Tailoring Nickel-Rich LiNi0.8Co0.1Mn0.1O2 Cathode Material with LiNi0. 4Co0. 2Mn0. 4O2 Surface Composition

Abstract

Nickel-rich cathode material, LiNi0.8Co0.1Mn0.1O2, exhibits high specific capacity of approximately 200 mAh/g-oxide and potential for use in plug-in hybrid electric vehicles. However, significant challenges remain to improve the cycle life and thermal-abuse tolerance of this material. To improve the stability of this material, several researchers have investigated a core-shell approach resulted in a nickel-rich LiNi0.8Co0.1Mn0.1O2 core and a manganese-rich LiNi0.5Mn0.5O2shell for surface stabilization [1]. However, the structural mismatch between the core and shell compositions leads to large void formation at the core-shell interface which triggers a sudden drop in capacity after long-term cycling. To overcome the volume change between the core and shell compositions, concentration gradient shell was investigated [2] and full concentration gradient material was suggested which shows the gradual decrease of nickel concentration and increase of manganese concentration from the centre towards the outer layer of the particle [3]. Even though many researchers showed the promising high energy, long calendar life and excellent abuse tolerance of core-shell, core-concentration gradient shell and full concentration gradient materials by their synthesis optimization, the compared nominal composition of LiNi0.8Co0.1Mn0.1O2 was not well-optimized. Here, we report the optimized synthesis condition of a nominal composition of LiNi0.8Co0.1Mn0.1O2, core-shell and core-concentration gradient shell materials with LiNi0.4Co0.2Mn0.4O2 surface composition. The detailed comparison of the physical and electrochemical properties of the prepared materials will be discussed. References Y.-K. Sun, S.-T. Myung, M.H. Kim, J. Prakash and K. Amine, J. Am. Chem. Soc. 127(38), 13411 (2005). Y.-K. Sun, S.-T. Myung, B.-C. Park, J. Prakash, I. Belharouak and K. Amine, Nature Mater. 8, 320 (2009). Y.-K. Sun, Z. Chen, H.-J. Noh, D.-J. Lee, H.-G. Jung, Y. Ren, S. Wang, C.S. Yoon, S.-T. Myung and K. Amine, Nature Mater. 11, 942 (2012).