Crystal Structure Changes of LiNi0.5Co0.2Mn0.3O2 Cathode Materials During the First Charge Investigated by in situ XRD |
Sang-Woo Lee, Dong-Hyuk Jang, Jeong-Bae Yoon, Yong-Hun Cho, Yun-Sung Lee, Do-Hoon Kim, Woo-Seong Kim, Won-Sub Yoon |
Department Of Energy Science, Sungkyunkwan University;Department Of Energy Science, Sungkyunkwan University;Department Of Energy Science, Sungkyunkwan University;School of Advanced Materials Engineering, Kookmin University;Faculty of Applied Chemical Engineering, Chonnam National University;Kokam;Daejung EM Co. LTD.;Department Of Energy Science, Sungkyunkwan University; |
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Abstract |
The structural changes of $Li_{1-x}Ni_{0.5}Co_{0.2}Mn_{0.3}O_2$ cathode material for lithium ion battery during the first charge was investigated in comparison with $Li_{1-x}Ni_{0.8}Co_{0.15}Al_{0.05}O_2$ using a synchrotron based in situ X-ray diffraction technique. The structural changes of these two cathode materials show similar trend during first charge: an expansion along the c-axis of the unit cell with contractions along the a- and b-axis during the early stage of charge and a major contraction along the c-axis with slight expansions along the a- and b-axis near the end of charge at high voltage limit. In $Li_{1-x}Ni_{0.5}Co_{0.2}Mn_{0.3}O_2$ cathode, however, the initial unit cell volume of H2 phase is bigger than that of H1 phase since the c-axis undergo large expansion while a- and b- axis shrink slightly. The change in the unit cell volume for $Li_{1-x}Ni_{0.5}Co_{0.2}Mn_{0.3}O_2$ during charge is smaller than that of $Li_{1-x}Ni_{0.8}Co_{0.15}Al_{0.05}O_2$. This smaller change in unit cell volume may give the $Li_{1-x}Ni_{0.5}Co_{0.2}Mn_{0.3}O_2$ cathode material a better structural reversibility for a long cycling life. |
Keywords:
Lithium ion battery, Cathode material, $LiNi_{0.5}Co_{0.2}Mn_{0.3}O_2$, In situ X-ray diffraction |
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