An all-paper, scalable and flexible supercapacitor based on vertically aligned polyaniline (PANI) nano-dendrites@fibers

Keeping in view the huge demands of green and flexible supercapacitors to further digitalize and electrify human community, it is imperative to develop cost-effective and eco-friendly solutions. Herein, we report a sequential protocol to fabricate flexible, lightweight and inexpensive cellulose fiber thin film electrode based on vertically aligned polyaniline (PANI) nano-dendrites@fiber for supercapacitors. In this process, the mechanical shearing not only induces the branched architecture on cellulose fibers, but also promotes the subsequent growth of vertically aligned nano-dendrites of PANI on the cellulose fibers with increased PANI loading. The high fibrillation caused by mechanical shearing and the well-ordered growth of vertically aligned PANI dendrites on cellulose fibers make the resultant PANI@Paper hierarchically porous with high specific surface area, conductivity, mechanical strength and flexibility. The PANI@Paper based supercapacitor demonstrates excellent specific capacitance of 296 Fg-1 at 1 Ag-1 and areal capacitance of 5017 mF cm-2 at 10 mA cm-2. Furthermore, a solid-state supercapacitor based on PANI@Paper demonstrates excellent capacitance (282 Fg-1 at 1 Ag-1), high energy density (2.5 Wh kg-1) and power density of (0.3 kW kg-1). Impressively, all-paper supercapacitor fabricated with PANI@Paper and commercial paper shows remarkable capacitance (271 Fg-1 at 1 Ag-1) and flexibility while maintaining the electrochemical stability.