The present invention relates to a binder solution for a secondary battery, comprising at least one non-aqueous
solvent and at least one
fluoropolymer comprising recurring units derived from a) vinylidene difluorides and b) at least one fluorinated olefin
monomer containing at least one —SO2X functional group, X being selected from X′ and OM, X′ being selected from the consisting of F, Cl, Br, and I; and M being selected from the group consisting of H, an alkaline
metal and NH4, wherein b) the fluorinated olefin
monomer is present in an amount from 0.1 to 10.0 mol %, the mol % being relative to the total moles of recurring units; to a
solid composite electrolyte comprising at least one
fluoropolymer according to the present invention and at least one
sulfide-based
solid ionic conducting
inorganic particle; to a
slurry for manufacturing a
solid composite electrolyte comprising a binder solution according to the present invention and at least one
sulfide-based solid ionic conducting
inorganic particle, optionally further comprising at least one electroactive material and / or at least one conductive agent; and to an
electrode comprising at least one
fluoropolymer according to the present invention and at least one electroactive material, optionally further comprising at least one conductive agent and / or at least one
sulfide-based solid ionic conducting
inorganic particle. The present invention also relates to a secondary battery comprising a positive
electrode, a negative
electrode, and a membrane that is positioned between the positive electrode and the negative electrode, wherein at least one of the positive electrode, the negative electrode and the membrane comprises at least one fluoropolymer according to the present invention, optionally further comprising at least one sulfide-based solid ionic conducting inorganic particle, at least one electroactive material and / or at least one conductive agent.