Study on Electrochemical Performance of Various Oxides-Coated LiNi0.5Mn1.5O4 Cathode for Lithium Ion Battery

In this study, LiNi0.5Mn1.5O4 was prepared by solid-state synthesis method and MgCO3, Al2O3, SiO2, TiO2 were dry-coated on the surface of LiNi0.5Mn1.5O4. The structure and geometry of pure-LNMO and coated-LNMO were characterized by XRD, SEM, SEM-EDS. Dry coating method was applied and various coating materials were evaluated in terms of the stability study at room/high temperature and electrochemical property. The results of XRD and SEM-EDS demonstrated that MgCO3, Al2O3, SiO2, TiO2 were coated on the LiNi0.5Mn1.5O4 surface without any structural changes. Compared with pure-LNMO, the coated-LNMO shows significant decrease in side-reaction with electrolyte solution at the first cycle of the electrochemical test. In addition, coated-LNMO displays prominent thermal-stability at 25 degrees C and 55 degrees C and high c-rate, compared with pure-LNMO. Especially the coating layer of SiO2 inhibits the side-reaction with electrolyte solution induced by initial moisture formation. Therefore, the stability of capacity is significantly improved at the temperature of 55 degrees C and high c-rate, which are same results with those obtained by the electrochemical impedance spectroscopy results. This study has employed solid-state synthesis and dry coating method for the evaluation of various coated-LNMO materials and demonstrated the possibility to develop new high energy density electrode materials by surface modification. [GRAPHICS] .