Interconnected porous and nitrogen-doped carbon network for supercapacitors with high rate capability and energy density

Interconnected porous and nitrogen-doped carbon network (a-PNC) has been prepared by using SiO2 spheres as template and polyaniline as carbon and nitrogen precursor followed by chemical activation. Such hierarchical porous carbon architecture possesses high specific surface area (1676 m2 g−1), large pore volume (2.13 cm3 g−1) and relatively high nitrogen content. As a result, a-PNC electrode exhibits a specific capacitance of 369 F g−1 at 2 mV s−1 and still retains 243 F g−1 even at a high scan rate of 1000 mV s−1, indicating an outstanding high-rate performance. In addition, the electrode displays a fascinated electrochemical cyclability with 97% retention after 5000 cycles. More importantly, the assembled a-PNC symmetric supercapacitor achieves a maximum energy density of 24.8 Wh kg−1 based on the total mass of the active material on two electrodes in 1 mol L−1 Na2SO4 electrolyte.