MnO_2/NiCo_2O_4的静电自组装合成及其电化学性能

通过带负电荷的MnO2纳米片与带正电荷的Co-Ni层状双氢氧化物(LDHs)纳米片的静电自组装外加后续热处理合成了异质层状结构的MnO2/NiCo2O4复合物.采用X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱、拉曼光谱、原子吸收光谱(AAS)、场发射扫描电镜(FESEM)和透射电子显微镜(TEM)对其结构和形貌进行了表征.用循环伏安(CV)、恒流充放电和电化学交流阻抗技术对其电化学性能进行了测试.研究结果表明,该方法制得的异质复合物具有多孔层状堆垛结构,这种特殊的结构不仅增大了电解液离子的接触面积,而且还为其嵌入-脱出提供了有效途径.该复合物在1 A·g-1电流密度时,-0.6-0.45 V电位窗口内的比电容达482 F·g-1,优于纯组分MnO2和NiCo2O4的电容性能.

Synthesis of a MnO2/NiCo2O4 Composite by Electrostatic Self-Assembly and Its Electrochemical Performance

A hetero-layered MnO₂/NiCo₂O₄ composite was fabricated according to an electrostatic self-assembly process between negatively charged MnO₂-layered nanosheets and positively charged Co-Ni-layered double hydroxide nanosheets, followed by a heat-treatment process. The morphology, composition, and microstructure characteristics of the resulting material were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectrometry, atomic absorption spectrometry (AAS), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Furthermore, the electrochemical behaviors of the composite were evaluated by cyclic voltammetry (CV), galvanostatic chargedischarge, and electrochemical impedance spectroscopy (EIS). The test results indicated that the hetero-layered composite showed porous stacking structure, which increased the effective liquid-solid interfacial area, and provided a fast path for the insertion and extraction of electrolyte ions. A specific capacitance of 482 F·g^-1 was obtained in the potential window from-0.6 to 0.45 V at a current density of 1 A·g^-1. These values were therefore superior to those of pure MnO₂ or pure NiCo₂O₄.