Biomass-based flexible fire warning sensor with excellent flame retardancy and sensitivity

Traditional fire warning sensors usually work under directly fire attack or relatively high temperature with short service life and poor sensitivity. Therefore, the preparation of thermosensitive sensors with excellent fire resistance, sustainability and sensitive fire detection function is critical. In this work, biomass-based carbon nanofibers (CNFs) are designed and constructed by phosphating treatment and polyaniline modification co-functionalization strategy. The introduction of lignin molecules significantly improves the compatibility and spinnability of polyaniline and biomass-based spinning aid, thus effectively reducing the generation of the bead like defects and fine fibrous morphologies. The optimized CNFs exhibit good structure stability, electrical conductivity and sensitivity (responsive temperature 100 ℃, thermosensitive sensor response about 2 s, and sustained working time at least 5 min in the flame). Furthermore, the specific capacitance of biomass-based CNFs reaches 358F/g, energy density of 49.7 Wh/kg at a power density of 542.4 W/kg. This work provides a novel strategy and paradigm for achieving excellent flame resistance and ideal fire warning sensor of biomass-based materials. The resulting biomass-based carbon nanofibers can be processed into intelligent thermosensitive sensor with various shapes and have a broad application prospect in flexible devices and wearable electrodes fields.