xxx
List of Figures
Fig. 8.4
XRD scans with fits obtained with Rietveld refinement (red) and
difference plots (blue). All are fit as layered, except for the top
scan which is fit as C/2m (monoclinic). Scans are offset vertically
for clarity................................................................. 109
Fig. 8.5
a XRD patterns in the region where superlattice peaks appear. b
Peak near 44.5
◦ degrees in sample A 8 fit as both layered (top) and
monoclinic (bottom) with scattering angle steps of 0.02
◦ . Vertical
lines in R-3m (top) correspond to Kα 1 and Kα 2 for the (104)
peak, and to the (−202) and (131) peaks for C/2m (bottom) ...... 110
Fig. 8.6
Mn K-edge XANES patterns collected for samples showing
metal site vacancies, along with Mn 2 O 3 as a reference for Mn
3+ ,
and Li 2 MnO 3 for Mn
4+ . The red arrows indicate the positions of
the absorption edge near 6.545 keV for Mn 2 O 3 and 6.548 keV for
all other samples ........................................................ 112
Fig. 8.7
Results of a Monte Carlo simulation for sample D 8 using the
vacancy content and average nickel oxidation state from
Table 8.1. The structures were obtained with β T = 0.5 (a) and
β T = 2.0 (b)............................................................. 113
Fig. 8.8
XRD pattern of Li[Ni 1/6 P 1/6 Mn 2/3 ]O 2 with the result of Rietveld
refinement. Vertical lines are the calculated peak positions for
Kα 1 (full length) and Kα 2 (half length) .............................. 114
Fig. 8.9
Voltage versus capacity and dQ/dV plots for
Li[Ni 1/6 P 1/6 Mn 2/3 ]O 2 cycled at 30
◦ C with a specific current of
10 mA/g, or 0.020 mA/cm
2 . The red line in the dQ/dV curve
represents the first cycle................................................ 115
Fig. 8.10 Capacity versus cycle number for Li[Ni 1/6 P 1/6 Mn 2/3 ]O 2 . All
closed symbols shown in the legend represent charging, while the
open symbols are discharge capacities................................ 115
Fig. 9.1
Partial phase diagram with contours for the a lattice parameter
showing the boundaries of the single-phase layered region. The
lower boundary is shown connecting LiNiO 2 to Li 2 MnO 3 (no
attempt was made to determine how this boundary changes with
synthesis conditions, since the current study focuses on
compositions near the top of the layered region). The insert
shows approximate upper boundaries of the layered region
consistent with the current study. Points A 9 and B 9 were
determined using elemental analysis and are referred to
throughout the text. The red points are discussed in Chap. 7. The
blue dotted line is the cubic to layered phase transition ............ 118
Fig. 9.2
X-ray diffraction (XRD) scans of samples with composition A 9
heated at 800
◦ C. Black lines represent samples that were regular
cooled, while red lines are for quenched samples. The difference
plots in blue in the left panel represent the quenched scan
subtracted from the regular cooled scan.............................. 121
List of Figures
Fig. 8.4
XRD scans with fits obtained with Rietveld refinement (red) and
difference plots (blue). All are fit as layered, except for the top
scan which is fit as C/2m (monoclinic). Scans are offset vertically
for clarity................................................................. 109
Fig. 8.5
a XRD patterns in the region where superlattice peaks appear. b
Peak near 44.5
◦ degrees in sample A 8 fit as both layered (top) and
monoclinic (bottom) with scattering angle steps of 0.02
◦ . Vertical
lines in R-3m (top) correspond to Kα 1 and Kα 2 for the (104)
peak, and to the (−202) and (131) peaks for C/2m (bottom) ...... 110
Fig. 8.6
Mn K-edge XANES patterns collected for samples showing
metal site vacancies, along with Mn 2 O 3 as a reference for Mn
3+ ,
and Li 2 MnO 3 for Mn
4+ . The red arrows indicate the positions of
the absorption edge near 6.545 keV for Mn 2 O 3 and 6.548 keV for
all other samples ........................................................ 112
Fig. 8.7
Results of a Monte Carlo simulation for sample D 8 using the
vacancy content and average nickel oxidation state from
Table 8.1. The structures were obtained with β T = 0.5 (a) and
β T = 2.0 (b)............................................................. 113
Fig. 8.8
XRD pattern of Li[Ni 1/6 P 1/6 Mn 2/3 ]O 2 with the result of Rietveld
refinement. Vertical lines are the calculated peak positions for
Kα 1 (full length) and Kα 2 (half length) .............................. 114
Fig. 8.9
Voltage versus capacity and dQ/dV plots for
Li[Ni 1/6 P 1/6 Mn 2/3 ]O 2 cycled at 30
◦ C with a specific current of
10 mA/g, or 0.020 mA/cm
2 . The red line in the dQ/dV curve
represents the first cycle................................................ 115
Fig. 8.10 Capacity versus cycle number for Li[Ni 1/6 P 1/6 Mn 2/3 ]O 2 . All
closed symbols shown in the legend represent charging, while the
open symbols are discharge capacities................................ 115
Fig. 9.1
Partial phase diagram with contours for the a lattice parameter
showing the boundaries of the single-phase layered region. The
lower boundary is shown connecting LiNiO 2 to Li 2 MnO 3 (no
attempt was made to determine how this boundary changes with
synthesis conditions, since the current study focuses on
compositions near the top of the layered region). The insert
shows approximate upper boundaries of the layered region
consistent with the current study. Points A 9 and B 9 were
determined using elemental analysis and are referred to
throughout the text. The red points are discussed in Chap. 7. The
blue dotted line is the cubic to layered phase transition ............ 118
Fig. 9.2
X-ray diffraction (XRD) scans of samples with composition A 9
heated at 800
◦ C. Black lines represent samples that were regular
cooled, while red lines are for quenched samples. The difference
plots in blue in the left panel represent the quenched scan
subtracted from the regular cooled scan.............................. 121