Thermal performance enhancement of ceramics based thermal energy storage composites containing inorganic salt/metallic micro-encapsulated phase change material

Abstract

To simultaneously enhance the latent heat storage density per unit volume and thermal conductivity of inorganic salt/ceramic composites, metallic microencapsulated phase change materials (MEPCMs) that match the phase change temperature of inorganic salts were incorporated into them. In addition, industrial graphene, carbon fiber, and Sn were strategically introduced as thermal conductivity enhancers, while SiO₂ nanoparticles were utilized to optimize the specific heat capacity. The experiment results reveal that the most pronounced improvement in thermal conductivity was achieved through the synergistic effect of industrial graphene and Sn. Notably, the composite attained a thermal conductivity of 2.17 W m⁻¹ K⁻¹, marking a significant 128.4 % increase, when 3 wt% industrial graphene and 2 wt% Sn were incorporated. Meanwhile, the specific heat capacity was effectively enhanced by 8.9 % with the addition of 1 wt% SiO₂ nanoparticles into the inorganic salt matrix. The simultaneous enhancement of both thermal conductivity and specific heat capacity underscores the innovation of this composite design, as it overcomes the conventional trade-off between these properties. The optimized combination of 3 wt% industrial graphene, 2 wt% Sn, and 1 wt% SiO₂ nanoparticles establishes a synergistic thermal performance improvement, paving the way for next-generation high-efficiency thermal energy storage materials.