NOVELTY - Production of a lithium composite oxide involves subjecting an organic acid solution of metal elements constituting a final composite oxide other than lithium to a spray pyrolysis process to obtain an intermediate composite oxide powder, and solid state-mixing the oxide powder and organic acid salt of lithium, followed by thermally treating the mixture.    USE - For production of lithium composite oxide useful as a positive electrode active material for lithium secondary batteries (claimed) useful for portable electronic device e.g. mobile communication equipment for information communication, digital cameras and camcorders.    ADVANTAGE - Lithium secondary batteries allows the molar ratio of lithium (Li) and other metals present in the composite oxide to be maintained within a preferred range and exhibit excellent charge-discharge cycle characteristics and capacity maintenance characteristics. Liquid droplets is passed through a furnace at high temperature with ultrasonic spray pyrolysis, the lithium is easily evaporated due to its low vapor pressure, and thus eliminates the problems caused by nickel such as frequent occurrence of intercalation/deintercalation of lithium ions in the crystal structure of a final composite oxide, low thermal hysteresis, deterioration of the crystal growth, and destruction of the crystal structure of a composite oxide as a positive electrode active material according to increasing number of charge-discharge cycles. Since the lithium composite oxide thus produced has constant lithium content, it exhibits a relatively high thermal hysteresis and has a stable crystal structure (layered structure, or polycrystalline structure including the layered structure).    DETAILED DESCRIPTION - Formation of intermediate composite oxide involves dissolving the organic acid salt in distilled water or alcohol, adding a chelating agent, and spraying the aqueous/alcoholic solution of organic acid salt to form liquid droplets that are pyrolyze at 400 - 1000degreesC.