Li3PO4 Surface Modification to Improve Performance of LiNiuMn15O4 Cathode Material

Spherical LiNi0.5Mn1.5O4@Li3PO4 composite was prepared by a co-precipitation method. The structure and electrochemical performance were investigated by X-ray powder diffraction (XRD), scanning electron microscope (SEM), FT-IR spectroscopy, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and charge-discharge measurements. XRD and SEM shows that Li3PO4 coating influence the lattice parameter of LiNi0.5Mn1.5O4 composed of spherical particle size. CV and EIS imply that 5% (mass percent) Li3PO4-coated LiNi0.5Mn1.5O4 has higher reversible intercalation and deintercalation of Li+, larger lithium -ion diffusion coefficient and smaller charge transfer resistance corresponding to a much higher conductivity than those of pristine LiNi0.5Mn1.5O4 corresponding to the extraction of Li+ ions. Charge -discharge test reveals that the in situ Li3PO4 modifying improves the electronic conductivity of the electrode in the local environment, electrochemical activity, and then results in their relatively higher capacity at high charge -discharge rate. The enhanced performance of 5% (mass percent) Li3PO4-coated LiNia(5)Mn(1.5)O(4) is ascribed to the improved electronic conduction and the reduced polarization resulting from the Li3PO4 modification together with sphere -like particles composed of nano particle LiNi0.5Mn1.5O4.