Carbonaceous material, method for producing the same, and secondary battery and electric device containing the same

Abstract

The application provides a carbonaceous material and a preparation method thereof, and a secondary battery and an electric device containing the carbonaceous material, wherein the carbonaceous material has an O element content of A tested by X-ray photoelectron spectroscopy, an O element content of B tested by elemental analysis, and satisfies A / B >= 3 and 5 wt% <= A <= 20 wt%. The carbonaceous material provided by the application can greatly improve the cycle performance and rate performance of the secondary battery.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of batteries, and particularly relates to a carbonaceous material and a preparation method thereof, and a secondary battery and an electric device containing the same. BACKGROUND

[0002] In recent years, secondary batteries are widely applied in energy storage power systems such as water power, fire power, wind power and solar power stations, and in many fields such as electric tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc. With the application and promotion of secondary batteries, their energy density, service life and rate performance are attracting more and more attention. Graphite is the most commonly used negative active material for secondary batteries, but its theoretical specific capacity is only 372 mAh / g, and the space for improving its energy density is very limited. At the same time, the interlayer spacing of graphite is small, and the improvement of its rate performance is also limited. Hard carbon is a new type of negative active material, which can realize the rapid intercalation and deintercalation of active ions during the charging and discharging process of secondary batteries, so its development prospect is very broad. However, the cycle performance and rate performance of the currently marketed hard carbon materials are not ideal. SUMMARY

[0003] The present application aims to provide a carbonaceous material and a preparation method thereof, and a secondary battery and an electric device containing the same, which can greatly improve the cycle performance and rate performance of the secondary battery.

[0004] The first aspect of the present application provides a carbonaceous material, the content of O element of the carbonaceous material tested by X-ray photoelectron spectroscopy is denoted as A, the content of O element tested by elemental analysis method is denoted as B, and the carbonaceous material satisfies A / B≥3 and 5wt%≤A≤20wt%.

[0005] The inventors of the present application surprisingly found that when the carbonaceous material satisfies A / B≥3 and 5wt%≤A≤20wt%, the secondary battery has greatly improved cycle performance and rate performance. The carbonaceous material provided in the present application has a high content of O element on the surface. During charging (i.e. before the formation of SEI film), negative charges can be enriched at the position of O atoms on the surface of the carbonaceous material, thereby inducing the rapid decomposition of organic solvents such as esters or ethers in the electrolyte, and further increasing the content of organic components in the SEI film. The inventors of the present application also found in the research process that these organic components have a large number of advantages compared to inorganic components: first, the organic components in the SEI film have higher flexibility, which can improve the anti-deformation ability of the SEI film, so that it remains stable during long-term cycling, thereby reducing the consumption of active ions during cycling, further improving the cycle performance of the secondary battery; second, the organic components in the SEI film can improve the ionic conductivity on the negative side, which is beneficial to further improve the rate performance of the secondary battery, and also can avoid the reduction and precipitation of active ions on the negative side during cycling, thereby also being beneficial to further improve the cycle performance of the secondary battery; third, the O atoms on the surface of the carbonaceous material can also participate in the formation of the SEI film, which is beneficial to improve the adhesion of the SEI film on the surface of the carbonaceous material particles, and is beneficial to the high stability of the SEI film during long-term cycling, thereby reducing the consumption of active ions during cycling, further improving the cycle performance of the secondary battery.

[0006] In any embodiment of the present application, 3≤A / B≤10, and optionally 6≤A / B≤9.2. Thereby, it is helpful to further improve the cycle performance and rate performance of the secondary battery.

[0007] In any embodiment of the present application, 5wt%≤A≤16wt%, and optionally 10wt%≤A≤16wt%. Thereby, it is helpful to further improve the cycle performance and rate performance of the secondary battery.

[0008] In any embodiment of the present application, 1.5wt%≤B≤6wt%, and optionally 1.5wt%≤B≤3wt%. Thereby, it is helpful to further improve the cycle performance and rate performance of the secondary battery.

[0009] In any embodiment of the present application, the specific surface area of the carbonaceous material is ≤10m 2 / g, and optionally 0.1m 2 / g-10m 2 / g. The specific surface area of the carbonaceous material provided in the present application is low, which is helpful to reduce the surface activity of the carbonaceous material, reduce the formation of SEI film, and thereby reduce the irreversible consumption of active ions, so that the carbonaceous material has higher specific capacity and first coulomb efficiency, and the secondary battery has better cycle performance and rate performance.

[0010] In any embodiment of the present application, the carbonaceous material comprises a plurality of nanopore structures.

[0011] In any embodiment of the present application, in the Raman spectrum of the carbonaceous material, I d / I g is 0.90-1.25, optionally 0.95-1.10, I d represents the intensity of the d peak with a Raman shift in the range of 1350±50 cm -1 -1.25, I g represents the intensity of the g peak with a Raman shift in the range of 1580±50 cm -1 -1.25. At this time, the carbonaceous material has higher specific capacity and higher first coulomb efficiency, while also having excellent rate performance.

[0012] In any embodiment of the present application, the interlayer spacing of the (002) crystal plane of the carbonaceous material is ≥0.37 nm, optionally 0.37 nm-0.42 nm.

[0013] In any embodiment of the present application, in the X-ray diffraction spectrum of the carbonaceous material, the (002) crystal plane peak corresponds to a 2θ value between 22° and 24°.

[0014] In any embodiment of the present application, the volume particle size Dv50 of the carbonaceous material is 3 μm-15 μm, optionally 4 μm-6 μm.

[0015] In any embodiment of the present application, the volume particle size Dv90 of the carbonaceous material is 8 μm-30 μm, optionally 9 μm-12 μm.

[0016] When the volume particle size Dv50 and / or Dv90 of the carbonaceous material is in a suitable range, it is beneficial to improve the transport performance of active ions and electrons, thereby further improving the cycle performance and rate performance of the secondary battery.

[0017] In any embodiment of the present application, the powder compaction density of the carbonaceous material under a force of 50000 N is 0.92 g / cm 3 -1.05 g / cm 3 , optionally 0.95 g / cm 3 -1.02 g / cm 3 . When the powder compaction density of the carbonaceous material is in a suitable range, the compaction density of the negative electrode sheet can be improved, thereby improving the energy density of the secondary battery.

[0018] In any embodiment of the present application, the tap density of the carbonaceous material is 0.80 g / cm 3 -0.95 g / cm3 Optionally 0.85 g / cm3 3 -0.90 g / cm3 3 When the tap density of the carbonaceous material is in the proper range, the compaction density of the negative electrode sheet can be improved, and thus the energy density of the secondary battery can be improved.

[0019] The second aspect of the present application provides a preparation method of a carbonaceous material, comprising the following steps: S10, providing raw materials, wherein the raw materials comprise a hard carbon material; S20, grinding the raw materials, abrasive bodies and an oxidizing solution in a grinder; and S30, obtaining the carbonaceous material by washing and drying the product obtained by grinding, wherein the carbonaceous material satisfies A / B≥3 and 5wt%≤A≤20wt%, wherein A represents the content of O element in the carbonaceous material tested by X-ray photoelectron spectroscopy, and B represents the content of O element in the carbonaceous material tested by elemental analysis.

