9.7 Conclusions Regarding Layered–Layered Nano-Composites
129
Fig. 9.8 Partial X-ray
diffraction (XRD) patterns for
samples A 9 (x = 0.00), B 9
(x = 0.04) and C 9 (x = 0.08)
obtained as part of the
composition series
Li 1+x [Ni 0.5 Mn 0.5 ] 1−x O 2 . The
arrow indicates the presence
of a second peak in sample
A 9 . The red lines are
single-phase layered fits
9.7 Conclusions Regarding Layered–Layered Nano-Composites
The structural changes taking place during regular cooling of materials with metallic
compositions near that of LiNi 0.5 Mn 0.5 O 2 were studied after heating under various
oxygen partial pressures and were related to features in the phase diagram determined previously. Materials made with 5 % excess lithium (at point B 9 in Fig. 9.1)
were found to stay single phase even when the regular cooling rate of 5–10
◦ C/min
was used. These single-phase layered materials showed good electrochemical performance with a reversible capacity of 180 mAh/g for the quenched sample and
170 mAh/g for the regular cooled sample when cycled up to 4.8 V. By contrast,
under the same cycling conditions, samples without excess lithium (at point A 9 in
Fig. 9.1) made in 2 % oxygen had a capacity of 140 mAh/g when quenched and only
90 mAh/g when regular cooled. The changes in the XRD pattern for this A 9 sample
129
Fig. 9.8 Partial X-ray
diffraction (XRD) patterns for
samples A 9 (x = 0.00), B 9
(x = 0.04) and C 9 (x = 0.08)
obtained as part of the
composition series
Li 1+x [Ni 0.5 Mn 0.5 ] 1−x O 2 . The
arrow indicates the presence
of a second peak in sample
A 9 . The red lines are
single-phase layered fits
9.7 Conclusions Regarding Layered–Layered Nano-Composites
The structural changes taking place during regular cooling of materials with metallic
compositions near that of LiNi 0.5 Mn 0.5 O 2 were studied after heating under various
oxygen partial pressures and were related to features in the phase diagram determined previously. Materials made with 5 % excess lithium (at point B 9 in Fig. 9.1)
were found to stay single phase even when the regular cooling rate of 5–10
◦ C/min
was used. These single-phase layered materials showed good electrochemical performance with a reversible capacity of 180 mAh/g for the quenched sample and
170 mAh/g for the regular cooled sample when cycled up to 4.8 V. By contrast,
under the same cycling conditions, samples without excess lithium (at point A 9 in
Fig. 9.1) made in 2 % oxygen had a capacity of 140 mAh/g when quenched and only
90 mAh/g when regular cooled. The changes in the XRD pattern for this A 9 sample