The present invention relates to a composition comprising an alkali metal salt of bis(fluorosulfonyl)imide and to the use of such composition in an electrolyte for batteries.

The present invention relates to a composition comprising an alkali metal salt of bis(fluoro sulfonyl)imide and to the use of such composition in an electrolyte for batteries.

The present disclosure relates to a dry dispersion of ammonium bis(fluorosulfonyl)imide (NH.sub.4FSI) salt of formula (I): [FSO.sub.2N.sup.SO.sub.2F], NH.sub.4.sup.+ (I) characterized by having at least two particle size fractions, i.e. a small-size fraction and a large-size fraction. The present disclosure also relates to the use of such dispersion to prepare a salt of bis(fluorosulfonyl)imide selected from the group consisting of a lithium slat, a sodium salt or a potassium salt.

The present invention provides an alkali metal salt of fluorosulfonyl imide having favorable heat resistance and a reduced content of specific impurities and a water content, and provides a method for producing an alkali metal salt of fluorosulfonyl imide, which is capable of easily removing a solvent from a reaction solution. An alkali metal salt of fluorosulfonyl imide of the present invention is represented by the following general formula (I) and has a mass loss rate of 2% or less when the alkali metal salt of fuluorosulufonyl imide is kept at 100 C. for 8 hours under an air current. A method for producing an alkali metal salt of fluorosulfonyl imide of the present invention comprises a step of concentrating a solution of the alkali metal salt of fulorosulfonyl imide by bubbling a gas into a reaction solution containing the alkali metal salt of fulorosulfonyl imide, and/or concentrating a solution of the alkali metal salt of fulorosulfonyl imide by thin layer distillation.

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The present invention provides an alkali metal salt of fluorosulfonyl imide having favorable heat resistance and a reduced content of specific impurities and a water content, and provides a method for producing an alkali metal salt of fluorosulfonyl imide, which is capable of easily removing a solvent from a reaction solution. An alkali metal salt of fluorosulfonyl imide of the present invention is represented by the following general formula (I) and has a mass loss rate of 2% or less when the alkali metal salt of fluorosulfonyl imide is kept at 100 C. for 8 hours under an air current. A method for producing an alkali metal salt of fluorosulfonyl imide of the present invention comprises a step of concentrating a solution of the alkali metal salt of fluorosulfonyl imide by bubbling a gas into a reaction solution containing the alkali metal salt of fluorosulfonyl imide, and/or concentrating a solution of the alkali metal salt of fluorosulfonyl imide by thin layer distillation. ##STR00001##

The invention provides a bis(fluorosulfonyl)imide impurity removal and purification system and a bis(fluorosulfonyl)imide impurity removal and purification method. The system comprises a light-component stripping tank, a gas-liquid separator, a product buffer tank, an impurity removal reactor, and a film evaporator. The light-component stripping tank is connected to a reaction product liquid supply source. The gas-liquid separator is connected to the light-component stripping tank and also connected to the light-component product recovery device. The product buffer tank is connected to the light-component stripping tank and also connected to the gas-liquid separator. The impurity removal reactor is connected to the product buffer tank and also connected to an impurity removal reactant supply source. The film evaporator is connected to the impurity removal reactor, connected to a gas-phase separation system, and also connected to an impurity collection tank. The bis(fluorosulfonyl)imide impurity removal and purification system and the bis(fluorosulfonyl)imide impurity removal and purification method according to the invention make it possible to remove impurities from bis(fluorosulfonyl)imide continuously and efficiently and purify it.

The present invention relates to a process for preparing a salt of bis(fluorosulfonyl)imide, preferably lithium bi(fluorosulfonyl)imide (LiFSI).

The present invention relates to a method for producing a salt of bis(chlorosulfonyl) imide, which is economically feasible at industrial scale and which provides a high-purity product.

The invention relates to a process for preparing bis(fluorosulfonyl)imide, comprising the steps of: i) providing a stream A1 containing HF and a reactor containing a liquid phase A2 that contains bis(chlorosulfonyl)imide; ii) in said reactor, bringing said liquid phase A2 into contact with said stream A1 to produce bis(fluorosulfonyl)imide, said process being characterized in that said stream A1 is injected into said liquid phase A2.

The present disclosure relates to a process for preparing a lithium salt of bis(fluorosulfonyl)imide (LiFSI) in solid form, wherein the solid form LiFSI salt is extracted from a solution comprising at least one solvent through supercritical fluid extraction. The present invention also relates to the LiFSI in solid form obtained therefrom, as well as the use of such LiFSI in an electrolyte for batteries.