Ultrasonic synthesis of CoO/graphene nanohybrids as high performance anode materials for lithium-ion batteries

来源期刊:中国有色金属学报(英文版)2012年第10期

论文作者:陈炳地 彭成信 崔征

文章页码:2517 - 2522

关键词:锂离子电池;石墨烯;氧化亚钴;负极材料;超声制备

Key words:lithium-ion battery; graphene; CoO; anode material; ultrasonic synthesis

摘    要: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3~5 nm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650 mA·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。

Abstract: 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.

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