2004 Fiscal Year Final Research Report Summary
Mechanochemical Preparation and Characterization of All-Solid-State Lithium Secondary Batteries
| Project/Area Number |
15360350
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Inorganic materials/Physical properties
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
TATSUMISAGO Masahiro Osaka Prefecture University, Prof, 大学院・工学研究科, 教授 (50137238)
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| Co-Investigator(Kenkyū-buntansha) |
TADANAGA Kiyoharu Osaka Prefecture University, Assoc.Prof., 大学院・工学研究科, 助教授 (90244657)
HAYASHI Akitoshi Osaka Prefecture University, Reseach.Assoc., 大学院・工学研究科, 助手 (10364027)
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| Project Period (FY) |
2003 – 2004
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| Keywords | mechanical milling / glass / ionics / all-solid-state battery / ion conductor / sulfide / energy / lithium battery |
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| Research Abstract |
1.Glass ceramic materials with various compositions in the system Li_2S-P_2S_5 were prepared by mechanical milling of starting materials and subsequent heat treatment. The 70Li_2S-30P_2S_5 glass-ceramic obtained by crystallization of mechanically milled glass showed a higher ambient-temperature conductivity of 2.2x10^<-3> Scm^<-1>. The enhancement of conductivity was due to the formation of the new, highly conductive, metastable crystalline phase. The main structural units of the crystal were the P_2S_7^<4-> ions.
2.The Li_2S-P-S glasses were prepared by mechanical milling from the mixture of Li_2S and elemental phosphorus and sulfur. The Li_2S-P-S glass-ceramics contained mainly PS_4^<3-> ions with a small amount of S-S bonds, and the homo bonds present in the corresponding glasses almost disappeared by the heat treatment of the glasses.
3.The all-solid-state cells with the combination of the SnS-P_2S_5 glassy electrode and the Li_2S-P_2S_5 glass-ceramic electrolyte were constructed. The cell using the 80SnS - 20P_2S_5 glass as an anode worked as a secondary battery, which was a first step of glassy monolithic cells with a common glass network.
4.All-solid-state cells using cathode materials consisting of sulfur and CuS were successfully prepared and exhibited excellent cycling performance at room temperature.
5.The effects of conductive additives in composite positive electrodes on charge-discharge behaviors of all-solid-state In/LiCoO_2 cell with Li_2S-P_2S_5 glass-ceramic electrolytes were investigated. Under relatively high current densities, the cell with VGCF kept larger discharge capacities during 50 cycles compared with the cells with other conductive additives like AB.
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