[0020] The cycle performance and rate performance of the currently marketed hard carbon material are not ideal, and the preparation method provided in the present application can greatly optimize the cycle performance and rate performance of the raw material (i.e. the hard carbon material), and the preparation method provided in the present application has universality.

[0021] In any embodiment of the present application, in S20, the mass ratio of the dry weight of the raw materials to the abrasive bodies is ≤1, and is optionally 0.2-1. In this way, on the one hand, the production efficiency can be improved, and on the other hand, the surface of the obtained carbonaceous material can have a suitable content of oxygen-containing functional groups, and the carbonaceous material can also greatly improve the cycle performance and rate performance of the secondary battery.

[0022] In any embodiment of the present application, in S20, the mass ratio of the dry weight of the raw materials to the oxidizing solution is ≤0.6, and is optionally 0.1-0.6. In this way, on the one hand, the production efficiency can be improved, and on the other hand, the surface of the obtained carbonaceous material can have a suitable content of oxygen-containing functional groups, and the carbonaceous material can also greatly improve the cycle performance and rate performance of the secondary battery.

[0023] In any embodiment of the present application, in S20, the concentration of the oxidizing solution is ≥0.1 moL / L, and is optionally 0.1 moL / L-10 moL / L. In this way, on the one hand, the production efficiency and safety production can be improved, and on the other hand, the surface of the obtained carbonaceous material can have a suitable content of oxygen-containing functional groups, and the carbonaceous material can also greatly improve the cycle performance and rate performance of the secondary battery.

[0024] In any of the embodiments of the present application, in S20, the grinding time is 1h-24h, optionally 4h-16h. In this way, the surface of the obtained carbonaceous material can have a suitable content of oxygen-containing functional groups, and the carbonaceous material can also greatly improve the cycle performance and rate performance of the secondary battery.

[0025] In any of the embodiments of the present application, in S20, the solute in the oxidizing solution comprises one or more selected from nitric acid, sulfuric acid and perchloric acid, and the solvent comprises water. In this way, on the one hand, the surface of the obtained carbonaceous material can have a suitable content of oxygen-containing functional groups, and on the other hand, the introduction of other impurity elements can be avoided, thereby reducing the irreversible consumption of active ions.

[0026] In any of the embodiments of the present application, in S20, the grinding speed is 100rpm-1200rpm.

[0027] In any of the embodiments of the present application, in S20, the grinding instrument comprises a ball mill.

[0028] In any of the embodiments of the present application, in S20, the volume ratio of all materials in the grinding instrument is 1 / 5-3 / 4, based on the volume of the grinding instrument. In this way, on the one hand, the production efficiency can be improved, and on the other hand, the wet grinding effect can be improved.

[0029] In any of the embodiments of the present application, in S10, the volume particle size Dv50 of the raw material is 3μm-15μm, optionally 4μm-6μm.

[0030] In any of the embodiments of the present application, in S10, the volume particle size Dv90 of the raw material is 8μm-30μm, optionally 9μm-12μm.

[0031] By adjusting the volume particle size Dv50 and / or Dv90 of the raw material within a suitable range, the active ion and electron transport performance of the obtained carbonaceous material can be improved, thereby further improving the cycle performance and rate performance of the secondary battery.

[0032] In any of the embodiments of the present application, the raw material is prepared by the following method: heating the carbon source to 1000℃-1600℃ at a rate of ≤10℃ / min under a protective gas atmosphere, holding for 1h-24h, and then crushing to obtain the raw material.

[0033] The third aspect of the present application provides a secondary battery comprising a negative electrode sheet, wherein the negative electrode sheet comprises the carbonaceous material of the first aspect of the present application or the carbonaceous material prepared by the method of the second aspect of the present application.

[0034] The fourth aspect of the present application provides a power consumption device comprising the secondary battery of the third aspect of the present application.

[0035] The carbonaceous material provided by the present application can greatly improve the cycle performance and rate performance of the secondary battery. The power consumption device provided by the present application comprises the secondary battery provided by the present application, and thus has at least the same advantages as the secondary battery. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by the drawings without creative labor for those skilled in the art.

[0037] Figure 1 is a schematic diagram of an embodiment of the battery cell of the present application.

[0038] Figure 2 is an exploded schematic diagram of an embodiment of the battery cell of the present application.

[0039] Figure 3 is a schematic diagram of an embodiment of the battery module of the present application.

[0040] Figure 4 is a schematic diagram of an embodiment of the battery pack of the present application.

[0041] Figure 5 is Figure 4 is an exploded schematic diagram of an embodiment of the battery pack shown in the figure.

[0042] Figure 6 is a schematic diagram of an embodiment of the power consumption device comprising the secondary battery of the present application as a power supply.

[0043] In the drawings, the drawings are not necessarily drawn according to the actual scale. The reference signs are explained as follows: 1 battery pack, 2 upper box body, 3 lower box body, 4 battery module, 5 battery cell, 51 shell, 52 electrode assembly, 53 cover plate. DETAILED DESCRIPTION

[0044] Hereinafter, specific embodiments of the carbonaceous material and the method for producing the same according to the present application, and the secondary battery and the electric device including the same will be described in detail with appropriate reference to the accompanying drawings. However, there will be cases where unnecessary detailed descriptions are omitted. For example, there will be cases where detailed descriptions of matters known to those skilled in the art, redundant descriptions of substantially identical configurations are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present application, and are not intended to limit the subject matter recited in the claims.

[0045] The ranges disclosed herein are defined by their lower and upper limits. Ranges can be defined by any upper and lower limits, whether or not they are explicitly disclosed. Ranges can be combined, i.e., any lower limit of a range or a value can be combined with any upper limit of another range or value. For example, if a range of 60-120 and a range of 80-110 are disclosed, it is understood that a range of 60-110 and a range of 80-120 are also disclosed. Furthermore, if a minimum range value of 1 and 2 are disclosed, and if a maximum range value of 3, 4, and 5 are disclosed, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, the use of "or" means "and / or" unless specifically stated otherwise, e.g., the phrase "A or B" means "A and / or B" or "A and B." In addition, the use of "comprising" means "including, but not limited to" unless otherwise indicated. Furthermore, the use of the term "integers" for a parameter means that the parameter is an integer of, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0046] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0047] Unless otherwise specified, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0048] If not specified otherwise, all steps of the present application can be carried out in sequence or randomly, preferably in sequence. For example, the method comprising steps (a) and (b) means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method can further comprise step (c) means that step (c) can be added to the method in any sequence, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0049] If not specified otherwise, the terms "comprising" and "including" mentioned in the present application mean open-ended, and can also mean closed-ended. For example, the terms "comprising" and "including" can mean that other components not listed can also be included, or can mean that only the listed components are included.

[0050] If not specified otherwise, in the present application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, any of the following satisfy the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0051] If not specified otherwise, the terms used in the present application have the commonly understood meanings understood by those skilled in the art.

