In this work, two-dimensional VO nanosheet arrays/one-dimensional CoO nanoneedle arrays (2D VNSAs/1D CNNAs) composite is successfully prepared on nickel foam substrate. A variety of structural characterization techniques (SEM, XRD, EDS, TEM, and XPS) show that the as-prepared composite is VO monocrystal with a layered structure grafting by CoO polycrystal with a 1D needle-like structure. The VNSAs/CNNAs composite is used as supercapacitor electrode material. In a three-electrodes system, it shows high specific capacitance (C) values (1023 F g@5 mV s from CV curve and 826 F g@0.5 A/g from GCD curve), a high coulombic efficiency (98.6 %@10 A/g), a good cyclic stability (92.7 % after 6000 cycles), a low charge transfer resistance (2.7 Ω), and a fast ionic diffusion rate (2.01 × 10 cm s). In a two-electrodes system, the assembled VNSAs/CNNAs//VNSAs/CNNAs symmetric supercapacitor has C values of 445 F g@5 mV s and 363 F g@0.5 A/g. Its cycle stability and rate capability could reach up to 92.3 % and 90.7 % after 6000 cycels, respectively. It also shows a high energy density (E) of 127.3 Wh kg@400 W kg and can retain 72.2 Wh kg@8000 W kg. The excellent electrochemical properties indicate that VNSAs/CNNAs composite can greatly increase the E of supercapacitors.

中文翻译：

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V2O5纳米片阵列/Co3O4纳米针阵列复合材料用于增强能量密度的超级电容器

本工作在泡沫镍基底上成功制备了二维VO纳米片阵列/一维CoO纳米针阵列（2D VNSA/1D CNNA）复合材料。各种结构表征技术（SEM、XRD、EDS、TEM 和 XPS）表明所制备的复合材料是具有层状结构的 VO 单晶，由具有一维针状结构的 CoO 多晶接枝。 VNSAs/CNNAs复合材料用作超级电容器电极材料。在三电极系统中，它表现出高比电容 (C) 值（CV 曲线为 1023 F g@5 mV s，GCD 曲线为 826 F g@0.5 A/g）、高库仑效率（98.6 %@10 A/g)、良好的循环稳定性(6000次循环后为92.7%)、低电荷转移电阻(2.7 Ω)和快的离子扩散速率(2.01 × 10 cm s)。在双电极系统中，组装的 VNSA/CNNAs//VNSAs/CNNAs 对称超级电容器的 C 值为 445 F g@5 mV s 和 363 F g@0.5 A/g。 6000次循环后，其循环稳定性和倍率性能分别达到92.3%和90.7%。它还表现出127.3 Wh kg@400 W kg的高能量密度（E），并且可以保留72.2 Wh kg@8000 W kg。优异的电化学性能表明VNSAs/CNNAs复合材料可以大大提高超级电容器的E。