Facile preparation of nanocellulose/multi-walled carbon nanotube/polyaniline composite aerogel electrodes with high area-specific capacitance for supercapacitors

As a natural biological macromolecule, nanocellulose is a promising substrate for high-performance supercapacitor electrodes. However, it shows that a low area-specific capacitance can limit its use. To strengthen the area-specific capacitance of nanocellulose-based composite aerogel electrodes to obtain high-performance supercapacitors, we combined the addition of conductive materials and physical cross-linking. After physical cross-linking and polyaniline embedding in the original conductive framework, a nanocellulose-based composite aerogel with a conductive network and outstanding electrochemical performance was obtained. The good electrochemical performance of the composite aerogel film electrode can be attributed to the high specific surface area of 46.32 m2·g-1, mesoporous structure, and uniform growth of polyaniline. The electrode exhibited the highest area-specific capacitance of 2176.3 mF·cm-2 at a current density of 1 mA·cm-2. Even at a current density of 10 mA·cm-2, the capacitance was retained at 1071.67 mF·cm-2, thereby showing good rate performance. Furthermore, the as-prepared aerogel film electrode exhibited electrochemical stability with a capacitance retention of 64 % at a current density of 10 mA·cm-2 after 1050 cycles. The as-assembled all-solid-state supercapacitor showed the highest area-specific capacitance of 968.94 mF·cm-2 at a current density of 0.5 mA·cm-2 and considerable energy and power density of 86.1 μWh·cm-2 and 200 μW·cm-2, respectively. In this study, we demonstrated that the proper construction of conductive networks by conductive polymers could maximize electrochemical performance.