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
2015/2/23

課題番号 Project No.

装置責任者 Name of responsible person

2014A0251

Toru Ishigaki

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Effects of charge and discharge process on crystal structure ofiMATERIA/BL20

oxygen-deficient Li(Mn,Co,Ni,Li)O2-d cathodes by

実施日 Date of Experiment

reduction

methods

2014/6/6 - 2014/6/7

実験責任者名 Name of principal investigator

2014/6/21 - 2014/6/23

Yasushi Idemoto

2014/11/7 - 2014/11/8

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.

Li(Mn0.54Co0.13Ni0.13Li0.2)O2-, powder

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
Li(Mn0.54Co0.13Ni0.13Li0.2)O2- were synthesized by a conventional co-precipitation and solid-state
reaction method using Mn-, Ni- and Co- nitrates and LiOH as starting materials. Reductive heat-treatments wereperformed with sucrose additives (0.03 g/mol, 0.05 g/mol). The lattice parameters of these samples wereestimated by powder X-ray diffraction measurements, and the metal compositions were confirmed byinductively-coupled plasma (ICP) technique. The oxygen compositions were determined by titration technique.
For these samples, cathode properties were investigated charge-discharge cycle tests.
In order to reveal crystal-structure changes of the samples after the reduction treatment, about 1 g
powders were prepared. Neutron diffraction measurements of the powders were performed by iMATERIA
installed at J-PARC. Each powder with a weight of 0.5 g was loaded in a vanadium can, and then mounted in asample holder. The measurements were conducted at room temperature with a SF mode, and the measurement
time was ca. 20 min for each powder specimen. Crystal structures of the samples were refined by the Rietveld
technique using the 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
A Rietveld refinement patterns of Li(Mn0.54Co0.13Ni0.13Li0.2)O2-d for pristine, adding 0.03 g/mol sucrose
and 0.05 g/mol sucrose samples are presented in Fig. 1. In the analysis, we assumed a space group of the crystal
structure as C2/m (the Li2MnO3-type structure), and refined atomic positions and displacement parameters of all
the elements. Site occupancies of metals were also refined under constraints of analysis metal compositions. The
oxygen occupancies in the two sites were fixed with equally divided values estimated by titration method. It wasdemonstrated that the samples after reduction had a single phase as well as pristine sample although the lattice
parameter, c became shorter than pristine due to a decrease in the oxygen-oxygen repulsion.
The coulombic efficiency of the initial cycle was improved from 74% to 83% by addition of sucrose(0.03mol/g). From the results of Rietveld analysis, Mn-ordering increased after the reductive treatments whileoxygen amounts and the cation-mixing decreased. Especially the sample with 0.03 mol/g addition of sucrose
showed the lowest cation mixing of the present samples. It was found that the improvement for coulombic
efficiency was attributed to the effect of suppression of the nickel mixing in Li layer.
(a)

(b)

(c)

Fig. 1

Rietveld refinement patterns of 0.5Li2MnO3-0.5LiMn5/12Ni5/12Co1/6O2 materials for (a)untreated, (b)heat-treatment with 0.03 mol/g sucrose, and (c) heat-treatment with 0.05 mol/g sucrose. Plus marks show
observed neutron diffraction intensities [iMATERIA] and a solid line represents calculated intensities. The
vertical marks indicate positions of allowed Bragg reflections. The curve at the bottom is a difference between
the observed and calculated intensities in the same scale.
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