Polydopamine/copper nanoparticles synergistically modified carbon foam/ octadecanol composite phase change materials for photothermal energy conversion and storage

Latent heat storage provides an efficient pathway to address the intermittent energy supply of solar irradiation as an energy source. Conventional organic phase change materials (PCMs) for latent heat storage possess the advantage of the high latent heat, but suffer from the poor sunlight absorption capacity and low thermal conductivity. Carbon foam (CF) has excellent sunlight absorption and superior porous properties, and copper nanoparticles (Cu) have superb thermal conductivity. In this study, a composite photothermal material, CF/Cu, was fabricated by in-situ growth of copper (Cu) nanoparticles on carbon foam (CF) surfaces via aqueous copper plating strategy. The adhesion properties of polydopamine (PDA) facilitated the in-situ growth process. CF/Cu was employed as a porous matrix for the encapsulation of octadecanol (OC), and a composite photothermal PCM (CF/Cu/OC) with superb photothermal conversion performance and high thermal conductivity was successfully prepared. The composite photothermal PCM containing 80 wt% OC showed a photothermal conversion efficiency of 81.6 % and a thermal conductivity of 3.17 W m- 1 K-1.-1 . The synergistic interaction between CF and Cu within CF/Cu/OC resulted in a dramatic improvement in photothermal conversion of CF/Cu/OC. In addition, CF/Cu/OC95 exhibits excellent thermal storage performance with the melting enthalpy reached 270.8 J g- 1 .