A Comparison among Viscosity, Density, Conductivity, and Electrochemical Windows of N-n-Butyl-N-methylpyrrolidinium and Triethyl-n-pentylphosphonium Bis(fluorosulfonyl imide) Ionic Liquids and Their Analogues Containing Bis(trifluoromethylsulfonyl) Imide Anion

Abstract

Ionic liquid consists of an organic cation and generally an inorganic anion. The properties of liquids can be modulated by changing the anion or the cation or both. Two ionic liquids derived from the anion [FSI] were synthesized and characterized: (N-n-butyl-N-methylpyrrolidinium bis-(fluorosulfonyl imide), [BMPYR][FSI]) and triethyl-n-pentylphosphonium bis(fluorosulfonyl)imide), [P 2225 ][FSI]). We also report the comparison with [TFSI] based ionic liquids, namely: (N-n-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide), [BMPYR][TFSI]), (N-n-butyl-N-methylpiperidinium bis(trifluoromethylsulfonyl)imide), [BMP][TFSI]), triethyl-npentylphosphonium bis(trifluoromethylsulfonyl)imide), [P 2225 ][TFSI]) and (triethyl(2-methoxyethyl) phosphonium bis(trifluoromethylsulfonyl imide), [P 222201 ][TFSI]. Thermophysical properties, such as viscosity (298.15−373.15 K), density (298.15−373.15 K), conductivity (298.15−361.15 K), electrochemical (cutoff density current within 150 μA•cm −2 ), and thermal stability (303.15−973.15 K) were experimentally determined. The results showed that [FSI] derivatives exhibit better transport properties and lower thermal and electrochemical stability when compared with their [TFSI] counterparts.

Underpotential Deposition of Silver on Au(111) from an Air‐ and Water‐Stable Ionic Liquid Visualized by In‐Situ STM

“…Estimated dynamic viscosity η of [BMP][DCA] under standard conditions was 50 mPa s . For comparison, the viscosity of other common organic ILs is considerably higher: η =110 mPa s for [BMIm][BF 4 ], where BMIm is 1‐butyl‐3‐methylimidazolium; η =78 mPa s for [BMP][TFSI], where TFSI is bis(trifluoromethylsulfonyl)imide; η =828 mPa s for the choline chloride/urea (1 : 2 mole ratio) DES …”

Acyclic and Cyclic Alkyl and Ether‐Functionalised Sulfonium Ionic Liquids Based on the [TFSI]− and [FSI]− Anions as Potential Electrolytes for Electrochemical Applications

“…[23,24] This difference may be the result of several contributing factors such as; trace levels of water or other impurities or different pan materials used. [34] However, the substitution of the fluorine atom to a ÀCF 3 group on the [TFSI] À anion provide a better negative charge localisation and stabilisation due to a lower electron-withdrawing effect than [FSI] À . [29] Generally, reports in literature suggest the incorporation of an ether group has a negative effect on the ILs thermal stability.…”

“…ILs, reputed for having wide electrochemical stability windows are of great interest for electrochemical devices such as Li-batteries and EDLCs. Compared to quaternary ammonium, [34,49,54,55] and phosphonium ILs, [56,57] these sulfonium based ILs exhibited lower electrochemical stabilities, and their electrochemical windows range from 3.15-4.76 V (Table 5 and Figure 8). The electrochemical stability window (DE) reported in Table 5, is defined as the difference in the anodic (E a ) and cathodic (E c ) limits which are due to oxidation and reduction, respectively.…”

“…For example, at 298.15 K the reported viscosity of [TFSI] À -based ILs with an Sbutyl-S,S-dimethylsulfonium cation (ca. [23,24] The influence of ether functionalisation of sulfonium cation based ILs has been studied by Han et al, [25] Orita et al, [26] Neale et al, [27] and Coadou et al [13] explored a range of [TFSI] Àbased acyclic sulfonium cations with mono-and bis-ether group functionalisation which exhibited low viscosities (27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46) mPa · s at 298 K) and moderate conductivities (2.34-4.93 mS · cm À1 at 298 K). 105.2 mPa · s); an analogous tetraalkylammonium cation-based IL of comparable size.…”

The effect of diameter size of single-walled carbon nanotubes on their high-temperature energy storage behaviour in ionic liquid-based electric double-layer capacitors

“…[1][2][3] These attractive properties sparked a large body of research revolving around the use of ionic liquids for electrochemical energy applications, especially those involving elevated temperatures. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Electrochemical energy storage devices use electrodes made from porous materials with high surface area provided by a network of pores on the surface of the electrode. These pores offer the space needed for diverse physical and chemical changes to take place, leading to energy storage.…”