Electrospun carbon nanofiber-based flexible films for electric heating elements with adjustable resistance, ultrafast heating rate, and high infrared emissivity

Carbon nanomaterials have shown great potential as electric heating elements in electrothermal applications. However, carbon-based heating elements with high flexibility, ultrafast electrothermal response, low driving voltage, high heating temperature, and stretchability are still lacking. Here, continuous electrospun carbon nanofiber films (CNFFs) and corresponding composite films additionally containing silicone (CSCFs) as electric heating elements are proposed. CNFFs were prepared by electrospinning and subsequent heat treatment, and CSCFs were prepared by composing CNFFs with silicone via hot-pressing procedure. Both of them have shown excellent performance as electrothermal films, such as ultrafast electrothermal response, high resistance adjustability, high flexibility, high operation stability, and high infrared emissivity. In particular, a temperature as high as 200 °C can be reached within 2 s at 8 V. Suitable robustness and flexibility allow CSCFs to bear various deformations, such as bending, twisting, folding, and even stretching by a factor of 1.3, without worsening electrothermal performance. Also, excellent water resistance has been confirmed. The superior electrothermal performance is mainly attributed to the high electrical conductivity, continuous fiber structure, high specific surface area, and adjustability of nanofiber stacking density and thickness of CNFFs. Graphical abstract: [Figure not available: see fulltext.]