Ultra-light, ultra-resilient and ultra-flexible, multifunctional composite carbon nanofiber aerogel for physiological signal monitoring and hazard warning in extreme environments

The emergence of multimodal wearable flexible self-powered electronic devices undoubtedly plays a positive role in areas such as healthcare and energy. However, the preparation of three-dimensional elastic bodies suitable for humidity, temperature, and pressure sensing often involves complex fabrication processes, internal network discontinuities, and difficulties in achieving applications in extreme environments. In this paper, a one-step preparation of three-dimensional fluffy and interlayer porous nanofiber precursors is achieved using direct electrostatic spinning technology. Subsequently, high-temperature calcination and in situ polymerization processes were used to obtain multifunctional composite carbon nanofiber aerogels (MCCNA), which are characterized by ultra-lightness, super elasticity, three-dimensional fluffiness, and interlayer porousness, and are suitable for extreme environments. The ultra-light (53.67 mg cm−3) MCCNA can accurately detect humidity signals over an extremely wide range (10 %RH to 95 %RH), with a minimum temperature response time of 0.5 K. Its pressure response time is only 20 ms, and even after 5000 cycles of pressure loading, it still maintains a stable electrical signal response. Most notably, through demonstration, MCCNA can monitor the actions of firefighters in high-temperature and complex situations such as fires. Furthermore, it can monitor and provide high-temperature warnings for the temperature thresholds in the microenvironment of firefighting suits. The developed self-powered flexible wearable electronic device holds outstanding prospects for applications in healthcare, energy, and extreme conditions.