Three-dimensional electrospinning and catalytic graphitization directly prepared high flexibility, elasticity and graphitization interwoven crimp micro/nano-carbon-fibrous aerogels

This study presents a effective approach for fabricating highly graphitized, flexible micro/nano-carbon-fibrous aerogels (MNCFAs) using an integrated sol humidity-regulated electrospinning technique combined with an iron-catalyzed graphitization. Through coordinating polyacrylonitrile (PAN) with Fe³⁺ ions, a template-free, one-step 3D electrospinning process to directly produce self-supporting PAN aerogel precursors is achieved. After pre-oxidation and iron-catalyzed carbonization, the MNCFAs exhibit remarkable properties, including an ultra-low density of about 8.0–15.9 mg cm⁻³, superior flexibility, superelasticity retaining 87 % stress after 1000 cycles, excellent thermal insulation with a conductivity of about 0.039 W m⁻¹ K⁻¹, and outstanding electrical conductivity exceeding 1.42 S cm⁻¹. Importantly, the iron catalyst enables high graphitization at a moderate temperature of 1200 °C, overcoming the low conductivity typical of electrospun carbon aerogels. The MNCFAs also demonstrate a stable piezoresistive response with high sensitivity over a wide operational range from −196 °C to 300 °C, 163.5 kPa⁻¹ at low pressure and 83.2 kPa⁻¹ at high pressure, making them ideal for flexible piezoresistive sensors. This synthesis method enhances production efficiency and opens new possibilities for designing multifunctional aerogels for next-generation intelligent robotics and extreme-environment sensing applications.