Hierarchical porous hollow carbon spheres derived from spirofluorene- and aniline-linked conjugated microporous polymer for phase change energy storage

Thermal energy storage with phase change materials (PCMs) offers a high thermal storage density for energy saving and management in greenhouses. However, the leakage of PCMs during the phase change process hinders their applications. Herein, to tackle this problem, PCM material of 1-octadecanol (ODA) was encapsulated in hierarchical porous carbon spheres (HCSPs) derived from a spirofluorene- and aniline-linked conjugated microporous polymer (SACMP) with a high specific surface area of～476.1 m 2 /g. The HCSPs showed an optimal heating rate of 0.14 °C/s, which was comparable to the charging rate of pure ODA, signifying a great potential for the thermal energy storage. The obtained HCSP/ODA composites had a high package of ODA (up to 80 wt%) and excellent shape stability without the leakage of ODA. The optimized HCSP/ODA composites show a high phase change enthalpy (～184.4 J/g) and good thermal cycling stability (169.5 J/g after 50 heating/cooling cycles), indicating a great potential for the stable thermal energy storage.