Abstract: A lithium-ion electrochemical cell comprising: a negative electrode comprising an active material selected from the group consisting of carbon, silicon and a carbon-silicon composite; a positive electrode; a gel-type electrolyte comprising a matrix which is a polymer resulting from the cross-linking of a monomer comprising at least two acrylate groups, in which matrix there is embedded a liquid mixture comprising at least one solvent, lithium hexafluorophosphate (LiPF6), at least one of lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium difluoro(oxalato)borate (LiDFOB) and a thermal initiator of radical polymerization.