[0052] If not specified otherwise, the values of the parameters mentioned in the present application can be measured by various test methods commonly used in the art, for example, can be measured according to the test methods given in the present application.

[0053] If not specified otherwise, in the present application, the term "active ion" means an ion that can be reversibly intercalated and deintercalated between the positive electrode and the negative electrode of a secondary battery, including but not limited to lithium ion, sodium ion, etc.

[0054] In the present application, the terms "plurality" and "a plurality of" mean two or more.

[0055] Carbonaceous material

[0056] In a first aspect, the present application provides a carbonaceous material, the content of O element of the carbonaceous material is denoted as A by X-ray Photoelectron Spectroscopy (XPS) method, and the content of O element is denoted as B by Elemental analysis (EA) method, wherein the carbonaceous material satisfies A / B≥3 and 5wt%≤A≤20wt%.

[0057] The O element content tested by X-ray photoelectron spectroscopy is the O element content on the surface of the carbonaceous material, and the O element content tested by elemental analysis is the O element content of the entire sample of the carbonaceous material. Before testing by X-ray photoelectron spectroscopy and elemental analysis, the carbonaceous material needs to be vacuum dried at 120°C for 12h, and then sealed and stored using an aluminum plastic bag.

[0058] The X-ray photoelectron spectroscopy is tested by an X-ray photoelectron spectrometer. The testing instrument can be a Nexsa / EscaLab 250Xi X-ray photoelectron spectrometer of Thermo Fisher Corporation, USA.

[0059] The elemental analysis test is tested by an elemental analyzer, and the test mode is O mode, that is, the sample is cracked in H2 / He mixed gas at 1150°C, and then reduced to CO by carbon powder, and the O element content is obtained by thermal conductivity detection. The mass of the test sample can be more than 30mg. The testing instrument can be a vario macro cube elemental analyzer of Elementar Corporation, Germany, or a Flash 2000 / Flash Smart elemental analyzer of Thermo Fisher Corporation, USA.

[0060] The inventors of the present application were surprised to find during research that when the carbonaceous material satisfies A / B≥3 and 5wt%≤A≤20wt%, the secondary battery can have greatly improved cycle performance and rate performance. The carbonaceous material provided in the present application has a high content of O elements on the surface, and during charging (i.e., before the formation of the SEI film), negative charges can be enriched at the O atom positions on the surface of the carbonaceous material, thereby inducing the rapid decomposition of organic solvents such as esters or ethers in the electrolyte, and further increasing the content of organic components in the SEI film. The inventors of the present application also found during research that these organic components have a large number of advantages compared to inorganic components: first, the organic components in the SEI film have higher flexibility, which can improve the anti-deformation ability of the SEI film, so that it remains stable during long-term cycling, thereby reducing the consumption of active ions during cycling, further improving the cycle performance of the secondary battery; second, the organic components in the SEI film can improve the ionic conductivity on the negative side, which is beneficial to further improve the rate performance of the secondary battery, and also avoids the reduction and precipitation of active ions on the negative side during cycling, thereby also being beneficial to further improve the cycle performance of the secondary battery; third, the O atoms on the surface of the carbonaceous material can also participate in the formation of the SEI film, which is beneficial to improve the adhesion of the SEI film on the surface of the carbonaceous material particles, and is beneficial to the high stability of the SEI film during long-term cycling, thereby reducing the consumption of active ions during cycling, further improving the cycle performance of the secondary battery.

[0061] When A / B is less than 3 or A is less than 5 wt%, the content of O element on the surface of the carbonaceous material is low, which is not conducive to the formation of SEI film with excellent performance, thereby leading to less than ideal cycle performance and rate performance of the secondary battery. When A is greater than 20 wt%, the content of O element on the surface of the carbonaceous material is too high, at this time, the hydrogen bond between O atom and water molecule is too strong, leading to too many water molecule clusters blocking on the surface of the carbonaceous material, hindering the intercalation and deintercalation of active ions, thereby leading to less than ideal cycle performance and rate performance of the secondary battery. In addition, when the content of O element on the surface of the carbonaceous material is too high, too many active ions are captured by O atoms, which also hinders the continuity of active ion transmission on the surface of the particles, at this time, the kinetic performance of the carbonaceous material is poor, thereby also leading to less than ideal cycle performance and rate performance of the secondary battery.

[0062] In some embodiments, optionally, 3≤A / B≤10, 4≤A / B≤10, 5≤A / B≤9.5, 6≤A / B≤9.2. Thereby, it is helpful to further improve the cycle performance and rate performance of the secondary battery.

[0063] In some embodiments, optionally, 5 wt%≤A≤18 wt%, 5 wt%≤A≤16 wt%, 6 wt%≤A≤16 wt%, 7 wt%≤A≤16 wt%, 8 wt%≤A≤16 wt%, 9 wt%≤A≤16 wt%, 10 wt%≤A≤16 wt%. Thereby, it is helpful to further improve the cycle performance and rate performance of the secondary battery.

[0064] The inventors of the present application also found in the research process that the content of O element of the entire sample of the carbonaceous material also affects the cycle performance and rate performance of the secondary battery. Since O atoms cannot reversibly deintercalate active ions after combining with the active ions, when the content of O element of the entire sample of the carbonaceous material is high, the irreversible consumption of active ions is high, thereby reducing the energy density of the secondary battery and affecting the cycle performance of the secondary battery. In some embodiments, 0

[0065] In some embodiments, the carbonaceous material satisfies 6≤A / B≤9.2, 10 wt%≤A≤16 wt% and 1.5 wt%≤B≤3 wt%. The inventors of the present application also found in the research process that at this time, the secondary battery can have better cycle performance and rate performance at the same time.

[0066] In some embodiments, the specific surface area of the carbonaceous material is ≤10 m 2 / g, which is optionally 0.1 m 2 / g-10 m2 / g, 1 m 2 / g-10 m 2 / g, 2 m 2 / g-10 m 2 / g, 3 m 2 / g-10 m 2 / g, 4 m 2 / g-10 m 2 / g, 4 m 2 / g-9 m 2 / g, 4 m 2 / g-8.5 m 2 / g, 4 m 2 / g-8.2 m 2 / g, 4 m 2 / g-8 m 2 / g, 4 m 2 / g-7.8 m 2 / g, 4 m 2 / g-7.6 m 2 / g, 4.5 m 2 / g-7.6 m 2 / g, 5 m 2 / g-7.6 m 2 / g. The carbonaceous material provided in the present application has a low specific surface area, which helps to reduce the surface activity of the carbonaceous material, reduce the formation of SEI film, thereby reducing the irreversible consumption of active ions, so that the carbonaceous material can have higher specific capacity and first coulombic efficiency, and at the same time, the secondary battery can have better cycle performance and rate performance. When the specific surface area of the carbonaceous material is high, more binder needs to be added during the preparation of the pole piece to bond the particles, and the binder is generally an insulating material, which can cause the increase of the internal resistance of the battery, the decrease of the ion conductivity and the electronic conductivity, and further cause the deterioration of the cycle performance and rate performance of the secondary battery.

