In order to meet the requirements for both high thermal conductivity and large latent heat storage and release of thermal management materials for spacecraft, a multidimensional carbon-based, thermally enhanced microencapsulated phase change composite is prepared by using a hot-pressing technique in this work. This method solves the limitations of traditional phase change materials, which suffer from low thermal conductivity and a propensity for liquid leakage. The effects of different content values and ratios of microencapsulated phase change materials, flake graphite, and pitch-based carbon fibers on the composite’s thermal properties, specifically thermal conductivity and latent heat are systematically investigated by integrating experimental assessments with finite element numerical simulations. Furthermore, the mechanism for forming an internal multidimensional heat conduction network is elucidated.

These results indicate that introducing multidimensional thermally conductive materials into the microencapsulated phase change system, can establish a continuous and dense multidimensional carbon-based conduction network through optimizing component composition and structure. Using the synergistic effects of these conductive materials and a multi-size flake graphite filling strategy, the overall thermal conductivity of the composite is significantly enhanced, reaching 1.021 W/(m·K), while maintaining a high latent heat of 81.540 J/g. These findings provide theoretical and practical guidance for optimizing and applying advanced thermal management materials to spacecraft.