Structure Refinement of Mn-Substituted LiMn<sub>x</sub>Fe</sub>1-x</sub>PO<sub>4</sub>
- 1 Department of Materials Science, Graduate School of Osaka Prefecture University, Osaka, Japan
- 2 Department of Materials Science, Graduate School of Osaka Prefecture University, Osaka, Japan
Abstract
For Mn substituted LiMn x Fe 1- x PO 4 synthesized by hydrothermal process, the structural differences caused by Mn substitution were characterized by SEM, ICP, XRD, XAFS, and FT-IR. In this study, by using XAFS advantageous to the atomic selectivity, the local structure of MeO 6 octahedral was investigated. From ICP, Mn composition in the products was similar to Mn addition amount, and the peak shifts of XRD patterns with increasing Mn addition were observed. The lattice constants refined by Rietveld analysis were a = 1.0338 ± 5 nm, b = 0.5995 ± 4 nm and c = 0.4696 ± 1 nm in LiFePO 4 , and it was ex panded linearly with increasing Mn addition. Fe-O bond distance, which was calculated by curve fitting of the radius distribution function of LiMn x Fe 1- x PO 4 , was 0.208 nm smaller than 0.214 nm of Mn-O bond. In addition, MeO 6 octahedral expansion was affected to PO 4 vibrational structure from FT-IR spectra.
- Padhi, A.K., Nanjundaswamy, K.S. and Goodenough, J.B. (1997) Phospho-Olivines as Positive-Electrode Materials for Rechargeable Lithium Batteries. Journal of Electrochemical Society, 144 1188-1194. https://doi.org/10.1149/1.1837571
- Delacourt, C., Poizot, P., Morcrette, M., Tarascon, J.M. and Masquelier, C. (2004) One-Step Low-Temperature Route for the Preparation of Electrochemically Active LiMnPO4 Powders. Chemistry of Materials, 16, 93-99. https://doi.org/10.1021/cm030347b
- Morgan, D., Van der Ven, A. and Ceder, G. (2004) Li Conductivity in LixMPO4 (M = Mn,Fe,Co,Ni) Olivine Materials. Electrochemical and Solid-State Letters, 7, A30-A32. https://doi.org/10.1149/1.1633511
- Chung, S.-Y., Blocking, J.T. and Chiang, Y.-M. (2002) Electronically Conductive Phosphor-Olivines as Lithium Storage Electrodes. Nature Materials, 1, 123-128. https://doi.org/10.1038/nmat732
- Shiratsuchi, T., Shigeto, O., Takayuki, D. and Yamaki, J. (2009) Cathodic Performance of LiMn1-xMxPO4 (M = Ti, Mg and Zr) Annealed in an Inert Atmosphere. Electrochimica Acta, 54, 3145-3151. https://doi.org/10.1016/j.electacta.2008.11.069
- Fang, H., Yi, H., Hu, C., Yang, B., Yao, Y., Ma, W. and Dai, Y. (2012) Effect of Zn Doping on the Performance of LiMnPO4 Cathode for Lithium Ion Battery. Electrochimica Acta, 71, 266-269. https://doi.org/10.1016/j.electacta.2012.03.160
- Wang, D., Ouyang, C., Drézen, T., Exnar, I., Kay, A., Kwon, N., Gouerec, P., Miners, J.H., Wang, M. and Gratzel, M. (2010) Improving the Electrochemical Activity of LiMnPO4 via Mn-Site Substitution. Journal of Electrochemical Society, 157, A225-A229. https://doi.org/10.1149/1.3271112
- Nishijima, M., Ootani, T., Kamimura, Y., Sueki, T., Murai, S., Fujita, K., Tanaka, K., Ohira, K., Koyama, Y. and Tanaka, I. (2014) Accelerated Discovery of Cathode Materials with Prolonged Cycle Life for Lithium-Ion Battery. Nature Communications, 5, 4553. https://doi.org/10.1038/ncomms5553
- Yamada, A., Kudo, Y. and Liu, K.-Y. (2001) Phase Diagram of Lix(MnyFe1-y)PO4 ( 0 ≤ x, y ≤1 ). Journal of Electrochemical Society, 148, A1153-A1158. https://doi.org/10.1149/1.1401083
- Yamada, A., Chung, S.C. and Hinokuma, K. (2001) Optimized LiFePO4 for Lithium Battery Cathodes, Journal of Electrochemical Society, 148, A224-A229. https://doi.org/10.1149/1.1348257
- Yang, S., Zavalij, P.Y. and Whittingham, M.S. (2001) Hydrothermal Synthesis of Lithium Iron Phosphate Cathodes. Electrochemistry Communications, 3, 505-508. https://doi.org/10.1016/S1388-2481(01)00200-4