The excellent capacitive capability for N,P-doped carbon microsphere/reduced graphene oxide nanocomposites in H2SO4/KI redox electrolyte
In order to ameliorate the capacitance and energy density of supercapacitors in aqueous electrolytes, nitrogen- and phosphorus-codoped carbon microspheres/reduced graphene oxide nanocomposites are obtained by hydrothermal treatment of graphite oxide and N,P-doped carbon microsphere. The as-prepared nanocomposites display a high specific surface area of 604.3 m2 g−1 and hierarchical pore structure composed of micropores, mesopores, and macropores. N,P-codoped carbon microspheres/reduced graphene oxide are used as electrode materials in the redox electrolyte of H2SO4 and KI aqueous solution, exhibiting a excellent capacitance performance of up to ~ 654 F g−1 at 2 A g−1, corresponding to the energy density of 14.53 Wh kg−1 at power density of 402 W kg−1. Even at a high current of 20 A g−1, the electrode can keep a capacitance of 318 F g−1, showing an energy density of 7 Wh kg−1 at power density of 3984 W kg−1. This study indicates the potential of nitrogen- and phosphorus-codoped carbon microspheres/reduced graphene oxide in high energy density supercapacitor.
This work was financially supported by the Natural Science Foundation of Hebei Province (Grant No. E2014203033), the foundation of State Key Laboratory of Metastable Materials Science and Technology, and the open foundation of Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) (111 Project, B12015).
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