An antimony-containing negative electrode active material, a preparation method thereof, and a lithium ion battery

Abstract

According to a first aspect of the present invention, there is provided an antimony-containing negative electrode active material: the antimony-containing negative electrode active material includes graphite and an antimony-carbon composite material, and the antimony-carbon composite material includes a metallic antimony core and a carbon coating layer; in the Raman spectrum of the antimony-containing negative electrode active material, I D / I G = 0.52 to 1.54; in the X-ray diffraction pattern of the antimony-containing negative electrode active material, C 110 / C 002 = 0.043 to 0.085. The antimony-containing negative electrode active material provided by the present invention has excellent cycle stability and a relatively high plateau voltage. The carbon coating layer included in the above-mentioned antimony-carbon composite material can provide reliable protection for the metallic antimony core and can improve the conductivity of the antimony-based negative electrode material. Among them, the graphite contained in the antimony-containing negative electrode active material can be used as a support for the antimony-carbon composite material, further improving the conductivity and lithium storage performance of the antimony-based negative electrode material.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium-ion batteries, and specifically relates to an antimony-containing negative electrode active material, a preparation method thereof, and a lithium-ion battery. Background Art

[0002] Rechargeable lithium-ion batteries have been widely used in power batteries, 3C batteries, and energy storage fields due to their advantages such as high working voltage, high energy density, light weight, long cycle life, and environmental friendliness. Products such as new energy vehicles and mobile phones have higher requirements for the capacity of lithium batteries, which requires accelerating the application of high-capacity negative electrode materials. As a traditional negative electrode material, graphite has good cycle stability and rate performance, but its theoretical capacity is only 372 mAh / g, and the current capacity of graphite negative electrodes has approached its theoretical capacity, making it difficult to meet the market demand for high-capacity lithium-ion batteries. In order to increase the battery density, new negative electrode materials need to be developed.

[0003] In recent years, antimony-based materials have shown great potential as negative electrode materials for lithium-ion batteries. Antimony has a theoretical capacity of 660 mAh / g, is rich in reserves, and has a low discharge voltage, making it a potential negative electrode material for lithium-ion batteries. Although the capacity of antimony is higher than that of graphite, during the charge and discharge process, the antimony negative electrode will undergo alloying and dealloying reactions, facing a huge volume expansion (290%) problem while obtaining high capacity. The huge volume expansion leads to the fragmentation and pulverization of the electrode material, causing the rapid attenuation of the battery's cycle performance. Summary of the Invention

[0004] In order to improve the structural stability of a lithium-ion battery using an antimony-based negative electrode active material during cyclic charge and discharge, the present invention provides an antimony-containing negative electrode active material, a preparation method thereof, and a lithium-ion battery.

[0005] According to the first aspect of the present invention, an antimony-containing negative electrode active material is provided: the antimony-containing negative electrode active material includes graphite and an antimony-carbon composite material, and the antimony-carbon composite material includes a metallic antimony core and a carbon coating layer; in the Raman spectrum of the antimony-containing negative electrode active material, the peak intensity I D of the D peak and the peak intensity I G of the G peak, the ratio I D / I G = 0.52 to 1.54; in the X-ray diffraction pattern of the antimony-containing negative electrode active material, the peak intensity C 110 of the (110) plane characteristic peak and the peak intensity C 002 of the (002) plane characteristic peak, the ratio C 110 / C 002 = 0.043 to 0.085.

[0006] Preferably, in the Raman spectrum of the antimony-containing negative electrode active material, the peak intensity ID and the peak intensity I of the G peak G The ratio I D / I G ≥ 1.

[0007] Preferably, in the X-ray diffraction pattern of the antimony-containing negative electrode active material, the peak intensity C of the (110) plane characteristic peak 110 and the peak intensity C of the (002) plane characteristic peak 002 The ratio C 110 / C 002 = 0.05 to 0.065.

[0008] Preferably, in the antimony-containing carbon composite material, the mass of metallic antimony: the mass of the carbon coating layer = 0.4 to 2.5: 0.4 to 4.

[0009] Preferably, in the antimony-containing negative electrode active material, the mass of metallic antimony: the mass of graphite = 4 to 26: 5 to 50.

[0010] Preferably, the D of the antimony-containing negative electrode active material 90 = 8 to 10 μm, and the D of the antimony-containing negative electrode active material 10 = 0.5 to 1.5 μm.

