In Situ Chemical Synthesis of MnO2/HMCNT Nanocomposite with a Uniquely Developed Three-Dimensional Open Porous Architecture for Supercapacitors

The successful application of supercapacitors in energy conversion and storage hinges on the development of highly efficient and stable electrode materials. While a fast and facile synthesis of superior performance of supercapacitors is still a challenge. Motivated by this, MnO 2 /heteroatom-doped mesoporous carbon nanotubes (HMCNTs) with a uniquely developed three-dimensional open porous system containing mesopores and micropores are synthesized by a facile one-step chemical coprecipitation method for supercapacitor electrodes. The HMCNTs in the composite serve not only as the template for the growth of MnO 2 particles, but also as the electrically conductive channel for electrochemical performance enhancement. The MnO 2 /HMCNTs nanocomposite electrode exhibits much larger specific capacitance compared with both the HMCNTs electrode and the pure MnO 2 electrode and significantly improves rate capability compared to the pure MnO 2 electrode. The superior supercapacitive performance of the MnO 2 /HMCNTs nanocomposite electrode is due to its high specific surface area and unique hierarchy architecture which facilitate fast electron and ion transport. Moreover, the MnO 2 /HMCNTs also shows superior cycling stability with only 3.7% capacitance drop after 5000 cycles. The enhanced electrochemical performance of the MnO 2 /HMCNTs makes them a promising electrode material for application in supercapacitors and potentially other energy storage devices.