Birnessite-type manganese dioxide (MnO2) is coated uniformly on carbon nanotubes (CNTs) by employing a spontaneous direct redox reaction between the CNTs and permanganate ions (MnO4-). The initial specific capacitance of the MnO2/CNT nanocomposite in an organic electrolyte at a large current density of 1 A g-1 is 250 F g-1. This is equivalent to 139 mAh g-1 based on the total weight of the electrode material that includes the electroactive material, conducting agent and binder. The specific capacitance of the MnO2 in the MnO2/CNT nanocomposite is as high as 580 F g-1 (320 mAh g-1), indicating excellent electrochemical utilization of the MnO2. The addition of CNTs as a conducting agent improves the high-rate capability of the MnO2/CNT nanocomposite considerably. The in situ X-ray absorption near-edge structure (XANES) shows improvement in the structural and electrochemical reversibility of the MnO2/CNT nanocomposite after heat-treatment.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering