Lithium bis(fluorosulfonyl)imide

Battery grade lithium bis(fluorosulfonyl)imide (LiFSI) is a white, powdery lithium salt often used as the source of lithium in high-performance electrolytes for lithium-ion batteries. LiFSI is soluble in water and many organics including the carbonates and ethers typically used in liquid electrolytes, like ethylene carbonate or dimethyl carbonate. Our battery grade LiFSI is differentiated by its high purity with low impurities of sodium, potassium, chloride, and sulfate, and low moisture content.

Battery grade LiFSI is used as the source of lithium ions in battery electrolytes for LiBs. In comparison to LiPF₆, LiFSI has marked advantages including a higher ionic conductivity in organic solvents and improved thermal stability. In addition, LiFSI has advantages in better stability against hydrolysis, lower aluminum corrosion with stability up to 4.7 V, higher transference number, and generally higher columbic efficiency for Li metal anode cycling.[3] Because of these advantages, many of the groundbreaking works to improve electrolytes use LiFSI. For example, researchers leveraged the improved solubility of LiFSI in ethers compared to LiTFSI or LiPF₆ to formulate a LiFSI-based electrolyte that operates even at ultra-low temperatures like -30 °C, demonstrate cathodic stability up to 6 V vs Li/Li⁺, and achieve fast cycling with high columbic efficiency LiFSi is also commonly used as a co-salt with LiPF₆ to improve the performance at high operating temperatures, for example 0.6 M LiFSI and 0.6 M LiPF₆ in carbonate blends Researchers also often use LiFSI or a blend of LiFSI and LiTFSI as the source of lithium ions in polymer electrolytes, especially with Li metal anodes. LiFSI is shown to produce a LiF-rich solid-electrolyte interphase on Li metal surfaces, which promotes cycling with high coulombic efficiencies