Physicochemical properties of N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide for sodium metal battery applications (original) (raw)
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The Journal of Physical Chemistry C, 2019
Tm2 / K 0 n.d. 205 & 257 474 480 n.d. n.d. 0.10 n.d. 205 & 257 n.d. n.d. n.d. n.d. 0.20 n.d. 205 & 255 n.d. n.d. n.d. n.d. 0.27 n.d 206 & 258 n.d. n.d. n.d. n.d. 0.30 188 n.d. n.d. n.d. n.d. n.d. 0.40 198 n.d. n.d. n.d. n.d. n.d. 0.50 211 n.d. n.d. n.d. n.d. n.d. 0.60 214 n.d. 241 266 n.d. n.d. 0.70 216 n.d. 240 272 n.d. n.d. 0.75 217 n.d. 242 309 254 277 0.80 218 n.d. 240 370 253 278 0.85 220 n.d. 237 386 254 277 0.90 221 n.d. 230 393 254 278 1.00 n.d. 375 391 401 Tm1: the onset temperature of melting, Tm2: the end temperature of melting, Tm1 ′ : the onset temperature of melting for the metastable phase, Tm2 ′ : the end temperature of melting for the metastable phase, Tss: solidsolid transition temperature, Tg: glass transition temperature and n.d.: not detected.
Journal of Physical Chemistry C, 2019
A hybrid inorganic-organic ionic liquid based on sodium bis(fluorosulfonyl)amide (Na[FSA]) and [N-ethyl-N-methylpyrrolidinium][FSA] ([C2C1pyrr][FSA]) is investigated as an electrolyte for sodium secondary battery operation over an extended temperature and Na + ion fraction ranges. The phase diagram of the system reveals a wide liquid-phase temperature range at Na[FSA] mole fractions ranging from 0.3 to 0.7 near room temperature, where the 0.7 mole fraction equates to a molar concentration of 5.42 mol L −1. The viscosity and molar ionic conductivity are consistent with the fractional Walden rule, and the temperature dependence of these quantities obeys the Vogel−Tammann−Fulcher equation. The optimal Na[FSA] content of the ionic liquid occurs at mole fractions between 0.3 and 0.7 based on the sodium metal deposition/dissolution behavior and the rate and cycle properties of a NASICON-type cathode, Na3V2(PO4)3/C (NVPC). The greatest cycle efficiency, εcycle, of Na metal deposition/dissolution is observed at x(Na[FSA]) = 0.6 (εcycle = 93.3%). Although Na/NVPC half-cell tests indicate a maximum rate and cycle performance at x(Na[FSA]) = 0.6 (83.5% retention at 100 C (11700 mA g −1) and 80% retention after 4000 cycles at 2 C (234 mA g −1), NVPC/NVPC symmetric cell tests indicate that the greater Na[FSA] fraction provides better rate performance and that half-cell tests with a Na metal electrode do not provide reliable data for the target electrode/electrolyte system.
The redox couples M/M+ of the Group I alkali metals Lithium, Sodium, Potassium, Rubidium and Caesium have been extensively investigated in a room temperature ionic liquid (IL) and compared for the first time. Cyclic voltammetric experiments in the IL N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C4mpyrr][NTf2]) and subsequent simulation of the data has allowed the determination of the formal potential (Ef0 vs. ferrocene/ferrocenium), standard electrochemical rate constant (k0) and transfer coefficient (α) for each couple in the group. The trend in Ef0 in [C4mpyrr][NTf2] is remarkably similar to the established trend in the common battery electrolyte, propylene carbonate. http://dx.doi.org/10.1016/j.cplett.2010.04.063
Properties of sodium-based ionic liquid electrolytes for sodium secondary battery applications
The enormous demands on available global lithium resources have raised concerns about the sustainability of the supply of lithium. Sodium secondary batteries have emerged as promising alternatives to lithium batteries. We describe here sodium bis(trifluoromethylsulfonyl) amide (NaNTf 2 ) electrolyte systems based on 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) amide (C 4 mpyrNTf 2 ) ionic liquids. The electrochemical stability of the system was examined; a pair of facile cathodic and anodic processes around 0 V vs. Na/Na + were observed in cyclic voltammetry measurements and interpreted as deposition and dissolution of sodium metal. Density, viscosity and conductivity of the electrolytes were studied. It was found that the ionic conductivity of electrolytes reached as high as 8 mS/cm, decreasing slowly as the salt content increased due to increasing of viscosity and density of the electrolyte. Therefore, sodium electrolytes based on C 4 mpyrNTf 2 appear to be promising for secondary sodium battery applications.
