Wei Jian, Liang Di, Ji Yuxuan, Chen Bing, Jiang Chao, Li Xueting
College of Materials Science and Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, Shaanxi, China.
College of Materials Science and Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, Shaanxi, China.
J Colloid Interface Sci. 2022 Jun 15;616:520-531. doi: 10.1016/j.jcis.2022.02.095. Epub 2022 Feb 22.
LiNiCoMnO (NCM811) stands out among many cathode materials for lithium-ion batteries due to its high energy density. However, the Li-Ni mixing phenomenon and the side reactions between the active cathode material and the electrolyte during the charging and discharging process have hindered its commercial application. CoO is a transition metal oxide with a spinel structure that can provide Li embedding sites for NCM811 and is considered a competitive coating material. Here, we use polyvinylpyrrolidone (PVP) as the assisting material and Co(NO)·6HO as the cobalt source to form a uniform and continuous CoO coating on the surface the of NCM811 by a simple wet chemical method. The formed coating can avoid direct contact between NCM811 and the electrolyte, enhance the structural stability of the material surface, and reduce the polarization of the electrode during cycling. The experimental results demonstrate that the performance of the modified cathode materials is higher than that of NCM811, with a higher initial specific capacity (183.59 mAh·g at 0.1C), specific capacity (151.10 mAh·g at 2C) and cycle performance. The performances are better than those of many oxide coating materials at this research stage and provide a potential solution for the practical application of NCM811 lithium-ion batteries that provide high energy.
锂镍钴锰氧化物（NCM811）因其高能量密度在众多锂离子电池正极材料中脱颖而出。然而，在充放电过程中，Li-Ni混合现象以及活性正极材料与电解质之间的副反应阻碍了其商业应用。CoO是一种具有尖晶石结构的过渡金属氧化物，可为NCM811提供锂嵌入位点，被认为是一种有竞争力的涂层材料。在此，我们使用聚乙烯吡咯烷酮（PVP）作为辅助材料，以Co(NO₃)₂·6H₂O作为钴源，通过简单的湿化学方法在NCM811表面形成均匀连续的CoO涂层。所形成的涂层可避免NCM811与电解质直接接触，增强材料表面的结构稳定性，并降低循环过程中电极的极化。实验结果表明，改性正极材料的性能高于NCM811，具有更高的初始比容量（0.1C时为183.59 mAh·g⁻¹）、比容量（2C时为151.10 mAh·g⁻¹）和循环性能。在该研究阶段，这些性能优于许多氧化物涂层材料，并为高能量的NCM811锂离子电池的实际应用提供了一种潜在的解决方案。
