Soft-template carbonization approach of MOF-5 to mesoporous carbon nanospheres as excellent electrode materials for supercapacitor

Herein, we report the pyrolytic conversion of a metal-organic framework (MOF-5) encapsulated activated carbon (AC) composite to carbon nanospheres at controlled carbonization temperature. The synthesized carbon nanospheres obtained at 850 °C have exhibited Brunauer-Emmett-Teller (BET) surface area and pore volume up to 677 m2 g−1 and 0.412 cm3 g−1, respectively. As an electrode material, a high specific capacitance of 193 F g−1 at 2 mV s−1 and 300 F g−1 at 1.5 A g−1 were calculated from electrochemical studies and during cycling test excellent stability was observed with 91.5% capacitance retention over 3000 cycles. The superior electrochemical performance of the carbon nanospheres as compared to the fragmented porous and activated carbon confirmed that soft-template approach of MOF-5 and AC can be used to produce carbon with enhance mechanical strength. The encapsulation of activated carbon by porous metal-organic frameworks to produce carbon nanospheres is a novel research strategy to obtain desired structural morphology for numerous applications.