Negative electrode and secondary battery
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- LG ENERGY SOLUTION LTD
- Filing Date
- 2023-10-10
- Publication Date
- 2026-06-09
AI Technical Summary
【0010】 本明細書に記載の実施態様によれば、負極活物質層の2層構造において2層の空隙率が異なるように調整することにより、急速充填性能を向上させることができる。具体的には、空隙率が高いほど急速充填には有利となるが、上層(第2負極活物質層)の空隙率が下層(第1負極活物質層)に比べて高いと、全体的な空隙率は同じながらも、電解質に近い部分の空隙率が高い効果を示すこととなり、改善された急速充填効果を有することができる。
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Abstract
Claims
1. Current collector and, A first negative electrode active material layer provided on the current collector, The present invention includes a second negative electrode active material layer provided on the first negative electrode active material layer, The porosity of the second negative electrode active material layer is 5% to 20% greater than that of the first negative electrode active material layer. The first negative electrode active material layer and the second negative electrode active material layer each contain a negative electrode active material, the negative electrode active material includes a silicon-based active material, artificial graphite, and natural graphite, and the silicon-based active material includes at least one of SiO x (0 ≤ x < 2), SiM y (M is a metal, 1 ≤ y ≤ 4), and Si / C, a negative electrode for a secondary battery.
2. The negative electrode for a secondary battery according to claim 1, wherein the porosity of the second negative electrode active material layer is 10% to 20% greater than that of the first negative electrode active material layer.
3. The negative electrode for a secondary battery according to claim 1, wherein the porosity of the first negative electrode active material layer and the porosity of the second negative electrode active material layer are each 15% to 40%.
4. The silicon-based active material is included in an amount of 1 to 40 parts by weight, based on 100 parts by weight of the total amount of active material contained in the first negative electrode active material layer and the second negative electrode active material layer, respectively, as described in claim 1.
5. The negative electrode for a secondary battery according to claim 1, wherein the first negative electrode active material layer and the second negative electrode active material layer include a conductive material, and the conductive material includes at least one of a point conductive material, a linear conductive material, and a planar conductive material.
6. The negative electrode for a secondary battery according to claim 5, wherein the conductive material is included in an amount of 0.1 to 5 parts by weight, based on 100 parts by weight of each of the first negative electrode active material layer and the second negative electrode active material layer.
7. The negative electrode for a secondary battery according to claim 1, wherein the silicon-based active material comprises silicon-based composite particles including SiO₂x (0 < x < 2) and pores.
8. The negative electrode for a secondary battery according to claim 7, wherein the silicon-based composite particles further comprise at least one of an Mg compound and a Li compound.
9. The negative electrode for a secondary battery according to claim 7, wherein a carbon layer is provided on the surface and / or inside the pores of the silicon-based composite particle.
10. The negative electrode for a secondary battery according to Claim 1, wherein the average particle size of the silicon-based active material is 2 μm to 15 μm.
11. A secondary battery comprising a negative electrode, a positive electrode, and a separator membrane according to any one of claims 1 to 10.
12. The secondary battery according to claim 11, wherein the positive electrode contains a lithium composite transition metal compound containing nickel (Ni) and cobalt (Co) as an active material.
13. The secondary battery according to claim 12, wherein the lithium composite transition metal compound further comprises at least one of manganese and aluminum.
14. A method for manufacturing a negative electrode for a secondary battery according to any one of claims 1 to 10, The process involves coating a current collector with a first composition containing a negative electrode active material and a conductive material, and rolling it to form a first negative electrode active material layer. A manufacturing method comprising the steps of coating a second composition containing a negative electrode active material and a conductive material onto the first negative electrode active material layer, rolling the mixture, and forming a second negative electrode active material layer having a void ratio 5% to 20% greater than that of the first negative electrode active material layer.