<p>Hydrated salt phase-change materials (PCMs) are difficult to widely use because of their problems, such as supercooling, phase separation, low thermal conductivity and loss of crystal water due to cyclic stability. In this paper, MCTs-Na₂SO₄·10H₂O/Na₂HPO₄·12H₂O-based phase-change materials were prepared using hydrogen peroxide-modified functional groups of cross-linked carbon tubes surfaces (MCTs) to improve the overall properties of the materials. The results show that after modification, microporous cross-linked carbon tubes' surface and channel structure show wrinkled and rough texture and are rich in hydrophilic functional groups, which is conducive to loading more phase-change energy storage materials. Based on the relationship between PCMs and MCTs, the thermal conductivity of carbon-based type phase-change energy storage material is predicted and compared with the actual test value. After 1000 solid–liquid phase cyclic tests, the latent heat loss of PCMs-0 was 14.50% and 34.72%, respectively, compared with that before the phase transformation cycle. The melting, latent heat loss of PCMs-3 is 5.48%, the solidification latent heat loss is 9.37%, and the stereotype phase-change energy storage material has better cycle stability.</p>