Facile Preparation of MnO2 with Large Surface Area in a Rotor–Stator Reactor for Supercapacitors

Facile preparation of MnO 2 with large specific surface area was explored in a rotor–stator reactor (RSR). The MnO 2 product was characterized by FESEM, TEM, XRD, XPS, TG, FTIR and automated surface area and pore size analyzer. The electrochemical performance of the as-prepared MnO 2 nanospheres as an electrode material for supercapacitors was investigated using three-electrode and two-electrode methods. The results show that the MnO 2 nanospheres were well dispersed and had a surface area of 337.01 m 2 g -1 . The specific capacitance was as high as 320.7 F g -1 at 0.3 A g -1 and 477.5 F g -1 at 5 mV s -1 . The as-prepared MnO 2 also exhibited good stability with 107.4 % capacitance retention after 1000 cycles. Moreover, the MnO 2 //active carbon asymmetric supercapacitor in 1 M Na 2 SO 4 electrolyte showed a maximum energy density of 27.23 W h kg -1 and correspondingly power density was 225 W kg -1 .