Fmc Corporation

Lithium Corporation of America

Gould Inc.

Dennis J Salmon

D Wayne Barnette

Teresita C Frianeza-Kullberg

Glynn R Ramsay

Rebecca A Barnett

The present invention provides a process for generating acid-free lithium salt solutions for lithium and lithium ion batteries and for preparing high purity lithium salts. The invention comprises removing acid species from lithium salt solutions such as lithium hexafluorophosphate solutions using weak base resins. The process does not require the addition of a base such as ammonia which when added to the electrolytic solution generally must be removed from the final product. Once the lithium salt has been treated by the weak base resin, the substantially acid-free lithium salt solution may be recovered from the weak base resin to provide a solution which may be used as an electrolytic solution or which may be used to prepare high purity lithium salts.

Process for removing acids from lithium salt solutions

The present invention provides a process for generating acid-free lithium salt solutions for lithium and lithium ion batteries and for preparing high purity lithium salts. The invention comprises removing acid species from lithium salt solutions such as lithium hexafluorophosphate solutions using weak base resins. The process does not require the addition of a base such as ammonia which when added to the electrolytic solution generally must be removed from the final product. Once the lithium salt has been treated by the weak base resin, the substantially acid-free lithium salt solution may be recovered from the weak base resin to provide a solution which may be used as an electrolytic solution or which may be used to prepare high purity lithium salts. The highly pure salts and solutions have a hydrogen fluoride concentration of less than 10 ppm

A process for preparing solutions of lithium hexafluorophosphate comprising reacting, under basic conditions, a lithium salt with a salt selected from sodium, potassium, ammonium, or organo ammonium hexafluorophosphate salt in a low boiling, non-protic organic solvent to produce a solution of lithium hexafluorophosphate and a precipitated sodium, potassium, ammonium, or organo ammonium salt containing the anion of the reactant lithium salt.

Preparation of lithium hexafluorophosphate solutions

A process for the removal of lithium nitride from lithium metal by adding to liquid lithium metal containing lithium nitride, at a temperature between the melting point of lithium and 300.degree. C., with agitation, a stochiometric quantity of aluminum to react with the lithium nitride, in an inert, nitrogen free atmosphere, continuing the agitation for at least one hour to form aluminum nitride and separating the aluminum nitride from the liquid lithium metal.

Removal of lithium nitride from lithium metal

A process for producing high purity lithium oxide comprising decomposing lithium peroxide at a temperature of 350.degree. to 450.degree. C., in an inert atmosphere in the substantial absence of water to produce impure lithium oxide followed by heating the impure lithium oxide under moderate vacuum at 900.degree. C. or more for at least one hour to obtain high purity lithium oxide of 99% or greater purity.

High purity lithium oxide process

A method of preventing overpressurization of a lithium-thionyl chloride battery cell by formation of excessive SO.sub.2 during high rate discharge. The method comprises the step of providing PCl.sub.5 in the cathode. Alternatively, the PCl.sub.5 may be provided in the electrolyte or in both the cathode and electrolyte as desired. The PCl.sub.5 may be incorporated in the cathode by introduction thereof into the porous carbon structure of a preformed carbon element. Alternatively, the PCl.sub.5 may be dry mixed with the carbon and the mixture formed into the desired cathode element.

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Gastonia, NC, United States of America

Dennis J Salmon