TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preparation (Claimed): Preparation of particles of doped lithium cobalt comprises: preparing nano-sized doping agent (lanthanide oxide) by obtaining doping agent precursor starting from acetate or nitrate of lanthanide by co-precipitation or sol-gel method, and calcinating doping agent precursor at 450-700 degrees C to obtain nano-sized doping agent having a controlled crystallites size; and preparing the lithium cobalt oxide (LiCoyOz) particles comprising mixing the cobalt oxide with lithium carbonate to obtain a homogenous lithium cobalt oxide particles, where the particles of doped lithium cobalt oxide (I) are obtained by mixing the lithium cobalt oxide particles with the nano-sized doping agent, homogenizing and milling the mixture, and calcinating the mixture at 600-1200 degrees C. Preferred Components: The molar ratio t of the doping agent is 0.005-0.3, preferably 0.01-0.2. The molar ratio z of oxygen is 1.55-1.993. The molar ratio y of cobalt is 0.98. The particles comprise LiCo(0.98)O(1.97), CeOx(0.02). The particles of LiCoyOz have a mean diameter of less than or equal to 200 nm, preferably less than or equal to 180 nm. The particles of doping agent have a mean diameter less than or equal to 50 nm. The difference between the charging and discharging capacity is less than 0.3%. The separation electrolyte is a liquid, a gel, or a solid. The specific discharge capacities of cobalt lithium oxide doped with nanosized ceria is greater than or equal to 165 mAh/g. The battery generates heat of less than 50 J/g. Preferred Method: The additives are mixed together with lithium cobalt oxide particles and nano-sized doping agent in step of mixing the lithium cobalt oxide particles. The calcination step is carried out for 3-40 hours. EXAMPLE - Nitrates of cerium hexahydrate were dissolved in distilled water. A precipitating agent comprising ammonium hydroxide solution for co-precipitation was added under stirring until the pH was 9-11. The precipitate was then subjected to successive steps of washing with deionized water to remove residual ammonium ions. The washed precipitate was dried at 80-130 degrees C. The dried precipitate (MOx precursor) was calcinated at 450-700 degrees C to obtain nano-sized MOx (lanthanide oxide) particles having a controlled crystallites size.