A Study of Transient Phase Transformation in LFS/C using in-situ Time Resolved X-ray Absorption Spectroscopy

作者：Kamon in Onlamee^*; Buakeaw Sunisa; Klysubun Wantana; Limphirat Wanwisa; Srilomsak Sutham; Meethong Nonglak

来源：International Journal of Electrochemical Science, 2014, 9(8): 4257-4267.

• local structure transformation
• relaxation
• in-situ absorption spectroscopy
• Li2FeSiO4

Li2FeSiO4 (LFS) is one of the most studied materials for use as cathodes in next generation high capacity Li-ion batteries. In this work, high purity and nanosized LFS/C material with the monoclinic crystal structure in P2(1) space group are studied. Structural transformations upon cycling and during relaxation of the high performance LFS/C material are investigated using in situ time resolved X-ray absorption spectroscopy (XAS). Results show that phase transformation involving the present of Fe ion in the Fe4+state when cycling above 4.43 V is responsible for high capacity characteristics in this LFS/C material. The Fe K-edge energy variations during relaxation indicate that local structural and oxidation state of Fe also change. This transient change in local structure of Fe in LFS materials is captured by this technique for the first time.

• 出版日期2014-8