To prepare polymer dispersions containing large quantities of solid particles, with at least some of these consisting of materials with a high specific area (>50 m 2 /g) or oil absorption capacity, the mixture of particles is first co-ground in a non polar solvent. The co-ground mixture is dried until obtaining a dry powder of reagglomerated particles, which is dispersed in a solution containing a polymer and possibly a salt. Large quantities of solid particles can thus be dispersed while maintaining adequate rheological properties for the dispersion, and low porosities and few surface defects in the films obtained by coating the dispersion. This process can be used to prepare thin films of positive electrode for lithium polymer batteries, as well as in the paint, coatings and magnetic tape industry.