Electrochemical Evaluation and Structural Characterization of Commercial LiCoO[sub 2] Surfaces Modified with MgO for Lithium-Ion Batteries

Commercial cathode material was modified by coating its surface with a thin layer of amorphous magnesium oxide (MgO). The surface morphology, crystalline structure, and electrochemical performance of the modified cathode material were characterized and compared with that of pristine It is found that surface modification can improve the structural stability of without decreasing its available specific capacity. Specific capacities of 145, 175, and 210 mAh/g were obtained in test cells composed of MgO-coated cathode material when charged to 4.3, 4.5, and 4.7 V respectively. This improvement is attributed to the pillaring effect of the ions in the interslab space of the lattice and the protective effect of the MgO film against the escape of ions from the bulk of particles. © 2002 The Electrochemical Society. All rights reserved.