1,4-dioxane slovate of lithium difluorobis(oxalato)phosphate, method for preparing the same, and electrolyte composition comprising the same

A method for preparing a crystalline 1,4-dioxane solvate of lithium difluorobis (oxalato) phosphate comprising:

• (i) adding 1,4-dioxane to a solution of lithium difluorobis (oxalato) phosphate dissolved in a non-aqueous solvent, followed by stirring;
• and
• (ii) filtering a solid produced in step (i),
• wherein the crystalline solvate shows an X-ray powder diffraction (XRPD) pattern characterized by peaks having I/Io values of at least 10% (I is the intensity of each peak;
• Io is the intensity of the highest peak) at diffraction angles (2θ) of 9.7±0.2, 9.9±0.2, 15.4±0.2, 15.7±0.2, 16.9±0.2, 17.5±0.2, 17.9±0.2, 19.6±0.2, 19.8±0.2, 20.3±0.2, 21.3±0.2, 23.4±0.2, 23.8±0.2, 24.6±0.2, 24.9±0.2, 26.4±0.2, and 41.4±0.2.