[0011] Preferably, the D of the antimony-containing negative electrode active material 50 = 2.5 to 5 μm.

[0012] Preferably, the specific surface area of the antimony-containing negative electrode active material is 1.5 to 4.5 m 2 / g.

[0013] The antimony-containing negative electrode active material provided by the present invention has excellent cycle stability and a relatively high plateau voltage. A large amount of amorphous carbon is contained in the carbon coating layer included in the above-mentioned antimony-carbon composite material, so that the carbon coating layer can form a uniform and dense coating layer on the surface of the metallic antimony core. It is not easy to break and is not easy to fall off from the surface of the metallic antimony core, and can provide reliable protection for the metallic antimony core. Thus, it can effectively separate the metallic antimony from the electrolyte, thereby reducing the interfacial side reactions between the metallic antimony and the electrolyte, inhibiting the volume expansion of the metallic antimony during the cyclic charge and discharge process, and avoiding the rupture of the SEI film caused by the expansion of the metallic antimony. At the same time, the close contact between the carbon coating layer and the metallic antimony can improve the conductivity of the antimony-based negative electrode material. Among them, the graphite contained in the antimony-containing negative electrode active material of the present invention can be used as the carrier of the antimony-carbon composite material. The gaps formed between the graphite can provide a buffer space for the expansion stress generated by the expansion of the antimony-based material, so as to avoid obvious deformation of the negative electrode sheet using the antimony-carbon composite material, thereby further strengthening the structural stability of the negative electrode sheet using the antimony-based negative electrode material. Moreover, the three-dimensional framework constructed by the graphite has excellent conductivity. Using it as the load of the antimony-carbon composite material can further improve the conductivity and lithium storage performance of the antimony-based negative electrode material.

[0014] According to the second aspect of the present invention, there is provided a preparation method of the antimony-containing negative electrode active material as described above, including the following operations: S1. Pulping with an antimony source, an organic carbon source, graphite, and a solvent to obtain a reaction slurry; S2. Completely volatilize the solvent in the reaction slurry, and grind the remaining dried material to obtain a precursor; S3. Place the precursor into a reaction system provided with a reducing agent, and then raise the temperature of the reaction system to 500-1000 °C so that: the antimony source is converted into metallic antimony under the action of the reducing agent, and the organic carbon source undergoes a pyrolysis reaction to form a carbon coating layer on the surface of the metallic antimony.

[0015] Preferably, in S1, the particle size of the antimony source used is 100-200 nm.

[0016] Preferably, in S1, the organic carbon source used includes at least one of glucose, asphalt, polyvinyl alcohol, polyacrylic acid, and polybutyl acrylate.

[0017] Preferably, in S1, the particle size D of the graphite used 50 = 5-20 μm.

[0018] Preferably, in S1, the solvent used includes at least one of water, ethanol, methanol, toluene, and tetrahydrofuran.

[0019] Preferably, in the heating operation involved in S3, the heating rate of the reaction system is 1-10 °C / min.

[0020] Preferably, in S3, the temperature of the reaction system is raised to 500-1000 °C and then held for 2-10 hours.

[0021] According to the third aspect of the present invention, a lithium-ion battery is provided, including a negative electrode, and the negative electrode active material layer of the negative electrode includes the antimony-containing negative electrode active material as described above. Description of the Drawings

[0022] Figure 1 It is the Raman spectrum diagram measured corresponding to the antimony-containing negative electrode active material prepared in Example 1;

[0023] Figure 2 It is the X-ray diffraction spectrum measured corresponding to the antimony-containing negative electrode active material prepared in Example 1. Detailed Embodiments

[0024] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0025] Example 1

[0026] The raw materials used in this example include: antimony source, antimony trioxide, spherical, D 50 = 100 nm; dispersant, polyvinylpyrrolidone; organic carbon source, glucose; graphite, flaky, D 50 = 5 μm; solvent, water. The above raw materials are specifically used to prepare the antimony-containing negative electrode active material according to the following operations:

[0027] S1. Weigh the raw materials according to the mass ratio of antimony trioxide: polyvinylpyrrolidone: glucose: graphite: solvent water = 1:1:6:1:100, mix the weighed raw materials, and use ultrasonic dispersion for 30 min, while providing high-speed stirring during this period, and the stirring speed is 100 r / min to obtain a uniform reaction slurry.

