高性能锂离子电池负极材料CoO/石墨烯纳米复合结构的超声法制备

摘要

以羰基钻为原料,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3～5 nm的氧化亚钻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钻/石墨烯纳米复合结构的特点:纳米尺寸的氧化亚钻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.%A facile ultrasonic method was used to synthesize CoO/graphene nanohybrids by employing Co4(CO)12 as a cobalt precursor.The nanohybrids were characterized by SEM,TEM and XPS,and the results show that CoO nanoparticles (3-5 nm)distribute uniformly on the surface of graphene.The CoO/graphene nanohybrids display high performance as an anode material for lithium-ion battery,such as high reversible lithium storage capacity (650 mA·h/g after 50 cycles,almost twice that of commercial graphite anode),high coulombic efficiency (over 95％) and excellent cycling stability.The extraordinary performance arises from the structure of the nanohybrids:the nanosized CoO particles with high dispersity on conductive graphene substrates are beneficial for lithium-ion insertion/extraction,shortening diffusion length for lithium ions and improving conductivity,thus the lithium storage performance was improved.