Method for preparing lithium difluorophosphate salt for lithium secondary battery
AssigneeEp Chemtech Co., Ltd.
InventorSoon Ho LEE
Life of this patent
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Abstract
The present invention relates to a method for preparing lithium difluorophosphate salt in high yield by using low-unit-cost raw materials. In particular, the present invention relates to a method for preparing lithium difluorophosphate salt with high purity and high yield by preparing same without using lithium hexafluorophosphate salt. Therefore, the lithium difluorophosphate salt prepared according to the present invention may be used in an electrolyte for a lithium secondary battery, and when used in an electrolyte for a lithium secondary battery, has electrochemical property, output, and gas reduction effects, and so on.
Claims23
A method for preparing lithium difluorophosphate salt, the method comprising:
- step 1) reacting a phosphoryl halide (POX3) compound of formula 2 below, an oxidizing agent of formula 3 below, and lithium salt to prepare lithium dihalophosphate salt of formula 4 below;
- and
- step 2) reacting lithium dihalophosphate salt of formula 4 and fluoride salt of formula 5 below to prepare lithium difluorophosphate salt of formula 1 below:
- in the above formulas,
- X is Cl, Br or I,
- R1 and R2 are each independently H, C1-10 alkyl group, phenyl group, OH, OR3, NH2, NHR4, NR5R6, ONa, OK, or ONH4,
- R3, R4, R5, and R6 are each independently C1-10 alkyl group or phenyl group,
- R1 and R2 together may form a ring having two to five carbon atoms which may additionally include one or more heteroatoms of O or N,
- M is H, Li, Na, K, Ca, Zn, Sb, Rb, Cs, or onium ion, and
- n is 1 or 2.
A method for preparing lithium difluorophosphate salt, the method comprising:
- step 1′) reacting a phosphoryl halide (POX3) compound of formula 2 below, an oxidizing agent of formula 3 below, and fluoride salt of formula 5 below to prepare difluorophosphate salt of formula 6 below;
- and
- step 2′) reacting difluorophosphate salt of formula 6 and lithium salt to prepare lithium difluorophosphate salt of formula 1 below:
- in the above formulas,
- X is Cl, Br or I,
- R1 and R2 are each independently H, C1-10 alkyl group, phenyl group, OH, OR3, NH2, NHR4, NR5R6, ONa, OK, or ONH4,
- R3, R4, R5, and R6 are each independently C1-10 alkyl group or phenyl group,
- R1 and R2 together may form a ring having two to five carbon atoms which may additionally include one or more heteroatoms of O or N,
- M is H, Li, Na, K, Ca, Zn, Sb, Rb, Cs, or onium ion, and
- n is 1 or 2.
A method for preparing lithium difluorophosphate salt, the method comprising:
- reacting a phosphoryl fluoride (POF3) compound of formula 7 below, an oxidizing agent of formula 3 below, and lithium salt to prepare lithium difluorophosphate salt of formula 1 below:
- in the above formulas,
- R1 and R2 are each independently H, C1-10 alkyl group, phenyl group, OH, OR3, NH2, NHR4, NR5R6, ONa, OK, or ONH4,
- R3, R4, R5, and R6 are each independently C1-10 alkyl group or phenyl group, and
- R1 and R2 together may form a ring having two to five carbon atoms which may additionally include one or more heteroatoms of O or N.
Lithium difluorophosphate salt comprising 0-500 ppm by weight of F−, 0-500 ppm by weight of Cl−, 0-500 ppm by weight of SO42−, or 0-500 ppm by weight of PO43−.
Dependencies are inferred from the claim text.