Hierarchical Co3O4@PPy@MnO2 core–shell–shell nanowire arrays for enhanced electrochemical energy storage

Abstract

Combining hydrothermal synthesis, electrodeposition with soaking process, we synthesized coaxial nanowire arrays consisting of Co3O4 nanowire as the core, polypyrrole (PPy) as the inner shell and MnO2 outer layer as the exodermis. The key to fabricate one-dimensional hierarchical architecture, Co3O4@PPy@MnO2 “core–shell–shell” nanowires, was to introduce a PPy intermediate layer on the surface of Co3O4 nanowire, which could enhance the conductivity of nanowire arrays and act as a reactive template to induce a coating of amorphous MnO2. The device based on the ternary composite Co3O4@PPy@MnO2 nanowire arrays exhibited prominent electrochemical performance with a high energy density of 34.3Whkg−1 at a power density of 80.0Wkg−1 and a remarkable long-term cycling stability. In addition, the performance of as-assembled asymmetrical supercapacitor was demonstrated using a DC motor. The results imply that ternary composite based electrode materials have enormous potential for energy storage devices and systems.