Lithium secondary battery
By adding specific oligomeric additives to the non-aqueous electrolyte of lithium secondary batteries, the problem of lithium salt anion instability caused by Fe elution of lithium iron phosphate particles is solved, and the high-temperature cycling and high-temperature storage performance of lithium secondary batteries is significantly improved.
Patent Information
- Application Number
- CN202380074204.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-11-04
- Filing Date
- 2023-11-03
- Publication Date
- 2025-05-30
AI Technical Summary
In lithium secondary batteries, Fe elution of lithium iron phosphate particles leads to instability of lithium salt anions, affecting high-temperature cycling and high-temperature storage performance.
A specific repeating unit is added as an additive to the nonaqueous electrolyte of the lithium secondary battery, including oligomers containing acrylate cyanide functional groups and terminal lactam groups, to chelate Fe ions and form a complex with lithium salt anions, and stabilize the pyrolytic product of the lithium salt.
It effectively suppresses the elution of Fe ions and the instability of lithium salt anions, and improves the high-temperature storage and high-temperature cycling performance of lithium secondary batteries.
Smart Images
Figure BDA0005367432250000021 
Figure BDA0005367432250000031 
Figure BDA0005367432250000032
Abstract
Claims
1. A lithium secondary battery, comprising: a positive electrode; a negative electrode; a separator; and a non-aqueous electrolyte, wherein, the positive electrode contains a positive electrode active material, and the positive electrode active material contains lithium iron phosphate particles, the non-aqueous electrolyte contains a lithium salt, an organic solvent, and an additive, the additive includes an oligomer containing a repeating unit derived from a monomer represented by Formula 1, a repeating unit derived from a monomer represented by Formula 2, and a repeating unit derived from a monomer represented by Formula 3, and the weight-average molecular weight Mw of the oligomer is from 5000 g / mol to 25000 g / mol; [Formula 1] Among them, in Formula 1, R 1 is hydrogen or an alkyl group having 1 to 3 carbon atoms, and R 2 is an alkyl group having 1 to 20 carbon atoms. [Formula 2] Among them, in Formula 2, R 3 is hydrogen or an alkyl group having 1 to 3 carbon atoms, and R 4 and R 5 are each independently an alkylene group having 1 to 10 carbon atoms; [Formula 3] Among them, in Formula 3, R 6 is hydrogen or an alkyl group having 1 to 3 carbon atoms, and R 7 is an alkylene group having 1 to 10 carbon atoms.
2. The lithium secondary battery according to claim 1, wherein, In the above formula 1, R 1 is hydrogen or an alkyl group having 1 to 10 carbon atoms, In the above formula 2, R 4 and R 5 each independently represents an alkylene group having 1 to 7 carbon atoms, In formula 3 above, R 7 is an alkylene group having 1 to 7 carbon atoms.
3. The lithium secondary battery according to claim 1, wherein, In Formula 1 above, R 1 is hydrogen or an alkyl group having 1 to 7 carbon atoms, In Formula 2 above, R 4 and R 5 each independently represents an alkylene group having 1 to 5 carbon atoms, In Formula 3 above, R 7 is an alkylene group having 1 to 5 carbon atoms.
4. The lithium secondary battery according to claim 1, wherein, the oligomer is an oligomer represented by Formula 4: [Formula 4] wherein, in Formula 4, R 1 、R 3 and R 6 each independently represents hydrogen or an alkyl group having 1 to 3 carbon atoms, R 2 is an alkyl group having 1 to 20 carbon atoms, R 4 、R 5 and R 7 each independently represents an alkylene group having 1 to 10 carbon atoms, m is a molar number from 0.1 to 30, n is a molar number from 0.1 to 80, o is a molar number from 0.1 to 80.
5. The lithium secondary battery according to claim 1, wherein, the oligomer is at least one selected from the group consisting of oligomers represented by Formula 4-1 and Formula 4-2: [Formula 4-1] wherein, in Formula 4-1, m1 is a molar number from 0.1 to 30, n1 is a molar number from 0.1 to 80, o1 is a molar number from 0.1 to 80, [Formula 4-2] wherein, in Formula 4-2, m2 is a molar number from 0.1 to 30, n2 is a molar number from 0.1 to 80, o2 is a molar number from 0.1 to 80.
6. The lithium secondary battery according to claim 1, wherein, in the non-aqueous electrolyte, the content of the oligomer is from 0.1 wt% to 25 wt%.
7. The lithium secondary battery according to claim 1, wherein, the additive includes at least one additional additive selected from the group consisting of: halogen-substituted or unsubstituted carbonate compounds, sultone compounds, sulfate / salt compounds, phosphate / salt compounds, or phosphite / salt compounds, borate / salt compounds, nitrile compounds, amine compounds, silane compounds, and lithium salt compounds.
8. The lithium secondary battery according to claim 1, wherein, the organic solvent includes a cyclic carbonate organic solvent and a linear carbonate organic solvent.
9. The lithium secondary battery according to claim 8, wherein, the cyclic carbonate organic solvent includes ethylene carbonate, and the linear carbonate organic solvent includes ethyl methyl carbonate and dimethyl carbonate.
10. The lithium secondary battery according to claim 1, wherein, the lithium iron phosphate particles include a compound represented by Formula A: [Formula A] Li 1+a Fe 1-s M s (PO 4-b )X b wherein, in the above Formula A, M is at least one element selected from Co, Ni, Al, Mg, Ti, and V; X is F, S, or N; 0 ≤ s ≤ 0.5; -0.5 ≤ a ≤ 0.5; 0 ≤ b ≤ 0.
1.
11. The lithium secondary battery according to claim 1, wherein, the positive electrode active material further includes a carbon coating located on the lithium iron phosphate particles.
Citation Information
Patent Citations
Nanoparticles for modulating expression of target genes and / or signal transduction pathways
KR1020220146437A