Synthesis of SiO₂-Modified Li₂MnO₃-LiMn_1/3Ni_1/3Co_1/3O₂ by Spray Pyrolysis with Acid Addition as Cathode Materials for Lithium Ion Batteries

SiO₂-modified Li₂MnO₃-LiMn_1/3Ni_1/3Co_1/3O₂ cathode materials for lithium ion batteries were synthesized by a spray pyrolysis technique using starting solutions containing citric acid and boric acid. SEM images showed that most of the particles using citric acid had spherical shapes and thin shell structures. Some particles were collapsed when the amount of citric acid was large. The specific surface area of the particles prepared from the citric acid-added solution was higher than that without citric acid. The addition of boric acid decreased the specific surface area of the material by acting as a sintering agent. The charge and discharge capacities for the synthesized materials were investigated and it was found that the addition of citric acid, which gave a higher specific surface area, enhanced the rate capability.