Adjusting the slurry solid content and foaming agent addition effectively tuned the pore structure and composite properties. A continuous, relatively dense SiC skeleton was identified as the primary origin of the enhanced thermal conductivity, whereas the amount ratio of cell window/cell governed the infiltration kinetics. Notably, the C2 composite exhibited an NaCl loading of 34.16 wt%, latent heat of 164.03 J/g, energy density of 992.70 J/g, compressive strength of 60.95 MPa, and thermal conductivity of 10.12 W/m K, representing a 628.06% increase over pure NaCl (1.39 W/m K). Moreover, 91.35% of the salt was retained after 400 thermal cycles. These results establish porous SFC as a promising skeleton material for high‐temperature ss‐phase‐change materials (PCMs) requiring high‐thermal conductivity, heat‐storage capacity, and cycling durability.