xxvi
List of Figures
Fig. 5.13 The result of using the lever rule in the coexistence regions for
samples prepared in oxygen by regular cooling. Red points
represent the compositions of the samples in the two-phase region
while the black points are the results of the lever rule calculations
73
Fig. 5.14 X-ray diffraction (XRD) scans of samples in the coexistence
region between the ordered rocksalt structures and the spinel
structures along with the corresponding two-phase fits and the
difference plots below each scan. The expected peaks for
LiNi 0.5 Mn 1.5 O 4 are from JCPDS #80-2162. Samples A 5 and B 5
are labeled in Fig. 5.4 and the other samples are evenly spaced
between A 5 and B 5 ......................................................
74
Fig. 5.15 The spinel lattice parameter obtained in the coexistence region
between the spinel and ordered rocksalt regions as a function of β
74
Fig. 5.16 The ordered rocksalt lattice parameter obtained in the coexistence
region between the spinel and ordered rocksalt regions as a
function of γ .............................................................
75
Fig. 6.1
a Metal compositions obtained by atomic absorption for samples
prepared by regular cooling in oxygen. The open symbols
indicate multiple phases in the XRD patterns while the closed
symbols indicate single-phase scans. b A portion of the phase
diagram obtained in oxygen by quenching. The compositions are
assumed to be identical to those determined by atomic absorption
for samples prepared by regular cooling. The red points are
two-phase samples connected to the point obtained by the lever
rule to generate the edge of the layered region ......................
78
Fig. 6.2
Contour plots of the a and c lattice parameters obtained by fitting
all regular cooled layered structures made in oxygen as
hexagonal structures. The green dotted line in a is the constant
oxidation number line for layered structures with Ni
2+ and Mn
4+ .
Filled points represent single-phase samples while open symbols
represent multiple-phase samples .....................................
79
Fig. 6.3
XRD scans of quenched samples in the coexistence region
showing both layered and spinel structures near the Li–Mn line.
The compositions of samples H 6 and G 6 are indicated in Fig. 6.5
79
Fig. 6.4
XRD scans of quenched samples in the layered–layered (left) and
layered–spinel (right) coexistence regions. J 6 , K 6 , G 6 , and H 6
are indicated in Fig. 6.5. M
∗ represents Li 2 MnO 3 and the
unlabeled dashed line is a guide for the eye near the spinel peak.
N and M correspond to two corners of the three-phase regions ...
80
Fig. 6.5
A partial phase diagram indicating compositions used in
Figs. 6.4, 6.7, 6.10, and 6.11...........................................
80
Fig. 6.6
Lattice parameters obtained in the layered–spinel coexistence
region as a function of the distance to the SM line. The spinel
lattice parameter is a cub while the layered lattice parameters are
a hex and c hex . The lines are guides for the eye.......................
81
List of Figures
Fig. 5.13 The result of using the lever rule in the coexistence regions for
samples prepared in oxygen by regular cooling. Red points
represent the compositions of the samples in the two-phase region
while the black points are the results of the lever rule calculations
73
Fig. 5.14 X-ray diffraction (XRD) scans of samples in the coexistence
region between the ordered rocksalt structures and the spinel
structures along with the corresponding two-phase fits and the
difference plots below each scan. The expected peaks for
LiNi 0.5 Mn 1.5 O 4 are from JCPDS #80-2162. Samples A 5 and B 5
are labeled in Fig. 5.4 and the other samples are evenly spaced
between A 5 and B 5 ......................................................
74
Fig. 5.15 The spinel lattice parameter obtained in the coexistence region
between the spinel and ordered rocksalt regions as a function of β
74
Fig. 5.16 The ordered rocksalt lattice parameter obtained in the coexistence
region between the spinel and ordered rocksalt regions as a
function of γ .............................................................
75
Fig. 6.1
a Metal compositions obtained by atomic absorption for samples
prepared by regular cooling in oxygen. The open symbols
indicate multiple phases in the XRD patterns while the closed
symbols indicate single-phase scans. b A portion of the phase
diagram obtained in oxygen by quenching. The compositions are
assumed to be identical to those determined by atomic absorption
for samples prepared by regular cooling. The red points are
two-phase samples connected to the point obtained by the lever
rule to generate the edge of the layered region ......................
78
Fig. 6.2
Contour plots of the a and c lattice parameters obtained by fitting
all regular cooled layered structures made in oxygen as
hexagonal structures. The green dotted line in a is the constant
oxidation number line for layered structures with Ni
2+ and Mn
4+ .
Filled points represent single-phase samples while open symbols
represent multiple-phase samples .....................................
79
Fig. 6.3
XRD scans of quenched samples in the coexistence region
showing both layered and spinel structures near the Li–Mn line.
The compositions of samples H 6 and G 6 are indicated in Fig. 6.5
79
Fig. 6.4
XRD scans of quenched samples in the layered–layered (left) and
layered–spinel (right) coexistence regions. J 6 , K 6 , G 6 , and H 6
are indicated in Fig. 6.5. M
∗ represents Li 2 MnO 3 and the
unlabeled dashed line is a guide for the eye near the spinel peak.
N and M correspond to two corners of the three-phase regions ...
80
Fig. 6.5
A partial phase diagram indicating compositions used in
Figs. 6.4, 6.7, 6.10, and 6.11...........................................
80
Fig. 6.6
Lattice parameters obtained in the layered–spinel coexistence
region as a function of the distance to the SM line. The spinel
lattice parameter is a cub while the layered lattice parameters are
a hex and c hex . The lines are guides for the eye.......................
81