実験報告書様式（一般利用課題・成果公開利用）（ ※本報告書は英語で記述してください。ただし、産業利用課題として採択されている方は日本語で記述していただいても結構です。 ）MLF Experimental Report

提出日 Date of Report
2011/6/25

課題番号 Project No.

装置責任者 Name of responsible person

2010B0058

Takashi Kamiyama

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Changes of crystal structures during charge-discharge processes inSuperHRPD/BL08

Li(Mn, Co, Ni, Li)O2 as a cathode active material for a lithium ion

実施日 Date of Experimentbattery

2010/12/16 - 2010/12/17

実験責任者名 Name of principal investigator

2011/2/14 - 2011/2/15

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.

Pristine sample:

Li1.2Mn0.567Ni0.167Co0.067O2(0.6Li2MnO3- 0.4LiMn0.417Ni0.417Co0.166O2),

Charged sample:

Li0.3Mn0.567Ni0.167Co0.067O2-δ,powderpowder

2. 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
Li1.2Mn0.567Ni0.167Co0.067O2 was synthesized by a solution method using a citric acid as a dispersing agent.
The precursor obtained from the solution was heat-treated in air at 650 oC for 15 h and then at 950 oC for 15 h.
Preliminary phase identification was carried out by powder X-ray diffraction technique, and the metalcomposition was determined by ICP. The cathode property was evaluated by charge-discharge cycle tests using acoin cell. We also prepared a sample after electrochemical charge, Li0.3Mn0.567Ni0.167Co0.067O2, in order to clarify
an effect of the charging process on the crystal structure.
Crystal-structure analyses were performed based on the Rietveld method. In this experiment, neutron
diffractions were collected by SuperHRPD. Each sample was applied to Al foil, and then the sheet was loaded ina vanadium can. Diffraction patterns of the sheets were measured under vacuum at room temperature. By using
the data, the crystal structures were refined with Z-Rietveld program.
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2. 実験方法及び結果（つづき） Experimental method and results (continued)

Results
Table 1 shows structure parameters of pristine Li1.2Mn0.567Ni0.167Co0.067O2 refined by assuming the spacegroup as R-3m. As shown in this table, the Rietveld analysis could be successfully carried out even though themeasured specimen was a film with a weight of ca. 0.7 g. From these parameters, it was found that a cation
mixing amount ― i.e., an amount of Ni2+ occupying Li+ site in this case ― was low and an oxygen deficit
amount was negligible in this material.
In order to reveal a crystal-structure change of the cathode material during charge-discharge cycle, wealso measured neutron diffraction patterns of the electrochemically-charged sample, which was a film with aweight of ca. 0.01 g. The diffraction pattern is given in Fig. 1. As a reference, this figure also shows thediffraction pattern of the pristine sample discussed above. From this figure, it was clarified that the crystal
structure was varied and some impurity phases were formed by the charging process. Such a change in thecathode may be related with a deterioration process of the battery.
Table 1 Refined structure parameters of Li1.2Mn0.567Ni0.167Co0.067O2 (0.6Li2MnO3- 0.4LiMn0.417Ni0.417Co0.166O2)
in the space group of R-3m. R-factors were Rwp=12.0 %, Rp=8.81 % and Re=5.80 %. Lattice constants werea=0.28579(5) nm and c=1.4243(3) nm.
22SiteSitexyz

10 ×B(nm )Li13a0001.98(10)0.980(2)Ni1

3a=x(Li1)=y(Li1)=z(Li1)=B(Li1)0.020(2)Ni23b001/20.37(10)0.131(2)Li23b=x(Ni2)=y(Ni2)=z(Ni2)=B(Ni2)0.214(2)Mn

3b=x(Ni2)=y(Ni2)=z(Ni2)=B(Ni2)0.554

Co

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

0.0931O6c

00

0.24104(5)0.85(2)0.990(3)Normalized Intensity /arb. unit

Atomoccupancy

(b)

(a)

0.1

0.12

0.14

0.16

d spacing / nm
Fig. 1 Neutron diffraction patterns of (a) the pristine Li1.2Mn0.567Ni0.167Co0.067O2 and (b) the electrochemicallycharged sample.
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