Method for manufacturing transition metal oxide films of formula A a M b O d, in which: A is an alkali metal, A advantageously being chosen from the group consisting of Li, Na and K, or their mixtures; M is a metal or a mixture of metals chosen from the transition metals, M preferably being a transition metal or a mixture of transition metals chosen from the elements of columns 3 to 12 of the periodic table, M advantageously being chosen from the group consisting of Co, Ni, Mn, Fe, Cu, Ti, Cr, V and Zn, and their mixtures; O is oxygen; and a, b and d are real numbers higher than 0 and are chosen so as to ensure electroneutrality, said method comprising the following steps: a) preparing a solution comprising one or more, preferably two or more than two, precursors containing one or more of the elements A, M and O, a chelating agent and a polar organic solvent having a boiling point at atmospheric pressure below 150°C, wherein the chelating agent is chosen from aliphatic dicarboxylic acids comprising 2 to 20 carbon atoms and salts or mixtures thereof, or the chelating agent is a mixture between at least one carboxylic diacid such as defined above and at least one aliphatic tricarboxylic acid comprising 2 to 20 carbon atoms and salts or mixtures thereof, the proportion of said at least one tricarboxylic acid being lower than 30 mol% relative to the total molar amount of said at least one dicarboxylic acid and said at least one tricarboxylic acid in said solution; b) forming a sol by stirring said solution; and c) processing the sol in the form of said transition metal oxide film, characterised in that step c) comprises the following steps: c') depositing one or more layers of said sol on a substrate; and c") preparing said transition metal oxide film by calcinating said one or more layers formed in step c'). A is an alkali metal, A advantageously being chosen from the group consisting of Li, Na and K, or their mixtures; M is a metal or a mixture of metals chosen from the transition metals, M preferably being a transition metal or a mixture of transition metals chosen from the elements of columns 3 to 12 of the periodic table, M advantageously being chosen from the group consisting of Co, Ni, Mn, Fe, Cu, Ti, Cr, V and Zn, and their mixtures; O is oxygen; and a, b and d are real numbers higher than 0 and are chosen so as to ensure electroneutrality, said method comprising the following steps: a) preparing a solution comprising one or more, preferably two or more than two, precursors containing one or more of the elements A, M and O, a chelating agent and a polar organic solvent having a boiling point at atmospheric pressure below 150°C, wherein the chelating agent is chosen from aliphatic dicarboxylic acids comprising 2 to 20 carbon atoms and salts or mixtures thereof, or the chelating agent is a mixture between at least one carboxylic diacid such as defined above and at least one aliphatic tricarboxylic acid comprising 2 to 20 carbon atoms and salts or mixtures thereof, the proportion of said at least one tricarboxylic acid being lower than 30 mol% relative to the total molar amount of said at least one dicarboxylic acid and said at least one tricarboxylic acid in said solution; b) forming a sol by stirring said solution; and c) processing the sol in the form of said transition metal oxide film, a) preparing a solution comprising one or more, preferably two or more than two, precursors containing one or more of the elements A, M and O, a chelating agent and a polar organic solvent having a boiling point at atmospheric pressure below 150°C, wherein the chelating agent is chosen from aliphatic dicarboxylic acids comprising 2 to 20 carbon atoms and salts or mixtures thereof, or the chelating agent is a mixture between at least one carboxylic diacid such as defined above and at least one aliphatic tricarboxylic acid comprising 2 to 20 carbon atoms and salts or mixtures thereof, the proportion of said at least one tricarboxylic acid being lower than 30 mol% relative to the total molar amount of said at least one dicarboxylic acid and said at least one tricarboxylic acid in said solution; b) forming a sol by stirring said solution; and c) processing the sol in the form of said transition metal oxide film, c') depositing one or more layers of said sol on a substrate; and c") preparing said transition metal oxide film by calcinating said one or more layers formed in step c').