碳球@纳米片状钴镍金属氧化物核壳型复合材料的制备及其电化学性能

Synthesis and capacitive properties of carbon sphere@nanosheet-like cobalt-nickel oxides core-shell structured composites

以葡萄糖为碳源,采用水热炭化法制备碳球,然后以氯化钴和氯化镍为钴源和镍源,六次甲基四胺为沉淀剂,采用水热法和高温处理合成一种核壳结构的碳球@钴镍金属氧化物纳米复合材料,并研究其作为超级电容器电极材料的储能性能。借助X射线衍射、扫描电镜和低温氮气吸附/脱附等对材料的形貌和结构进行表征。采用循环伏安、恒电流充放电及交流阻抗等对材料的电化学性能进行研究。结果表明:碳球的加入能有效改善钴镍金属氧化物的分散性,同时降低材料的电子转移阻力,进而提高其电化学性能。当电流密度为1A/g时,所得碳球@钴镍金属氧化物核壳型复合材料的比电容为984.8F/g;当电流密度增大10倍(10A/g)时,仍保留86.3%的初始比电容值。当电流密度为15A/g时,经过2000次恒电流充放电后复合材料的比电容量保持率为94.6%,体现出较好的循环稳定性能。

Carbon sphere@cobalt-nickel oxides core-shell structured composites were successfully fabricated by growing cobalt-nickel oxides on the surface of carbon spheres,and the carbon spheres were derived from glucose via a facile hydrothermal method.The morphology and structure of the materials were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),N2 adsorption/desorption and X-ray photoelectron spectroscopy(XPS),respectively.The capacitive performance of the samples was analyzed by electrochemical tests such as cyclic voltammetry,galvanostatic charge and discharge and AC impedance.The results showed that the addition of carbon sphere increased dispersion of cobalt-nickel oxides and reduced electron transfer resistance of electrical conductivity of electrode materials,thus ultimately promoting capacitive performance.The specific capacitance of the core-shell structured composites was 984.8F/g at the current density of 1A/g,and the retention rate of 86.3%can be kept with the current density of 10A/g.After 2000 cycles,the capacitive retention rate of composites electrodes material kept above 94.6%at a current density of 15A/g,showing excellent cyclic stability.