| 研究実績の概要 |
In my research period, to improve the cycleability of Li-O2 battery, I had tried to synthesize the 1D MnO2 nanotube array. Improved cycle retention could be obtained, but capacity needed to be increased. One of ways is CNT substrate in cathode material especially single wall carbon nanotube. In our early research, we confirmed that β-MnO2 could significantly reduce over-potential for OER(oxygen evolution reaction). Provided that CNT having proper nanoscale dimensions and architectures is covered well with catalysis β-MnO2, then improved cycle stability with increased capacity will be obtained.Much improved cycle stability with reasonably high capacity is obtained.
Another issue which makes a major contribution to poor stability on cycling is the Li metal anode in Li-O2 cell. In last year, we elucidated critical importance of Li anode on cycle performance in Li-O2 battery. As a solution, we proposed polymer coating on Li metal with poly(vinylidene fluoride-co-hexafluoropropylene). Capacity fading is much higher with increasing Li utilization; however, it was found that coating the Li metal with PVdF-HFP highly and effectively increased the cycle stability of a Li-O2 battery. This indicates that the coating may prevent shape changes of the metal during discharge and charge cycles. Furthermore, addition of inorganic carbon MAGD graphite on PVdF-HFP coating layer improved electrochemical performance significantly than only PVdF-HFP layer. Because MAGD can intercalate Li+ ion into the lattice, easier movement would result in increased conductivity.
|
