Kaewmala Songyoot, Chantrasuwan Patcharapohn, Wiriya Narinthron, Srilomsak Sutham, Limphirat Wanwisa, Limthongkul Pimpa, Meethong Nonglak
Materials Science and Nanotechnology Program, Department of Physics, Faculty of Science, Khon Kaen University, Muang, Khon Kaen, 40002, Thailand.
Synchrotron Light Research Institute, Muang, Nakhon Ratchasima, 30000, Thailand.
Sci Rep. 2017 Oct 16;7(1):13196. doi: 10.1038/s41598-017-13740-2.
Layered-layered composite oxides of the form xLiMnO·(1-x) LiMO (M = Mn, Co, Ni) have received much attention as candidate cathode materials for lithium ion batteries due to their high specific capacity (>250mAh/g) and wide operating voltage range of 2.0-4.8 V. However, the cathode materials of this class generally exhibit large capacity fade upon cycling and poor rate performance caused by structural transformations. Since electrochemical properties of the cathode materials are strongly dependent on their structural characteristics, the roles of these components in 0.5LiMnO·0.5LiCoO cathode material was the focus of this work. In this work, the influences of LiMnO domain size and current rate on electrochemical properties of 0.5LiMnO·0.5LiCoO cathodes were studied. Experimental results obtained showed that a large domain size provided higher cycling stability. Furthermore, fast cycling rate was also found to help reduce possible structural changes from layered structure to spinel structure that takes place in continuous cycling.
xLiMnO·(1-x)LiMO（M = Mn、Co、Ni）这种形式的层状复合氧化物，因其高比容量（>250mAh/g）以及2.0 - 4.8V的宽工作电压范围，作为锂离子电池的候选正极材料受到了广泛关注。然而，这类正极材料在循环过程中通常会出现较大的容量衰减，并且由于结构转变导致倍率性能较差。由于正极材料的电化学性能强烈依赖于其结构特征，因此本工作聚焦于这些组分在0.5LiMnO·0.5LiCoO正极材料中的作用。在本工作中，研究了LiMnO域尺寸和电流倍率对0.5LiMnO·0.5LiCoO正极电化学性能的影响。所获得的实验结果表明，较大的域尺寸提供了更高的循环稳定性。此外，还发现快速循环倍率有助于减少在连续循环过程中从层状结构到尖晶石结构可能发生的结构变化。