[0067] In the present application, the specific surface area of the carbonaceous material has the meaning known in the art and can be determined by instruments and methods known in the art. For example, GB / T 19587-2017 can be referred to, and the nitrogen adsorption specific surface area analysis test is tested by the BET (Brunauer Emmett Teller) method, wherein the nitrogen adsorption specific surface area analysis test can be determined by the ASAP 3020 type surface area and pore size analyzer of the American Micromeritics company.

[0068] In some embodiments, the carbonaceous material comprises a plurality of nanoporous structures.

[0069] In some embodiments, the carbonaceous material can have regular or irregular morphology, for example, the morphology of the carbonaceous material can be irregular polyhedral.

[0070] In some embodiments, the carbonaceous material has a low content of impurity elements, and the impurity elements mainly include Na. In some embodiments, the content of Na element is ≤0.011wt%, and optionally ≤0.005wt%.

[0071] In some embodiments, in the Raman spectrum of the carbonaceous material, I d / I g is 0.90-1.25, I d represents the intensity of the d-peak with a Raman shift in the range of 1350±50cm -1 , and I g represents the intensity of the g-peak with a Raman shift in the range of 1580±50cm -1 . For example, I d / I g may be 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25 or any range consisting of any two of the above values. Alternatively, I d / I g may be 0.95-1.10.

[0072] The Raman spectrum of the carbonaceous material can be tested using a Raman spectrometer, and the intensities of the d-peak and the g-peak of 100 points are obtained, and the I d / I g of the 100 points is calculated, 30 largest and 30 smallest I d / I g are removed, and the average value of the remaining 40 I d / I g is taken as the I d / I g of the carbonaceous material. The testing instrument can be a Horiba LabRAM HR800 Raman spectrometer. The testing conditions can be: excitation wavelength 532nm, grating 600 lines, objective lens 50x, integration time 10s, accumulation number 3 times, area scan.

[0073] The d-peak is generated from the defects of carbon atom lattice, and the g-peak is generated from the in-plane vibration of sp2 carbon atom. In the structure of the carbonaceous material, the intensity of the d-peak is related to the number of defects in the structure of the carbonaceous material, and the intensity of the g-peak is related to the number of graphite crystallites in the structure of the carbonaceous material, therefore, I d / I g can represent the order degree of the structure of the carbonaceous material. I d / I gThe smaller the carbonaceous material structure, the higher the order degree of the carbonaceous material structure, the higher the integrity of the carbon plane, and the first coulomb efficiency of the carbonaceous material is increased, but the specific capacity is lowered and the rate performance is deteriorated. The carbonaceous material of the present application satisfies I d / I g 0.90-1.25, at this time, the order degree of the carbonaceous material structure is moderate, so that the carbonaceous material has higher specific capacity and higher first coulomb efficiency, and also has excellent rate performance.

[0074] In some embodiments, the interlayer spacing of the (002) crystal plane of the carbonaceous material is ≥0.37 nm, and optionally 0.37 nm-0.42 nm.

[0075] In some embodiments, in the X-ray diffraction spectrum of the carbonaceous material, the 2θ value corresponding to the (002) crystal plane peak is between 22° and 24°.

[0076] In the present application, the interlayer spacing of the (002) crystal plane of the carbonaceous material can be tested by using an X-ray diffractometer according to JIS K 0131-1996, JB / T4220-2011. The testing instrument can be a Bruker D8Discover X-ray diffractometer.

[0077] In some embodiments, the volume particle size Dv50 of the carbonaceous material is 3 μm-15 μm, and optionally 4 μm-6 μm.

[0078] In some embodiments, the volume particle size Dv90 of the carbonaceous material is 8 μm-30 μm, and optionally 9 μm-12 μm.

[0079] In some embodiments, the carbonaceous material simultaneously satisfies the volume particle size Dv50 of 3 μm-15 μm and the volume particle size Dv90 of 8 μm-30 μm. Optionally, the carbonaceous material simultaneously satisfies the volume particle size Dv50 of 4 μm-6 μm and the volume particle size Dv90 of 9 μm-12 μm.

[0080] When the volume particle size Dv50 and / or Dv90 of the carbonaceous material is within a suitable range, the active ion and electron transmission performance is improved, so that the cycle performance and rate performance of the secondary battery can be further improved.

[0081] In the present application, the volume particle size Dv50, Dv90 of the carbonaceous material is the meaning known in the art, which represents the particle size corresponding to the cumulative volume distribution percentage of 50%, 90% respectively, and can be determined by using the instruments and methods known in the art. For example, it can be conveniently determined by using a laser particle size analyzer according to GB / T 19077-2016 Particle Size Distribution Laser Diffraction Method. The testing instrument can be a Mastersizer 2000E laser particle size analyzer of Malvern Instruments Ltd., UK.

[0082] In some embodiments, the powder compaction density of the carbonaceous material under the action of 50000N force is 0.92g / cm 3 -1.05g / cm 3 , and optionally 0.95g / cm 3 -1.02g / cm 3 . When the powder compaction density of the carbonaceous material is within the appropriate range, the compaction density of the negative electrode sheet can be improved, and thus the energy density of the secondary battery can be improved.

[0083] In the present application, the powder compaction density of the carbonaceous material is the meaning known in the art, and can be determined by using the instruments and methods known in the art. For example, it can be determined by using an electronic pressure testing machine (for example, it can be a UTM7305) according to the standard GB / T24533-2009. The exemplary testing method is as follows: 1g of carbonaceous material powder is weighed and added into a mold with a bottom area of 1.327cm 2 , and is pressed to 5000kg (equivalent to 50000N), and is kept for 30s, then is unloaded, and is kept for 10s, then the powder compaction density of the carbonaceous material under the action of 50000N force is recorded and calculated.

[0084] In some embodiments, the tap density of the carbonaceous material is 0.80g / cm 3 -0.95g / cm 3 , and optionally 0.85g / cm 3 -0.90g / cm 3 . When the tap density of the carbonaceous material is within the appropriate range, the compaction density of the negative electrode sheet can be improved, and thus the energy density of the secondary battery can be improved.

[0085] In the present application, the tap density of the carbonaceous material is the meaning known in the art, and can be determined by using the instruments and methods known in the art. For example, it can be determined by using a powder tap density tester according to GB / T 5162-2006. The testing instrument can be a Dandong Baiter BT-301.

[0086] Method for producing carbonaceous material

[0087] The second aspect of the embodiments of the present application provides a preparation method of a carbonaceous material, which can prepare the carbonaceous material of any one of the first aspect of the embodiments of the present application.

[0088] The preparation method comprises the following steps: S10, providing a raw material, wherein the raw material comprises a hard carbon material; S20, grinding the raw material with a grinding body and an oxidizing solution in a grinder; and S30, obtaining the carbonaceous material by washing and drying the product obtained by grinding, wherein the carbonaceous material satisfies A / B≥3 and 5wt%≤A≤20wt%, wherein the content of O element in the carbonaceous material is denoted as A by X-ray photoelectron spectroscopy, and the content of O element is denoted as B by elemental analysis.

