Electrochemical Properties of PEO‐Based Polymer Electrolytes Blended with Different Room Temperature Ionic Liquids

Abstract

Polymer electrolyte (PE) based on poly(ethylene oxide)-lithium bis(trifluoromethane sulfonyl)imide (PEO-LiTFSI) was blended with three room temperature ionic liquids (RTILs), namely 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide (BMITFSI), 1-butyl-3-methylimidazolium tetrafluoroborate (BMIBF 4 ) and 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMICF 3 SO 3 ) with a view to enhance the room temperature ionic conductivity to acceptable levels for use in lithium batteries. The incorporation of 80 parts by weight (pbw) of the RTILs in 100 pbw of PEO-LiTFSI resulted in enhanced ionic conductivity, the effect being more pronounced at lower temperatures. Evaluation of electrochemical properties showed that PEs with RTILs exhibit an electrochemical stability window between À1.0 V and 4.5 V vs Li/Li þ and good reversibility of redox reactions on cycling. The optimum results were obtained with the incorporation of BMITFSI in the PE, which exhibited a low and stable interfacial resistance on lithium metal.

Electrochemical performance of electrospun poly(vinylidene fluoride-co-hexafluoropropylene)-based nanocomposite polymer electrolytes incorporating ceramic fillers and room temperature ionic liquid

“…The positive cathodic limit of the RTIL with respect to lithium suggests that it is unsuitable for use in lithium metal batteries, as reported for ethyl-methylimidazole (EMI)-based RTILs [32]. However, our earlier studies [15,31] have shown that when BMITFSI and BMIBF 4 are incorporated into PEO-LiTFSI blend, the resulting PEs were capable of exhibiting a well-defined lithium reduction process at −0.5 V and were stable up to −1.0 V versus Li/Li + . In the present article, we report unique NCPEs incorporating BMITFSI and nano-sized ceramic fillers (SiO 2 , Al 2 O 3 or BaTiO 3 ) hosted in electrospun P(VdF-HFP) membranes for use in LPBs.…”

“…The best results were obtained in the presence of BMITFSI. Its addition (80% by weight) to PEO-LiTFSI resulted in ionic conductivity of 3.2 × 10 −4 S cm −1 at 25 • C [15]. The nature of counter anion (TFSI or BF 4 ) significantly affected the electrochemical performance of the cell, as BMITFSI incorporated PE delivered a high discharge capacity of 149 mA h g −1 for a Li/LiFePO 4 cell at 0.1 Crate and 25 • C [16].…”

Poly(ethylene oxide)-based electrolytes for lithium-ion batteries

“…They found that this system had good compatibility with lithium electrode, enhanced ionic conductivity and satisfactory performance at 40 °C. Ahn et al 182,183 compared the electrochemical properties of PEO-LiTFSI electrolyte by incorporating 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide (BMITFSI). Ionic conductivity of PEO-LiTFSI increased with the increase of BMITFSI content and reached 3.2 × 10 -4 S cm -1 at 25 °C (entry 21).…”

Electrochemical properties of new organic radical materials for lithium secondary batteries

“…Since ILs possess the attractive features of a negligible vapor pressure and high thermal stability, they are particularly suitable for electrochemical applications [18]. ILs based on the imidazolium [19][20][21][22], pyrrolidinium [23,24] and piperidinium [25,26] cations have been found to be promising electrolyte components for rechargeable batteries. However, no studies have been reported so far on the use of IL-supported organic radicals as the electrodeactive material for lithium batteries.…”