Three-dimensional nano MnO2/CB composite and its application for electrochemical capacitor

A three-dimensional nanostructure composed of birnessite MnO2 and carbon black (CB) was built via a quite simple co-precipitation method at room temperature. The natural porous construction of conductive CB granules provided enough sites for MnO2 deposition. The as-prepared composite showed that dispersive MnO2 nanowires were directly crystallized on the surface of CB matrix, which was believed to be beneficial to its electrochemical performance. The further investigation of cyclic voltammetry (CV) in 1 M Na2SO4 confirmed the inference, which showed good symmetrical rectangular shape, and the specific capacitance was calculated about 186 F/g at a scan rate of 2 mV/s. After 1000 cycles of CV at 10 mV/s, the initial capacitance was maintained at about 91%, indicating that the designed structure had benefit to high electrochemical stability.

► A MnO2/CB composite was prepared through co-precipitation at room temperature.
► Highly dispersed MnO2 was deposited on the surface of CB to build a 3D structure.
► The initial capacitance was maintained at about 91% after 1000 cycles.