Hybrid network structure of boron nitride and graphene oxide in shape-stabilized composite phase change materials with enhanced thermal conductivity and light-to-electric energy conversion capability

Graphene oxide (GO) and boron nitride (BN) are introduced into polyethylene glycol (PEG) as supporting materials and thermally conductive fillers to improve shape-stability and thermal conductivity. The obtained PEG/BN/GO composite phase change material (PCM) with 4wt% GO and 30wt% BN exhibits a thermal conductivity as high as 3.00Wm^‑1K^‑1, 10-fold higher than that of pure PEG. Owing to the hybrid network structure of GO and BN in the matrix, the shape-stability of the composite PCM is greatly enhanced, even when compressed by a constant normal force of 5N as the temperature rises to 120°C. Simultaneously, the thermal energy storage density of the composite PCM reaches 107.4Jg^‑1, which ensures the potential application to realize an efficient light-to-electric energy conversion and storage. The composite PCM maintains stable thermophysical properties and chemical structure after 100 cycles of melting and freezing. The enhanced comprehensive performance of the composite PCMs contributes to enabling their practical application for effective energy conversion, storage and utilization, especially for the lasting renewable solar energy.