Multiphase LiNi0.33Mn0.54Co0.13O2 Cathode Material with High Capacity Retention for Li-Ion Batteries

Abstract

An integrated layered-spinel LiNi0.33Mn0.54Co0.13O2 material was synthesized through a self-combustion reaction (SCR), characterized by using X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), and Raman spectroscopy. It was studied as a cathode material for Li-ion batteries and its electrochemical performance was compared with that of the layered cathode material LiNi0.33Mn0.33Co0.33O2 when operated over a wide potential window. The Rietveld analysis of LiNi0.33Mn0.54Co0.13O2 indicated the presence of monoclinic Li[Li1/3Mn2/3]O-2 (31%) and rhombohedral (LiNixMnyCozO2) (62%) phases as the major components, and the spinel (LiNi0.5Mn1.5O4) (7%) as a minor component, which is supported by TEM and electron diffraction analyses. A discharge specific capacity of about 170mAhg(-1) is obtained in the potential range of 2.3-4.9V versus Li at low rate (C/10) with excellent capacity retention upon cycling. On the other hand, LiNi0.33Mn0.33Co0.33O2 (NMC111) synthesized through SCR exhibits an initial discharge capacity of about 208mAhg(-1) in the potential range of 2.3-4.9V, which decreases to a value of 130mAhg(-1) after only 50 cycles. In turn, the multiphase structure of LiNi0.33Mn0.54Co0.13O2 seems to stabilize the behavior of this cathode material, even when polarized to high potentials. LiNi0.33Mn0.54Co0.13O2 shows superior retention of the average discharge voltage upon cycling, as compared to that of LiNi0.33Mn0.33Co0.33O2 when cycled over a wide potential range. Overall, LiNi0.33Mn0.54Co0.13O2 can be considered as a promising low-cobalt-content cathode material for Li-ion batteries.