Process for preparing solutions of a positive electrode for polymer electrolyte battery by pre-dispersion of solid powders

Process for preparing a dispersion containing at least about 20 weight percent of a mixture of solid particles, with at least one of the types of particles consisting of materials with a specific surface higher than 50 m.sup.2 /g while maintaining the rheological properties of said dispersion adequate for coating thin films with relatively low porosities and few surface defects which comprises:

• co-grinding a mixture of solid particles of a first and a second type in a non-polar solvent, said particles of the first type having a size between about 5 and 100 .mu.m, and said particles of the second type, with a surface area higher than 50 m.sup.2 /g, having a size lower than 2 .mu.m, and obtaining a co-ground mixture,
• drying the co-ground mixture until obtaining a dry powder of encapsulated and reagglomerated particles, and
• dispersing the powder in a polar solvent or in a dilute solution of polymer in said polar solvent, and adding a concentrated polymer/salt solution to obtain a final dispersion.