New surface modified material for LiMn2O4 cathode material in Li-ion battery

The LiMn2O4 cathode powders derived from co-precipitation method was calcined with the surface modified material to form fine powder of single spinel phase with different particle size, size distribution and morphology. The structure and phase was identified with X-ray diffractometer (XRD) along with the lattice constant calculated by a least-squares program. The electron probe microanalyzer (EPMA) was employed to evaluate the composition of LiCuxMn2-xO4-coated LiMn2O4. The morphology was observed with field emission scanning electron microscope (FE-SEM), and the particle size in the range of several microns was measured by Laser Scattering. The electrochemical behavior of the cathode powder was examined by using two-electrode test cells consisting of a cathode, metallic lithium as anode, and an electrolyte of 1 M LiPF6. Cyclic charge/discharge testing of the coin cells, fabricated by both LiCuxMn2-xO4-coated and base LiMn2O4 material were conducted. The LiCuMn2-xO4-coated cathode powder with the fading rate of 11.98% at 0.5 C and 11.93% at 0.2 C showed better cyclability than the base one. It is demonstrated that the employment of LiCuxMn2-xO4-Coated LiMn2O4 cathode material reduced the fading rate after cyclic test, especially at high C rate. (c) 2005 Elsevier B.V All rights reserved.