Negative electrode material, negative electrode plate and electrochemical device containing same, and electronic device
A negative electrode material includes silicon-based particles and graphite particles. In a case that a D n50 /D v50 ratio of the graphite particles is A and a D n50 /D v50 ratio of the silicon-based particles is B, the following conditional expressions (1) to (3) are satisfied: 0.1≤A≤0.65 (1); 0.3≤B≤0.85 (2); and B>A (3), where, D v50 is a particle diameter of particles measured when a cumulative volume fraction in a volume-based distribution reaches 50%, and D n50 is a particle diameter of particles measured when a cumulative number fraction in a number-based distribution reaches 50%. The present invention further provides a negative electrode plate, a lithium-ion secondary battery or electrochemical device containing the negative electrode plate, and an electronic device containing the lithium-ion secondary battery and/or electrochemical device.
1 . A negative electrode material, wherein the negative electrode material contains silicon-based particles and graphite particles; wherein,
0.1≤A≤0.65, wherein A is a D n50 /D v50 ratio of the graphite particles;
0.3≤B≤0.85, wherein B is a D n50 /D v50 ratio of the silicon-based particles; and
B>A;
wherein, D v50 is a particle diameter of particles measured when a cumulative volume fraction in a volume-based distribution reaches 50%; and D n50 is a particle diameter of particles measured when a cumulative number fraction in a number-based distribution reaches 50%; and
in an X-ray diffractogram of the silicon-based particles, a maximum intensity value when 2θ falls within a range of 20.5° to 21.5° is I1 and a maximum intensity value when 2θ falls within a range of 28.0° to 29.0° is I2, and I2/I1 is less than or equal to 1.
2 . The negative electrode material according to claim 1 , wherein
0.1 ≤D−C ≤0.3;
C is an average sphericity of the graphite particles and D is an average sphericity of the silicon-based particles.
3 . The negative electrode material according to claim 1 , wherein an average sphericity D of the silicon-based particles is greater than or equal to 0.8.
4 . The negative electrode material according to claim 1 , wherein an average sphericity C of the graphite particles falls between 0.55 and 0.75.
5 . The negative electrode material according to claim 1 , wherein a general formula of the silicon-based particles is SiO x C y M z (I), wherein 0≤x≤2, 0≤y≤1, 0≤z≤0.5, and M comprises at least one of lithium, magnesium, titanium, or aluminum;
a coating is provided on a surface of the silicon-based particles, a thickness of the coating is 0.5 to 50 nm, and a mass of the coating is 0.1% to 10% of a total mass of the silicon-based particles, wherein the coating is a carbon coating, a polymer coating or a composited coating of carbon and polymer;
a particle diameter range of the silicon-based particles is 0.01 to 50 μm, and a specific surface area of the silicon-based particles is 0.1 to 50 m 2 /g.
6 . The negative electrode material according to claim 1 , wherein the graphite particles comprise a secondary particle, and a weight percent of the secondary particle is at least 70 wt % of a total weight of the graphite particles;
a carbon coating, a polymer coating, or a composite coating of carbon and polymer is provided on a surface of the graphite particles;
in a Raman scattering peak of the graphite particles, a peak intensity at 1330 cm −1 is I 1330 and a peak intensity at 1580 cm −1 is I 1580 , wherein
0.05 ≤I 1330 /I 1580 ≤0.9; and
in an X-ray diffraction peak of the graphite particles, a peak intensity ratio between a (004) peak and a (110) peak is an orientation index (OI) value, and
1≤orientation index (OI) value≤30 (6).
7 . The negative electrode material according to claim 5 , wherein the carbon coating comprises at least one of amorphous carbon, carbon nanotubes, carbon nanoparticles, vapor grown carbon fibers, or graphene; and the polymer coating is formed by at least one of polyvinylidene difluoride or a derivative thereof, carboxymethyl cellulose or a derivative thereof, polyvinylpyrrolidone or a derivative thereof, polyacrylic acid or a derivative thereof, or polystyrene butadiene rubber.
8 . The negative electrode material according to claim 6 , wherein the carbon coating comprises at least one of amorphous carbon, carbon nanotubes, carbon nanoparticles, vapor grown carbon fibers, or graphene; and the polymer coating is formed by at least one of polyvinylidene difluoride or a derivative thereof, carboxymethyl cellulose or a derivative thereof, polyvinylpyrrolidone or a derivative thereof, polyacrylic acid or a derivative thereof, or polystyrene butadiene rubber.
9 . The negative electrode material according to claim 1 , wherein an average sphericity D of the silicon-based particles is greater than or equal to 0.9.
10 . The negative electrode material according to claim 1 , wherein an average sphericity C of the graphite particles falls between 0.55 and 0.6.
11 . The negative electrode material according to claim 1 , wherein an average sphericity C of the graphite particles falls between 0.6 and 0.75.
12 . An electrochemical device, comprising a negative electrode material, wherein the negative electrode material contains silicon-based particles and graphite particles, and, a D n50 /D v50 ratio of the graphite particles is A and a D n50 /D v50 ratio of the silicon-based particles is B, wherein:
0.1≤A≤0.65;
0.3≤B≤0.85; and
B>A,
wherein, D v50 is a particle diameter of particles measured when a cumulative volume fraction in a volume-based distribution reaches 50%; and D n50 is a particle diameter of particles measured when a cumulative number fraction in a number-based distribution reaches 50%; and
in an X-ray diffractogram of the silicon-based particles, a maximum intensity value when 2θ falls within a range of 20.5° to 21.5° is I1 and a maximum intensity value when 2θ falls within a range of 28.0° to 29.0° is I2, and I2/I1 is less than or equal to 1.
13 . The electrochemical device according to claim 12 , wherein an average sphericity D of the silicon-based particles is greater than or equal to 0.9.
14 . The electrochemical device according to claim 12 , wherein an average sphericity C of the graphite particles falls between 0.55 and 0.6.
15 . The electrochemical device according to claim 12 , wherein an average sphericity C of the graphite particles falls between 0.6 and 0.75.
16 . An electronic device, comprising the electrochemical device according to claim 12 .
17 . The negative electrode material according to claim 5 , wherein the specific surface area of the silicon-based particles is 0.1 to 5 m 2 /g.
18 . The negative electrode material according to claim 1 , wherein I2/I1 is less than or equal to 0.64.
19 . The negative electrode material according to claim 1 , wherein an average particle diameter of the silicon-based particles is smaller than an average particle diameter of the graphite particles.
20 . The electrochemical device according to claim 12 , wherein an average particle diameter of the silicon-based particles is smaller than an average particle diameter of the graphite particles.