Porous carbon with interpenetrating framework from Osmanthus flower as electrode materials for high-performance supercapacitor

Series of porous carbons are prepared from Osmanthus flower by simple hydrothermal carbonization followed by KOH activation. The structure and morphology of the as-prepared Osmanthus flower-derived porous carbon materials (OC) were investigated by X-ray diffraction, Raman spectrum, N2 adsorption/desorption isotherm and electron microscopy, respectively. The results indicate that the OC are mainly microporous with 3D interpenetrating framework, and the pore-structure of the OC is associated with the dosage of KOH. As electrode material for supercapacitors, the electrochemical measurements showed that the OC-2 (the weight ratio of KOH/biochar is 2) exhibited better electrochemical performance than other OC samples and reported porous carbon materials, which is mainly due to the higher micropore surface/volume and the interpenetrating framework in the texture of the OC-2. Furthermore, a symmetric supercapacitor assembled by OC-2 can delivered a high energy density of 7.95 W h kg−1 with a power density of 10 kW kg−1 at 20 A g−1, and an excellent cycling stability (a high capacitance retention of 92.9% after 10,000 cycles). The impressive electrochemical performances of OC-2 electrodes demonstrated that the fully utilization of cheap resource acquisition endowed by nature is a good avenue to design and fabricate materials with great promising applications as high-performance energy storage system.