[0028] S2. Stir the reaction slurry prepared in S1 under heating until the solvent in it is completely volatilized, the stirring speed is 100 r / min, the heating temperature is 50 °C, then the remaining material is dried at 50 °C, and then the remaining dried material is ground to obtain a precursor.

[0029] S3. Place the precursor prepared in S2 into a muffle furnace filled with a reducing gas. Among them, the reducing gas is an argon-hydrogen mixture, and the volume content of hydrogen in this argon-hydrogen mixture is 5%. Then, the muffle furnace is heated to 600 °C at a heating rate of 2 °C / min and held for 2 h. During this process, antimony trioxide is converted into metallic antimony, and glucose undergoes a pyrolysis reaction to form a carbon coating layer on the surface of the metallic antimony. After the reaction, the antimony-containing negative electrode active material is prepared.

[0030] Example 2

[0031] The types of raw materials used in this example for preparing the antimony-containing negative electrode active material are the same as those in Example 1. Using the above raw materials, referring to the method provided in Example 1 for preparing the antimony-containing negative electrode active material, the antimony-containing negative electrode active material of this example is prepared. The difference from Example 1 is that in terms of the raw material ratio, the raw materials are weighed according to the mass ratio of antimony trioxide: polyvinylpyrrolidone: glucose: graphite: solvent water = 2:1:6:1:100. Except for the above differences, the raw materials and process steps applied in this example are strictly the same as those in Example 1.

[0032] Example 3

[0033] The types of raw materials used in this example for preparing the antimony-containing negative electrode active material are the same as those in Example 1. Using the above raw materials, referring to the method provided in Example 1 for preparing the antimony-containing negative electrode active material, the antimony-containing negative electrode active material of this example is prepared. The difference from Example 1 is that in terms of the raw material ratio, the raw materials are weighed according to the mass ratio of antimony trioxide: polyvinylpyrrolidone: glucose: graphite: solvent water = 3:1:6:1:100. Except for the above differences, the raw materials and process steps applied in this example are strictly the same as those in Example 1.

[0034] Example 4

[0035] The difference in the types of raw materials used in this example for preparing the antimony-containing negative electrode active material from those in Example 1 is that the graphite used in this example is flake graphite with D 50 = 10 μm, and except for this, the other raw materials used in this example are the same as those in the example. Using the above raw materials, according to the method for preparing the antimony-containing negative electrode active material in Example 1, the antimony-containing negative electrode active material of this example is prepared, and all process steps are strictly the same as those in Example 1.

[0036] Example 5

[0037] The difference in the types of raw materials used in this example for preparing the antimony-containing negative electrode active material from those in Example 1 is that the graphite used in this example is flake graphite with D 50 = 20 μm, and except for this, the other raw materials used in this example are the same as those in Example 1. Using the above raw materials, according to the method for preparing the antimony-containing negative electrode active material in Example 1, the antimony-containing negative electrode active material of this example is prepared, and all process steps are strictly the same as those in Example 1.

[0038] Example 6

[0039] The types of raw materials used in this example for preparing the antimony-containing anode active material are the same as those in Example 1. Using the above raw materials, referring to the method for preparing the antimony-containing anode active material provided in Example 1, the antimony-containing anode active material of this example is prepared. The difference from Example 1 is that in S3 for preparing the antimony-containing anode active material, the holding temperature of the muffle furnace is 700 °C. Except for the above difference, all the process steps involved in preparing the antimony-containing anode active material in this example are strictly consistent with those in Example 1.

[0040] Example 7

[0041] In this example, the raw materials used for preparing the antimony-containing anode active material are paired with the raw materials for preparing the antimony-containing anode active material by referring to Example 1. The difference from Example 1 is that the dispersant used in this example is carboxymethyl cellulose, and the organic carbon source used is polyacrylic acid. Except for this, all other raw materials used for preparing the antimony-containing anode active material in this example are the same as those in Example 1. The antimony-containing anode active material is specifically prepared according to the following operations using the above raw materials:

[0042] S1. Weigh the raw materials according to the mass ratio of antimony trioxide: polyvinylpyrrolidone: glucose: graphite: solvent water = 1:1:6:1:100. Mix the weighed raw materials and disperse them by ultrasound for 30 min, while providing high-speed stirring at the same time. The stirring speed is 100 r / min to obtain a uniform reaction slurry.

