1993 Fiscal Year Final Research Report Summary
Metal Hydride Battery Electrodes for High Current Density
| Project/Area Number |
04650621
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属精錬・金属化学
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| Research Institution | Tokai University |
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Principal Investigator |
UCHIDA Hirohisa Tokai University, Department of Applied Physics, Professor, 工学部, 教授 (20147119)
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| Co-Investigator(Kenkyū-buntansha) |
UCHIDA Haruhisa Tokai University, Department of Human Development, Assistant Professor, 教養学部, 講師 (50232856)
MATSUMURA Yoshihito Kanagawa Academy of Science and Technology, Laboratory No.6, Researcher, 研究員 (60239085)
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| Project Period (FY) |
1992 – 1993
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| Keywords | MH-Ni Battery / Hydrogen Storage Alloy / Rapid Charge-Discharge / KOH Pretreatment / Hydrogen Absorption Rate / 液相反応 / 水素吸収速度 / 表面処理 |
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| Research Abstract |
Recently, some types of Metal Hydride batteries have been commercialized. At present, there are still many material problems to be solved for manufacturing more improved Metal Hydride batteries which enable the rapid charge-discharge with high current densities. Many works point out the importance of substitutions of various elements for rare earths and Ni in the rare earth - Ni based alloys. However, the role of each substitutive elements in the electrodes is not well understood. This is mainly because of the complicated electrochemical reactions on the electrode surface which cannot be readily investigated.
In this work, we tried to make an fundamental research to understand the roles of the cobalt substitution for Ni in hydriding kinetics of LaNi_5. Activation behaviors of LaNi_<2.5>Co_<2.5> alloys in hydrogen gas atmosphere and KOH solution were investigated. The samples surface were pretreated by heating in a 6N-KOH solution at 353 K for 3 hours.
Co substitution shows an effective improvement in the initial activations, which may be explained by the formation of relatively stable oxidized surface. The LaNi_<2.5>Co_<2.5> alloy exhibits also no significant pulverization. The presence of cobalt may induce relatively high coherent oxide-metal interfaces which inhibits the generation of cracks in the cycling. After pretreatment of 6N-KOH solution at 353 K, LaNi_<2.5>Co_<2.5> alloy showed shortened incubation periods for both the initial activations and subsequent cyclic hydridings.
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