镍钴氢氧化物的制备及其电化学性能

采用化学共沉淀法成功制备了片状镍钴氢氧化物,并探究了不同镍钴物质的量比对样品形貌及电化学性能的影响。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱仪(XPS)及比表面积孔径分析仪(BET)对样品的结构、形貌进行了表征,并利用循环伏安法、恒电流充放电法等对其电化学性能进行了分析。结果表明,n(Ni)∶n(Co)=4∶1的样品直接用作电极材料时,具有最好的电化学性能:在0.5 A/g的电流密度下拥有1852 F/g的高比容量;电流密度增大20倍时,仍拥有1330 F/g的高比容量。以镍钴氢氧化物为正极,活性炭为负极组装的非对称式超级电容器在346 W/kg的功率密度下,能量密度达52 Wh/kg,在循环10000圈之后电容保持率为92%。优异的电化学性能表明,片状镍钴氢氧化物是很有应用潜力的电极材料之一。

Synthesis of Nickel Cobalt Hydroxide and Its Electrochemical Properties

In this work, the flake nickel cobalt hydroxide was successfully prepared by the chemical co-precipitation method, and the effect of nickel to cobalt molar ratios on the morphologies and electrochemical properties were explored. The structures and morphologies of samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscope (XPS) and specific surface area and pore size analyzer (BET). The electrochemical properties were analyzed by cyclic voltammetry, galvanostatic charge/discharge, etc. The results show that when nickel cobalt hydroxide (n(Ni):n(Co)=4:1) is directly used as electrode material, it has a high specific capacitance of 1852 F/g at a current density of 0.5 A/g. When the current density is increased by 20 times, it still has a high specific capacitance of 1330 F/g. The asymmetric supercapacitor is assembled with nickel cobalt hydroxide as the positive electrode material and active carbon as the negative electrode material. The asymmetric cell possesses a high energy density of 52 Wh/kg at a power density of 346 W/kg, and superior cycle stability (the capacitance retention of 92% after 10000 cycles). Excellent electrochemical properties indicate that flake nickel cobalt hydroxide is one of the most promising electrode materials.