[0089] The present application introduces a suitable content of oxygen-containing functional groups on the surface of the hard carbon material by a wet grinding process, thereby obtaining the carbonaceous material satisfying A / B≥3 and 5wt%≤A≤20wt%. In the present application, the oxygen-containing functional groups can include one or more of phenolic group, ether group, quinone group, carbonyl group, acid anhydride, ester group, hydroxyl group, carboxyl group, etc. The inventors of the present application found in the research process that the negative charge can be enriched on the oxygen-containing functional groups on the surface of the carbonaceous material during charging (i.e. before the formation of SEI film), thereby the organic solvents such as esters or ethers in the electrolyte can be induced to decompose rapidly, and further the content of organic components in the SEI film can be increased.

[0090] The inventors of the present application also found in the research process that these organic components have a large number of advantages compared with inorganic components: first, the organic components in the SEI film have higher flexibility, which can improve the anti-deformation ability of the SEI film, so that it remains stable during long-term cycling, thereby reducing the consumption of active ions during cycling, and further improving the cycle performance of the secondary battery; second, the organic components in the SEI film can improve the ionic conductivity on the negative side, which is beneficial to further improve the rate performance of the secondary battery, and also can avoid the reduction and precipitation of active ions on the negative side during cycling, thereby also being beneficial to further improve the cycle performance of the secondary battery; third, the O atoms on the surface of the carbonaceous material can also participate in the formation of the SEI film, which is beneficial to improve the adhesion of the SEI film on the surface of the carbonaceous material particles, and is beneficial to the high stability of the SEI film during long-term cycling, thereby reducing the consumption of active ions during cycling, and further improving the cycle performance of the secondary battery.

[0091] Therefore, the carbonaceous material obtained by the preparation method of the present application has good cycle performance and rate performance. The preparation method of the carbonaceous material provided by the present application is simple and suitable for commercial production.

[0092] The cycle performance and rate performance of the currently commercially available hard carbon material are not ideal, and the preparation method provided in the present application can greatly optimize the cycle performance and rate performance of the raw material (i.e., the hard carbon material), and the preparation method provided in the present application has universality, and the raw material can be obtained by purchase or prepared according to the method provided in the present application.

[0093] In some embodiments, the raw material is prepared by the following method: heating the carbon source to 1000-1600℃ at a rate of ≤10℃ / min under a protective gas atmosphere, and then holding for 1-24h, and then crushing to obtain the raw material. The carbon source can include one or more of polymers, resins and biomass materials, and the protective gas can include nitrogen, argon or a combination thereof.

[0094] In some embodiments, in S10, the volume particle size Dv50 of the raw material can be 3-15μm, and can be selected to be 4-6μm. In some embodiments, in S10, the volume particle size Dv90 of the raw material can be 8-30μm, and can be selected to be 9-12μm. In some embodiments, in S10, the volume particle size Dv50 of the raw material is 3-15μm and the volume particle size Dv90 is 8-30μm, and optionally, the volume particle size Dv50 of the raw material is 4-6μm and the volume particle size Dv90 is 9-12μm. By adjusting the volume particle size Dv50 and / or Dv90 of the raw material within a suitable range, the active ion and electron transport performance of the obtained carbonaceous material can be improved, thereby further improving the cycle performance and rate performance of the secondary battery.

[0095] In some embodiments, in S20, the mass ratio of the dry weight of the raw material to the mass of the grinding body is ≤1, for example, can be ≤0.9, ≤0.8, ≤0.7, ≤0.6, ≤0.5.

[0096] When grinding, the grinding body will exert a large shear force on the raw material particles. Under the action of the shear force, the covalent bonds on the surface of the raw material particles are easily broken, and then the broken bond positions are easily reacted with the oxidizing solution to introduce oxygen-containing functional groups. When the mass ratio of the dry weight of the raw material to the mass of the grinding body is too large, the grinding body exerting the shear force will be too small, thereby causing only a small number of covalent bonds on the surface of the raw material particles to be broken and oxygen-containing functional groups to be introduced, and then the obtained carbonaceous material has a small number of oxygen-containing functional groups introduced on the surface of the particles, and the cycle performance and rate performance of the secondary battery are still poor. At this time, the carbonaceous material has a low content of O element tested by X-ray photoelectron spectroscopy.

[0097] The ratio of the dry weight of the raw material to the mass of the grinding body when designed also needs to consider the actual volume of the grinding instrument and the wet grinding effect. Further, the ratio of the dry weight of the raw material to the mass of the grinding body should not be too small. When the volume of the material in the grinding instrument is the same, due to the ratio of the dry weight of the raw material to the mass of the grinding body being too small, the amount of raw material that can be processed each time is too small, which affects the production efficiency. When the dry weight of the raw material is the same, due to the ratio of the dry weight of the raw material to the mass of the grinding body being too small, the mass of the grinding body is too large, at this time, the material in the grinding instrument is too much, which affects the wet grinding effect; in addition, the situation that the specific surface area of the carbonaceous material obtained is greatly increased and / or more oxygen-containing functional groups are introduced on the surface of the carbonaceous material particles may occur, which leads to the carbonaceous material exhibiting a high content of O element tested by X-ray photoelectron spectroscopy, and further leads to the optimization effect on the cycle performance and rate performance of the secondary battery being poor.

[0098] In some embodiments, in S20, the ratio of the dry weight of the raw material to the mass of the grinding body can be 0.2-1, 0.3-0.9, 0.4-0.8, 0.4-0.7. In this way, on the one hand, the production efficiency can be improved, and on the other hand, the surface of the obtained carbonaceous material can have a suitable content of oxygen-containing functional groups, and the carbonaceous material can also greatly improve the cycle performance and rate performance of the secondary battery.

[0099] In some embodiments, in S20, the ratio of the dry weight of the raw material to the mass of the oxidizing solution is ≤0.6, for example, it can be ≤0.55, ≤0.5, ≤0.45, ≤0.4, ≤0.35, ≤0.3, ≤0.25, ≤0.2.

[0100] After the covalent bonds on the surface of the raw material particles are broken by the grinding body, the broken bond positions can react with the oxidizing solution and introduce oxygen-containing functional groups. When the ratio of the dry weight of the raw material to the mass of the oxidizing solution is too large, the oxidizing solution is too little, which leads to the material in the grinding instrument being unable to form a slurry state, at this time, the contact between the oxidizing solution and the raw material particles is uneven, and part of the raw material particles cannot contact the oxidizing solution, which leads to the distribution area of the introduced oxygen-containing functional groups on the surface of the obtained carbonaceous material particles being less, and the cycle performance and rate performance of the area on the surface of the obtained carbonaceous material particles which fails to introduce oxygen-containing functional groups being poor, which leads to the cycle performance and rate performance of the entire secondary battery being poor. At the same time, when the ratio of the dry weight of the raw material to the mass of the oxidizing solution is too large, the oxidizing solution is too little, the material in the grinding instrument is too dry and basically flocculent, at this time, the wet grinding effect is poor, which leads to the amount of oxygen-containing functional groups introduced on the surface of the obtained carbonaceous material particles being less, and further leads to the optimization effect on the cycle performance and rate performance of the secondary battery not being obvious. At this time, the carbonaceous material exhibits a low content of O element tested by X-ray photoelectron spectroscopy.

