Improvement of Electrochemical Performance of Li-Rich Cathode Material with Specific Morphology for Lithium Ion Batteries

Abstract

Li-rich cathode materials (Li2MnO3-LiMO2) have been reported as promising cathode materials since they can deliver high specific capacity and perform with a very good rate capability [1]. Considering the relatively high content of Mn and low content of Ni and Co, Li[Li0.2Mn0.56Ni0.16Co0.08]O2which is a solid solution between Li2MnO3 and LiMn0.4Ni0.4Co0.2O2 with mole ratio of 5:5, fulfills the requirements of a next-generation cathode material very well: low cost, higher energy density and safe. However, high cut-off voltages of up to 4.6-4.8 V are required during charge to obtain high specific capacity as well as high energy.The morphology of a material has obvious influence to its electrochemical properties, especially for nanostructure materials. In this work, the specific morphology of Li[Li0.2Mn0.56Ni0.16Co0.08]O2, has been successfully synthesized by high temperature annealing assisted by molten salt. XRD characterization proved that it belongs to the R-3m layered structure with the monoclinic Li2MnO3-like (C2/m) super lattice. The electrochemical experiments proved that the specific structure like spherical (Figure 1A) or porous (Figure 1B) could increase the rate capability and improve the cycle performance [2]. The morphology control during synthesis is a significant way to improve the performance of Li-rich cathode in lithium-ion batteries, and is a promising candidate for the realization of high voltage lithium and lithium-ion batteries.Reference[1] J. Li, R. Klöpsch, M. C. Stan, S. Nowak, M. Kunze, M. Winter, and S. Passerini. J. Power Sources, 196 (2011) 4821[2] X. He, J. Wang, R. Klöpsch, S. Krueger, H. Jia, H. Liu, B. Vortmann, and J. Li. Nano Research, 7 (2014) 110.[3] J. Wang, X. He, R. Klöpsch, S. Wang, B. Hoffmann, S. Jeong, Y. Yong and J. Li. Energy Technology, 2 (2014) 188