Relaxation Analysis of Li Inserted γ-Fe2O3 at Various Rates Seungwon Park, Kaoru Takasu, and Takeshi Yao S. Park ;; K. Takasu ;; T. Yao (M) Department of Fundamental Energy Science, Graduate School of Energy Science, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, JapanMyao@energy.kyoto-u.ac.jp

摘要

Lithium was electrochemically inserted into γ-Fe2O3 with different current densities and its crystal structure was analyzed by X-ray Rietveld method. Iron migrated from 8a site to 16c site in the process of lithium insertion and from 16c site to 8a site gradually at relaxation process after the lithium insertion. It was considered that lithium was inserted at 8a site during the lithium insertion process and migrated to 16c site with relaxation time. Iron occupancy of 8α site just after lithium insertion increased with the decrease of insertion rate. It was considered that lithium migrated from 8a site to 16c site even during lithium insertion process at low insertion rate. These results were very well consistent with the site preference that lithium prefers 8a site to occupy kinetically and prefers 16c site thermodynamically.