Two-dimensional mesoporous carbon sheet-like framework material for high-rate supercapacitors

Two-dimensional mesoporous carbon sheet-like framework (MCSF) material has been prepared using mesoporous SiO2 nanosheet as template and coal tar pitch as carbon precursor. MCSF sheets consisting of numerous mesopores have a specific surface area of 582.7 m2 g−1. As a result, the MCSF electrode possesses a maximum specific capacitance of 264 F g−1 at 5 mV s−1, excellent rate capability (74% retention ratio at 1000 mV s−1), and impressive cycling stability with 91% initial capacitance retained after 5000 cycles at 200 mV s−1 in 6 mol L−1 KOH. MCSF symmetric supercapacitor exhibits a maximum energy density of 9.6 Wh kg−1 at 5 mV s−1 and a maximum power density of 119.4 kW kg−1 based on the total mass of the two electrodes in 1 mol L−1 Na2SO4 electrolyte.