Three-dimensional layered multifunctional carbon aerogel for energy storage and pressure sensors

Carbon aerogel has a broad application prospect in various intelligent electronic devices. However, due to the complex preparation process and poor mechanical properties of carbon aerogel, its practical application was seriously affected. Therefore, in this study, a low-energy bidirectional freezing method was designed, using natural renewable cellulose nanofibers (CNF) and chitosan (CS) as biological matrix, and graphene oxide (GO) as conductive filler to successfully prepare a high-performance multi-functional carbon aerogel. Its ordered three-dimensional sheet microstructure is conducive to stress transfer and electron transfer. The test results show that the carbon aerogel has a large specific surface area (622.79 m2/g) and can withstand 80 % high compressive strain. The carbon aerogel electrode material showed high specific capacitance in 3 M KCl electrolyte in the three-electrode system (299 F/g at 1A/g). The assembled symmetric solid-state supercapacitors were tested in a two-electrode system with excellent area-specific capacitance (381.8 mF/cm2 at 1.8 mA/cm2) and cycle stability (10,000 cycles, capacitance retention rate of 86.2 %). In addition, the carbon aerogel exhibits an excellent linear sensitivity of 25.2 kPa−1, which can be assembled into pressure sensors to monitor human biological signals such as fingers, wrists and throat in real time. These excellent properties enable carbon aerogels to be used in energy storage devices and wearable electronics.