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

Abstract

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, MnO2/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 MnO2 particles, but also as the electrically conductive channel for electrochemical performance enhancement. The MnO2/HMCNTs nanocomposite electrode exhibits much larger specific capacitance compared with both the HMCNTs electrode and the pure MnO2 electrode and significantly improves rate capability compared to the pure MnO2 electrode. The superior supercapacitive performance of the MnO2/HMCNTs nanocomposite electrode is due to its high specific surface area and unique hierarchy architecture which facilitate fast electron and ion transport. Moreover, the MnO2/HMCNTs also shows superior cycling stability with only 3.7% capacitance drop after 5000 cycles. The enhanced electrochemical performance of the MnO2/HMCNTs makes them a promising electrode material for application in supercapacitors and potentially other energy storage devices.