Enhanced High-Voltage Cycling Stability of Nickel-Rich Cathode Materials by Surface Modification Using LaFeO3 Ionic Conductor

LaFeO 3 is introduced as an ideal protective coating layer with excellent conductivity to enhance LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) cathode material for use at higher operating voltage (especially 4.6 V). Various material characterization methods are employed to characterize the structural and morphological characteristics of the pristine and modified samples, including x-ray diffraction analysis, field-emission scanning electron microscopy, transmission electron microscopy, and x-ray photoelectron spectroscopy. The electrode with 2 wt.% LaFeO 3 coating showed capacity retention of 80% at current density of 1 C after 200 charge/discharge cycles at 25°C, compared with 63% for the pristine electrode. Cyclic voltammogram results indicated that the LaFeO 3 coating reduced the cell polarization during extended cycling. The results therefore show that LaFeO 3 has potential for coating of NCM523 for use even at high voltage.