[0043] S2. Stir the reaction slurry prepared in S1 under heating conditions until the solvent in it is completely volatilized. The stirring speed is 100 r / min, and the heating temperature is 50 °C. Then, keep the remaining material dried at 50 °C, and then grind the remaining dried material to obtain a precursor.

[0044] S3. Place the precursor prepared in S2 into a muffle furnace filled with a reducing gas. The reducing gas is a mixed gas of argon and hydrogen, and the volume content of hydrogen in this mixed gas of argon and hydrogen is 5%. Then, let the muffle furnace rise to 800 °C at a heating rate of 5 °C / min and hold for 2 h. During this process, antimony trioxide is converted into metallic antimony, and glucose undergoes a pyrolysis reaction to form a carbon coating layer on the surface of metallic antimony. After the reaction, the antimony-containing anode active material is prepared.

[0045] Example 8

[0046] The types of raw materials used in this example for preparing the antimony-containing negative electrode active material are the same as those in Example 1. Using the above raw materials, referring to the method for preparing the antimony-containing negative electrode active material provided in Example 1, the antimony-containing negative electrode active material of this example is prepared. The difference from Example 1 is that in terms of the raw material ratio, the raw materials are weighed according to the mass ratio of antimony trioxide: polyvinylpyrrolidone: glucose: graphite: solvent water = 1:1:0.15:1:100. Except for the above differences, the raw materials and process steps applied in this example are strictly consistent with those in Example 1.

[0047] Example 9

[0048] The types of raw materials used in this example for preparing the antimony-containing negative electrode active material are the same as those in Example 1. Using the above raw materials, referring to the method for preparing the antimony-containing negative electrode active material provided in Example 1, the antimony-containing negative electrode active material of this example is prepared. The difference from Example 1 is that in terms of the raw material ratio, the raw materials are weighed according to the mass ratio of antimony trioxide: polyvinylpyrrolidone: glucose: graphite: solvent water = 1:1:11:1:100. Except for the above differences, the raw materials and process steps applied in this example are strictly consistent with those in Example 1.

[0049] Example 10

[0050] The types of raw materials used in this example for preparing the antimony-containing negative electrode active material are the same as those in Example 1. Using the above raw materials, referring to the method for preparing the antimony-containing negative electrode active material provided in Example 1, the antimony-containing negative electrode active material of this example is prepared. The difference from Example 1 is that in terms of the raw material ratio, the raw materials are weighed according to the mass ratio of antimony trioxide: polyvinylpyrrolidone: glucose: graphite: solvent water = 1:1:6:15:100. Except for the above differences, the raw materials and process steps applied in this example are strictly consistent with those in Example 1.

[0051] Comparative Example 1

[0052] The raw materials for preparing the antimony-containing negative electrode active material in this comparative example do not include graphite, and the types of the remaining raw materials are the same as those in Example 1. Using the above raw materials, referring to the method for preparing the antimony-containing negative electrode active material provided in Example 1, the antimony-containing negative electrode active material of this comparative example is prepared. The difference from Example 1 is that in the feeding operation, the feeding step of graphite is omitted in this comparative example. Except for the above differences, the raw materials and process steps applied in this comparative example are strictly consistent with those in Example 1.

[0053] Comparative Example 2

[0054] The types of raw materials used in this comparative example for preparing the antimony-containing negative electrode active material are the same as those in Example 1. Using the above raw materials, referring to the method for preparing the antimony-containing negative electrode active material provided in Example 1, the antimony-containing negative electrode active material of this comparative example was prepared. The difference from Example 1 is that in S3 for preparing the antimony-containing negative electrode active material, the holding temperature of the muffle furnace is 1100 °C. Except for the above differences, all the process steps involved in preparing the antimony-containing negative electrode active material in this comparative example are strictly the same as those in Example 1.

[0055] Comparative Example 3

[0056] The types of raw materials used in this comparative example for preparing the antimony-containing negative electrode active material are the same as those in Example 1. Using the above raw materials, referring to the method for preparing the antimony-containing negative electrode active material provided in Example 1, the antimony-containing negative electrode active material of this comparative example was prepared. The difference from Example 1 is that in S3 for preparing the antimony-containing negative electrode active material, the holding temperature of the muffle furnace is 400 °C. Except for the above differences, all the process steps involved in preparing the antimony-containing negative electrode active material in this comparative example are strictly the same as those in Example 1.

