Block copolymers including a polyanionic based on a monomer type anion tfsili as a battery electrolyte.

The invention relates to a BA diblock or BAB triblock copolymer, in which the A block is a non-substituted polyoxyethylene chain having a mean molecular weight that is no higher than 100 kDa, and the B block is an anionic polymer which can be prepared using one or more monomers selected from among the vinyl monomers and derivatives thereof, said monomers being substituted with a (trifluoromethylsulfonyl)imide (TFSI) anion. The invention also relates to the uses of such a copolymer, in particular for preparing an electrolyte composition for lithium metal polymer (LMP) batteries.