Gel-polymer electrolytes plasticized with pyrrolidinium-based ionanofluid for lithium battery applications

In the present study, hexafluoropropylene copolymer (P(VDF-HFP))-based active polymer membranes are prepared by entrapping different extent of pyrrolidinium ionic liquid-based nanofluid (ionanofluid). X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FT-IR) spectroscopy are implemented to characterize the membranes. The study reveals that ionanofluid improves the electroactive phase nucleation of P(VDF-HFP) and suppresses the membranes' crystallinity. SEM micrographs and butanol absorption study indicate that ionanofluid improves the electrolyte uptake ability and facilitates forming unified ion-conducting channels within the membranes. The 50 wt% ionanofluid (INF) incorporated gel-polymer electrolyte (GPE) exhibits the highest room-temperature ionic conductivity (2.33 x 10(-3) S cm(-1)at 25 degrees C), a high lithium-ion transference number (t(Li+similar to)0.6), superior electrochemical stability window up to similar to 5.3 V (vs. Li/Li+) and excellent interfacial compatibility with the lithium electrode. The LiFePO4/Li battery comprising INF-based GPE demonstrates good C-rate performance and excellent cycling stability with a discharge capacity of similar to 156 mAh g(-1) and similar to 116 mAh g(-1) at C/5 and 2 C rates, respectively, and capacity retention of > 95% after 50 cycles at C/5 rate.

Automated summary

In this study, active polymer membranes based on P(VDF-HFP) are prepared by entrapping ionanofluid, which improves electroactive phase nucleation and electrolyte uptake ability. The resulting membranes show enhanced room-temperature ionic conductivity, high lithium-ion transference number, excellent electrochemical stability, and good compatibility with lithium electrodes. The LiFePO4/Li battery with ionanofluid-based gel-polymer electrolyte exhibits good C-rate performance and excellent cycling stability, demonstrating high discharge capacities and capacity retention after cycles.