[0057] Comparative Example 4

[0058] The types of raw materials used in this example for preparing the antimony-containing negative electrode active material are the same as those in Example 1. Using the above raw materials, referring to the method for preparing the antimony-containing negative electrode active material provided in Example 1, the antimony-containing negative electrode active material of this example was prepared. The difference from Example 1 is that in terms of the raw material ratio, the raw materials were weighed according to the mass ratio of antimony trioxide: polyvinylpyrrolidone: glucose: graphite: solvent water = 2.5: 1: 6: 1: 100. Except for the above differences, all the other raw materials used in this example for preparing the antimony-containing negative electrode active material are the same as those in Example 1. Using the above raw materials, referring to the method for preparing the antimony-containing negative electrode active material provided in Example 1, the antimony-containing negative electrode active material of this comparative example was prepared. The difference from Example 1 is that in S3 for preparing the antimony-containing negative electrode active material, the holding temperature of the muffle furnace is 550 °C. Except for the above differences, all the process steps involved in preparing the antimony-containing negative electrode active material in this comparative example are strictly the same as those in Example 1.

[0059] Comparative Example 5

[0060] The types of raw materials used in this comparative example for preparing the antimony-containing negative electrode active material are different from those in Example 1 as follows: The graphite used in this comparative example is D 50Flaky graphite with a size of 20 μm; the dispersant used in this comparative example is carboxymethyl cellulose, and the organic carbon source used is polyacrylic acid. Except for the above, all other raw materials used in this comparative example are the same as those in Example 1. Using the above raw materials, according to the method for preparing the antimony-containing negative electrode active material in Example 1, the antimony-containing negative electrode active material of this comparative example was prepared, and all process steps were strictly the same as those in Example 1.

[0061] Test Example

[0062] 1. Test Objects and Control Objects

[0063] The antimony-containing negative electrode active materials prepared in Examples 1 to 7 and Comparative Examples 1 to 6 were used as the test objects of this test example; and metallic antimony was used as the negative electrode active material, marked as the control object.

[0064] 2. Assembly of Lithium-Ion Batteries

[0065] Using the test objects and control objects of different examples and comparative examples as the negative electrode active substances respectively, materials were prepared according to the mass ratio of negative electrode active substance: conductive agent carbon black (sp): binder sodium carboxymethyl cellulose (CMC) of 8:1:1. The above materials were mixed to make a slurry, and then the resulting mixed slurry was mixed and ground to obtain a uniformly dispersed battery slurry; the battery slurry was evenly coated on the surface of the copper foil, then transferred to a vacuum condition of 60 °C, vacuum dried for 12 hours, and then pressed into a sheet for use as the negative electrode sheet. A lithium sheet was used as the positive electrode sheet, and Celgard 2500 was used as the separator. An electrolyte was prepared using EC, DEC, FEC, and LiPF6. First, EC and DEC were mixed according to a mass ratio of 1:1, and then LiPF6 and FEC were added to the resulting mixed organic solvent to obtain the electrolyte. The finally obtained electrolyte contained 1 M LiPF6 and 5% FEC. Finally, a button-type half-cell was assembled using the above positive electrode sheet, negative electrode sheet, separator, and electrolyte in a glove box.

[0066] 3. Test Items

[0067] (1) Raman Spectroscopy Detection

[0068] The antimony-containing negative electrode active material was tested by Raman spectroscopy according to GB / T 33252-2016 Test Method for the Performance of Laser Confocal Micro-Raman Spectrometer, and in the measured Raman spectrogram, the intensity I of the D peak with a peak value located near 1300 cm -1 was read, and the intensity I of the G peak with a peak value located near 1600 cm D was read. -1 near the position. G .

[0069] (2) X-ray Diffraction Spectroscopy Detection

[0070] Perform X-ray diffraction spectroscopy tests on the antimony-containing negative electrode active material according to T / CSTM 00166.2-2020 Characterization of graphene materials - Part 2: X-ray diffraction method, and read the peak intensity C of the (110) plane characteristic peak. 110 And the peak intensity C of the (002) plane characteristic peak. 002 .

[0071] (3) Particle size test

[0072] Perform particle size tests on the antimony-containing negative electrode active material according to GB / T 19077_1-2003 Particle size analysis - Laser diffraction method.

