74
5 Combinatorial Studies of the Spinel and Rocksalt Regions . . .
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
Fig. 5.15 The spinel lattice
parameter obtained in the
coexistence region between
the spinel and ordered
rocksalt regions as a function
of β
Figure 5.15 shows the spinel lattice parameter obtained in the coexistence region
by regular cooling in oxygen as a function of the angle β defined in Fig. 5.4. Up
to β = 55
◦ , the spinel lattice parameter remains constant and the 13 scans in this
region have an average lattice parameter of 8.1722 ± 0.0005 Å with a standard
deviation of 0.0019 Å which corresponds to 0.02 % of the lattice parameter. The
average lattice parameter is therefore consistent with tie-lines fanning out from a
single point. Furthermore, the value of the average lattice parameter is very close to
8.173 ± 0.001 Å, the lattice parameter obtained for LiNi 0.5 Mn 1.5 O 4 , as shown in the
contour plot of Fig. 5.7 (a). The tie-lines were therefore drawn fanning out from this
point up to a maximum angle of β = 55
◦ .
By contrast, in air, LiNi 0.5 Mn 1.5 O 4 is not single-phase but shows a small amount
of a second phase as discussed in Sect. 1.4.1. The tie-line drawn at the composition of LiNi 0.5 Mn 1.5 O 4 in Fig. 5.3 shows that the spinel structure is coexisting
5 Combinatorial Studies of the Spinel and Rocksalt Regions . . .
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
Fig. 5.15 The spinel lattice
parameter obtained in the
coexistence region between
the spinel and ordered
rocksalt regions as a function
of β
Figure 5.15 shows the spinel lattice parameter obtained in the coexistence region
by regular cooling in oxygen as a function of the angle β defined in Fig. 5.4. Up
to β = 55
◦ , the spinel lattice parameter remains constant and the 13 scans in this
region have an average lattice parameter of 8.1722 ± 0.0005 Å with a standard
deviation of 0.0019 Å which corresponds to 0.02 % of the lattice parameter. The
average lattice parameter is therefore consistent with tie-lines fanning out from a
single point. Furthermore, the value of the average lattice parameter is very close to
8.173 ± 0.001 Å, the lattice parameter obtained for LiNi 0.5 Mn 1.5 O 4 , as shown in the
contour plot of Fig. 5.7 (a). The tie-lines were therefore drawn fanning out from this
point up to a maximum angle of β = 55
◦ .
By contrast, in air, LiNi 0.5 Mn 1.5 O 4 is not single-phase but shows a small amount
of a second phase as discussed in Sect. 1.4.1. The tie-line drawn at the composition of LiNi 0.5 Mn 1.5 O 4 in Fig. 5.3 shows that the spinel structure is coexisting