Controlled Nanoparticle Metal Phosphates (Metal=Al, Fe, Ce, and Sr) Coatings on LiCoO[sub 2] Cathode Materials

Despite the fact that the same coating concentration and annealing temperature are used for nanoparticle coatings ( , Fe, Ce, and SrH) on a cathode, the extent of the coating coverage is influenced by the nanoparticle size or morphology. Nanoparticles ( or ) with a size smaller than 20 nm led to the complete encapsulation of , but those with sizes greater than 150 nm or with whisker shapes led to partial encapsulation. This difference affected the discharge capacity. The completely encapsulated with or showed the highest discharge capacity of at 4.8 and 3 V at a rate of 0.1 C , which diminished with decreasing coating coverage in the order of cathode. However, the capacity retention during cycling increased in the order of cathode. This is consistent with the capacity retention result obtained at 90°C storage for 4 h.