[0073] (4) Cycle performance detection

[0074] In this study, standard charge-discharge cycle test methods were used to evaluate the cycle performance of coin cells. First, the battery was charged to a full charge state using a constant current and constant voltage charging method, and allowed to stand for a period of time to ensure that the electrochemical reactions inside the battery reached stability. Then, the battery was discharged with a fixed constant current load, and the voltage changes and corresponding discharge capacities during the discharge process were recorded. Among them, in the selection of coin cell samples, for the coin cell samples prepared from the antimony-containing negative electrode active material provided in the same example or comparative example, coin cell samples with similar parameters were selected (twenty repeated coin cell samples were selected for the antimony-containing negative electrode active material provided in each example or comparative example, and each coin cell sample was one repetition), ensuring that the differences between the coin cell samples prepared from the same antimony-containing negative electrode active material were as small as possible.

[0075] Perform constant current discharge (0.1 mA / mg, 0.005 V) on the fabricated button-type half cell, let it stand for 5 minutes, and then perform constant current charging (0.1 mA / mg, 3.000 V). Record the number of cycles corresponding to when the capacity retention rate of the button-type half cell drops to 80%.

[0076] 4. Test results

[0077] The test results of this test example are shown in Table 1. As a control object, only antimony metal was used as the negative electrode active material to fabricate a lithium-ion battery. During the process of cyclic charge and discharge of the lithium-ion battery, obvious volume expansion of antimony metal occurred. As a result, in the process of testing the lithium-ion battery, as the number of cycles of cyclic charge and discharge increased, the degree of decline in its capacity retention rate was significantly greater than that of other test products. In addition, after the test was completed, the control object and other test objects were disassembled. It could be seen that the negative electrode in the control object had obvious swelling compared with that before the lithium-ion battery participated in the cyclic test, and the negative electrode active material layer also showed damage. In contrast to the negative electrode of the control object, the negative electrodes of other test objects could better maintain their morphology before participating in the cyclic test after completing the test of this test example. The antimony-containing negative electrode active materials prepared in Examples 1 to 10 and Comparative Examples 1 to 5 were all coated with a carbon coating layer on the surface of antimony metal. The carbon coating layer could isolate antimony metal from the electrolyte, reduce the side reaction between the electrolyte and antimony metal, and to a certain extent limit the expansion of antimony metal. Therefore, compared with the control object using only antimony metal as the negative electrode material, the lithium-ion batteries prepared in the above-mentioned examples and comparative examples had negative electrodes with higher structural stability, making these lithium-ion batteries show better cyclic characteristics in the test.

[0078] In Examples 1 to 10 and Comparative Examples 1 to 5, the antimony-containing negative electrode active material prepared in Comparative Example 1 did not contain graphite. From the test results of this test example, it could be seen that the number of cycles measured for the lithium-ion battery prepared in Comparative Example 1 was significantly less than the number of cycles measured for the lithium-ion batteries prepared in other examples and comparative examples. Therefore, it could be shown that by using graphite and antimony-carbon composite materials in combination in the antimony-containing negative electrode active material provided by the present invention, the cyclic performance of the lithium-ion battery using the antimony-carbon composite material as the negative electrode active material could be effectively optimized.

[0079] The negative electrode active materials used in Examples 1 to 10 and Comparative Examples 2 to 5 were all antimony-containing negative electrode active materials prepared by combining graphite and antimony-carbon composite materials (including a metal antimony core and a carbon coating layer). However, compared with the lithium-ion batteries prepared in Comparative Examples 2 to 5, the number of cycles measured for the lithium-ion batteries provided in Examples 1 to 10 was significantly higher. The antimony-containing negative electrode active materials prepared in Examples 1 to 10 had both the Raman spectrum characteristics of I D / I G = 0.52 to 1.54 and the C 110 / C 002The X-ray diffraction pattern features are 0.043 to 0.085. Among the antimony-containing negative electrode active materials with the above features, the included antimony-carbon composite material has excellent structural stability. The carbon coating layer can form a uniform and dense coating layer on the surface of the metallic antimony core, which is not easy to break and not easy to fall off from the surface of the metallic antimony core, and can provide reliable protection for the metallic antimony core. In addition, graphite and the antimony-carbon composite material are compounded in an appropriate ratio, and the gaps formed between the graphites can provide a buffer space for the expansion stress generated by the expansion of the antimony-based material, so as to avoid obvious deformation of the negative electrode sheet using the antimony-carbon composite material, thereby further strengthening the structural stability of the negative electrode sheet using the antimony-based negative electrode material.

