[EMIM][TFSI] (1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, >99.5%) Ionic Liquid as Electrolyte Solvent and Additive, 25 g/bottle, CESAILEMIMTFSI

EMIMTFSI (1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) is a popular and widely studied example of an ionic liquid (IL) used as an electrolyte component in various electrochemical devices, particularly batteries and supercapacitors. It serves as the high-stability, non-flammable solvent into which a mobile metal salt is dissolved (e.g., LiTFSI, NaTFSI, or KTFSI) to create the working electrolyte.

Lithium-Ion & Sodium-Ion Batteries: [EMIM][TFSI] is used as a co-solvent or additive to enhance safety and voltage. It is non-flammable and has negligible vapor pressure, acting as a flame retardant in standard carbonate electrolytes. It is highly stable at high potentials, making it suitable for high-voltage cathodes (e.g., LNMO). It should be noted that Imidazolium cations can intercalate into graphite anodes, potentially causing exfoliation. Therefore, it is often used with film-forming additives like VC (Vinylene Carbonate) or in "solvent-in-salt" configurations.

CO2 Electroreduction (CO2RR): While [EMIM][BF4] is more famous for CO2 reduction, [EMIM][TFSI] is used in non-aqueous CO2 reduction or as a hydrophobic additive. The [EMIM]+ cation stabilizes the CO2'- radical, lowering the overpotential for CO production. Moreover, it can be used to create a "water-lean" interface at the catalyst due to its hydrophobicity, which effectively suppresses the competing Hydrogen Evolution Reaction (HER).

Supercapacitors: It is a premier choice for high-energy density supercapacitors. By replacing aqueous electrolytes with pure [EMIM][TFSI], the operating voltage can be pushed from 1.2V to 3.0 V. Since energy density scales with V^2, this leads to a massive increase in stored energy.

Part Number	CESAILEMIMTFSI (C-ESA-ILEMIMTFSI) Also named as [EMIM][Tf2N]
CAS	174899-82-2
Chemical Formula	C8H11F6N3O4S2
Appearance	Colorless liquid
Purity	>99.5% (Battery Grade) Water level: <500 ppm
Molecular Weight	391.31 g/mol
Density	1.52 g/cm3
Package Size	25 g/bottle

Notes: Please try to store the [EMIM][TFSI] ionic liquid in the dry place. 

References: 

1. H. S. Dhattarwal, et al. Heterogeneity and Nanostructure of Superconcentrated LiTFSI–EmimTFSI Hybrid Aqueous Electrolytes: Beyond the 21 m Limit of Water-in-Salt Electrolyte, J. Phys. Chem. B 2022, 126, 28, 5291–5304.
2. C. A. Bridges, et al. Dynamics of Emim+ in [Emim][TFSI]/LiTFSI Solutions as Bulk and under Confinement in a Quasi-liquid Solid Electrolyte, J. Phys. Chem. B 2021, 125, 20, 5443–5450. 
3. A. Fortunati, et al., Understanding the role of imidazolium-based ionic liquids in the electrochemical CO2 reduction reaction, Communications Chemistry, 2023, 6, 84.
4. M. Saha, et al., A Comprehensive Review of Novel Emerging Electrolytes for Supercapacitors: Aqueous and Organic Electrolytes Versus Ionic Liquid-Based Electrolytes, Energy Fuels 2024, 38, 10, 8528–8552.