1990 Fiscal Year Final Research Report Summary
An Approach ro Active Material Design for Rechargeable Nonaqueous Cell
| Project/Area Number |
01470084
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
工業物理化学
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| Research Institution | Osaka City University |
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Principal Investigator |
HIRAI Taketsugu Osaka City Univ., Dept. of Appl Chem., Prof., 工学部, 教授 (70032919)
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| Co-Investigator(Kenkyū-buntansha) |
SAWAI Keijiro Osaka City Univ., Dept. of Appl., Res. Ass., 工学部, 助手 (50206017)
OHZUKU Tsutomu Osaka City Univ,. Dept. of Appl. Chem., Ass. Prof., 工学部, 助教授 (40116439)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Lithium Cells / Manganese Dioxide / Rechargeable Nonaqueous Cell / Nickel Dioxide / Cobalt Dioxide / Mixed Metal Oxides |
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| Research Abstract |
Research directed toward the better understanding on the depolarizability of manganese dioxide in lithium nonaqueous cell was carried out in the fiscal years 1989-1990. The specific works done at the Osaka City University including the active material design for rechargeable nonaqueous cells therewith are ;
(1) NiAsーType Manganese Dioxide-manganese and lithium ions are located at octahedral sites in a hexagonally close-packed oxygen array. During the reduction of this material tetravalent manganese ions are reduced to trivalent manganese ions in the same lattice sites and the lithium ions are inserted into the octahedral sites without the destruction of core structure (topotactic reduction). For oxidation of the reduced sample the movements of electrons and litium ions are reverse direction. Rechargeable capacity was observed to be 120 - 160 mAh g^<-1> in the voltage range of 2.5 - 3.8 V inlithium nonaqueous cell.
(2) Rock Salt-Type Manganese Dioxide ー manganese and lithium ions are loca
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ted at octahedral sites in a cubic-close packed oxygen array. The reaction proceeds in a topotactic manner. The working voltage is ca. 4 V due to the low-spin trivalent manganese ions. Rechargeable capacity was observed to be 100 - 120 mAh g^<-1>. This material may be used as cathode active material for the 4-volts class of rechargeable nonaqueous cells.
(3) Rock Salt-Type Mixed Metal Dioxide- A series of mixed metal dioxides having a cubicーclose packed oxygen array was examined by an analogy with the crystal structure of a rock salt-type manganese dioxide. The materials we have succeeded were LiNi<@D2x@>D2 Co<@D21-x@>D2 O<@D22@>D2 (O<x<1) in which metal and lithium ions were located at octahedral sites in a cubic-close packed oxygen array. Trivalent metal ions, Ni<@D13+@>D1 and Co<@3+@>D1 ions, in a cubic-close packed oxygen array. Trivalent metal ions, Ni<@D13+@>D1 and Co<@D13+@>D1 ions, in these material were low-spin state. These materials showed 4 V of the working voltage and 130 - 160 mAh g<@D1-1@>D1 of rechargeable capacity.
Materials proposed in this work are applicable to the 4-volts class of rechargeable nonaqueouse cells. We believe that these materials prompt the development of new generation in rechargeable nonaqueous cells. Less
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Research Products
(18 results)
