Structure of yttrium doped LiNi0.5-xMn1.5O4 (x = 0.05, 0.1).

Lithium containing manganese and nickel in the form of LiNi0.5Mn1.5O4 (LNMO) as cathode material for Li-ion battery was synthesized with addition of yttrium (Y) as doping element. Characterization and analysis were emphasized to study the effect of Y addition to the crystal structure of LNMO. X-ray diffraction (XRD) technique was employed to obtain diffraction pattern and the crystal structure was determined by using Rietveld analysis. The results shows that LNMO with Y=0 fit with space group Fd-3m with some LixNi1-xO detected as impurities. The addition of Y=0.05 mol and Y=0.1 mol resulted in the change of structure to space group P4332 marked with the emergence of some superstructure diffraction peaks. Yttrium was confirmed to enter 4b site co-existed with Ni and this result is closely related to the increase in lattice parameters of LNMO and crystal unit volume with increasing Y addition. The addition of Y is liable to the formation of more stable (Ni,Y)O6 and MnO6 octahedra and whole crystal structure. The result from this study is important to determine and understand the relationship between structure and physical properties of LNMO with Y doping in order to improve electrochemical performance as cathode material in Li-ion battery. [ABSTRACT FROM AUTHOR]