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
11/06/21

課題番号 Project No.

装置責任者 Name of responsible person

2010B0024

Toru Ishigaki

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Crystal Structure Analyses of Li-Fe-Mn Silicates Synthesized by Soft Chemical Routes

iMATERIA/(BL No.20)

実験責任者名 Name of principal investigator

実施日 Date of Experiment

Shinichi Komaba

Jan, 25th, 2011

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.
Lithium iron silicate, Li2FeSiO4
Lithium iron-manganese silicate, Li2Fe0.5Mn0.5O4
Lithium manganese silicate, Li2MnSiO4

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.

Lithium iron-manganese silicates, Li2FeSiO4, Li2Fe0.5Mn0.5O4, and Li2MnSiO4, have been prepared by ahydrothermal method at 150 oC. Time-of-Flight neutron scattering experiments of the samples have been
carried out in iMATERIA at J-PARC. It is found that broad background profile for the all three samples,
because adsorbed water at the materials surface cannot be eliminated by drying.

The collected diffraction data

have been analyzed after the background removal. Figure 1 compares synchrotron and neutron diffraction
patterns of the samples.

Since the iron and manganese have the similar X-ray scattering factors, the identical

X-ray diffraction patterns are obtained in these samples.

In contrast to the XRD, clear difference is noted in theneutron diffraction patterns, because the iron and manganese have quite different neutron scattering length.
From the data of both XRD and ND, the structural details are summarized below; (1) the crystal structures can be
assigned to the ordered β-Li3PO4-type structure. (2) Li2FeSiO4 has a non-negligible amount of twin defect aspreviously reported (N. Yabuuchi, S. Komaba et al., Dalton Trans., 2011, 40, 1846-1848), whereas theLi2MnSiO4 crystallizes into the ordered β-Li3PO4-type structure without the twin defects.

(3) A few percent ofcation intermixing between Li / Me sites exists in all samples, which are not influenced by the difference in the1

2. 実験方法及び結果（つづき） Experimental method and results (continued)
transition metal species.

From these results, we conclude that the difference in the role between the iron andmanganese ions in the lithium silicates framework is mainly attributed to the formation of the twin defects.

It isexpected that the existence of defects would accelerate the lithium conduction in the bulk as the electrodematerials for the rechargeable lithium batteries.

ND

Intensity / A. U.

Intensity / A. U.

SXRD

65 4

Figure 1

32d/Å

65 4

1

32d/Å

1

A comparison between synchrotron X-ray diffraction patterns and neutron diffraction patterns:(bottom) Li2FeSiO4, (middle) Li2Fe0.5Mn0.5O4, and (top) Li2MnSiO4.

Neutron diffraction clearly reveals thatiron and manganese ions similarly distribute in the rigid lithium silicate framework structure.

LiO4FeO4SiO4caFigure 2[010] LTA schematic illustration of the low-temperature phase of Li2MeO4 (Me = Fe and / or Mn) synthesized

by the hydrothermal method at 150 oC, which is the related structure of the β-Li3PO4-type structure.

Though

Li2MnSiO4 crystallizes into the defects-free phase, substitution of Fe for Mn results in the formation of the twin
defects in the host structure.

2