| Project/Area Number |
05555172
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Inorganic materials/Physical properties
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| Research Institution | University of Osaka Prefecture |
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Principal Investigator |
IWAKURA Chiaki University of Osaka Prefecture, College of Engineering, Professor, 工学部, 教授 (00029183)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Hiroshi University of Osaka Prefecture, College of Engineering, Research Associate, 工学部, 助手 (00213174)
MATSUOKA Masao Ritsumeikan University Faculty of Science and Engineering, Associate Professor, 理工学部, 助教授 (10081340)
FURUKAWA Naoji University of Osaka Prefecture, College of Engineering, Assistant Professor, 工学部, 講師 (70081338)
FUKUMOTO Yukio University of Osaka Prefecture, College of Engineering, Associate Professor, 工学部, 助教授 (80081339)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥4,800,000 (Direct Cost: ¥4,800,000)
Fiscal Year 1994: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1993: ¥3,100,000 (Direct Cost: ¥3,100,000)
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| Keywords | Nickel-Metal Hydride Battery / Hydrogen Storage Systems / Pressure-Composition Isotherm / High Energy Density / Secondary Battery / Hydrogen Evolution Reaction / Hydrogen Diffusion Coefficient / High-rate Charge-Discharge Characteristics / ニッケル-水素化物電池 / 希土類系水素吸蔵合金 / ラーベス相水素吸蔵合金 / 水素電極反応 / 高エネルギー密度二次電池 / 高率放電特性 / 無公害二次電池 / 電気自動車用二次電池 |
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| Research Abstract |
For the purpose of improving the performance of negative electrode in a nickel-metal hydride battery, the effects of surface modification of alloys by electroless plating, electroplating, treatment with an alkaline solution containing a reducing agent and mixing of metal oxides and bulk-composition control of alloys by the partial substitution of foreign metals for constituent metals and the deviation of alloy composition from stoichiometric ratio such as AB_2 and AB_5 on the electrochemical characteristics of hydrogen storage alloys were investigated. The information obtained from this work can be summarized as follows.
1. Electrochemical characteristics of the hydrogen storage alloys was improved by substituting foreign metals for a part of constituent metals and deviating alloy composition from stoichiometric ratio such as AB_5 and AB_2.
2. Catalytic activity for hydrogen electrode reaction and high-rate chargeability increased by modifying various metals and metal oxides on the surface of the rare earth hydrogen storage alloys.
3. Surface modification of the Laves-phase hydrogen storage alloys by a reducing agent resulted in easier initial activation and the increase in the high-rate dischargeability.
4. Diffusion coefficient of hydrogen in the hydrogen storage alloys evaluated from the potential step method increased by substituting foreign metals having smaller atomic radius for constituent metals.
5. Additional deviations of the alloy composition from the stoichiometric ratio lead to the decrease in activation energy for the hydrogen diffusion in the hydrogen storage alloys and the increase in discharge efficiency.
Thus, several guidelines of designing the hydrogen storage alloys and developing the negative electrodes for high performance secondary batteries could be proposed.
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