| Project/Area Number |
10450237
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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 | Tohoku University |
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Principal Investigator |
ENDO Tadashi Graduate school of Engineering, Tohoku University, Professor, 大学院・工学研究科, 教授 (30176797)
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| Co-Investigator(Kenkyū-buntansha) |
UHEDA Kyota Graduate school of Engineering, Tohoku University, Assistant, 大学院・工学研究科, 助手 (50271862)
TAKIZAWA Hirotsugu Graduate school of Engineering, Tohoku University, Assistant Professor, 大学院・工学研究科, 助教授 (90226960)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥15,800,000 (Direct Cost: ¥15,800,000)
Fiscal Year 2000: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1999: ¥4,800,000 (Direct Cost: ¥4,800,000)
Fiscal Year 1998: ¥9,000,000 (Direct Cost: ¥9,000,000)
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| Keywords | Ion conductor / Tin double oxide / Tin oxide / Microporous materials / Hollandite / Tunnel structure / Layered structure / Crystal growth / 針状結晶 / カリウム / フラックス / スズ / トンネル型構造 / ホーランダイト型構造 / 層状化合物 / イオン伝導体 / スズ複酸化物 / インターカレーション反応 / ホーランダイト型化合物 |
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| Research Abstract |
First, we have prepared new tin double oxides with open framework. C.Keller and A.R.West had reported Li_2MgSn_3O_8 with a ramsdellite structure. (J.Mater. Sci. Lett., 2 (1983) 451-452) The framework of Li_2MgSn_3O_8 is constructed by SnO_6 and MgO_6 Li^+ ions are located in 1×2 tunnel. We have tried to synthesize new tin double oxides with larger tunnels, for example 2×2 or 3×3, by using lager alkali ions, K^+, Rb^+, or Cs^+ instead of Li^+ ion. As a restult, we succeeded in preparing A_xMg_<x/2>Sn_<8-x/2>O_<16> (x≦2)(K, Rb and Cs) and K_xCa_<x/2>Sn_<8-x/2>O_<16> (x≦2) with a hollandite structure.
Both A_xMg_<x/2>Sn_<8-x/2>O_<16> (x≦2)(K, Rb and Cs) and K_xCa_<x/2>Sn_<8-x/2>O_<16> (x≦2) were expected that they would have excellent ion and electron conductivities. In order to investigate electrical properties of both compounds, we have studied the flux growth of their crystals. Polycrystalline K_xCa_<x/2>Sn_<8-x/2>O_<16> (x≦2) was obtained by using excess K_2CO_3 as flux. The polycrystal was made by tying fibrous single crystals of K_xCa_<x/2>Sn_<8-x/2>O_<16> (x≦2) in a bundle. Its size (mm_3) was 1.5 mm×0.2 mm×0.2 mm. After conductivity measurement, the conductivity of K_xCa_<x/2>Sn_<8-x/2>O_<16> (x≦2) was σ_<300>=2.2×10^<-9>Ω^<-1> m^<-1> at room temperature, and the activation energy was calculated to be 0.63eV.The result suggested that the chief charge carrier is potassium ion in 1D channels.
In conclusion, it is expected that both new hollandite tin double oxides, A_xMg_<x/2>Sn_<8-x/2>O_<16> (K, Rb, and Cs) and K_xCa_<x/2>Sn_<8-x/2>O_<16> (x≦2) will be applied to electrolytes, especially to
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