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以羰基钴为原料,采用简易超声法制备氧化亚钴和石墨烯纳米复合结构。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)及光电子能谱(XPS)对该纳米复合结构进行表征。结果表明:粒径为3~5nm的氧化亚钴纳米颗粒均匀分布于石墨烯表面。将氧化亚钴/石墨烯纳米复合结构用作锂离子电池负极材料,电化学测试结果表明,该复合结构具有高电容量(50次循环后电容量为650mA·h/g,约是商用石墨电极的2倍)、高库伦效率(高于95%)以及很好的循环稳定性。该优异的电化学性能源于氧化亚钴/石墨烯纳米复合结构的特点:纳米尺寸的氧化亚钴颗粒分散于导电的石墨烯衬底上,有利于锂离子的嵌入和脱嵌,缩短了锂离子的扩散路径,提高了氧化物的导电性,从而改善了材料的电性能。
Using cobalt carbonyl as raw material, nanostructures of cobalt oxide and graphene were prepared by simple ultrasonic method. The nanocomposite structure was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoelectron spectroscopy (XPS). The results show that nano-particles of cobalt oxide with particle size of 3 ~ 5nm are uniformly distributed on the surface of graphene. The cobaltous oxide / graphene nanocomposite structure is used as the negative electrode material for lithium ion batteries. The electrochemical test results show that the composite structure has a high capacity (capacity of 650 mA · h / g after 50 cycles, about a commercial graphite electrode 2 times), high coulombic efficiency (above 95%) and good cycling stability. The excellent electrochemical properties derived from the characteristics of the cobalt oxide / graphene nanocomposite structure: nano-sized cobalt oxide particles dispersed in a conductive graphene substrate, is conducive to lithium ion insertion and extraction, shortening the lithium The diffusion path of ions increases the conductivity of the oxide, thereby improving the electrical properties of the material.