A novel wire-shaped supercapacitor based on MnO2 nanoflakes and carbon nanotubes with high performance synthesized by sacrificial template method

Abstract With the growing demand of wearable and portable electronic devices, design and development of flexible energy storage devices are essential and urgent. In this study, MnO2//PVA-KOH//carbon nanotubes based wire-shaped supercapacitor with high performance is fabricated, in which copper wire is used as current collector in inner electrode to overcome poor electrical conductivity of MnO2. As outer electrode, carbon nanotubes are obtained by an in-situ chemical vapor deposition (CVD) method, in which cobalt-based catalyst particles are evenly distributed over the surface of SiO2. Finally, etching removal of SiO2 and filling of gel electrolyte are carried out simultaneously by hydrothermal method. The wire-shaped supercapacitor exhibits a good capacitive performance (0.99 F cm-3 or 1.98 F cm-2), a high energy density (0.16 mWh cm-3) at a power density of 37 mV cm-3, and long-term cycling stability (90.38% of capacitance retention at 0.15 A cm-3 after 4000 cycles) with excellent flexibility. Therefore, excellent performance of wire-shaped supercapacitor indicates its broad application prospects in the field of portable and wearable energy storage devices.