The structural rearrangement on the surface of lithium transition metal layered oxide is a critical issue on affecting the ion transport behavior in lithium-ion batteries. In layered metal oxides, the local elemental segregations before and/or after cycling is closely associated to the structural evolution, which lead to voltage and capacity fades and poor rate capability. In this study, we show the control of 3d or 4d transition metal segregations and their chemical inhomogeneity on the crystallographic surface planes in lithium- and manganese-rich layered oxides. By developing synthesis processes based on the modification of particle morphology, the relationship between the structural changes and the electrochemical properties is demonstrated by atomic-scale observations. It will be a significant investigation to understand the general trends of surface chemistry of lithium layered oxide, development of efficient surface layer and related diffusion characteristics for ion transportation.

Figure. EDS mapping taken along the [010]_monoclinic zone axis for relative distribution of chemical species on the surface layer of lithium- and manganese-rich layered oxide (LMR). (a) Zr-segregated LMR. (b) Zr-unsegregated LMR. (c) Zr-uncontained LMR.

This work is supported by the National Research Foundation of Korea (NRF-2011-C1AAA001-0030538).