Wood Pulp Fiber Wrapped by Fish-Scale Graphene as Flexible and Free-Standing Supercapacitor Electrode

Poplar wood pulp was adopted as both frame and precursor for the synthesis of pulp fiber (PF)/reduced graphene oxide composite via a simple and low-cost method. In this method, the PF based on graphene (PFG) composite film electrode was prepared by a simple vacuum filtration process with various ratios (PF: reduced graphene oxide (RGO)=5:1, PF:RGO=5:2, PF:RGO=5:3, PF:RGO=5:4, PF:RGO=5:5). In terms of special structures, the PFG can be used as electrodes without metal-collector, adhesives, and additives. The optimal ratio (PF:RGO=5:4) film electrode displayed a high areal-specific capacitance of 683 mF/cm(2) at 1mA/cm(2) with a mass of 5.3mg/cm(2) (specific capacitance of 129F/g) and good cycling stability (87.5% capacitance retention after 10,000 cycles at 5mA/cm(2)) as well as excellent rate capability and high flexibility (suitable for any angle, even 180 degrees). Moreover, the device could possess a maximum energy density of 47.71Wh/cm(2) and a maximum power density of 1251W/cm(2). These results suggest that the composite PGF film is a promising electrode material.