Patent ID: 8632904
Filing Date: 2014-01-21
Classification: H01G,H01M,Y02E,Y10T

Abstract:
1. A method of preparing a composite material for electrodes, which comprises: preparing a solution containing at least one polymer P1 that has an O, N, P or S heteroatom mass content of 15% or higher, at least one polymer P2 that has an O, N, P or S heteroatom mass content of 5% or less, and at least one nonvolatile solvent S1 in a volatile solvent; preparing a homogeneous suspension of a material C1 conferring electronic conductivity and an active electrode material M1 in a volatile solvent; preparing a viscous solution by adding the solution of P1, P2 and S1 in a volatile solvent to the homogeneous suspension of C1 and M1 in a volatile solvent; and producing a film from the viscous solution obtained, wherein: when the viscous solution is prepared, the nonvolatile solvent S1 uniformly impregnates the polymer P1 in such a way that the polymer P1 and the material C1 conferring electronic conductivity form a dense, homogeneous and continuous phase around the particles of active material M1; the polymer P2 forms a dispersed phase which contains no or very little material C1 and the morphology of this phase is of the sphere, cylinder, needle or ribbon type and creates porosity; the polymer P1 is selected from the group consisting of polyethers, polyesters, polyacrylic polymers, polycarbonates, polyimines, polyamides, polyacrylamides, polyurethanes, polyepoxides, polyphosphazenes and polysulfones; the polymer P2 is selected from the group consisting of vinyl chloride, vinylidene fluoride, vinylidene chloride, tetrafluoroethylene and chlorotrifluoroethylene homopolymers and copolymers, and vinylidene fluoride/hexafluoropropylene copolymers; the nonvolatile solvent S1 is a polar aprotic solvent consisting of one or more carbonates selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ether carbonate and mixtures thereof; C1 is comprised of graphite, carbon fibers, carbon nanowires, carbon nanotubes, or electronically conductive polymers.