リチウム空気二次電池のためのナノ構造制御した新規空気極触媒

在我的研究期间，为了提高Li-O2电池的循环性能，我尝试合成了一维MnO2纳米管阵列。循环保留率可以得到改善，但容量需要增加。其中一种方法是在正极材料特别是单壁碳纳米管中使用碳纳米管作为衬底。在我们的早期研究中，我们证实了β-MnO2可以显著降低OER(放氧反应)的过电位。只要具有合适的纳米尺寸和结构的碳纳米管被β-MnO2催化剂很好地覆盖，那么就可以获得更好的循环稳定性和更大的容量，从而获得更好的循环稳定性。另一个导致循环稳定性差的问题是Li-O2电池中的锂金属阳极。去年，我们阐述了锂负极对锂-O2电池循环性能的关键作用。作为解决方案，我们提出了聚偏氟乙烯-六氟丙烯共混物在锂金属表面的聚合物涂层。容量衰减率随着锂利用率的提高而大大提高；然而，研究发现，在锂金属表面高度覆盖PVDF-HFP，有效地提高了锂-O2电池的循环稳定性。这表明涂层可以防止金属在放电和充电循环期间的形状变化。此外，在PVDF-HFP涂层中添加无机碳磁化石墨比单独在PVDF-HFP涂层中添加无机碳磁化石墨显著提高了电化学性能。由于Magd可以嵌入Li+离子到晶格中，更容易的移动将导致更高的电导率。

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.