[0101] The mass ratio of the dry weight of the raw material to the mass of the oxidizing solution also needs to be considered in the design of the actual volume of the grinder and the wet grinding effect. Further, the mass ratio of the dry weight of the raw material to the mass of the oxidizing solution should not be too small. When the volume of the material in the grinder is the same, if the mass ratio of the dry weight of the raw material to the mass of the oxidizing solution is too small, the amount of raw material that can be processed each time is too small, which affects the production efficiency. When the dry weight of the raw material is the same, if the mass ratio of the dry weight of the raw material to the mass of the oxidizing solution is too small, the mass of the oxidizing solution is too large, and at this time, the amount of material in the grinder is too much, which affects the wet grinding effect; in addition, it is also possible that more oxygen-containing functional groups are introduced on the surface of the obtained carbonaceous material particles, resulting in the carbonaceous material showing a high content of O element tested by X-ray photoelectron spectroscopy, and further resulting in a poor optimization effect on the cycle performance and rate performance of the secondary battery.

[0102] In some embodiments, in S20, the mass ratio of the dry weight of the raw material to the mass of the oxidizing solution can be 0.1-0.6, 0.1-0.5, 0.1-0.5, 0.1-0.4. In this way, on the one hand, the production efficiency can be improved, and on the other hand, the surface of the obtained carbonaceous material can have a suitable content of oxygen-containing functional groups, and the carbonaceous material can also greatly improve the cycle performance and rate performance of the secondary battery.

[0103] In some embodiments, in S20, the concentration of the oxidizing solution is ≥0.1 moL / L.

[0104] When the concentration of the oxidizing solution is too low, although more covalent bonds on the surface of the raw material particles are broken during grinding, due to the small amount of solute, the oxidation ability is weak, and therefore only a small amount of broken covalent bonds finally become oxygen-containing functional groups, the remaining broken bond sites remain, and will be used as sites for capturing active ions in the subsequent process, thereby hindering the transmission continuity of active ions on the surface of the obtained carbonaceous material particles, resulting in poor kinetic performance of the carbonaceous material, and further deteriorating the cycle performance and rate performance, at this time, the carbonaceous material shows a low content of O element tested by X-ray photoelectron spectroscopy.

[0105] Further, the concentration of the oxidizing solution should not be too large, on the one hand, it will increase the safety risk, and on the other hand, it is also possible that more oxygen-containing functional groups are introduced on the surface of the obtained carbonaceous material particles, resulting in the carbonaceous material showing a high content of O element tested by X-ray photoelectron spectroscopy, and further resulting in a poor optimization effect on the cycle performance and rate performance of the secondary battery.

[0106] In some embodiments, the concentration of the oxidizing solution is 0.1-10 moL / L, 0.2-8 moL / L, 0.3-5 moL / L, 0.4-2.5 moL / L, 0.5-1.5 moL / L. On the one hand, this can improve production efficiency and ensure safe production, and on the other hand, the surface of the obtained carbon material can have a suitable content of oxygen-containing functional groups, and the carbon material can also greatly improve the cycle performance and rate performance of the secondary battery.

[0107] In some embodiments, in S20, the grinding time is 1-24 h, for example, it can be 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h or any range consisting of the above any value. Alternatively, the grinding time is 2-20 h, 4-16 h, 6-12 h. In this way, the surface of the obtained carbon material can have a suitable content of oxygen-containing functional groups, and the carbon material can also greatly improve the cycle performance and rate performance of the secondary battery.

[0108] When grinding, the grinding body will exert a large shear force on the raw material particles. When the grinding time is too long, the shear force will act for too long, which can easily cause the raw material particles to break, and in turn, the specific surface area of the obtained carbon material will increase greatly, and a large amount of binder needs to be added during the preparation of the electrode plate to bond the particles, and the binder is generally an insulating substance, which can cause the battery resistance to increase, the ion conductivity and electronic conductivity to decrease, and in turn, the cycle performance and rate performance of the secondary battery to deteriorate. At this time, the carbon material has a high O element content as tested by X-ray photoelectron spectroscopy.

[0109] When grinding, under the action of shear force, the covalent bond on the surface of the raw material particles is easily broken, and then the broken bond position is easily reacted with the oxidizing solution to introduce oxygen-containing functional groups. When the grinding time is too short, the surface of the obtained carbon material has a small amount of oxygen-containing functional groups introduced, which can also cause the cycle performance and rate performance of the secondary battery to be poor. At this time, the carbon material has a low O element content as tested by X-ray photoelectron spectroscopy.

[0110] In the present application, the oxidizing solution refers to a solution obtained by uniformly mixing an oxidizing solute with an oxidizing solvent, which has an oxidizing ability and can introduce oxygen-containing functional groups on the surface of the particles. In some embodiments, in S20, the solute in the oxidizing solution includes one or more selected from nitric acid, sulfuric acid and perchloric acid, and the solvent includes water.

[0111] Thus, on one hand, the surface of the obtained carbonaceous material can be ensured to have a proper content of oxygen-containing functional groups, and on the other hand, the introduction of other impurity elements can be avoided, so that the irreversible consumption of active ions can be reduced.

[0112] In some embodiments, in S20, the speed of the grinding is 100 rpm-1200 rpm.

[0113] In some embodiments, in S20, the grinder includes a ball mill.

[0114] In some embodiments, in S20, the grinding body includes grinding balls, such as zirconium oxide balls. Optionally, the diameter of the grinding balls can be 2 mm-16 mm. Thus, the grinding effect can be improved, and the cycle performance and rate performance of the secondary battery can be greatly improved.

[0115] In some embodiments, in S20, the volume ratio of all materials (including the grinding body, the raw material and the oxidizing solution) in the grinder can be 1 / 5-3 / 4, based on the volume of the grinder (such as the volume of the ball mill tank in the ball mill). Thus, on one hand, the production efficiency can be improved, and on the other hand, the wet grinding effect can be improved.

[0116] In some embodiments, in S30, the washing can be water washing. The number of times of the water washing can be one or more than two, until the pH of the filtrate is 7±0.5.

[0117] In some embodiments, in S30, the drying can be vacuum drying. Optionally, the temperature of the drying is 60℃-120℃. Optionally, the time of the drying is 1h-24h.

[0118] In some embodiments, the preparation method includes the following steps: S10, providing a raw material, the raw material including a hard carbon material; S20, grinding the raw material with a grinding body and an oxidizing solution in a grinder, wherein the dry weight of the raw material and the mass of the grinding body are in a ratio of ≤1, optionally 0.2-1, the dry weight of the raw material and the mass of the oxidizing solution are in a ratio of ≤0.6, optionally 0.1-0.6, the concentration of the oxidizing solution is ≥0.1 moL / L, optionally 0.1 moL / L-10 moL / L, and the time of the grinding is 1h-24h, optionally 4h-16h; and S30, obtaining a carbonaceous material by washing and drying the product obtained by the grinding. At this time, the carbonaceous material obtained by the preparation method of the present application can greatly improve the cycle performance and rate performance of the secondary battery.

