TY - JOUR
T1 - Structure determination of high-voltage LiMg
δ
Ni
0.5-δ
Mn
1.5
O
4
spinels for Li-ion batteries
AU - Ooms, F. G.B.
AU - Wagemaker, M.
AU - Van Well, A. A.
AU - Mulder, F. M.
AU - Kelder, E. M.
AU - Schoonman, J.
PY - 2002/12/1
Y1 - 2002/12/1
N2 -
A series of cathode materials has been synthesized with the general formula LiMg
δ
Ni
0.5-δ
Mn
1.5
O
4
(δ = 0.00, 0.05 and 0.10). These are promising cathode materials for lithium and Li-ion batteries due to the high voltage (> 4.7 V vs. Li/Li
+
) and the high energy density (> 570 W h/kg). The cycling stability of these materials is strongly influenced by the method of synthesis and is particularly improved by a very low cooling rate. To study the effect of such slow cooling on the crystal structure, a detailed diffraction analysis was performed. Initial X-ray-diffraction (XRD) measurements revealed that the materials crystallized in the spinel structure, which is normally refined in the Fd(3̄)m space group. Neutron-diffraction (ND) experiments, however, indicate space group P4
3
32 and refinements of the ND and XRD patterns result in the site occupations: Li
+
on 8c, Mg
2+
and Ni
2+
on 4b, Mn
4+
on 12d and O
2-
on 24e and 8c. It was also found that, as a function of the Mg content, the cubic lattice constant increases from 8.1685 Å (δ = 0.00) to 8.1733 Å (δ = 0.10).
AB -
A series of cathode materials has been synthesized with the general formula LiMg
δ
Ni
0.5-δ
Mn
1.5
O
4
(δ = 0.00, 0.05 and 0.10). These are promising cathode materials for lithium and Li-ion batteries due to the high voltage (> 4.7 V vs. Li/Li
+
) and the high energy density (> 570 W h/kg). The cycling stability of these materials is strongly influenced by the method of synthesis and is particularly improved by a very low cooling rate. To study the effect of such slow cooling on the crystal structure, a detailed diffraction analysis was performed. Initial X-ray-diffraction (XRD) measurements revealed that the materials crystallized in the spinel structure, which is normally refined in the Fd(3̄)m space group. Neutron-diffraction (ND) experiments, however, indicate space group P4
3
32 and refinements of the ND and XRD patterns result in the site occupations: Li
+
on 8c, Mg
2+
and Ni
2+
on 4b, Mn
4+
on 12d and O
2-
on 24e and 8c. It was also found that, as a function of the Mg content, the cubic lattice constant increases from 8.1685 Å (δ = 0.00) to 8.1733 Å (δ = 0.10).
UR - http://www.scopus.com/inward/record.url?scp=0347927540&partnerID=8YFLogxK
U2 - 10.1007/s003390101196
DO - 10.1007/s003390101196
M3 - Article
AN - SCOPUS:0347927540
VL - 74
JO - Applied Physics A: materials science & processing
JF - Applied Physics A: materials science & processing
SN - 0947-8396
IS - SUPPL.II
ER -