We present the structural properties and electrochemical capacitance of mesoporous MCo₂O₄ (M = Co, Zn, and Ni) rods synthesized by a facile solvothermal route without necessity to use templates. The Brunauer–Emmett–Teller specific surface areas of these mesoporous rods are found to be about 24, 54, and 62 m² g^–1 with major pore diameters of about 31, 15, and 9 nm for MCo₂O₄, M = Co, Zn, and Ni, respectively. X-ray photoelectron spectroscopy and X-ray diffraction studies reveal the phase purity of the samples with a predominant spinel-type crystal structure. The spinel crystal structure with lattice parameters of 8.118, 8.106, and 8.125 Å is obtained for MCo₂O₄, M = Co, Zn, and Ni, respectively. The transmission electron microscopy study reveals that the mesoporous rods are built by self-assembled aggregates of nanoparticles which are well-interconnected to form stable mesoporous rods. The electrochemical capacitor performance was investigated by means of cyclic voltammetry, galvanostatic charge/discharge cycling, and impedance spectroscopy in a three-electrode configuration. As a result, the spinel-type MCo₂O₄ rods exhibit high specific capacitances of 1846 F g^–1 (CoCo₂O₄), 1983 F g^–1 (ZnCo₂O₄), and 2118 F g^–1 (NiCo₂O₄) at a scan rate of 2 mV/s. Furthermore, the mesoporous spinel-type metal oxides show desirable stability in alkaline electrolyte during long-term cycling with excellent cycling efficiency.

中文翻译：

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方便溶剂热法制备的介孔尖晶石型MCo ₂ O ₄（M = Co，Zn和Ni）棒的伪电容

我们介绍了通过方便的溶剂热途径合成的介孔MCo ₂ O ₄（M = Co，Zn和Ni）棒的结构性质和电化学电容，无需使用模板。这些中孔棒的Brunauer-Emmett-Teller比表面积约为24、54和62 m ² g ^–1，MCo ₂ O _4的主要孔径约为31、15和9 nm ，M =分别为Co，Zn和Ni。X射线光电子能谱和X射线衍射研究揭示了具有主要尖晶石型晶体结构的样品的相纯度。对于MCo _2，获得具有8.118、8.106和8.125Å的晶格参数的尖晶石晶体结构O ₄，M分别为Co，Zn和Ni。透射电子显微镜研究表明，介孔棒是由纳米颗粒的自组装聚集体构建的，纳米颗粒的自组装性良好，相互连接形成稳定的介孔棒。通过循环伏安法，恒电流充/放电循环和三电极配置的阻抗谱研究了电化学电容器的性能。结果，尖晶石型MCo ₂ O ₄棒表现出高的比电容，分别为1846 F g ^–1（CoCo ₂ O ₄），1983 F g ^–1（ZnCo ₂ O ₄）和2118 F g ^–1（NiCo _2个O ₄）的扫描速率为2 mV / s。此外，中孔尖晶石型金属氧化物在长期循环期间在碱性电解质中显示出所需的稳定性，具有优异的循环效率。