Method for producing lithium difluorophosphate, method for producing difluorophosphate ester, lithium difluorophosphate, method for producing non-aqueous electrolyte solution, and method for producing non-aqueous secondary battery

Provided are: a method for producing lithium difluorophosphate by reacting a difluorophosphate ester with a lithium salt compound in a non-aqueous organic solvent, in which water is not used as a starting material in the reaction; also provided are: a method for producing a difluorophosphoric acid ester, which comprises a step in which a dihalophosphoric acid ester and a fluorinating agent that contains hydrofluoric acid at a concentration of 15 mol% or less are reacted in a non-aqueous organic solvent; also provided are: a lithium difluorophosphate in which the value of the relational expression (d90-d10)/MV represented by the particle diameter d90 at a volume cumulative distribution of 90%, the particle diameter d10 at a volume cumulative distribution of 10%, and the volume average particle diameter MV is 10 or less; also provided are a method for producing a non-aqueous electrolyte solution and a method for producing a non-aqueous secondary battery using the production method. 本发明提供一种二氟磷酸锂的制造方法，该方法使二氟磷酸酯与锂