| A Study on the Structural and Electrochemical Properties of Li0.99Ni0.46Mn1.56O4 Cathode Material Using Synchrotron based in-situ X-ray Diffraction |
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Sol Choi, JeongBae Yoon, Shoaib Muhammad, Won-Sub Yoon |
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Department Of Energy Science, Sungkyunkwan University;Department Of Energy Science, Sungkyunkwan University;Department Of Energy Science, Sungkyunkwan University;Department Of Energy Science, Sungkyunkwan University; |
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| Abstract |
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The structural and electrochemical properties of $Li_{0.99}Ni_{0.46}Mn_{1.56}O_4$ ($Fd{ar{3}}m$, disordered spinel) cathode material were studied and compared with stoichiometric $LiNi_{0.5}Mn_{1.5}O_4$ ($P4_332$, ordered spinel). First cycle discharge capacity of $Li_{0.99}Ni_{0.46}Mn_{1.56}O_4$ was similar to that of $LiNi_{0.5}Mn_{1.5}O_4$ at C/3 and 1C rate, but cycling performance of $Li_{0.99}Ni_{0.46}Mn_{1.56}O_4$ was better than that of $LiNi_{0.5}Mn_{1.5}O_4$ especially at high rate of 1C. This can be explained by performing synchrotron based in-situ XRD and results of GITT measurements. It is considered that faster lithium ion diffusion in the $Li_{0.99}Ni_{0.46}Mn_{1.56}O_4$ cathode results in the improvement of the rate capability. To study structural changes during cycling, synchrotron in-situ XRD patterns of both the samples were recorded at C/3 and 1C rate. Compared to stoichiometric $LiNi_{0.5}Mn_{1.5}O_4$, disordered $Li_{0.99}Ni_{0.46}Mn_{1.56}O_4$ spinel sample has pseudo one phase behavior and one step phase transition between two cubic phases. So, $LiNi_{0.5}Mn_{1.5}O_4$ would experience a much greater strain and stress, originating from the two phase transitions between three cubic phases and suffer from capacity loss during cycling especially at high rate. |
| Key Words:
Lithium ion battery, Cathode material, $LiNi_{0.5}Mn_{1.5}O_4$, $Li_{0.99}Ni_{0.46}Mn_{1.56}O_4$, In situ X-ray Diffraction |
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