1999 Fiscal Year Final Research Report Summary
Control of Mg-Based Hydrogen Storage Alloy Nanocrystallites and Their Surface Modification
| Project/Area Number |
09555273
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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 | 展開研究 |
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| Research Field |
工業物理化学
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
IWAKURA Chiaki Osaka Prefecture University, College of Engineering, Professor, 工学部, 教授 (00029183)
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| Co-Investigator(Kenkyū-buntansha) |
ZHANG Shu guo Osaka Prefecture University, College of Engineering, Research Associate, 工学部, 助手 (10295719)
FURUKAWA Naoji Osaka Prefecture University, College of Engineering, Assistant Professor, 工学部, 講師 (70081338)
INOUE Hiroshi Osaka Prefecture University, College of Engineering, Associate Professor, 工学部, 助教授 (00213174)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Nickel-hydrogen battery / Mg-based hydrogen storage alloy / Ball-milling / Surface modification / Graphite / Mechanical alloying / Charge-discharge characteristics / X-ray photoelectron spectroscopy |
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| Research Abstract |
The results obtained in this study for three years are summarized as follows.
1. XPS and Raman spectroscopy showed that electron transfer from graphite with π electrons to the oxidized surface Mg by ball-milling weakened the Mg-O bond strength, leading to the formation of the Ni-O bonding. The ratio of metallic Ni to Mg on the MgNi surface was increased by the ball-milling.
2. The rate of hydrogen absorption for MgィイD22ィエD2Ni-70 wt.% Ni composite at 30℃ markedly increased in comparison with MgィイD22ィエD2Ni and MgィイD22ィエD2Ni-70 wt.% mixture and the amount of absorbed hydrogen reached H/M of about one within 1 h. In the charge-discharg test, the MgィイD22ィエD2Ni-70 wt.% Ni composite showed markedly high discharge capacity of about 870 mAh g(MgィイD22ィエD2Ni)ィイD1-1ィエD1. The discharge capacity, moreover, increased up to 1080 mAh g(MgィイD22ィエD2Ni)ィイD1-1ィエD1by using Ni powder with the weight ratio of Ni to alloy of 10 instead of Cu powder. The charge-discharge cycle performance was improved by increasing the amount of added Ni powder.
3. The charge-discharge cycle performance for MgィイD20.9ィエD2MィイD20.1ィエD2Ni (M=Ti, V) alloys was greatly improved in comparison with MgNi though the initial discharge capacity decreased. This was ascribed to the preference dissolution of V component in alkaline solution for the MgィイD20.9ィエD2VィイD20.1ィエD2Ni alloy and the formation of Ti oxides on the alloys surface for the MgィイD20.9ィエD2TiィイD20.1ィエD2Ni alloy. In addition, MgィイD20.9ィエD2TiィイD2xィエD2VィイD20.1-xィエD2Ni alloy showed cycle performance superior to the MgィイD20.9ィエD2MィイD20.1ィエD2Ni (M=ti, v) alloys due to the synegret effect of V and Ti components.
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