Morphology-controlled synthesis of MnO2 grown on carbon fiber paper for high-rate supercapacitor electrode

Nanostructured MnO2 with different morphologies based on carbon fiber paper (CFP) had been successfully synthesized via a hydrothermal process. The emphasis of this report focuses on the effect of the Co doping content on the morphologies and electrochemical properties of as-obtained MnO2 electrodes, thereby obtaining the optimal electrode material. Such optimal hierarchical porous nanoflowers entwined with nanowires architecture (Co-MnO2/CFP-1) was obtained by a certain Co content, which displayed an excellent capacitive performance. The Co-MnO2/CFP-1 electrode achieved a relatively high specific capacitance of 161 F g(-1) at 1 A g(-1), and 57% of the capacitance retention for Co-MnO2/CFP-1 when the current density ranging from 1 to 8 A g(-1), which was 27 times than MnO2 without Co doping (MnO2/CFP), proving its excellent rate capability. The Co-MnO2/CFP-1 electrode exhibited a prominent cycle stability of 98% in 10,000 cycles at 4 A g(-1). This significant improvement of capacitive performance benefits result from a well-developed interconnected hierarchical structure and provides more electrochemical active site, facilitating the penetration and diffusion of electrolyte. This study provides a general guidance to develop different morphologies of electrode materials for supercapacitor device.