[0119] Secondary battery

[0120] The third aspect of the embodiments of the present application provides a secondary battery.

[0121] The secondary battery mentioned in the embodiments or implementations of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the secondary battery mentioned in the present application can include a battery cell, a battery module, a battery pack, or the like. The battery cell is the smallest unit constituting the secondary battery, which can independently achieve the function of charging and discharging. The present application does not have a particular limitation on the shape of the battery cell, which can be cylindrical, square, or any other shape. For example, Figure 1 is a battery cell 5 of a square structure as an example.

[0122] In some embodiments, the battery cell includes an electrode assembly and an electrolyte, and the battery cell can further include an outer package. The outer package can be used to encapsulate the electrode assembly and the electrolyte. The outer package can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, or the like. The outer package can also be a soft package, such as a pouch-type soft package. The material of the soft package can be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0123] The electrode assembly generally includes a positive electrode sheet, a negative electrode sheet, and the like. During the charging and discharging of the secondary battery, active ions are inserted and extracted between the positive electrode sheet and the negative electrode sheet, and the electrolyte plays a role in conducting the active ions between the positive electrode sheet and the negative electrode sheet. The electrode assembly can be made by a rolling process and / or a stacking process.

[0124] In some embodiments, as shown in Figure 2 The outer package can include a shell 51 and a cover plate 53. The shell 51 can include a bottom plate and a side plate connected to the bottom plate, which enclose a receiving cavity. The shell 51 has an opening communicating with the receiving cavity, and the cover plate 53 is used to cover the opening to close the receiving cavity. The electrode assembly 52 is encapsulated in the receiving cavity. The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, which can be adjusted according to requirements.

[0125] In some embodiments of the present application, the battery cell can be assembled into a battery module, and the number of battery cells contained in the battery module can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module. Figure 3 is a schematic diagram of a battery module 4 as an example. As shown in Figure 3 In the battery module 4, a plurality of battery cells 5 can be arranged in sequence along the length direction of the battery module 4. Of course, other arbitrary arrangements can also be used. Further, the plurality of battery cells 5 can be fixed by fasteners.

[0126] Optionally, the battery module 4 can further include a housing having a receiving space, and the plurality of battery cells 5 are received in the receiving space.

[0127] In some embodiments, the above battery module can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack. Figure 4 and Figure 5 is a schematic diagram of a battery pack 1 as an example. As shown in Figure 4 and Figure 5 As shown in the battery pack 1 can include a battery box and a plurality of battery modules 4 arranged in the battery box. The battery box includes an upper box body 2 and a lower box body 3, the upper box body 2 is used to cover the lower box body 3, and forms a closed space for accommodating the battery module 4. The plurality of battery modules 4 can be arranged in the battery box in any manner.

[0128] [Negative electrode tab]

[0129] In some embodiments, the negative electrode tab includes a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector. For example, the negative electrode current collector has two opposite surfaces in the thickness direction of itself, and the negative electrode film layer is arranged on any one or both of the two opposite surfaces of the negative electrode current collector.

[0130] In some embodiments, the negative electrode film layer includes the carbonaceous material of the first aspect of the embodiments or the carbonaceous material prepared by the method of the second aspect of the embodiments. Thereby, the cycle performance and rate performance of the secondary battery can be greatly improved.

[0131] In some embodiments, the negative electrode film layer can further include other negative electrode active materials in addition to the above-mentioned carbonaceous material. In some embodiments, the other negative electrode active materials include, but are not limited to, one or more of natural graphite, artificial graphite, soft carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based materials can include one or more of elemental silicon, silicon oxide, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy material. The tin-based materials can include one or more of elemental tin, tin oxide, and tin alloy material.

[0132] In some embodiments, the negative electrode film layer can also optionally include a negative electrode conductive agent. The present application does not have a particular limitation on the type of the negative electrode conductive agent. As an example, the negative electrode conductive agent can include one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0133] In some embodiments, the negative electrode film layer can optionally further include a negative electrode binder. The present application does not have a particular limitation on the kind of the negative electrode binder, and as an example, the negative electrode binder can include one or more of styrene butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin (e.g., polyacrylic acid PAA, polymethylacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0134] In some embodiments, the negative electrode film layer can optionally further include other auxiliary agents. As an example, the other auxiliary agents can include a thickening agent, such as sodium carboxymethyl cellulose (CMC), PTC thermistor material, etc.

[0135] In some embodiments, the negative electrode current collector can adopt a metal foil or a composite current collector. As an example of the metal foil, a copper foil can be adopted. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material can include one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer can include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0136] The negative electrode film layer is generally formed by coating a negative electrode slurry on a negative electrode current collector, drying, and cold pressing. The negative electrode slurry is generally formed by dispersing a negative electrode active material, an optional conductive agent, an optional binder, and other optional auxiliary agents in a solvent and stirring uniformly. The solvent can be N-methyl pyrrolidone (NMP) or deionized water, but is not limited thereto.

[0137] The negative electrode tab does not exclude other additional functional layers in addition to the negative electrode film layer. For example, in some embodiments, the negative electrode tab described in the present application further includes a conductive primer layer (e.g., composed of a conductive agent and a binder) interposed between the negative electrode current collector and the negative electrode film layer and disposed on the surface of the negative electrode current collector; in some embodiments, the negative electrode tab described in the present application further includes a protective layer covering the surface of the negative electrode film layer.

[0138] [Positive electrode tab]

[0139] In some embodiments, the positive electrode tab includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector. For example, the positive electrode current collector has two surfaces opposite in the thickness direction thereof, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0140] The positive current collector can employ a metal foil or a composite current collector. As an example of the metal foil, an aluminum foil can be employed. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material can include one or more of aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy. As an example, the polymer material base layer can include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0141] The positive electrode film layer generally includes a positive active material, an optional binder, and an optional conductive agent. The positive electrode film layer is generally formed by coating a positive electrode slurry on the positive current collector, drying, and cold-pressing. The positive electrode slurry is generally formed by dispersing and uniformly stirring a positive active material, an optional conductive agent, an optional binder, and any other components in a solvent. The solvent can be N-methyl pyrrolidone (NMP), but is not limited thereto. As an example, the binder used in the positive electrode film layer can include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylic resin. As an example, the conductive agent used in the positive electrode film layer includes one or more of super P, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0142] The positive active material can employ a positive active material for a secondary battery known in the art.

[0143] When the secondary battery of the present application is a lithium ion battery, the positive active material can include, but is not limited to, one or more of a lithium-containing transition metal oxide, a lithium-containing phosphate, and a modified compound of each thereof. Examples of the lithium-containing transition metal oxide can include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and a modified compound of each thereof. Examples of the lithium-containing phosphate can include, but are not limited to, one or more of lithium iron phosphate, a composite of lithium iron phosphate and carbon, lithium manganese phosphate, a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite of lithium manganese iron phosphate and carbon, and a modified compound of each thereof.

