Flexible N-doped active carbon/bacterial cellulose paper for supercapacitor electrode with high areal performance

- The shaddock peels are used as precursor for N-doping porous carbon.
- The BC substrate permits large loading mass and remarkable tensile property.
- The paper electrode exhibits excellent areal capacitance of 2004 mF cm−2.
- The synthesis method is simple and cost-effective.

A flexible N-doped activated shaddock peel carbon (N-ASPC)/graphene (GN)/bacterial cellulose (BC) hybrid paper electrode with remarkable mechanical properties and large mass loading (8 mg cm−2) is fabricated. This flexible electrode integrates extraordinary special capacitance N-ASPC from resource-rich fruit waste (shaddock peel), highly conductive GN and ultrafine three-dimensional (3D) fibrous network structure BC, which exhibits remarkable areal capacitance of 2004 mF cm−2 (250.5 F g−1), excellent rate performance with 82.3% retention from 2 to 40 mA cm−2, good cyclic stability with 97% retention over 10,000 cycles, ultrahigh tensile strength (32 MPa) and good conductivity (1550 S m−1). The symmetric supercapacitor based on two identical N-ASPC/GN/BC film electrodes with an operation voltage of 1.4 V in Na2SO4 electrolyte can deliver a maximum energy density of 0.158 mW h cm−2 and a maximum power density of 28 mW cm−2. Therefore, the binder-free N-ASPC/GN/BC electrodes hold great promise for flexible energy-storage devices.

(a) Optical image of a free-standing N-ASPC/GN/BC paper. (b) Stress-strain curves of N-ASPC/GN/BC paper. (c) Specific capacitance at different current densities.97