CN-122000464-A - Electrolyte and secondary battery

Abstract

The invention belongs to the technical field of power batteries, and particularly discloses electrolyte and a secondary battery. The electrolyte comprises electrolyte, a solvent and an additive, wherein the additive at least comprises a first additive, and the first additive is an amide organic compound shown in a chemical general formula (I): In the formula (I), R 1 is selected from any one of a hydrogen atom or a substituent group with 1-6 carbon atoms, 0-4 unsaturation degree and 0-3 hetero atoms, R 2 and R 3 are respectively selected from any one of a substituent group with 1-6 carbon atoms, 0-4 unsaturation degree and 0-3 hetero atoms, and the hetero atoms are selected from at least one of oxygen, nitrogen, sulfur or phosphorus. According to the invention, the novel additive is added into the electrolyte and then applied to the secondary battery, so that the high-low temperature performance and the like of the battery are improved, and the overall performance and the safety of the battery are improved.

Inventors

• YU LE
• MA CAIYU

Assignees

• 远景动力技术(江苏)有限公司
• 远景睿泰动力技术(上海)有限公司

Dates

Publication Date

20260508

Application Date

20241104

Claims (10)

1. 1. An electrolyte comprising an electrolyte, a solvent, and an additive, the additive comprising at least a first additive; the first additive is an amide organic compound with a chemical formula shown in formula (I): In the formula (I), R 1 is selected from any one of a hydrogen atom or a substituent group with the carbon number of 1-6, the unsaturation degree of 0-4 and the heteroatom number of 0-3; R 2 and R 3 are selected from any one of substituent groups with carbon atoms of 1-6, unsaturation degree of 0-4 and heteroatom number of 0-3 respectively; the heteroatom is selected from at least one of oxygen, nitrogen, sulfur or phosphorus.
2. 2. The electrolyte of claim 1, wherein the additive further comprises a first additive and the second additive is lithium difluorodioxalate phosphate.
3. 3. The electrolyte according to claim 1, wherein in the formula (I), R 1 、R 2 and R 3 are each selected from any one of alkyl, alkenyl, alkynyl, carbonyl, ester, alkoxy, amino, phospho-heterocyclic, furan, thiophene, pyrrole, thiazole, imidazole, pyridine, pyrazine, pyrimidine or pyridazine substituents.
4. 4. The electrolyte of claim 1, wherein the first additive is at least one selected from the group consisting of compound 1, compound 2, compound 3, compound 4, compound 5 and compound 6, The chemical structural formula of the compound 1 is The chemical structural formula of the compound 2 is The chemical structural formula of the compound 3 is The chemical structural formula of the compound 4 is The chemical structural formula of the compound 5 is The chemical structural formula of the compound 6 is
5. 5. The electrolyte according to claim 1, wherein the mass percentage of the first additive is 0.05% -3% based on the total mass of the electrolyte.
6. 6. The electrolyte according to claim 2, wherein the mass percentage of the second additive is 0.05% -1% based on the total mass of the electrolyte.
7. 7. The electrolyte of claim 1, wherein the electrolyte is a lithium salt selected from at least one of lithium hexafluorophosphate, lithium bis (trifluoromethane) sulfonyl imide, lithium acetate, lithium methylsulfonate, or lithium trifluoromethane sulfonate; And/or, based on the total mass of the electrolyte, the mass percentage of the electrolyte is 12% -16%.
8. 8. The electrolyte according to claim 1, wherein the solvent is at least one selected from the group consisting of carbonate solvents, carboxylate solvents, ether solvents and nitrile solvents; and/or, based on the total mass of the electrolyte, the mass percentage of the solvent is 70% -80%.
9. 9. The electrolyte according to any one of claims 1 to 8, wherein the additive further comprises a third additive selected from at least one of fluoroethylene carbonate, propenyl-1, 3-sultone or tetravinyl silane.
10. 10. A secondary battery comprising the electrolyte according to any one of claims 1 to 9.

