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

Al 2 O 3 -coated LiCoO 2 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 Al 2 O 3 coating increases both the surface area and the electrical conductivity of LiCoO 2 , 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 Al 2 O 3 ) causes different capacity retention after 50 cycles. The optimum Al 2 O 3 coating amount for the highest capacity retention is 0.2 wt.%. This corresponds to 13.7% of surface coverage.