采用水分辅助化学气相沉积方法制备垂直排列碳纳米管（VACNTs），采用超临界二氧化碳辅助浸渍将锰前驱体负载于VACNTs表面，经不同温度（250~350 ℃）真空退火制备Mn₃O₄/VACNTs复合电极材料，研究了该复合电极材料的微观结构和电化学性能。结果表明：在复合电极材料中Mn₃O₄纳米颗粒负载在碳纳米管表面，且当在300 ℃真空退火后，Mn₃O₄纳米颗粒呈均匀分布，尺寸在6~10 nm；与纯VACNTs相比，复合电极材料的比电容提高了3~4倍，瓦尔堡阻抗、等效串联电阻和电极/电解质界面的电荷转移电阻均较小；300 ℃真空退火后，复合电极材料表现出最佳的电化学性能，其最大比电容为168 F·g^-1，且当充放电电流密度从1 A·g^-1增加到10 A·g^-1时，比电容保持率达56％，等效串联电阻最小（约2.5 Ω）。

Vertically aligned carbon nanotubes (VACNTs) were prepared by water-assisted chemical vapor deposition method. The manganese precursor was loaded on VACNTs surface by supercritical carbon dioxide assisted impregnation, and then the Mn₃O₄/VACNTs composite electrode material was prepared by vacuum annealing at different temperatures (250-350 ℃). The microstructure and electrochemical performance of the composite electrode material were studied. The results show that in the composite electrode material Mn₃O₄ nanoparticles were loaded on the surface of carbon nanotubes. After vacuum annealing at 300 ℃, Mn₃O₄ nanoparticles with diameter of 6-10 nm were evenly distributed on the surface of carbon nanotubes. Compared with pure VACNTs, specific capacitance of the composite electrode material increased by 3-4 times, and Warburg impedance, equivalent series resistance and charge transfer resistance at the electrode/electrolyte interface were relatively small. The composite electrode material by vacuum annealing at 300 ℃had the best electrochemical performance; the maximum specific capacitance was 168 F·g^-1, and the specific capacitance retention was 56% with the charge and discharge current density increasing from 1 A·g^-1 to 10 A·g^-1; the equivalent series resistance was the smallest (about 2.5 Ω).