Ozone-activated CNTs to induce uniform coating of MnO₂ as high-performance supercapacitor electrodes

Abstract

Carbon nanotube (CNT), as a promising material to enhance electrical conductivity and ionic diffusivity, plays an indispensable role in improving the electrochemical performance of transition metal oxides. In this work, a novel core-shell structure of MnO₂ coating on carbon nanotubes (MnO₂@CNT) was successfully synthesized via a simple solvothermal method. The internal porous structure of CNT as core can facilitate the penetration of electrolyte while improving the electrical conductivity. The thin MnO₂ nanosheets as shell can simultaneously achieve a large interaction area and rapid ion exchange. Benefitting from the synergistic effects, the MnO₂@CNT shows an excellent capacitance of 386 F g⁻¹ at 1 A g⁻¹ with the content of MnO₂ about 52 wt.%. In addition, the MnO₂@CNT retains nearly 93.6% of its initial capacitance after 5000 cycles, indicating its excellent cycling performance.

Keywords:

• Supercapacitor
• manganese dioxide
• carbon nanotubes
• synergistic effects

Disclosure statement

The authors declare no conflict of interest.

Additional information

Funding

This work is supported by the Finance Science and technology project of Hainan Province (Grant Nos. ZDYF2020009), the National Natural Science Foundation of China (22168016), and the Natural Science Foundation of Hainan Province (Grant Nos. 820QN423, 120RC454 and 2019RC142).