Flexible nanocomposites with ultrahigh specific areal capacitance and tunable properties based on a cellulose derived nanofiber-carbon sheet framework coated with polyaniline

Flexible supercapacitors are extremely important for future various electronic devices. However, the development of cost-efficient and high-performance flexible supercapacitor electrodes remains a big challenge today. Herein, we present a novel flexible nanocomposite based on a cellulose-derived framework coated with polyaniline (PANI). In this nanocomposite, the cellulose nanofiber (CNF) provides mechanical strength due to its interconnected network, while the strapped cellulose-derived carbon sheet (CCS) with a unique morphology produces a porous structure and offers fast transfer pathways for the efficient diffusion of electrode ions. PANI imparts conductivity to the CNF and provides abundant active sites for charge storage. The porous structure and supercapacitive performance of this kind of nanocomposite can be easily tailored by changing the feeding mass ratio of the CNF, CCS, and PANI. A relatively low CCS loading can produce a flexible electrode with an ultrahigh specific areal capacitance of 1838.5 mF cm(-2) (150 F g(-1)) (1 mA cm(-2)), while high CCS loading can produce a free-standing electrode with a higher specific areal capacitance of 3297.2 mF cm(-2) (220 F g-1) (1 mA cm(-2)). Besides, the robust three-dimensional network guarantees good cycling stability of the nanocomposite electrode (more than 83% retention after 3000 cycles). The tunable structure and electrochemical performance make the nanocomposite an ideal electrode for various electronic devices.