In the present study, we performed ex-situ measurements of the change in the crystal structure of the cathode material subjected to a charge - discharge cycle in a coin type cell fabricated for this purpose. The results of this study demonstrate that it is possible to perform ex-situ structural analysis by neutron diffraction of only 8.5 mg of an active material in a cathode together with the cathode fabrication materials. Moreover, the average, local and electronic structures of LiMn1/3Ni1/3Co1/3O2 prepared by various methods was investigated. In order to clarify how the preparation processes affected on the crystal structures in detail, local structure, i.e. cation mixing and transition-metal ordering, in the samples were analyzed by Pair Distribution Function (PDF) method using a neutron source and X-ray absorption fine structure measurements. From this analysis, it was found that the local structure in LiMn1/3Ni1/3Co1/3O2 depended on the preparation process. Such a difference in the local structures may result in different cathode properties among the samples synthesized.
Recent development of neutron devices have made possible the construction of small scale accelerator driven neutron sources that will be able to play a significant role in future advancements in neutron science and technology. A thermal and cold neutron sources with 7 MeV proton linac and Be target system are under construction at RIKEN.
The biological mechanism of the physiological function such as the enzymatic reaction is well understood by studying protonation states of the catalytic polar amino acid residues, which can be identified by neutron protein crystallography. It is proposed that the protonation states should be systematically discussed from the view point of the pKa values of the amino acid residues in proteins. Several examples of the protonation states of the catalytic residues determined by neutron protein crystallography, such as serine proteases (trypsin, elastase, thrombin, & acromobacter protease I), insulin, hen egg white lysozyme, RNase A, and HIV-1 protease were introduced and discussed on the basis of the pKa values.
Neutron crystallography for biomacromolecules was reborn in 1990’s, because a new neutron detector Neutron Imaging Plate (NIP) was successfully developed and installed at diffractoeters ; BIX-3, BIX-4 and others at reactor neutron sources in Japan and France, and it was found that NIP is so effective to collect Bragg diffraction spots from biological macromolecules with high efficiency. Furthermore, since the end of 2008, a new diffractometer, IBARAKI Biological Crystal Diffractometer (iBIX) in J-PARC has started to operate and it has been producing interesting results. It is expected to have about 50 times better efficiency in measurement after J-PARC accelerator arrives 1MW in power, compared to BIX-3 and BIX-4. In this report, we explain how to use neutron diffractometers in Japan from sample preparation, diffractometer’s characteristic, measurement, data reduction and finally to proposal submit.