Functionality of Oxide Coating for Li[Li0.05Ni0.4Co0.15Mn0.4]O2 as Positive Electrode Materials for Lithium-Ion Secondary Batteries
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- 作者：Seung-Taek Myung ; Kentarou Izumi ; Shinichi Komaba ; Hitoshi Yashiro ; Hyun Joo Bang ; Yang-Kook Sun ; Naoaki Kumagai
- 刊名：Journal of Physical Chemistry C
- 出版年：2007
- 出版时间：March 15, 2007
- 年：2007
- 卷：111
- 期：10
- 页码：4061 - 4067
- 全文大小：704K
- 年卷期：v.111,no.10(March 15, 2007)
- ISSN：1932-7455
文摘
Surface-modified Li[Li0.05Ni0.4Co0.15Mn0.4]O2 oxides were studied. The oxide particles were coated byheteroelements such as Al2O3, Nb2O5, Ta2O5, ZrO2 and ZnO. Metal oxide-coated Li[Li0.05Ni0.4Co0.15Mn0.4]O2did not show significant difference in X-ray diffraction patterns. Thickness of the formed coating layer wasaround 10 nm, as observed by transmission electron microscopy. Electrochemical properties of heteroelement-coated Li[Li0.05Ni0.4Co0.15Mn0.4]O2 were investigated using coin type Li-ion cells employing graphite as ananode at 60 
C. Metal oxide-coated Li[Li0.05Ni0.4Co0.15Mn0.4]O2 obviously showed higher capacity with goodcyclability. Also, area-specific impedance was significantly lower for the metal oxide-coated Li[Li0.05Ni0.4Co0.15Mn0.4]O2 during cycling, compared with that for bare Li[Li0.05Ni0.4Co0.15Mn0.4]O2. Among them, Al2O3-coated Li[Li0.05Ni0.4Co0.15Mn0.4]O2 had the best electrochemical performances. The metal oxide coating layertransformed to metal fluoride layer during cycling, as proved by time-of-flight-secondary ion massspectroscopy. The newly formed metal fluoride layer would be greatly effective against HF attack duringcycling. Possible reasons for the effectiveness of the metal oxide coating are discussed.
C. Metal oxide-coated Li[Li0.05Ni0.4Co0.15Mn0.4]O2 obviously showed higher capacity with goodcyclability. Also, area-specific impedance was significantly lower for the metal oxide-coated Li[Li0.05Ni0.4Co0.15Mn0.4]O2 during cycling, compared with that for bare Li[Li0.05Ni0.4Co0.15Mn0.4]O2. Among them, Al2O3-coated Li[Li0.05Ni0.4Co0.15Mn0.4]O2 had the best electrochemical performances. The metal oxide coating layertransformed to metal fluoride layer during cycling, as proved by time-of-flight-secondary ion massspectroscopy. The newly formed metal fluoride layer would be greatly effective against HF attack duringcycling. Possible reasons for the effectiveness of the metal oxide coating are discussed.