| 충방전 과정중 구조가 안정한 Zr이 도핑된 LiCoO2 분말 |
| 김선혜, 심광보1, 안재평2, 김창삼3 |
큐슈대학교 수소이용기술연구센터
1한양대학교 신소재공학과
2한국과학기술연구원 특성분석센터
3한국과학기술연구원 이차전지연구센터 |
| Structural Stability During Charge-Discharge Cycles in Zr-doped LiCoO2 Powders |
| Seon-Hye Kim, Kwang-Bo Shim1, Jae-Pyoung Ahn2, Chang-Sam Kim3 |
Faculty of Engineering, Kyushu University
1Division of Advanced Materials Science and Engineering, Hanyang University
2Advanced Analysis Center, Korea Institute of Science and Technology
3Battery Research Center, Korea Institute of Science and Technology |
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| ABSTRACT |
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Zirconium-doped $Li_{1.1}Co_{1-x}Zr_xO_2(0{leq}x{leq}0.05)$ powders as cathode materials for lithium ion batteries were synthesized using an ultrasonic spray pyrolysis method. Cyclic voltammetry and cyclic stability tests were performed, and the changes of microstructure were observed. The solubility limit of zirconium into $Li_{1.1}CoO_2$ was less than 5 mol%, and monoclinic $Li_2ZrO_3$ phase was formed above the limit. The Zr-doping suppressed the grain growth and increased the lattice parameters of the hexagonal $LiCoO_2$ phase. The Zr-dopiong of 1mol% resulted in the best cyclic performance in the range of $3.0{sim}4.3V$ at 1C rate (140 mA/g); the initial discharge capacity decreased from 158 mAh/g to 60 mAh/g in the undoped powder, while from 154 mAh/g to 135 mAh/g in the Zr-doped powder of 1 mol% after 30 cycles. The excellent cycle stability of Zr-doped powder was due to the low polarization during chargedischarge processes which resulted from the delayed collapse of the crystal structure of the active materials with Zr-doping. |
| Key words:
Lithium ion battery$LiCoO_2$, Zr-Doping, Cycle stability, Microstructure |
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