Targeting adequate thermal stability and fire safety in selecting ionic liquid-based electrolytes for energy storage

Abstract

The energy storage market relating to lithium based systems regularly grows in size and expands in terms of a portfolio of energy and power demanding applications. Thus safety focused research must more than ever accompany related technological breakthroughs regarding performance of cells, resulting in intensive research on the chemistry and materials science to design more reliable batteries. Formulating electrolyte solutions with nonvolatile and hardly flammable ionic liquids instead of actual carbonate mixtures could be safer. However, few definitions of thermal stability of electrolytes based on ionic liquids have been reported in the case of abuse conditions (fire, shortcut, overcharge or overdischarge). This work investigates thermal stability up to combustion of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C1C4Im][NTf2]) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([PYR14][NTf2]) ionic liquids, and their corresponding electrolytes containing lithium bis(trifluoromethanesulfonyl)imide LiNTf2. Their possible routes of degradation during thermal abuse testings were investigated by thermodynamic studies under several experimental conditions. Their behaviours under fire were also tested, including the analysis of emitted compounds.

Characterization of LTO//NMC Batteries Containing Ionic Liquid or Carbonate Electrolytes after Cycling and Overcharge

“…Similarly to cycling experiments, the gases generated during overcharge were identified by GC-IR as carbon monoxide CO, dihydrogen H 2 , fluorinated species, and alkanes such as methane, propane and butane, Figure 7. 4 At 60 …”

“…4 These electrolytes were prepared under inert conditions by adding 1 mol.L -1 of LiNTf 2 . [EC:DEC][LiPF 6 ] (BASF) was stored in a glove box and used as received.…”

“…1 To provide safer cells, ionic liquids (IL) are widely studied as they possess negligible vapor pressure and reduced flammability. 2 However, though information concerning the thermal stability of IL during combustion is beginning to emerge, 3,4 few data exist concerning their stability in case of short-circuit, overcharge or overdischarge. The aim of this work is to compare cycling and overcharge behavior at 25 and 60…”

“…• C of two IL-based electrolytes and a commercial electrolyte, in a system using Li 4 6 ], Figure 1. For each electrolyte, cycling and overcharge experiments were run in LTO // NMC coin or pouch cells.…”

From industrial black liquor to pure phenolic compounds: A combination of catalytic conversion with ionic liquids extraction

“…For this extraction, ILs were on the primary interest due to their fascinating and tunable physico-chemical proprieties including hydrophobicity [18], non-volatility [19] and non-flammability [20]. This results that ILs could be expected for a green and low cost liquid-liquid extraction [21][22][23], when compared to the use of conventional volatile solvent.…”