Effect of Co Content on Rate Performance of LiMn[sub 0.5−x]Co[sub 2x]Ni[sub 0.5−x]O[sub 2] Cathode Materials for Lithium-Ion Batteries

Layer-structured was prepared as cathode material for lithium-ion batteries. The structures of the layered materials and the oxidation states of the elements in the compounds were characterized by X-ray diffraction and X-ray photoelectron spectroscopy. Adsorbed oxygen was detected on the surface of material. With the increase of Co content in the oxidation state of Ni, Mn, Co, and O became higher gradually while the amount of oxygen adsorbed on the surface of grains reduced obviously. Electrochemical evaluation showed that addition of Co in is beneficial to its rate performance. The variations of the electronic structure of Ni, Mn, and O may be responsible for the improvement of the rate capability in with addition of Co. © 2004 The Electrochemical Society. All rights reserved.