ECS Transactions, 2007
Two room temperature ionic liquids based on the bis ((trifluoromethyl)sulfonyl)-imide anion (TFSI anion), the tributylmethylammonium-TFSI (Bu3MeN-TFSI) and the butylmethylpyrrolidinium-TFSI (BuMePy-TFSI), have been prepared for the electrochemical study of Li+/Li redox couple, the electrodeposition of Mn, Zn-Mn alloys and Cu-Mn alloys, and the extraction of Cu(II) ions from aqueous solutions, respectively. The best coulombic efficiency of Li+/Li couple is 97%. Mn(II), Zn(II) and Cu(I) species were introduced into the Bu3MeN-TFSI or BuMePy-TFSI by the anodic dissolution of the respective metallic electrodes. Coatings containing Mn, Zn, Cu, Zn-Mn or Cu-Mn can be obtained by controlled-potential electrolysis. The current efficiencies of Mn electrodeposition in either ionic liquid approach 100%. The Zn-Mn and Cu-Mn alloy deposits obtained in this study were compact and adherent. The surface morphology of these deposits depended on the Mn/Zn and Mn/Cu ratio, respectively. The BuMePy-TFSI...
Electrochimica Acta, 2012
The synergistic effect on the physical and electrochemical properties derived from mixing bis(trifluoromethanesulfonyl)imide-based, TFSI − , and (trifluoromethanesulfonyl)(nonafluorobutanesulfonyl)imide-based, IM 14 − , ionic liquids (ILs) with a common N-butyl-N-methylpyrrolidinium, PYR 14 + , cation has been examined. The incorporation of even small mole fractions (x ≤ 0.3) of PYR 14 IM 14 into PYR 14 TFSI is capable of strongly hindering the ability of the mixtures to crystallize. The lowering of the melting point caused by PYR 14 IM 14 addition, in conjunction with the relatively high conductivity of PYR 14 TFSI, results in an ionic conductivity for all of the mixtures approaching 10 −4 and 10 −3 S cm −1 at −20 • C and 20 • C, respectively. The PYR 14 TFSI/PYR 14 IM 14 binary mixtures may therefore be appealing for electrolyte applications in electrochemical devices operating at low temperatures.
Electrochimica Acta, 2013
Four room-temperature ionic liquids (RTILs) based on N-methyl-N-methoxyethylpyrrolidinium (PYR 12O1 +) and fluorinated sulfonylimides, bis(fluorosulfonyl)imide (FSI −), bis(trifluoromethanesulfonyl)imide (TFSI −), bis(pentafluoroethylsulfonyl)imide (BETI −) and (trifluoromethanesulfonyl) (nonafluorobutanesulfonyl)imide (IM 14 −) anion have been synthesised and intensively investigated from an electrochemical and physico-chemical point of view, including thermal behaviour, viscosity, conductivity and electrochemical stability. The prepared ionic liquids are thermally stable (over 200 • C in N 2 and over 180 • C in O 2 atmosphere) and electrochemically stable with electrochemical stability windows on platinum in the range from 4.7 V (PYR 12O1 FSI) to 5.4 V (PYR 12O1 IM 14). Conductivity decreases in the series FSI-TFSI-BETI-IM 14 according to the viscosity increase. DSC measurements showed no crystallisation down to −150 • C for PYR 12O1 TFSI and PYR 12O1 IM 14 .
Structure-Property Relation of Trimethyl Ammonium Ionic Liquids for Battery Applications
Applied Sciences
Ionic liquids are attractive and safe electrolytes for diverse electrochemical applications such as advanced rechargeable batteries with high energy densities. Their properties that are beneficial for energy storage and conversion include negligible vapor-pressure, intrinsic conductivity as well as high stability. To explore the suitability of a series of ionic liquids with small ammonium cations for potential battery applications, we investigated their thermal and transport properties. We studied the influence of the symmetrical imide-type anions bis(trifluoromethanesulfonyl)imide ([TFSI]−) and bis(fluorosulfonyl)imide ([FSI]−), side chain length and functionalization, as well as lithium salt content on the properties of the electrolytes. Many of the samples are liquid at ambient temperature, but their solidification temperatures show disparate behavior. The transport properties showed clear trends: the dynamics are accelerated for samples with the [FSI]− anion, shorter side chains...