Ultralong MnO2 nanowires intercalated graphene/Co3O4 composites for asymmetric supercapacitors

MnO2 nanowires, 5–10 μm long and ca. 20 nm in diameter, were intercalated with the RGO layers and Co3O4 nanoparticles. The MnO2 nanowire-incorporated ternary composites electrodes exhibited significantly higher specific capacitance than the RGO/Co3O4 binary composite in supercapacitors. The ternary composite exhibited a high rate capacitance, such as 1560 F g−1 of specific capacitance at current density of 2 A g−1, as well as excellent cycling stability (94.1% capacitance retention after 1500 cycles). The ternary composite approach offers an effective methodology for enhancing the device performance of metal-oxide based supercapacitors for long cycling applications.