Construction of Na2CO3·10H2O-Na2HPO4·12H2O eutectic hydrated salt/NiCo2O4-expanded graphite multidimensional phase change material

Structures of matrix channels are essential in the thermal performances of form-stable composite phase change material (fs-CPCM). As the special matrix in fs-CPCM, the expanded graphite (EG) has abundant pores and excellent thermal conduction channels, but it shows poor hydrophilia. In this study, the different dimensional NiCo 2 O 4 was selected to regulate controllably the microstructure of EG channels. Three kinds of NiCo 2 O 4 with one dimensional (1D) pine-needle-like, two dimensional (2D) honeycomb-like and three dimensional (3D) flower-like were used to modify EG (N-EG). A series of novel Na 2 CO 3 ·10H 2 O-Na 2 HPO 4 ·12H 2 O eutectic hydrated salt (EHS)/N-EG fs-CPCM with enhanced heat transfer and excellent thermal stability was developed. It was found that the 3D flower-like N-EG fs-CPCM possessed outstanding chemical compatibility, high latent heat (173.21 J/g), enhanced thermal conductivity (5.52 W/m·K), and great thermal reliability (−0.06 wt% weight loss). This work provides new insights that the matrix with 3D pore structures could be applied to encapsulate EHS, which is beneficial to obtain fs-CPCM with superior thermal properties.