Block copolymer electrolyte for lithium batteries

A solid polymer electrolyte for a battery, the solid polymer electrolyte including a diblock copolymer of AB type or a triblock copolymer of BAB type, in which:

• block A is an unsubstituted polyethylene oxide chain having a number-average molecular weight less than 80,000 g/mol;
• block B is an anionic polymer prepared from:
• (i) one or more monomers selected from vinyl monomers wherein block A and block B have the following formula:
• and to which is grafted at * an anion of lithium salt selected from the group consisting of LiCF3SO3, LiB(C2O4)2, LiN(CF3SO2)2, LiN(FSO2)2, LiC(CF3SO2)3, LiC(CH3)(CF3SO2)2, LiCH(CF3SO2)2, LiCH2(CF3SO2), LiC2F5SO3, LiN(C2F5SO2)2, LiN(CF3SO2), LiB(CF3SO2)2, LiPF6, LiSbF6, LiClO4, LiSCN, LiAsF6, and LiBF4;
• and
• wherein m is ≥1, x is ≥1, y is ≥1 and n is ≥1;
• and
• (ii) the one or more monomers are cross-linkable polyfunctional monomers having pendant chemical functions R1 and/or R2, the cross-linkable polyfunctional monomers including reactive groups for reaction during polymerization of the copolymer, the reactive groups selected from the group consisting of a vinyl phenyl substituted in ortho, meta or para position, an acrylate, a methacrylate, an allyl, an acrylamide, a methacrylamide and a vinyl;
• wherein, after the polymerization of the copolymer, the pendant chemical functions R1 and/or R2 are cross-linked to form a cross-linked copolymer network:
• and wherein proportion of the unsubstituted polyethylene oxide chain of block A relative to the anionic polymer of block B is between 40% and 80%.