Negative electrode active material, and electrochemical apparatus and electronic apparatus using the same
A negative electrode active material includes a carbon material, where the carbon material has a specific degree of graphitization and aspect ratio distribution. A degree of graphitization Gr of the carbon material measured by an X-ray diffraction analysis method is 0.82 to 0.92, and based on a total quantity of particles of the carbon material, a proportion of particles with an aspect ratio greater than 3.3 in the carbon material is less than 10%. The negative electrode active material helps to improve cycle performance of the electrochemical apparatus. FIG. 1.
1 . A negative electrode active material comprising: a carbon material; wherein a degree of graphitization Gr of the carbon material measured by an X-ray diffraction analysis method is 0.82 to 0.92; and based on a total quantity of particles of the carbon material, a proportion of particles with an aspect ratio greater than 3.3 in the carbon material is greater than 1% and less than 10%; and
based on the total quantity of the particles of the carbon material, a proportion of particles with an aspect ratio greater than 2 in the carbon material is greater than 30% and less than 50%.
2 . The negative electrode active material according to claim 1 , wherein, based on the total quantity of the particles of the carbon material, a proportion of particles with an aspect ratio greater than 1.5 in the carbon material is less than 80%.
3 . The negative electrode active material according to claim 1 , wherein, a ratio of a crystal grain size La of a crystal grain of the carbon material along a horizontal axis measured by the X-ray diffraction analysis method to a crystal grain size Lc of a crystal grain of the carbon material along a vertical axis measured by the X-ray diffraction analysis method is K, and 4.0≤K×Gr≤5.2.
4 . The negative electrode active material according to claim 1 , wherein, a particle size of the negative electrode active material satisfies the following relationship: 35 μm<Dv99−Dv10<50 μm.
5 . The negative electrode active material according to claim 1 , wherein, the negative electrode active material satisfies at least one of conditions (a) to (d):
(a) based on the total quantity of particles of the carbon material, a proportion of particles with an aspect ratio greater than 3.3 in the carbon material is 3% to 8%;
(b) a ratio of a crystal grain size La of a crystal grain of the carbon material along a horizontal axis measured by the X-ray diffraction analysis method to a crystal grain size Lc of a crystal grain of the carbon material along a vertical axis measured in the X-ray diffraction analysis method is K, and 4.2≤K×Gr≤5.0;
(c) based on the total quantity of the particles of the carbon material, the proportion of particles with an aspect ratio greater than 2 in the carbon material is less than 30% and less than 40%, and a proportion of particles with an aspect ratio greater than 1.5 in the carbon material is less than 70%;
(d) a particle size of the negative electrode active material satisfies the following relationship: 42 μm<Dv99−Dv10<48 μm.
6 . The negative electrode active material according to claim 1 , wherein, an interplanar spacing d002 of the negative electrode active material measured by the X-ray diffraction analysis method satisfies d002≥0.3365 nm.
7 . The negative electrode active material according to claim 1 , wherein, a ratio of a peak area C004 of a crystal plane (004) to a peak area C110 of a crystal plane (110) of the negative electrode active material measured by the X-ray diffraction analysis method satisfies C004/C110≤8.
8 . The negative electrode active material according to claim 1 , wherein, a gram capacity C mAh/g of the negative electrode active material and the degree of graphitization Gr of the carbon material satisfy the following relationships: 390Gr−C≤20, and C≤350.
9 . An electrochemical apparatus, comprising a positive electrode, an electrolyte solution and a negative electrode; the negative electrode comprising a negative electrode active material layer and a negative electrode current collector, wherein the negative electrode active material layer comprises the negative electrode active material;
the negative electrode active material comprises a carbon material, wherein a degree of graphitization Gr of the carbon material measured by an X-ray diffraction analysis method is 0.82 to 0.92; and based on a total quantity of particles of the carbon material, a proportion of particles with an aspect ratio greater than 3.3 in the carbon material is greater than 1% and less than 10%; and
based on the total quantity of the particles of the carbon material, a proportion of particles with an aspect ratio greater than 2 in the carbon material is greater than 30% and less than 50%.
10 . The electrochemical apparatus according to claim 9 , wherein, based on the total quantity of the particles of the carbon material, a proportion of particles with an aspect ratio greater than 1.5 in the carbon material is less than 80%.
11 . The electrochemical apparatus according to claim 9 , wherein, a ratio of a crystal grain size La of a crystal grain of the carbon material along a horizontal axis measured by the X-ray diffraction analysis method to a crystal grain size Lc of a crystal grain of the carbon material along a vertical axis measured by the X-ray diffraction analysis method is K, and 4.0≤K×Gr≤5.2.
12 . The electrochemical apparatus according to claim 9 , wherein, a particle size of the negative electrode active material satisfies the following relationship: 35 μm<Dv99−Dv10<50 μm.
13 . The electrochemical apparatus according to claim 9 , wherein, an interplanar spacing d002 of the negative electrode active material measured by the X-ray diffraction analysis method satisfies d002≥0.3365 nm.
14 . The electrochemical apparatus according to claim 9 , wherein, a ratio of a peak area C004 of a crystal plane (004) to a peak area C110 of a crystal plane (110) of the negative electrode active material that is measured in by the X-ray diffraction analysis method satisfies C004/C110≤8.
15 . The electrochemical apparatus according to claim 9 , wherein, a compacted density PD g/cm 3 of the negative electrode active material layer and the degree of graphitization Gr of the carbon material satisfy the following relationships: PD≤2.5Gr−0.45≤1.85, and PD is 1.45 to 1.75.
16 . The electrochemical apparatus according to claim 9 , wherein, a ratio C004′/C110′ of a peak area C004′ of a plane (004) to a peak area C110′ of a plane (110) of the negative electrode active material layer that is measured in the X-ray diffraction analysis method is 7 to 18.
17 . The electrochemical apparatus according to claim 9 , wherein, a ratio Id/Ig of a peak intensity Id of the negative electrode active material layer at 1340 cm −1 to 1380 cm −1 to a peak intensity Ig of the negative electrode active material layer at 1560 cm −1 to 1600 cm −1 measured in a Raman spectroscopy method is 0.2 to 0.5.
18 . An electronic apparatus, comprising an electrochemical apparatus; the electrochemical apparatus comprising a positive electrode, a negative electrode, a separator and an electrolyte solution; the negative electrode comprising a negative electrode current collector and a negative electrode active material layer, wherein the negative electrode active material layer comprises a negative electrode active material;
the negative electrode active material comprises a carbon material, wherein a degree of graphitization Gr of the carbon material measured by an X-ray diffraction analysis method is 0.82 to 0.92, and based on a total quantity of particles of the carbon material, a proportion of particles with an aspect ratio greater than 3.3 in the carbon material is greater than 1% and less than 10%; and
based on the total quantity of the particles of the carbon material, a proportion of particles with an aspect ratio greater than 2 in the carbon material is greater than 30% and less than 50%.
19 . The negative electrode active material according to claim 1 , wherein, based on the total quantity of particles of the carbon material, the proportion of particles with an aspect ratio greater than 3.3 in the carbon material is 3% to 8%.
20 . The negative electrode active material according to claim 1 , wherein a negative electrode active material layer formed from the negative electrode active material has a compacted density of 1.45 to 1.75 g/cm 3 .