文献类型：期刊文献

英文题名：Facile Ultrasonic Synthesis of CoO Quantum Dot/Graphene Nanosheet Composites with High Lithium Storage Capacity

作者：Peng, Chengxin[1,2];Chen, Bingdi[1,2];Qin, Yao[1,2];Yang, Shihe[3];Li, Chunzhong[4];Zuo, Yuanhui[1,2];Liu, Siyang[1,2];Yang, Jinhu[1,2]

机构：[1]Tongji Univ, Inst Adv Mat & Nano Biomed, Shanghai 200092, Peoples R China;[2]Tongji Univ, Dept Chem, Shanghai 200092, Peoples R China;[3]Hong Kong Univ Sci & Technol, William Mong Inst Nano Sci & Technol, Dept Chem, Nano Sci & Technol Program, Kowloon, Hong Kong, Peoples R China;[4]E China Univ Sci & Technol, Sch Mat Sci & Engn, Key Lab Ultrafine Mat, Minist Educ, Shanghai 200237, Peoples R China

年份：2012

卷号：6

期号：2

起止页码：1074

外文期刊名：ACS NANO

收录：;EI(收录号：20121014837751);WOS:【SCI-EXPANDED(收录号:WOS:000300757900011)】；

基金：We thank the National Natural Science Foundation (21001082, 20925621), Shanghai Pujiang Program (10PJ1410400), Research Fund for the Doctoral Program of Higher Education of China (20090072120013), Visiting scholar fund of the Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science, and Technology and the Program for Young Excellent Talents in Tongji University (2008KJ046 and 2009KJ075) for financial support.

语种：英文

外文关键词：ultrasonic synthesis; CoO quantum dots; graphene; composites; lithium-ion batteries; anode materials; lithium storage capacity

摘要：In this paper, we report a facile ultrasonic method to synthesize well-dispersed CoO quantum dots (3-8 nm) on graphene nanosheets at room temperature by employing Co-4(CO)(12) as cobalt precursor. The prepared CoO/graphene composites displayed high performance as an anode material for lithium-ion battery, such as high reversible lithium storage capacity (1592 mAh g(-1) after 50 cycles), high Coulombic efficiency (over 95%), excellent cycling stability, and high rate capability (1008 mAh g(-1) with a total retention of 77.6% after 50 cycles at a current density of 1000 mA g(-1), dramatically increased from the initial 50 mA g(-1)). The extraordinary performance arises from the structure advantages of the composites: the nanosized CoO quantum dots with high dispersity on conductive graphene substrates supply not only large quantity of accessible active sites for lithium-ion insertion but also good conductivity and short diffusion length for lithium ions, which are beneficial for high capacity and rate capability. Meanwhile, the isolated CoO quantum dots anchored tightly on the graphene nanosheets can effectively circumvent the volume expansion/contraction associated with lithium insertion/extraction during discharge/charge processes, which is good for high capacity as well as cycling stability. Moreover, regarding the anomalous behavior of capacity increase with cycles (activation effect) observed, we proposed a tentative hypothesis stressing the competition between the conductivity increase and the amorphorization of the composite electrodes during cycling in determining the trends of the capacity, in the hope to gain a fuller understanding of the inner working of the novel nanostructured electrode-based lithium-ion batteries.