Description

Electrolyte and secondary battery Technical Field The invention relates to the technical field of power batteries, in particular to an electrolyte and a secondary battery. Background In face of the worldwide rapid increase of the demands for electric automobile markets and portable electronic devices, the lithium ion battery technology is evolving at an unprecedented speed, and the improvement of the core competitiveness is particularly critical. In the construction of lithium ion batteries, the positive electrode material not only occupies more than half of the total mass and cost share, but also directly determines the energy density and cost control capability of the battery, and becomes a core element for promoting technological breakthroughs. Among the positive electrode material systems that are actively being explored, high-nickel positive electrode material LiNi xM1-xO2 (in which M represents a transition metal element such as Mn, co, al, etc.) stands out with its excellent potential, and is currently the most attractive research object. The material can realize energy density of 650Wh/kg to over 850Wh/kg, greatly meets the market demand for high endurance capacity, has remarkable cycle stability, can bear about 3000 charge and discharge cycles, and provides powerful guarantee for the long service life of the battery. However, widespread use of high nickel cathode materials is also accompanied by significant safety challenges, particularly their significant gassing problems. This problem is mainly caused by two complex side reactions, one of which is that lithium compounds (such as LiOH, liHCO 3、Li2CO3, etc.) remained on the surface of the positive electrode are decomposed under specific conditions or interact with the internal acidic environment of the battery, for example, transition metal ions are dissolved and diffused into the negative electrode to be reduced, so that internal short circuit is caused, the service life of the battery is greatly shortened, and even serious safety problems such as explosion of the battery are seriously restricted, so that the large-scale popularization of the high-nickel positive electrode material in commercial application is severely restricted. In addition, currently, lithium ion batteries generally use an electrolyte mainly composed of lithium hexafluorophosphate (LiPF 6) as an electrolyte salt, in combination with a mixed organic solvent composed of a cyclic carbonate and a chain carbonate. However, this electrolyte has some drawbacks in practical use. Particularly, if a large amount of gas is generated during the charge and discharge of the lithium battery, the contact area between the electrode and the electrolyte may be reduced, thereby reducing the charge and discharge efficiency of the battery. In addition, the presence of gas can interfere with electrochemical reactions within the cell, further reducing the energy density and power output of the cell, severely affecting the cycle life of the cell. Disclosure of Invention In view of the above-mentioned drawbacks of the prior art, the present invention aims to provide an electrolyte and a secondary battery, which can improve the high and low temperature performance of the battery, etc. by adding new additives into the electrolyte and then applying the additives to the secondary battery, thereby improving the overall performance and safety of the battery, solving the problem of gas production caused by the application of the high nickel positive electrode material, and further improving the commercial large-scale popularization prospect of the high nickel positive electrode material. To achieve the above and other related objects, the present invention provides an electrolyte comprising an electrolyte, a solvent, and an additive, the additive comprising at least a first additive; the first additive is an amide organic compound with a chemical formula shown in formula (I): In the formula (I), R 1 is selected from any one of a hydrogen atom or a substituent group with the carbon number of 1-6, the unsaturation degree of 0-4 and the heteroatom number of 0-3; R 2 and R 3 are selected from any one of substituent groups with carbon atoms of 1-6, unsaturation degree of 0-4 and heteroatom number of 0-3 respectively; the heteroatom is selected from at least one of oxygen, nitrogen, sulfur or phosphorus. Further, the additive also includes a first additive, and the second additive is lithium difluorodioxalate phosphate (Lithium difluorobis (oxyato) phosphate, liODFP). Further, in formula (I), R 1、R2 and R 3 are each selected from any one of alkyl, alkenyl, alkynyl, carbonyl, ester, alkoxy, amino, amine, phospho-heterocyclic, furan, thiophene, pyrrole, thiazole, imidazole, pyridine, pyrazine, pyrimidine, or pyridazine substituents. Further, the first additive is selected from at least one of compound 1, compound 2, compound 3, compound 4, compound 5 or compound 6, The chemical structural formula of the compound 1 is