A High Thermal Conductive Composite Phase Change Film for Flexible Solar/Electro-Thermal Energy Conversion

The applications of phase change materials (PCMs) in solar energy utilization, wearable thermal management and electro-thermal energy storage make it urgent to develop flexible PCMs with high thermal conductivity, electrical conductivity, morphological stability, and solar absorption capacity. Herein, we successfully fabricated a flexible multi-functional composite PCM film by adopting interwoven carbonized bamboo fibers (CBF) as the electrical and thermal conductive framework, with the introduction of polyvinylidene fluoride (PVDF) as the binder to enhance strength and flexibility and flexibility and paraffin as the thermal storage material. Besides, the introduction of Ti3C2Tx as a photon capturer and heating molecule further improved the solar-thermal conversion capability. The composite PCM films exhibited considerable flexibility, favorable thermal storage capacity (>103.6 J/g), and excellent long-term cycling stability. The interwoven electrical and thermal conductive skeleton endowed the flexible phase change films with satisfying electro-thermal conversion capacity and improving thermal conductivity, which further resulted in a promising solar-thermal conversion performance and remarkable Joule heating effect. The as-prepared flexible composite PCM films with excellent solar/electrothermal conversion responses would be suitable smart materials for future wearable thermal management application.