Core/sheath structured ultralong MnO_x/PPy nanowires feature improved conductivity and stability for supercapacitor

Increased conductivity of manganese oxide (MnO_x) for effectively improved supercapacity is studied in this work by addressing on introduced oxygen vacancies (OVs) besides a porous sheath of conductive polymer (polypyrrole, PPy). The assembly profile of core/sheath structured MnO_x/PPy nanowires by in-situ polymerization of PPy under mild condition showing better conductivity, specific capacitance, rate performance and cycling stability than so far reported MnO_x based materials. Structural characteristics of the MnO_x/PPy nanowires are studied in detail, including high weight percent of MnO_x core, underlying PPy layer chemically bonding MnO_x core and PPy nanoparticles in outlayer, as well as the simultaneously introduced conductive oxygen vacancies (OVs) in MnO_x during formation of PPy sheath. The contribution of assembly profile to the supercapacitor performances is discussed, especially concerning PPy sheath and OVs, essentially yielding improved conductivity between current collector and the MnO_x core to assure large energy density and power density.