Headway in rhodanide anion based ternary gel polymer electrolytes (TILGPEs) for applications in rechargeable lithium ion batteries: an efficient route to achieve high electrochemical and cycling performances

Abstract

In this present investigation, we developed a new category of rhodanide anion based ternary gel polymer electrolytes (TILGPEs) with high electrochemical and thermal stability, which advantageously use the harmonizing properties of a temperature-responsive polymer poly vinylidene fluoride-co-hexafluoropropylene (PVdF-co-HFP) and room temperature ionic liquid (1-ethyl-3-methylimiazolium rhodanide (thiocyanate), (EMImSCN)). TILGPEs were fabricated using a facile solution cast method by incorporating EMImSCN and lithium rhodanide (LiSCN) into PVdF-co-HFP based membranes. Among the series of electrochemical tests including electrochemical impedance spectroscopy, cyclic voltammetry, linear sweep voltammetry and chronoamperometry, the membrane with 80 wt% electrolyte mixtures (EMImSCN/LiSCN) showed better performance in all aspects. The maximum ionic conductivity was found to be in the order of 2.8 × 10⁻⁴ S cm⁻¹ at 298 K. The LiFePO₄/TILGPE3/Li cell offered a maximum discharge capacity of 149.8 mA h g⁻¹ at C/10 rate. The inimitable properties allowed the effective use of the rhodanide TILGPEs as active separators for the development of advanced lithium ion batteries.