Effect of Three-Dimensionally Connected Porous Hydroxyapatite Ceramics on Enhancing Heat Storage of Lithium Nitrate Phase Transformation Materials

As a medium-temperature phase change energy storage material, lithium nitrateLithium nitrate has many applications in phase change energy storage due to its excellent thermal properties and specific heat capacity. However, its inherent leakage and corrosion problems have adversely affected its continued development. A unique pore structure must be designed to solve the severe leakage problem. The porous hydroxyapatiteHydroxyapatite (Hap) ceramicCeramics (PHC) prepared by the microemulsion template methodMicroemulsion template method has a pore-window structure, uniform and controllable pore size, and three-dimensional permeability. Porous ceramicsPorous ceramics with different porosity can be obtained by adjusting the solid content, based on 80.2% porous ceramicPorous ceramics. The encapsulation of LiNO3 into permeable ceramicCeramics channels by the medium-temperature melting method can solve PCM's corrosion and leakage problems. In this work, the phase transition temperatures during melting and solidification are 255.7 and 235.8 ℃, and the latent heats are 240.2 and 252.2 J·g−1, respectively. The sample solids content is 35 wt%, and the maximum packing ratio is 78 wt%. Therefore, the prepared composite phase change materials (CPCMs) possess controllable three-dimensional poreThree-dimensional connected porous structures, excellent chemical properties, cycling stability, and chemical stability.