[0080] Further, among the antimony-containing negative electrode active materials respectively prepared in Examples 1 to 10, the Raman spectra measured for the antimony-containing negative electrode active materials in Examples 1, 2, and 5 further conform to the feature of I D / I G ≥1. The corresponding cycle numbers of the lithium-ion batteries prepared in these 3 examples are significantly more. This shows that when using an antimony-containing negative electrode active material with a Raman spectrum conforming to I D / I G ≥1 to prepare a lithium-ion battery, it is beneficial to further optimize the cycle characteristics of the lithium-ion battery. Among all the tested objects, the lithium-ion battery provided in Example 1 has the best cycle performance. The Raman spectrogram and X-ray diffraction spectrogram measured for the corresponding antimony-containing negative electrode active material used are respectively as Figure 1 、 Figure 2 shown.

[0081] Table 1. Statistical situation of the test results of this test example

[0082]

[0083] The above examples are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the above examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced, but these modifications or replacements are all within the protection scope of the present invention.

Claims

1. An antimony-containing negative electrode active material, characterized in that: The antimony-containing negative electrode active material includes graphite and an antimony-carbon composite material, and the antimony-carbon composite material includes a metallic antimony core and a carbon coating layer; In the Raman spectrum of the antimony-containing negative electrode active material, the peak intensity I of the D peak D and the peak intensity I of the G peak G The ratio I D / I G = 0.52 to 1.54; In the X-ray diffraction pattern of the antimony-containing negative electrode active material, the peak intensity C of the (110) plane characteristic peak 110 and the peak intensity C of the (002) plane characteristic peak 002 The ratio C 110 / C 002 = 0.043 to 0.085; In the antimony-containing negative electrode active material, the mass ratio of metallic antimony to graphite is 4-26:5-50.

2. The antimony-containing negative electrode active material according to claim 1, wherein: In the Raman spectrum of the antimony-containing negative electrode active material, the peak intensity I of the D peak D and the peak intensity I of the G peak G The ratio I D / I G ≥ 1.

3. The antimony-containing negative electrode active material according to claim 2, wherein: In the X-ray diffraction pattern of the antimony-containing negative electrode active material, the peak intensity C of the (110) plane characteristic peak 110 and the peak intensity C of the (002) plane characteristic peak 002 The ratio C 110 / C 002 = 0.05 to 0.

065.

4. The antimony-containing negative electrode active material according to claim 1, wherein: In the antimony-carbon composite material, the mass ratio of metallic antimony to the carbon coating layer is 0.4-2.5:0.4-4.

5. The antimony-containing negative electrode active material according to claim 1, wherein: The D of the antimony-containing negative electrode active material 90 is 8 to 10 μm, and the D of the antimony-containing negative electrode active material 10 is 0.5 to 1.5 μm.

6. The antimony-containing negative electrode active material according to claim 1, wherein: The D of the antimony-containing negative electrode active material 50 = 2.5 to 5 μm.

7. The antimony-containing negative electrode active material according to claim 1, wherein: The specific surface area of the antimony-containing negative electrode active material is 1.5 to 4.5 m 2 / g.

8. The preparation method of the antimony-containing negative electrode active material according to any one of claims 1 to 7, characterized in that, It includes the following operations: S1. Pulping is carried out using an antimony source, an organic carbon source, graphite, and a solvent to obtain a reaction slurry, and the organic carbon source includes at least one of glucose, asphalt, polyvinyl alcohol, polyacrylic acid, and butyl polyacrylate; S2. The solvent of the reaction slurry is completely volatilized, and the remaining dried material is ground to obtain a precursor; S3. The precursor is placed in a reaction system provided with a reducing agent, and then the temperature of the reaction system is raised to 500-1000 °C, so that: the antimony source is converted into metallic antimony under the action of the reducing agent, and the organic carbon source undergoes a pyrolysis reaction to form the carbon coating layer on the surface of the metallic antimony.

9. A lithium-ion battery, characterized in that: It includes a negative electrode, and the negative electrode active material layer of the negative electrode includes the antimony-containing negative electrode active material according to any one of claims 1-7.

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