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 NiCo2O4 was selected to regulate controllably the microstructure of EG channels. Three kinds of NiCo2O4 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 Na2CO3·10H2O-Na2HPO4·12H2O 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. [Display omitted] •The NiCo2O4 with different dimensions were used to regulate the pore structures.•The fs–CPCM encapsulated by 3D flower-like N–EG matrix showed favorable thermal performances, including thermalconductivity, thermal stability, and thermal reliability.•The non-isothermal kinetics analyses of SCD–DHPD/N–EG fs–CPCMs were conducted.