Polyethylene glycol/polypyrrole aerogel shape-stabilized phase change material for solar-thermal energy storage and thermoelectric power generation

The efficient utilization of solar energy requires advanced heat storage technology, while phase change heat storage materials cannot utilize their high-density latent heat storage performance due to defects such as poor light absorption and leakage. To address these deficiencies, here, shape-stabilized phase change materials (SSPCMs) of polyethylene glycol (PEG) encapsulated by polypyrrole (PPy) aerogel were prepared through chemical polymerization and physical infiltration methods. Particularly, our findings demonstrated that PPy aerogel simultaneously enhances the shape stability and improves the solar-thermal conversion efficiency of PEG. The developed SSPCMs have a melting enthalpy of 142.4 J/g and 86% solar-thermal conversion efficiency. SSPCMs can maintain a stable shape, enthalpy value, and heat release time after 100 cycles. When used as a solar-thermal conversion material in a solar thermoelectric power generation system and thermal therapy, a long-term stable output voltage of 318 mV and temperature of 40–50 °C are generated, respectively, achieving effective conversion from renewable solar energy to applicable electricity and heat energy. This work may pave an effective way for the integrated design of encapsulating materials and light-absorbing materials in SSPCMs.