Layered Li[Ni0.43Co0.22Mn0.35]O2-yFy (y = 0, 0.08) materials have been synthesized by a carbonate coprecipitation method. The structure, morphology, electrochemical properties, and thermal stability of the Li[Ni0.43Co0.22Mn0.35]O2-yFy have been studied. Monodispersed (similar to 15 mu m) powders with spherical shape were obtained by the carbonate process for both compositions. XPS analysis clearly showed that fluorine ions were successfully substituted for the oxygen and the concentration of the fluorine ions was depleted in the bulk compared to the surface of the particle. The fluorine addition substantially improved the overall electrochemical properties of Li[Ni0.43Co0.22Mn0.35]O-2, including the capacity retention, thermal stability, and rate capability. (c) 2005 The Electrochemical Society.