Effect of Al2O3 coating on electrochemical performance of LiCoO2 as cathode materials for secondary lithium batteries

Abstract

Al2O3-coated LiCoO2 particles are prepared by a gas-suspension spray method with coatings in the range from 0.1 to 2.0 wt.%, and are examined for their electrochemical performance with special attention to the surface coverage of cathode materials for lithium-ion batteries. The Al2O3 coating increases both the surface area and the electrical conductivity of LiCoO2, improves the cycle performance even at a higher cut-off charge voltage, and induces higher thermal stability. In the experimental range studied, different coating amounts (i.e., surface coverage of Al2O3) causes different capacity retention after 50 cycles. The optimum Al2O3 coating amount for the highest capacity retention is 0.2 wt.%. This corresponds to 13.7% of surface coverage. (C) 2004 Elsevier B.V. All rights reserved.