A novel flexible carbon fiber with carbon nanotubes growing in-situ via chemical vapor deposition to impregnate paraffin for thermal energy application

Aiming at solid waste resources reuse and energy saving issue, a novel flexible paraffin/carbon fiber@carbon nanotubes (Paraffin/CF@CNTs) composite PCM was prepared in this study. In the flexible composite PCM, CNTs grew in-situ surrounding by recycled CF trunk via chemical vapor deposition to construct the fiber net-structure utilized as the supporting material, and paraffin as a thermal energy storage material was absorbed into spongy CF@CNTs by vacuum impregnation methods. The prepared Paraffin/CF@CNTs composite has a best solid-liquid phase change latent heat of 81.94 Jg −1 after solid-solid phase transition with 15.28 Jg −1 , and still keep the high latent heat retention of 99.4 % even after being subjected to 300 melting/freezing cycles. The thermal conductivity of Paraffin/CF@CNTs composite (1.551 Wm −1  K −1 ) is enhanced by up to 573 % than that of pure paraffin, while this composite exhibits the good thermal stability that it decomposes over 215.6 °C with totally 51.9 % mass loss. Overall, the novel flexible Paraffin/CF@CNTs composite PCM behaves very stable performances in structure, chemical component, thermal storage and thermal stability, looking promising for applications in electronic device temperature control, near-infrared stealth, smart wear and textile industries.