Neutron and X-Ray Powder Diffraction Studies of LiMn2−yCryO4

LiNi0.5Mn1.5O4 Spinel and Its Derivatives as Cathodes for Li-Ion Batteries

“…The 4.1 V plateau was related to the oxidation of Mn 3+ to Mn 4+ and the 4.7 V plateau to the oxidation of Ni 2+ to Ni 4+ . The oxidation of chromium ion could bring about a high voltage of 4.9 V. Yang [20] suggested that a significant amount of Mn 4+ ion in the spinel framework was essential for electrochemical reaction to occur at around 5 V. His view was supported by Kawai [21] who argued that the presence of manganese was necessary to keep the high voltage capacity because manganese-free spinel oxides, such as Li 2 NiGe 3 O 8 , did not show any capacity above 4.5 V. The influence of doping metals including M = Cu [22][23][24], Co [25], Cr [26][27][28][29], Fe [30][31][32], Al [33,34], and Zn [35] 4 , then the corresponding capacity at 4 V will be less and that at 5 V will be large. [36,37].…”

Temperature dependence of the order and distribution of Mn3+ and Mn4+ cations in orthorhombic LiMn2O4

“…A strong overlap of the diffraction peaks implies a necessity of application of a high-resolution diffractometer. Insufficient resolution can be the reason of misinterpretation of powder diffraction data of such compounds [14,15].…”

“…After a stormy discussion in the literature during recent years [3][4][5][6][7][8][9][10][11][12][13][14], the near-room-temperature phase transition * Tel. : +48-61-8291262; fax: +48-61-8658008.…”

Cation distribution and crystallographic characterization of the quaternary spinel system Mg Co1−Cr Fe2−O4

“…The knowledge of the crystallography including the cation distribution is thus very important for controlling and forecasting the various properties in spinels. In view of that, the crystallography including site preferences of cations in spinels have been systematized intensively and increasing emphasis are given on the exact cation distributions in complex systems [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. In the present work we report crystallographic characterization and the cation distribution in the spinel system Mg x Co 1−x Cr x Fe 2−x O 4 (x = 0.0, 0.25, 0.50, 0.75 and 1.0) consisting of four different cations of which Co, Fe and Cr have close atomic numbers.…”