A computer-implemented method for determining a concentration of a component of an electrolyte in a lithium-ion or for a lithium-ion cell is provided. The method includes providing, to a spectrometer, instructions to capture a spectrum of a sample solution of the electrolyte and generate a signal. The method includes analyzing the signal to determine one or more spectral features of the spectrum. The method includes preparing a database of spectra corresponding to solutions having predetermined concentrations of the component of the electrolyte wherein the database includes a plurality for spectral features for each solution. The method further includes determining a machine learning (ML) model using the database of spectra. The method includes determining the concentration of the component of the electrolyte in the sample solution using the machine learning model.

A non-aqueous electrolyte solution and a lithium secondary battery including the same are disclosed herein. In some embodiments, a non-aqueous electrolyte solution includes a lithium salt, a first organic solvent that is ethylene carbonate, a second organic solvent excluding ethylene carbonate, and an oligomer represented by Formula 1 wherein a concentration of the lithium salt is 1.2 M to 3.3 M, and, wherein the first organic solvent is included in an amount of 0.1 wt % to 12 wt % based on a total weight of the non-aqueous electrolyte solution.

A lithium-ion battery with high safety is provided. A lithium-ion battery 20 includes an electrode group 6, an electrolyte, and a battery container 5 that contains the electrode group 6 and the electrolyte. The electrode group 6 is formed by stacking a positive electrode and a negative electrode via a separator. The positive electrode contains a composite oxide of lithium, nickel, manganese, and cobalt as a main positive active material. The negative electrode contains amorphous carbon as a main negative active material. The lithium-ion battery 20 has a discharge capacity of 20 Ah or more. The ratio (the value of Y/X) of a volume Y occupied by the electrolyte to a volume X of a void space in the battery container 5 is 0.65 or more.

Battery electrolytes comprising: (a) a solvent suitable for use in a battery electrolyte such as an organic liquid solvent or an ionic liquid; (b) a lithium ion or sodium ion salt suitable for use in a battery electrolyte; and (c) a dispersion of nanoparticles of carbon, metal or metalloid oxides or hydroxides, carbides, nitrides, sulfides, graphene or MXene particles; or a combination thereof. The present invention is also directed to battery cells and batteries comprising these electrolytes and devices comprising these battery cells and batteries.

Embodiments described herein relate generally to a system and methods for preparing engineered solid electrolyte interphases for electrochemical energy storage devices. Some of the engineered SEI layers include passivation films, some of the engineered SEI layers include polymerization films, and some SEI layers include both passivation and polymerization layers.

A process for recovering lithium phosphate and lithium sulfate from a lithium-bearing solution, such as a brine or pregnant process liquor is described. The process includes adding phosphate to the lithium-bearing solution to precipitate lithium phosphate and then separating the resulting lithium phosphate precipitate from the solution. The separated lithium phosphate precipitate is then digested in sulphuric acid to produce a digestion mixture from which a lithium sulfate precipitate is separated. An alkali metal hydroxide is added to the separated solution to produce an alkali metal phosphate solution and this is recycled for use as phosphate in the first step of the process.

A method of recovering a lithium salt from a lithium battery waste mass, comprising the steps of: (a) dissolving the lithium sail in the lithium battery waste mass in a weight of water equivalent to 100 to 0.1 times the weight of the lithium battery waste mass, either in a one-off treatment or successive treatments; (b) evaporating the aqueous solution to dryness; and (c) working up the dry residue with a solvent comprising water, a carbonate, or mixtures thereof.

The present disclosure discloses a method for recycling a lithium-ion battery electrolyte. After the waste lithium-ion battery is discharged, it is frozen and disassembled to obtain a battery cell containing an electrolyte. The battery cell is immersed in a lithium hydroxide solution containing a catalyst for reaction. The battery cell after the reaction is taken out and washed. The washing solution is mixed with the lithium hydroxide solution after the reaction to obtain a mixed solution. The mixed solution is filtered to obtain a filtrate and a filter residue. The filter residue is reacted with a hydrofluoric acid solution to obtain anhydrous lithium salt. The anhydrous lithium salt is mixed with an organic solution, and PF.sub.5 gas is introduced. The mixture is reacted, and filtered to obtain an organic liquid. The organic solution is frozen and filtered to obtain lithium hexafluorophosphate.

A process for producing a hexafluorophosphate salt comprises neutralizing hexafluorophosphoric acid with an organic Lewis base, to obtain an organic hexafluorophosphate salt. The organic hexafluorophosphate salt is reacted with an alkali hydroxide selected from an alkali metal hydroxide (other than LiOH) and an alkaline earth metal hydroxide, in a non-aqueous suspension medium, to obtain an alkali hexafluorophosphate salt as a precipitate. A liquid phase comprising the non-aqueous suspension medium, any unreacted organic Lewis base and any water that has formed during the reaction to form the precipitate, is removed. Thereby, the alkali hexafluorophosphate salt is recovered.

The present invention relates to processes for the preparation of phosphorus pentafluoride and lithium hexafluorophosphate.