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Abstract: Gel-type polymer electrolytes with 1-butyl-4-methylpyridinium bis(trifluoromethanesulfonyl)imide (B4MePyTFSI) ionic liquid are formed by the solution casting method. The conductivity and transference number measurements are carried out to investigate conductivity and charge transport in the gel polymer electrolytes. The conductivity of the samples increases when the amount of B4MePyTFSI ionic liquid is increased. The lithium ion ionic conductivity reaches the maximum value (2.01×10−4 S cm−1) when GPE contains 33.3 wt% B4MePyTFSI. The electrochemical stability window of ILGPE is about 5.5V versus Li+/Li at 20°C, meeting the basic requirement of rechargeable lithium batteries. Discharge performance of lithium battery using this ILGPE membrane shows a capacity of about 160 mAh g−1. The excellent performance with higher capacity, good cycle stability and compatibility are observed for the Li/ILGPE/LiFePO4 cells. The interfacial resistances between ILGPE and electrodes have the less change after 10 cycles. [Copyright &y& Elsevier]

Abstract: Ionic liquid gel polymer electrolyte (ILGPE) based on N-methyl-N-butylpiperidinium-bis(trifluoromethanesulfonyl)imide (PP14TFSI), bis(trifluoromethanesulfonyl)imide lithium salt (LiTFSI) and poly(vinylidene difluoride-co-hexafluoropropylene) (P(VdF-HFP)) is prepared for lithium ion batteries by solution casting. The ILGPE is characterized by scanning electron microscopy (SEM), thermogravimetry (TG) and electrochemical tests. The results indicate that the addition of PP14TFSI to the P(VdF-HFP)–LiTFSI polymer electrolyte leads to 3-dimensional network structures, and the ILGPE is stable below 150°C and will not decompose until 310°C without considering the volatilizing of the residual solvent. The ionic conductivity increases with the temperature rising, and the ionic conductivity is 0.23×10−3 Scm−1 and 2.1×10−3 Scm−1 at 20°C and 80°C, respectively. The electrochemical window is −0.15 to 4.85V vs. Li+/Li, which is wide enough to be used with common electrode materials. Battery tests show that the ILGPE is stable even at 80°C when operated in Li/LiFePO4 batteries, and Li/LiFePO4 batteries with the gel polymer electrolyte exhibit good cycling performance at 60°C at 1C current rate. The discharge capacity was 131.01mAhg−1 after 100 cycles with 90% capacity retention. [Copyright &y& Elsevier]

Abstract: Gel polymer electrolytes containing 1-ethyl-3-methylimidazolium-bis (trifluoromethyl-sulfnyl)imide (EMITFSI) ionic liquid were prepared for lithium ion batteries by solution casting method. Thermal and electrochemical properties have been determined for the gel polymer electrolytes. Proper addition of EMITFSI to the P(VdF-HFP)-LiTFSI polymer electrolyte improves the ionic conductivity and electrochemical window to 2.11 × 10−3 S cm−1 (30 °C) and 4.6 V. In combination of the prepared ternary P(VdF-HFP)-LiTFSI-EMITFSI ionic liquid polymer electrolytes, Li4Ti5O12 anode exhibited two extra voltage plateaus around 1.1 V and 2.3 V except the typical voltage plateau around 1.6 V by possible side reaction between ionic liquid and polymer. LiFePO4 cathode exhibited high capacity above 140 mA h g−1 and retention of 93.1% due to the suppressed polarization effect caused by enhanced ion transport properties. The high temperature of 80 °C didn''t have significant impact on the cycling performance. [Copyright &y& Elsevier]

Abstract: Gel polymer electrolytes containing N-butyl-N-methylpyrrolidinum bis(trifluoromethanesulfonyl) imide (PYR14TFSI) ionic liquid are prepared by the solution casting method. Thermal and electrochemical properties have been determined for these gel polymer electrolytes. The electrical properties are investigated in detail by the linear sweep voltammetry, cyclic voltammetry and impedance spectroscopy with the aid of the equivalent circuit fitting of the impedance spectra. The results show that the studied electrolytes have good self-standing characteristics, and also a sufficient level of thermal stability and a good electrochemical window. The conductivity increases with increasing amount of mixture, and for the studied system, the highest value of the conductivity measured at room temperature is 4.0×10−4 Scm−1. The lithium ions transference number reaches the maximum value when the gel electrolyte contains 33.3wt% PYR14TFSI ionic liquid. Based on the experiments, measurements and fitting, the models describing the lithium ion transmission and the properties of electrolyte/electrode interface are developed. [Copyright &y& Elsevier]

Highlights: [•] Method of radical polymerization is used to prepare electrolytes. [•] PP14TFSI+LiTFSI+PMMA electrolytes have good electrochemical properties. [•] Conductivity of 6.8×10−4 Scm−1 and of 0.37 are achieve at room temperature. [•] XPS show passivating film comprises multilayer films: Li2O and Li2CO3 layer. [•] Model describing Li electrode/electrolyte interface are developed. [ABSTRACT FROM AUTHOR]