The Development of New Multivalent Cation Conducting Solid Electrolyte and Their Application for Gas Sensors
| Project/Area Number |
15550172
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Inorganic industrial materials
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| Research Institution | Osaka University |
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Principal Investigator |
IMANAKA Nobuhito Osaka University, Professor, 大学院・工学研究科, 教授 (30192503)
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| Co-Investigator(Kenkyū-buntansha) |
MASUI Toshiyuki Osaka University, Assistant Professor, 大学院・工学研究科, 講師 (00304006)
ADACHI Gin-ya Juri Environmental and Chemical Laboratory, Center President, 化学研究所, 所長(研究職) (60029080)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2003: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | Multivalent Cation / Solid Electrolyte / Phosphate / NASICON-type / Sensor / Aluminum Ion / Boron Oxide / Carbon Dioxide / プラセオジムイオン / NOx |
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| Research Abstract |
UP to now, trivalent cation has been believed as a poor migrating ion species in solids because of the high valence state, whereas monovalent or divalent ion conducting solids were intensively studied. Recently, we have been succeeded in developing the trivalent cation conducting (M_<0.2>Zr_<0.8>)_<20/19> Nb(PO_4)_3 solid electrolytes (M = trivalent cations) with NASICON type structure. The trivalent ion conductivity of the (M_<0.2>Zr_<0.8>)_<20/19>(PO_4)_3 solid is as high as those for representative divalent O^<2-> ion conducting solid. However, it is necessary to enhance the ion conductivity to utilize for various electrochemical devises such as gas sensors. Furthermore, since the mechanical strength of (M_<0.2>Zr_<0.8>)_<20/19>(PO_4)_3 is not enough, we try to improve bath the ion conductivity aril the mechanical strength of the (M_<0.2>Zr_<0.8>)_<20/19>(PO_4)_3 solid. Here, we selected (Al_<0.2>Zr_<0.8>)_<20/19> Nb(PO_4)_3 as a target material due to it highest trivalent ion conductivity among the (M_<0.2>Zr_<0.8>)_<20/19>(PO_4)_3 series, and we synthesized the (M_<0.2>Zr_<0.8>)_<20/19>(PO_4)_3 solid with a sintering aid of B_2O_3.
By adding 6-8 Wt% B_2O_3 at the sintering step of the (Al_<0.2>Zr_<0.8>)_<20/19> Nb(PO_4)_3 solid, B_2O_3 vaporized With high aggregation between sample particles resulting in high mechanical strength and high density of the sintered sample. Furthermore, the trivalent Al^<3+> ion conductivity was also enhanced two times compared with that for B_2O_3 non-doped sample.
We have also fabricated the CO_2 gas sensor with above mentioned B_2O_3 added (Al_<0.2>Zr_<0.8>)_<20/19> Nb(PO_4)_3 solid together with O^<2-> ion conducting yttria stabilized zirconia (YSZ) and rare earth oxysulfate based sensing auxiliary electrode. Tile present sensor can detect the CO_2 concentration exactly with obeying theoretical Nernstian relationship between sensor output EMF and the logarithm of the CO_2 concentration at 550℃.
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Report
(3 results)
Research Products
(22 results)
