A sulfonimide-based alternating copolymer as a single-ion polymer electrolyte for high-performance lithium-ion batteries

Abstract

For the next generation of lithium-ion batteries (LIBs), single Li-ion polymer electrolytes (SPEs) are widely considered an effective substitute to traditional dual-ion electrolytes, due to their ability to restrain the salt concentration gradient and the polarization loss in the cells. A new single-ion conductor with an alternating structure is synthesized by the simple radical copolymerization of lithium 4-styrenesulfonyl(phenyl-sulfonyl)imide and maleic anhydride. Its SPE membrane composite with poly(vinylidene fluoride-co-hexafluoropropylene) exhibits both high lithium ion conductivity (σ_Li⁺ = 2.67 mS cm⁻¹) and transference number (t_Li⁺ = 0.98). The full cell with the prepared SPE sandwiched between a LiFePO₄ cathode and a Li₄Ti₅O₁₂ anode shows good cycling stability and rate capability. These results suggest that this novel electrolyte is promising for application in next-generation LIBs.