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US-12620623-B2 - Electrolyte additive, electrolyte for batteries including electrolyte additive, and secondary battery including electrolyte

US12620623B2US 12620623 B2US12620623 B2US 12620623B2US-12620623-B2

Abstract

The present invention relates to an electrolyte additive including a compound containing a substituent represented by Chemical Formula 1, an electrolyte including the electrolyte additive, and a secondary battery including the electrolyte. In Chemical Formula 1, P and O are phosphorus and oxygen, respectively; A is a bond or oxygen; Q is oxygen or an unshared electron pair; R 1 , R 2 , R 3 , and R 4 are each independently hydrogen, a linear or branched alkyl group having 1 to 10 carbon atoms, an alkenyl group, an alkynyl group, an alkoxy group, an alkoxycarbonyl group, an alkoxyalkyl group, a fluoroalkyl, or a cyclic sulfate; optionally, R 1 or R 2 is connected to R 3 or R 4 to form a double bond or a ring; n is an integer from 0 to 3; and * is a binding position.

Inventors

  • Ji Young Choi
  • Min Goo Kim
  • Sang Ho Lee
  • Wan Chul KANG
  • Jong Chul YUN
  • Hyeong Kyu Lim
  • Ji Seong Han
  • Min Jung Jang

Assignees

  • SOULBRAIN CO., LTD.

Dates

Publication Date
20260505
Application Date
20210628
Priority Date
20200626

Claims (14)

  1. 1 . An electrolyte additive comprising a compound containing a substituent represented by Chemical Formula 1 below: wherein P and O are phosphorus and oxygen respectively; A is a bond or oxygen; Q is oxygen or an unshared electron pair; R 1 , R 2 , R 3 , and R 4 are each independently hydrogen, a linear or branched alkyl group having 1 to 10 carbon atoms, an alkenyl group, an alkynyl group, an alkoxy group, an alkoxycarbonyl group, an alkoxyalkyl group, a fluoroalkyl, or optionally, R 1 or R 2 is connected to R 3 or R 4 to form a double bond or a ring; n is an integer from 0 to 3; and * is a binding position.
  2. 2 . The electrolyte additive according to claim 1 , wherein the compound comprises one or more selected from the group consisting of compounds represented by Chemical Formulas 2 to 32 below: wherein, in Chemical Formulas 2 to 32, lines are bonds; a point where one bond meets another bond is carbon when an element is not indicated separately; and hydrogens which number satisfies a valence of the carbon are omitted.
  3. 3 . An electrolyte for batteries comprising an organic solvent, a lithium salt, and an electrolyte additive, wherein the electrolyte additive comprises a compound containing a substituent represented by Chemical Formula 1 below: wherein P and O are phosphorus and oxygen, respectively; A is a bond or oxygen; Q is oxygen or an unshared electron pair; R 1 , R 2 , R 3 , and R 4 are each independently hydrogen, a linear or branched alkyl group having 1 to 10 carbon atoms, an alkenyl group, an alkynyl group, an alkoxy group, an alkoxycarbonyl group, an alkoxyalkyl group, a fluoroalkyl, or optionally, R 1 or R 2 is connected to R 3 or R 4 to form a double bond or a ring; n is an integer from 0 to 3; and * is a binding position.
  4. 4 . The electrolyte according to claim 3 , wherein, based on 100% by weight in total of the electrolyte, the compound is comprised in an amount of 0.1 to 10% by weight.
  5. 5 . The electrolyte according to claim 3 , wherein, in Chemical Formula 1, n is 1 or 2, and Q is an unshared electron pair.
  6. 6 . The electrolyte according to claim 3 , wherein the organic solvent comprises one or more selected from the group consisting of ethylene carbonate (EC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate (PC), dipropyl carbonate (DPC), butylene carbonate, methylpropyl carbonate, and ethylpropyl carbonate.
  7. 7 . The electrolyte according to claim 3 , wherein the lithium salt comprises one or more selected from the group consisting of LiPF 6 , LiF 4 , LiCl, LiBr, LiI, LiClO 4 , LiB 10 Cl 10 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, and (CF 3 SO 2 ) 2 NLi.
  8. 8 . The electrolyte according to claim 3 , wherein the electrolyte comprises a metal phosphate compound.
  9. 9 . The electrolyte according to claim 8 , wherein the metal phosphate compound comprises one or more selected from the group consisting of lithium difluoro(bisoxalato) phosphate, lithium tetrafluoro oxalato phosphate, lithium difluorophosphate, and lithium trioxalato phosphate.
  10. 10 . A secondary battery comprising a negative electrode, a positive electrode, a separator interposed between the negative and positive electrodes, and an electrolyte, wherein the electrolyte is the electrolyte according to claim 3 .
  11. 11 . The secondary battery according to claim 10 , wherein the secondary battery has an HPPC charge resistance value of 500 mΩ or less at 25° C.
  12. 12 . The secondary battery according to claim 10 , wherein the secondary battery has a recovery capacity of 580 mAh or more at 45° C.
  13. 13 . The secondary battery according to claim 10 , wherein the secondary battery has a lifespan maintenance efficiency of 80% or more at 45° C.
  14. 14 . The secondary battery according to claim 10 , wherein the secondary battery is a battery for automobiles.

