Process for the manufacture of a film of oxide of transition metals, comprising the stages of: (a) providing a powder of formula A a M b O c, in which: A is an alkali metal; advantageously, A is chosen from the group consisting of Li, Na and K, or their mixture; M is a metal or a mixture of metals chosen from transition metals, lanthanides or actinides; preferably, M is a transition metal or a mixture of transition metals chosen from the elements of Groups 3 to 12 of the Periodic Table; advantageously, M is chosen from the group consisting of Co, Ni, Mn, Fe, Cu, Ti, Cr, V and Zn, and their mixtures; O is oxygen, a, b and c are real numbers greater than 0; a, b and c are chosen so as to provide electrical neutrality; (b) preparing a colloidal sol from the said powder processed in stage (a), (c) processing the said colloidal sol in the form of the said film of oxide of transition metals on a substrate which has preferably been degreased beforehand using a solution containing a first alcoholic or alkaline solvent S1, the said processing comprising: (c') the deposition of one or more layers of the said sol on the said substrate and (c") the annealing of the said one or more layers formed in stage (c') in order to prepare the said film of oxide of transition metals, characterized in that the said colloidal sol is prepared by: (b') providing the said powder A a M b O c having a desired particle size distribution; (b") calcining the said A a M b O c powder from stage (b'), (b"') mixing the said powder obtained after the calcining of stage (b") with a second solvent S2 in order to form the said colloidal sol; the said colloidal sol thus formed consists of one or more calcined oxides of metals and one or more solvents. (a) providing a powder of formula A a M b O c, in which: A is an alkali metal; advantageously, A is chosen from the group consisting of Li, Na and K, or their mixture; M is a metal or a mixture of metals chosen from transition metals, lanthanides or actinides; preferably, M is a transition metal or a mixture of transition metals chosen from the elements of Groups 3 to 12 of the Periodic Table; advantageously, M is chosen from the group consisting of Co, Ni, Mn, Fe, Cu, Ti, Cr, V and Zn, and their mixtures; O is oxygen, a, b and c are real numbers greater than 0; a, b and c are chosen so as to provide electrical neutrality; A is an alkali metal; advantageously, A is chosen from the group consisting of Li, Na and K, or their mixture; M is a metal or a mixture of metals chosen from transition metals, lanthanides or actinides; preferably, M is a transition metal or a mixture of transition metals chosen from the elements of Groups 3 to 12 of the Periodic Table; advantageously, M is chosen from the group consisting of Co, Ni, Mn, Fe, Cu, Ti, Cr, V and Zn, and their mixtures; O is oxygen, a, b and c are real numbers greater than 0; a, b and c are chosen so as to provide electrical neutrality; (b) preparing a colloidal sol from the said powder processed in stage (a), (c) processing the said colloidal sol in the form of the said film of oxide of transition metals on a substrate which has preferably been degreased beforehand using a solution containing a first alcoholic or alkaline solvent S1, the said processing comprising: (c') the deposition of one or more layers of the said sol on the said substrate and (c") the annealing of the said one or more layers formed in stage (c') in order to prepare the said film of oxide of transition metals, characterized in that the said colloidal sol is prepared by: (b') providing the said powder A a M b O c having a desired particle size distribution; (b") calcining the said A a M b O c powder from stage (b'), (b"') mixing the said powder obtained after the calcining of stage (b") with a second solvent S2 in order to form the said colloidal sol; the said colloidal sol thus formed consists of one or more calcined oxides of metals and one or more solvents. (c') the deposition of one or more layers of the said sol on the said substrate and (c") the annealing of the said one or more layers formed in stage (c') in order to prepare the said film of oxide of transition metals, (b') providing the said powder A a M b O c having a desired particle size distribution; (b") calcining the said A a M b O c powder from stage (b'), (b"') mixing the said powder obtained after the calcining of stage (b") with a second solvent S2 in order to form the said colloidal sol;