| 研究概要 |
Lithium-oxygen batteries have recently received attention due to their extremely high theoretical energy densities, which far exceed that of any other existing energy storage technology. However, in order to build Li batteries with improved capacity and power capabilities, many problems should be overcame such as high over-potential, low capacity retention rate and high power density. Stated performance above is strongly influenced by electrode material and structure, where several electrochemical and transport processes occur simultaneously. Searching for stable cathode to replace carbon and effective morphology are one of the great challenges. To improve the cycleability of Li air battery, I had tried to synthesize the ID MnO_2 nanotube array using AAO template. As stated in my initial proposal, preparing the anodized porous nano-sized materials with the shape of tube is the objective at the first year. To obtain an AAO template, Al sheet was anodized with various conditions to optim
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ize the pore diameter and length. The estimated size of pore was between 50 to 100nm and length was 4um. To make MnO_2 nanotube, Mnnitrate solution was used. After impregnation method, the sample was calcinated at 350℃ to make MnO_2. Although MnO_2 solution was impregnated successfully in some part, it is likely Mn solutions are not infiltrated properly into AAO template. More detail studies of porous shape not only nanotube but also mesoporous, nano composite should be conducted. On the other hand, another possible factor which makes a major contribution to poor stability on cycling is the Li metal anode which is used in Li-air batteries to produce extremely high capacity in combination with the cathode. However, only a few studies have focused on the contribution of the Li metal anode to the poor cycling performance of Li-air batteries. To investigate the influence of Li anode on poor cyclestability in Li-air batteries, we designed the condition of high utilization of Li metal for capacity. In our study, we simply give a difference in the Li metal amount, which used as anode in lithium air rechargeable batteries. By reducing the Li metal, the effects of anode was magnified. Consequently, we could confirm the critical importance of Li anode on cycle performance in a Li-O_2 battery. This result is highly important for further research of the Li-O_2 battery systems for improving the cycle stability. 隠す
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
Develop of shape controlled cathode materials has been proceeded as planned. In addition, we confirmed the significant effects of Li anode on poor cycle stability of Li-O_2 batteries. Consequently, the purpose of the first year was accomplished. We have expected competent results on second year.
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| 今後の研究の推進方策 |
Along with the cathode materials, we confirmed much serious influence of Li metal anode and type of solvents on low cycleability of Li-O_2 batteries. Because the performance of Li-O_2 batteries is quiet complex and interdependent, it is necessary to study not only a cathode but also other compartment. Therefore, we have planned to search for the possible ways to decrease the influence of Li metal and to investigate the effects of solvents in more detail.
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