Electrochemical evaluation and modification of commercial lithium cobalt oxide p

2019-08-01 07:44:37

efficiency Plateau powders oxide cobalt

责任者: Zhang, J.;Xiang, Y.J.;Yu, Y.;Xie, S.;Jiang, G.S.;Chen, C.H. 单位: Dept. of Mat. Sci. and Engineering, Univ. of Sci./Technology of China, Anhui, Hefei 230026, China 来源出处: Journal of Power Sources,2004,132(1-2):187-194 摘要: As the cathode materials for rechargeable lithium batteries, five commercial lithium cobalt oxide powders have been investigated for a comparative study. The X-ray diffraction analysis indicates that all these powders exhibit the α-NaFeO2 layered structure. The size distribution and morphology were analyzed by particle sedimentation method and scanning electron microscopy (SEM). Their electrochemical properties including cycleability and especially 3.6V plateau efficiency, a recently required control parameter, are compared. Two kinds of modifications, i.e. Li2CO3 coating and high-temperature treatment, have been applied to improve the electrochemical performance of one of these five powders. After the high-temperature treatment in air, cobalt oxidation-state becomes higher and Li(LixCo 1-x)O2 is formed. Both of the two modified means can significantly improve the 3.6V-plateau efficiency through suppressing the cell impedance rise during cycling. A general discussion on the factors influencing the plateau efficiency is also given. © 2004 Published by Elsevier B.V. 关键词: Lithium batteries;Solid state physics;Morphology;Nanostructured materials;Electrolytes;Electrochemistry;Size determination;Electric conductivity;Doping (additives);Oxidation;Scanning electron microscopy;X ray diffraction;Lithium cobalt oxide;Cellular phones;Plateau efficiency;Oxidation state