In-situ copper-loaded hollow porous carbon nanospheres derived from phenolic resin for thermal energy storage

Hollow porous carbon nanospheres (HPCS) are ideal scaffolds for phase change materials in thermal energy storage. However, their synthesis traditionally relies on template-based routes, involving tedious procedures and high costs. This study presents a facile method for preparing HPCS through one-step carbonization of phenolic resin using CuCl₂ as the activation agent. This mild activation agent not only helps create a rich porous structure, but also maintains the hollow spherical architecture of the polymer precursor. More importantly, copper ions are reduced to copper nanoparticles during the carbonization process and are in-situ loaded into porous carbon, enhancing the thermal conductivity of the scaffold. After incorporating paraffin, the resulting composite exhibits a high phase change enthalpy of 104.4 J g⁻¹, improved thermal conductivity of 0.95 W m⁻¹ K⁻¹, and excellent thermal cycling stability (100.5 J g⁻¹ after 50 heating-cooling cycles), indicating significant potential for thermal energy storage and management.