[0144] In some embodiments, in order to further increase the energy density of the secondary battery, the positive active material for a lithium ion battery can include a compound represented by the general formula Li a Nib Co c M d O e A f One or more of lithium transition metal oxides and their modified compounds. 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M includes one or more selected from Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A includes one or more selected from N, F, S and Cl.

[0145] As an example, positive electrode active materials for lithium-ion batteries may include LiCoO2, LiNiO2, LiMnO2, LiMn2O4, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811), LiNi 0.85 Co 0.15 Al 0.05 One or more of O2, LiFePO4 and LiMnPO4.

[0146] When the secondary battery of this application is a sodium-ion battery, the positive electrode active material may include, but is not limited to, one or more of sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials.

[0147] As an example, positive electrode active materials for sodium-ion batteries may include NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue materials and materials with the general formula X p M'q (PO4) r O x Y 3-x one or more of materials selected from the group consisting of Li p M’ q (PO4) r O x Y 3-x , 0 < p ≤ 4, 0 < q ≤ 2, 1 ≤ r ≤ 3, 0 ≤ x ≤ 2, X includes one or more selected from the group consisting of H + , Li + , Na + , K + and NH4 + , M' is a transition metal cation, which can optionally include one or more selected from the group consisting of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halogen anion, which can optionally include one or more selected from the group consisting of F, Cl and Br.

[0148] In the present application, the modification compound of each of the above positive electrode active materials can be a doping modification and / or a surface coating modification to the positive electrode active material.

[0149] [Electrolyte]

[0150] The type of the electrolyte in the present application is not particularly limited and can be selected according to actual needs. For example, the electrolyte can be selected from at least one of a solid-state electrolyte and a liquid electrolyte (i.e., electrolyte solution).

[0151] In some embodiments, the electrolyte employs an electrolyte solution including an electrolyte salt and a solvent.

[0152] The type of the electrolyte salt is not particularly limited and can be selected according to actual needs.

[0153] When the secondary battery of the present application is a lithium ion battery, as an example, the electrolyte salt can include one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonylimide (LiFSI), lithium bis-trifluoromethanesulfonylimide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalato borate (LiDFOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalato phosphate (LiDFOP) and lithium tetrafluorodioxalato phosphate (LiTFOP).

[0154] When the secondary battery of the present application is a sodium-ion battery, the electrolyte salt can include one or more of sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), sodium bisfluorosulfonylimide (NaFSI), sodium bis-trifluoromethanesulfonylimide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluoro oxalate borate (NaDFOB), sodium bisoxalate borate (NaBOB), sodium difluorophosphate (NaPO2F2), sodium difluoro di-oxalate phosphate (NaDFOP), and sodium tetrafluoro oxalate phosphate (NaTFOP).

[0155] The kind of the solvent is not particularly limited, and can be selected according to actual needs. In some embodiments, as an example, the solvent can include one or more of ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0156] In some embodiments, the electrolyte solution can also optionally include an additive. For example, the additive can include a negative electrode film-forming additive, can also include a positive electrode film-forming additive, and can also include an additive capable of improving certain performance of the battery, such as an additive capable of improving overcharge performance of the battery, an additive capable of improving high-temperature performance of the battery, an additive capable of improving low-temperature power performance of the battery, etc.

[0157] [Separator]

[0158] In some secondary batteries using electrolyte, and some secondary batteries using solid-state electrolyte, a separator is also included. The separator is disposed between the positive electrode sheet and the negative electrode sheet, and functions to separate. The kind of the separator is not particularly limited in the present application, and any known porous structure separator having good chemical stability and mechanical stability can be selected.

[0159] In some embodiments, the material of the separator can include one or more of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film, or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of the layers can be the same or different.

[0160] [Preparation method]

[0161] The preparation method of the secondary battery of the present application is known. In some embodiments, the positive electrode sheet, the separator, the negative electrode sheet and the electrolyte can be assembled to form a secondary battery. As an example, the positive electrode sheet, the separator, the negative electrode sheet can be formed into an electrode assembly through a winding process and / or a stacking process, the electrode assembly is placed in an outer package, the electrolyte is injected after drying, and the battery monomer is obtained through processes such as vacuum packaging, standing, formation, shaping, etc. A plurality of battery monomers can further be connected in series or in parallel or in a hybrid manner to form a battery module. A plurality of battery modules can further be connected in series or in parallel or in a hybrid manner to form a battery pack. In some embodiments, a plurality of battery monomers can also be directly connected to form a battery pack.

[0162] Electric device

[0163] The fourth aspect of the embodiments of the present application provides a power consuming device, which comprises the secondary battery of the present application. The secondary battery can be used as a power source of the power consuming device, or can be used as an energy storage unit of the power consuming device. The power consuming device can be, but is not limited to, a mobile device (such as a mobile phone, a tablet computer, a notebook computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship and a satellite, an energy storage system, etc.

[0164] The specific type of the secondary battery, such as a battery monomer, a battery module or a battery pack, can be selected according to the use requirements of the power consuming device.

[0165] Figure 6 is a schematic diagram of a power consuming device as an example. The power consuming device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the requirements of high power and high energy density of the power consuming device, a battery pack or a battery module can be used as a power source.

[0166] The power consuming device as another example can be a mobile phone, a tablet computer, a notebook computer, etc. The power consuming device usually requires thinning, and a battery monomer can be used as a power source.

[0167] Embodiments

[0168] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0169] Example 1

[0170] Using phenolic resin as the carbon source, the temperature was raised to 1400℃ at a rate of 5℃ / min under a nitrogen atmosphere and held for 12 hours. The resulting material was then ball-milled to obtain a hard carbon material with a Dv50 of 6±0.5μm. The hard carbon material, along with zirconium oxide balls and an oxidizing solution, was placed in the ball mill jar of a planetary ball mill and ball-milled at 600 rpm for 10 hours. After washing and drying, the carbonaceous material was obtained. The dry weight ratio of the hard carbon material to the grinding media was 0.6, and the dry weight ratio of the hard carbon material to the oxidizing solution was 0.2. The concentration of the oxidizing solution was 0.1 mol / L, the solute was perchloric acid, and the solvent was deionized water.

[0171] After vacuum drying the carbonaceous material at 120℃ for 12 hours, it was sealed and stored in an aluminum-plastic bag. The oxygen content was then measured using an X-ray photoelectron spectrometer (XPS) and recorded as A, and the oxygen content was measured using an elemental analyzer and recorded as B. The testing instruments used were the Thermo Fisher Scientific Nexsa / EscaLab 250Xi XPS and the Thermo Fisher Scientific Flash 2000 / Flash Smart elemental analyzer.

[0172] The BET specific surface area of ​​carbonaceous materials was determined using the nitrogen adsorption specific surface area analysis method, in accordance with GB / T 19587-2017. The testing instrument can be the ASAP 3020 surface area and pore size analyzer from Micromeritics, USA.

[0173] Examples 2-16 and Comparative Examples 3-7

[0174] The preparation method of carbonaceous materials is similar to that in Example 1, except that the preparation process parameters of carbonaceous materials are adjusted, as detailed in Table 1.

[0175] