Novel Alkyl Aluminum Coating Method for Lithium Ion Batteries Cathode Materials

Abstract

Lithium ion batteries (LIBs) have high energy density compared with other batteries. However, LIBs require more energy density since mobile devices become high performance. In order to increase the energy density of LIBs, it is effective that increase of the charge-discharge operating voltage. However, increasing voltage simultaneously induced the decomposition of electrolyte in LIBs and deteriorate safety and durability of batteries. Coating positive electrode materials with the metal oxide has been developed as the effective techniques for improving the safety and durability of LIBs (1-3). It was well known that the coating methods with metal oxide protect the surface from chemical reaction with the electrolyte. On the other hands, coating with a metal oxide leads to an increase in interfacial resistance. We have been developing the Al materials for coating based on partially hydrolyzed alkyl aluminum wet process technology. The partially hydrolyzed alkyl aluminum coated on LiCoO2 active material exhibited a capacity retention of 85.6% after 500 charge-discharge cycles in the 3.0-4.35V (vs. Li/Li+) range. In contrast, the bare LiCoO2 active material displayed only a 9.6% capacity retention. The coating process with partially hydrolyzed alkyl aluminum can formed thin film on active materials in contrast to the sol-gel process. Therefore, this process does not cause an increase in interfacial resistance. In this presentation, we will report several battery characteristics using coating method with partially hydrolyzed alkyl aluminum. H.-J. Kweon, J. Park, J. Seo, G. Kim, B. Jung, and H. S. Lim Journal of Power Sources, 126, 156 (2004).J. Cho, Y. Kim, T.-J. Kim, and B. Park, Angewante Chemie International Edition, 18, 3367 (2001).Y. S. Jung, A. S. Cavanagh, A. C. Dillon, M. D. Groner, S. M. George, and S.-H. Lee, Journal of Electrochemical Society, 157(1), A75 (2010).