New fluorine-containing plasticized low lattice energy lithium salt for plastic batteries

The synthesis of a new plasticized low lattice energy lithium salt (PLI), structurally related to lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), is described. Incorporation of the plasticizing moiety in a single salt molecule greatly simplifies the solid polymer electrolyte (SPE) processing formulation without compromising performance. Thermally and electrochemically stable polymer electrolyte films of PLI exhibit good ionic conductivity, though somewhat lower than that for LiTFSI. The pentafluorophenyl analog of LiTFSI, prepared by two approaches, exhibits behavior similar to that of LiTFSI.