Multifunctional Electrospun Phase Change Material Mats for Solar-Thermal Energy Storage and Photothermal Conversion

Efficient solar-thermal energy conversion and storage demand materials that combine high latent heat with multifunctional performance were observed. Here, we report electrospun polyester-based phase change material (PCM) mats capable of simultaneous thermal energy storage and photothermal conversion. Among a series of PCMs, PPCM1218 (from 1,12-dodecanediol and octadecanedioic acid) showed the highest latent heat (157 J/g, melting point 90.6°C) and was incorporated into flexible, bead-free mats via blending with polyamide 11 to prevent leakage. Mats with high PCM loading retained up to 132 J/g enthalpy while maintaining mechanical integrity. Functionalization with biochar, graphene, or polypyrrole (PPy) enhanced stiffness, electrical, and thermal conductivity, with PPy-coated mats achieving 0.51 W/m·K and 18.5 S/m. Under 1.5 sun irradiation, surfaces exceeded 90°C, fully melting the PCM and demonstrating stable energy storage and release over 100 thermal and photothermal cycles. This approach offers a versatile platform for multifunctional electrospun mats suitable for high-temperature energy storage, solar-driven water purification, and thermal management applications.