実験報告書様式（一般利用課題・成果公開利用）

MLF Experimental Report

提出日 Date of Report
2010/5/11

課題番号 Project No.

装置責任者 Name of responsible person

2009B0013

Takashi Kamiyama

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Crystal structure of xLi2MnO3-(1-x)LiMn1/3Ni1/3Co1/3O2 as a

SuperHRPD/BL08

cathode active material for lithium ion battery

実施日 Date of Experiment

実験責任者名 Name of principal investigator

2010/1/28-1/29, 2010/2/1-2/2

Yasushi Idemoto
所属 Affiliation
Tokyo University of Science
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.

yLi2MnO3-(1-y)LiMn1/3-x/2Ni1/3-x/2CoxO2 (x=1/3, 2/9; y=0.5, 0.6)
powder2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

Experimental method
We prepared yLi2MnO3-(1-y)LiMn1/3-x/2Ni1/3-x/2CoxO2 by means of a solution method using each metal
acetate aqueous solution as starting materials. The precursor obtained from the solution was heat-treated in air at650 oC for 15 h and the at 950 oC for 15 h. The phase of the product was identified by a powder X-ray diffraction
and its metal composition was determined by an ICP. The cathode property was evaluated by CV andcharge-discharge cycle tests.
The crystal structure was investigated by the Rietveld analysis using neutron diffractions, which weremeasured with Super HRPD. The about 1 gram of the sample powder was loaded in a vanadium can and thenmounted in the apparatus. The experiment was performed in vacuum at room temperature, and the measurement
time was 5~5.5 hours. The Rietveld analysis was carried out by using Z-Code package.

1

2. 実験方法及び結果（つづき） Experimental method and results (continued)
Results
Figure 1 shows a Rietveld refinement pattern of a solid solution of 0.6Li2MnO3-0.4LiMn1/3Ni1/3Co1/3O2
measured with Super HRPD. In the analysis, we assumed that the sample had a single phase of a layeredrock-salt structure (S. G.; R-3m). As a result, it was found that diffraction peaks except for those around d=0.22
nm could be attributed to the layered structure. From the simulation and other previous works, it can beconsidered that the extra peaks were caused by a Li2MnO3 domain within the layered structure. Table 1 shows
the refined structure parameters of the sample. As shown in this table, the Li site (3a site) was occupied partiallyby Ni ― about 3 % ― in the same way as LiMn1/3Ni1/3Co1/3O2, and the occupancy at the oxygen site (6c site)
was almost unity, indicating that an oxygen vacancy was negligible. The larger atomic displacement parameter ofLi than the other elements may reflect that the sample could conduct Li ion. Similar results were also observed in
the other solid-solutions of yLi2MnO3-(1-y)LiMn1/3-x/2Ni1/3-x/2CoxO2, although Ni at the Li site tended to increase
with increasing the Ni content. From the quadratic elongation and the bond angle variance, it was also found thatthe distortion of the (Mn,Ni,Co,Li)-O6 octahedron became smaller with increasing the Mn content. Since asample with higher Mn content exhibited better cycle performance, Mn may play an important role in theNormalized intensity / arb. unit

cathode property from the viewpoint of the crystal structure.
+ observed
実測値 intensities― calculated
計算値 intensities| allowed
Bragg’s reflections
計算によって求められたピーク位置
実測値と計算値の差― differences
between observed andcalculated intensities

0.05

0.10

0.15

0.20

d / nmFig. 1 The Rietveld refinement patterns of 0.6Li2MnO3-0.4LiMn1/3Ni1/3Co1/3O2.
Table 1 The refined structure parameters of 0.6Li2MnO3-0.4LiMn1/3Ni1/3Co1/3O2 (S. G.; R-3m). R-factors were
Rwp=11.89, Rp=10.05 and S=1.43. The lattice constants were a=b=0.28427(2) nm and c=1.418(2) nm.
22SiteAtomSitexyz

10 ×B(nm )Li13a0002.00(9)0.965(1)Ni1

3a=Li1(x)=Li1(y)=Li1(z)=Li1(B)

0.034(1)Ni23b000.5

0.41(7)0.099(1)Li23b=Ni2(x)=Ni2(y)=Ni2(z)=Ni2(B)0.241(1)Mn

3b=Ni2(x)=Ni2(y)=Ni2(z)=Ni2(B)

0.528

Co3b=Ni2(x)=Ni2(y)=Ni2(z)=Ni2(B)

0.132

O

6c00

0.240717(2)0.570(6)0.999(3)2

occupancy