Fluorinated polysulfonamide based single ion conducting room temperature applicable gel-type polymer electrolytes for lithium ion batteries

Abstract

Single ion conducting polymer electrolytes (SIPEs) comprised of homopolymers containing a polysulfonylamide segment in the polymer backbone are presented. The polymer structure contains –C(CF₃)₂ functional groups that due to better solubility allow for effective lithiation, yielding well-defined materials. An optimized polymer electrolyte membrane was fabricated as a 3 : 1 blend of single ion conducting polymer and PVdF-HFP, which exhibits a high ionic conductivity of 0.52 mS cm⁻¹ and an impressive lithium ion transference number of 0.9, as well as a ⁷Li self-diffusion coefficient of 4.6 × 10⁻¹¹ m² s⁻¹ at 20 °C. The presented polymer electrolyte has superior oxidative stability and long-term stability against lithium metal, thus facilitating operation in LiNi_1/3Mn_1/3CO_1/3O₂ (NMC111)/lithium metal cells at 20 °C and 60 °C, thereby clearly demonstrating the application potential of this class of materials.