[EMIM][BF4] (1-Ethyl-3-methylimidazolium tetrafluoroborate, 99.5%) Ionic Liquid as Electrolyte Solvent and Additive, 25 g/bottle, CESAILEMIMBF4

EMIMBF4 (1-Ethyl-3-methylimidazolium tetrafluoroborate) 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 Battery (LIB) Additive: Used in small concentrations (1–5%) within standard carbonate-based electrolytes. (1) Flame Retardancy: It significantly reduces the flammability of the electrolyte, improving safety. (2) SEI Formation: It can assist in the formation of a more stable Solid Electrolyte Interphase (SEI) on the anode, especially in high-voltage cells.

CO2 Electroreduction (CO2RR): This is perhaps the most famous application for [EMIM][BF4]. The [EMIM]+ cation acts as a co-catalyst. It adsorbs onto the catalyst surface (like Silver or Gold) and forms a complex with CO2, lowering the activation energy barrier for the formation of the *CO2'- radical intermediate. It is highly effective at suppressing the Hydrogen Evolution Reaction (HER) and promoting the production of Carbon Monoxide (CO) at very low overpotentials.

Supercapacitors: [EMIM][BF4] is used as an electrolyte to increase the energy density of carbon-based supercapacitors. While aqueous electrolytes limit supercapacitors to ~1.2 V, [EMIM][BF4] allows operation up to 3.0 V or higher, which will increase the energy density since doubling the voltage quadruples the energy stored. 

Part Number	CESAILEMIMBF4 (C-ESA-ILEMIMBF4)
CAS	143314-16-3
Chemical Formula	C6H11BF4N2
Appearance	Colorless liquid
Purity	99.5% (Battery Grade)
Molecular Weight	197.97 g/mol
Density	1.294 g/cm3
Package Size	25 or 100 g/bottle

Notes: Please try to store the EMIMBF4 ionic liquid in the dry place. 

References: 

1. K. Hayamizu, et al. Ionic Conduction and Ion Diffusion in Binary Room-Temperature Ionic Liquids Composed of [emim][BF4] and LiBF4, J. Phys. Chem. B 2004, 108, 50, 19527–19532.
2. Sapna Rana, et al. Investigating the Solvation Behavior of Some Lithium Salts in Binary Aqueous Mixtures of 1-Ethyl-3-methylimidazolium Tetrafluoroborate ([EMIM][BF4]) at Equidistant Temperatures (T = 298.15, 303.15, 308.15, 313.15, 318.15) K, J. Chem. Eng. Data 2023, 68, 6, 1291–1304. 
3. N. Karki et al., Modulation of Selectivity in Electrocatalytic CO2 Reduction with a Magnetic Field and Imidazolium Ionic Liquids, J. Phys. Chem. C 2025, 129, 32, 14356–14365. 
4. X. Jiang, et al., Additive Engineering Enables Ionic-Liquid Electrolyte-Based Supercapacitors To Deliver Simultaneously High Energy and Power Density, ACS Sustainable Chem. Eng. 2023, 11, 14, 5685–5695.