Description

This application is the National Stage Application of PCT/KR2021/008111, filed on Jun. 28, 2021, which claims priority to Korean Patent Application Nos. KR 10-2020-0078782, filed on Jun. 26, 2020, and KR 10-2021-0083962, filed on Jun. 28, 2021, both of which are incorporated by reference for all purposes as if fully set forth herein. TECHNICAL FIELD The present invention relates to an electrolyte additive, an electrolyte for batteries including the electrolyte additive, and a secondary battery including the electrolyte, and more particularly, to an electrolyte additive capable of improving the charging efficiency and output of batteries, enabling long-term storage, and increasing a capacity retention rate at high temperatures. BACKGROUND ART In a lithium secondary battery, an electrolyte between a positive electrode and a negative electrode enables smooth movement of lithium ions, and use of electric energy is promoted according to a method in which electricity is generated or consumed by oxidation-reduction reaction according to intercalation and desorption at the positive and negative electrodes. Recently, as interest in the environment increases worldwide, environmental regulations are being strengthened. Accordingly, interest in eco-friendly automobiles that can replace internal combustion engine automobiles, which are one of the main causes of air pollution, is also increasing. Accordingly, domestic and foreign battery industries are actively developing automobile batteries. To use a battery in an automobile, the output and capacity of the battery must be greatly increased, and problems such as a decrease in output and an increase in resistance at high and low temperatures must be solved in consideration of use environments such as severe weather. In addition, considering that automobiles are used outdoors regardless of the season, it is necessary to develop a large-capacity battery that can be charged in various environments and has an increased capacity retention rate. RELATED ART DOCUMENTS [Patent Documents] Jap 2008-300126 A KR 10-1586199 B1 DISCLOSURE Technical Problem Therefore, the present invention has been made in view of the above problems, and it is one object of the present invention to provide a novel electrolyte additive for batteries, an electrolyte for batteries including the electrolyte additive, and a secondary battery including the electrolyte. It is another object of the present invention to provide a secondary battery having improved battery output due to reduced charge resistance, capable of long-term storage due to improved recovery capacity at high temperatures, and having excellent lifespan maintenance at high temperatures. The above and other objects can be accomplished by the present invention described below. Technical Solution In accordance with one aspect of the present invention, provided is an electrolyte additive including a compound containing a substituent represented by Chemical Formula 1 below: wherein P and O are phosphorus and oxygen, respectively; A is a bond or oxygen; Q is oxygen or an unshared electron pair; R1, R2, R3, and R4 are each independently hydrogen, a linear or branched alkyl group having 1 to 10 carbon atoms, an alkenyl group, an alkynyl group, an alkoxy group, an alkoxycarbonyl group, an alkoxyalkyl group, a fluoroalkyl, or optionally, R1 or R2 is connected to R3 or R4 to form a double bond or a ring; n is an integer from 0 to 3; and * is a binding position. The ring may be preferably an aromatic or aliphatic ring, n may be preferably 1 or 2, and the fluoroalkyl may be preferably an alkyl substituted with 2 to 8 fluoro (F) groups. In accordance with another aspect of the present invention, provided is an electrolyte for batteries including the electrolyte additive and a secondary battery including the electrolyte. Advantageous Effects A secondary battery including an electrolyte additive according to the present invention has improved charging efficiency and output due to low charge resistance, can be stored for a long time, and has excellent capacity retention at high temperatures. BEST MODE Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto. The present inventors have studied a secondary battery having improved output and excellent recovery capacity and lifespan characteristics at high temperatures to manufacture an automobile battery. While conducting the above research, the present inventors confirmed that all of the above objects were achieved when an additive having a specific structure was added to an electrolyte of a secondary battery. Based on these results, the present inventors conducted further studies to complete the present invention. An electrolyte additive for batteries according to examples of the present invention includes a compound containing a substituent represented by Chemical Formula 1 below. In this case, the charging efficiency and output of a secondary battery