| Research Abstract |
The objective of the present research project lies in to understand the role of the intermediate range structure in the ion transport properties of superionic glasses. In the present project, the problem has been approached by using keywords and concepts such as glasses, medium range structure, ionic conductivity, mechanism of ion transport, chemical bonding, average electronegativity, relaxation in supercooled liquids, fragility, etc. The results obtained have been published as papers. They have also been presented in meetings such as Physical Society of Japan, Solid State Ionics Society of Japan, Pacific Rim Ceramic Societies, International Conference on Amorphous and Microcrystalline Semiconductors, International Conference on Liquid and Amorphous Metals, etc.
A brief abstract of the result obtained during the 2 years research period is given below.
・Previously, I have found that in oxide glasses, the ionic conductivity increases and the activation energy for ion transport decreases a
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s the correlation length of the intermediate range structure becomes long. A model that explains this behavior has been presented. According to the model, there is an optimal correlation length of the medium range structure for the ion transport. Experimental studies are recommended to verify this prediction.
・It is found that the network structure of oxide and chalcogenide glasses behaves differently when the glasses are doped with salts. For instance, in oxide glasses such as AgI-Ag_2O-B_2O_3, the FSDP wave number that reflects the intermediate range structure decreases with the addition of AgI. On the other hand, in chalcogenide glasses such as Ag_2S-GeSe_2, the FSDP wave number increases with the addition of Ag_2Se.
・In Li ion conducting glasses such as LiI-Li_2O-B_2O_3, the FSDP wave number increases with the concentration of LiI.
・It is shown that the above mentioned behavior and the network expansion by salt doping are related to the average electronegativity of the glasses and the degree of glass formation of the compounds. Less
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