Author/Authors :
Kobayashi، نويسنده , , Hironori and Sakaebe، نويسنده , , Hikari and Komoto، نويسنده , , Kenichi and Kaneko، نويسنده , , Shinji and Kageyama، نويسنده , , Hiroyuki and Tabuchi، نويسنده , , Mitsuharu and Tatsumi، نويسنده , , Kuniaki and Yonemura، نويسنده , , Masao and Kanno، نويسنده , , Ryoji and Kamiyama، نويسنده , , Takashi، نويسنده ,
Abstract :
Charge–discharge cycle performance was examined for the cell Li1.08Mn1.92O4/1 M LiPF6 in EC:DEC(1:1)/MCMB. The structure and magnetic properties were determined before and after cycling using X-ray diffraction and SQUID measurements. After both 340 cycles at RT and 150 cycles at 55 °C, single-phase properties were observed for all samples, but samples in the discharged state showed broadening of X-ray diffraction peaks with decrease in the capacity retention ratio. Decreases in lattice parameter and increases in magnetic susceptibility were clearly observed for samples in the discharged state with decreased capacity retention ratios, while small changes in lattice parameter and magnetic susceptibility were observed for samples in the charged state. It was shown that Li intercalation/de-intercalation becomes difficult with cycling in the shallow charged state. Furthermore, it was suggested that the cell capacity decreases because of the disorder in the Li ion conductive pathway caused by the impaired stability of the samples.
