1997 Fiscal Year Final Research Report Summary
TRANSMISSION ELECTRON MICROSCOPY STUDIES ON DEGRADATION OF ALLOY ELECTRODE IN NICKEL-METAL HYDRIDE BATTERY
| Project/Area Number |
08455321
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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 |
Structural/Functional materials
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| Research Institution | NAGOYA UNIVERSITY |
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Principal Investigator |
KURODA Kotaro PROFESSOR,NAGOYA UNIVERSITY,DEPT OF MAT.SCI.&ENG., 工学研究科, 教授 (30161798)
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| Co-Investigator(Kenkyū-buntansha) |
SAKA Hiroyasu PROFESSOR,NAGOYA UNIVERSITY,DEPT OF QUANTUM ENG., 工学研究科, 教授 (90023267)
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| Project Period (FY) |
1996 – 1997
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| Keywords | transmission electron microscopy (TEM) / nickel-metal hydride battery / alloy electrode / hydrogen storage alloy / degradation / cross-sectional TEM / plan-view TEM / analytical electron microscopy (AEM) / focused ion beam (FIB) fabrication |
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| Research Abstract |
The hydrogen storage alloys have been applied to secondary batteries. Recently the nickel-metal hydride batteries catch much attention. The hydrogen absorption characterics of LaNi_5 and related compounds have been investigated. It has been suggested, but not proven, that defects such as dislocation, anti-phase boundary and structural disorder are produced by hydrogen reaction.
The influence of hydrogen absorption on the microstructure of Mg-Ni alloys has been investigated by transmission electron microscopy (TEM). Rapidly-quenched Mg-Ni alloys were annealed and then dehydrided. TEM specimens were fabricated by focused ion beam (FIB) technique. Many cracks are evident in the specimen after 5 hydriding-dehydriding cycles.
Deformation structures of LaNi_5 alloy have been observed using TEM in order to clarify the nature of dislocations which affect the degradation of the alloy electrode. LaNI_5 alloy is able to deform at temperatures higher than 850ﾟC.Many dislocations and subgrains are introduced after deformation. Dislocations in the alloy electrode are thought to be the trapped site of hydrogen, therefore high density of dislocation may affect the degradation of electrode.
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