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

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.