Multi-wall carbon nanotubes (MWCNTs) have achieved mass production, but their lengths are in the millimeter range, which is unfavorable for the diffusion of electrolyte ions into their innermost tube. We report an oxidation method to simultaneously cut and unzip MWCNTs along transverse and longitudinal directions, which leads to the formation of curved graphene sheets (CGSs). SEM shows that the curved morphology was retained but the diameters were large after unzipping. This could be caused by the interaction of oxygen-containing functional groups between layers on the edges of the CGSs. Because of the larger number of active sites the specific capacitance is improved. To further increase the capacitive performance, a sample was put into a 0.1 mol L⁻¹ KMnO₄ to incorporate MnO₂. The microstructure of the resulting CGS-MnO₂ hybrid was revealed by electron microscopy, Raman spectroscopy and powder X-ray diffraction. The results indicate that amorphous MnO₂ successfully grew on the surface of the CGSs. The capacitive behavior was measured by cyclic voltammetry in a 1 mol L⁻¹ Na₂SO₄ solution. The CGS-MnO₂ had a specific capacitance of 236 F g⁻¹ at 2 mV s⁻¹ (even 127 F g⁻¹ at 100 mV s⁻¹), which is superior to that of MWCNTs (15 F g⁻¹), CGS (88 F g⁻¹) and MWCNT-MnO₂ (111 F g⁻¹). In addition, excellent cycling performance was achieved for the CGS-MnO₂ hybrid electrode with a 97% capacitance retention over 1000 cycles.

多壁碳纳米管（MWCNTs）已实现量产，但其长度在毫米范围内，不利于电解质离子向其最内管的扩散。我们报告了一种氧化方法，可沿横向和纵向同时切割和解开 MWCNT，从而形成弯曲的石墨烯片 (CGS)。SEM 显示弯曲形态保留，但拉开后直径变大。这可能是由 CGS 边缘层之间含氧官能团的相互作用引起的。由于活性位点的数量较多，因此提高了比电容。为了进一步提高电容性能，将样品放入 0.1 mol L ^-1 KMnO ₄以掺入 MnO₂ . 通过电子显微镜、拉曼光谱和粉末X射线衍射揭示了所得CGS-MnO ₂杂化物的微观结构。结果表明无定形MnO ₂成功地在CGS 表面生长。电容行为通过循环伏安法在 1 mol L ^-1 Na ₂ SO ₄溶液中测量。在CGS-的MnO ₂具有236 F G的特定电容^-1在2毫伏小号^-1（甚至127 F G ^-1在100mV小号^-1），这是优于多壁碳纳米管的（15 F G ^-1） , CGS (88 F g ^-1 ) 和 MWCNT-MnO ₂(111 F g ^-1 )。此外，CGS-MnO ₂混合电极实现了优异的循环性能，在 1000 次循环中具有 97% 的电容保持率。