氧化铝包覆三元材料.doc

氧化铝包覆三元材料.docAvailable online at
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ELECTROCtilMICA
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Electrochimica Acta 52 (2006) 1316 - 1322
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Syn thesis a nd electrochemical characteristics of Al 203-coated
LiNi i/3Coi/3Mn1/3O2 cathodematerialsfor lithium ion batteries
Youngsik Kim a, Hyun Soo Kim b,?, SteveW. Martin a
a Departme nt of Materials Scie nee a nd Engin eeri ng, Iowa State U niversity, 2220 Hoover Hall, Ames, IA 50011, USA
b Battery Research Group, Korea Electrotech no logy Research In stitute, Changwon 641-120, South Korea
Received 9 March 2006; received in revised form 17 July 2006; accepted 24 July 2006
Available online 28 August 2006
Abstract
LiNi 1/38/3 Mn”3 O2 cathode materials have been coated with Al 2O3 nano-particles using sol - gqprocessing to improve its electrochemical properties. The X-ray diffraction (XRD) pattern of the as-preparedAl 2 O3 nano-particles was indexed to the cubic structure of the ?-Al 2O3 phase and hadan averagesizeof ~ showed that the structureof LiNi 1/3 Co1/3 Mn 1/3O2 wasnot affected by the Al 2O3 coating. However, the AI2O3 coatings on LiNi ”3Co”3Mn 1/3O2 improved the cyclic life performance and rate capability without decreasing its initial discharge capacity. These electrochemical properties were also compared with those of LiAlO 2-coated LiNi 1/3Co1/3Mn”3O2 cathode material. The electrochemical impedance spectroscopy (EIS) was studied to understand the enhanced electrochemical properties of the Al203-coated LiNi 1/381/3Mn 1/3O2 compared to uncoated LiNi 1/3Co1/3Mn”3O2.
? 2006 Elsevier Ltd. All rights reserved.
Keywords: LiNi 1/3Co1/3 M n 1/3O2; Al 2O3 nano -particles; Sol - gelmethod; Electrochemical property; Rate capability; Cyclic life
0013-4686/$ -see front matter ? 2006 Elsevier Ltd. All rights reserved. doi:.
Introduction
LiCoO 2, one of many hexagonal ?-NaFeO2-type materials such asLiNiO 2 [1] and LiMnO 2