Negative electrode material and electrochemical apparatus and electronic apparatus containing the negative electrode material
A negative electrode material of this application includes silicon-based particles, where the silicon-based particles include: a silicon oxide SiO x , where x is 0.5 to 1.6; and a carbon layer, where the carbon layer covers at least a portion of a surface of the silicon oxide SiO x . In a Raman spectrum, a ratio of a height I 1350 of the silicon-based particles at a peak of 1350 cm −1 to a height I 1580 at a peak of 1580 cm −1 satisfies 0<I 1350 /I 1580 <5, and a ratio of a height I 510 at a peak of 510 cm −1 to the height I 1350 at the peak of 1350 cm −1 satisfies 0<I 510 /I 1350 <12. A lithium ion battery prepared from the negative electrode active material has improved first efficiency, cycling performance, and rate performance.
1. A negative electrode material, wherein the negative electrode material comprises silicon-based particles, and the silicon-based particles comprise:
a silicon oxide SiO x , wherein x is 0.5 to 1.6; and
a carbon layer, wherein the carbon layer covers at least a portion of a surface of the silicon oxide SiO x ;
wherein in a Raman spectrum, a ratio of a height I 1350 of the silicon-based particles at a peak of 1350 cm −1 to a height I 1580 at a peak of 1580 cm −1 is 0<I 1350 /I 1580 <5; and
a ratio of a height I 510 at a peak of 510 cm −1 to the height I 1350 at the peak of 1350 cm −1 is 2.3<I 510 /I 1350 <12.
2. The negative electrode material according to claim 1 , wherein the silicon oxide SiO x comprises SiO, SiO 2 , nano-Si grains, or any combination thereof.
3. The negative electrode material according to claim 1 , wherein a specific surface area of the silicon-based particles is 2.5 m 2 /g to 15 m 2 /g.
4. The negative electrode material according to claim 1 , wherein a thickness of the carbon layer is 3 nm to 40 nm.
5. The negative electrode material according to claim 1 , wherein an average particle size of the silicon-based particles is 500 nm to 30 μm.
6. A negative electrode, wherein the negative electrode comprises a current collector and a coating on the current collector, and the coating comprises silicon-based particles;
wherein the silicon-based particles comprise:
a silicon oxide SiO x , wherein x is 0.5 to 1.5;
wherein the silicon-based particles further comprise a carbon layer, wherein the carbon layer covers at least a portion of a surface of the silicon oxide SiO x ; and
wherein in a Raman spectrum, a ratio of a height I 510 at a peak of 510 cm −1 to the height I 1350 at the peak of 1350 cm −1 is 2.3<I 510 /I 1350 <12.
7. The negative electrode according to claim 6 , wherein in the Raman spectrum, a ratio of a height I 1350 of the silicon-based particles at a peak of 1350 cm −1 to a height I 1580 at a peak of 1580 cm −1 is 0<I 1350 /I 1580 <5.
8. The negative electrode according to claim 6 , wherein the current collector comprises copper, aluminum, nickel, copper alloy, aluminum alloy, nickel alloy, or any combination thereof.
9. The negative electrode according to claim 6 , wherein an X-ray diffraction pattern of the coating comprises a [004] diffraction pattern and a [110] diffraction pattern, a ratio of a c-axis length C004 of a unit cell length acquired from the [004] diffraction pattern to an a-axis length C110 of a unit cell length acquired from the [110] diffraction pattern, C004/C110, is an orientation index (OI) value of the coating, and the OI value is 7.5<OI<18.
10. The negative electrode according to claim 6 , wherein a specific surface area of the silicon-based particles is 2.5 m 2 /g to 15 m 2 /g.
11. The negative electrode according to claim 6 , wherein the coating further comprises a binder, wherein the binder comprises polyacrylate, polyimide, polyamide, polyamide imide, polyvinylidene fluoride, styrene butadiene rubber, sodium alginate, polyvinyl alcohol, polytetrafluoroethylene, polyacrylonitrile, sodium carboxymethyl cellulose, potassium carboxymethyl cellulose, or any combination thereof.
12. The negative electrode according to claim 6 , wherein a peeling strength between the coating and the current collector is greater than or equal to 20 N/m.
13. The negative electrode according to claim 6 , wherein the coating further comprises graphite particles, wherein
a percentage of a quantity of silicon-based particles adjacent to the graphite particles in a total quantity of the silicon-based particles is greater than or equal to 40%; and
a distance between the silicon-based particles and the adjacent graphite particles is less than or equal to 500 nm.
14. The negative electrode according to claim 13 , wherein a weight ratio of the silicon-based particles to the graphite particles is 0.07 to 0.7.
15. The negative electrode according to claim 13 , wherein a thickness of the carbon layer is 3 nm to 40 nm.
16. The negative electrode according to claim 13 , wherein an X-ray diffraction pattern of the coating comprises a [004] diffraction pattern and a [110] diffraction pattern, a ratio of a c-axis length C004 of a unit cell length acquired from the [004] diffraction pattern to an a-axis length C110 of a unit cell length acquired from the [110] diffraction pattern, C004/C110, is an orientation index (OI) value of the carbon coating, and the OI value is 7.5<OI<18.
17. The negative electrode according to claim 13 , wherein, in the Raman spectrum, a ratio of a height I 1350 of the silicon-based particles at a peak of 1350 cm −1 to a height I 1580 at a peak of 1580 cm −1 is 0<I 1350 /I 1580 <5.
18. A method of preparing the negative electrode material according to claim 1 , wherein the method comprises:
heating the silicon oxide SiO x to 200° C. to 1500° C. in an inert gas atmosphere;
injecting a carbon source gas and heating the gas at 200° C. to 1500° C. for 30 min to 120 min to acquire solids; and
pulverizing and sieving the solids.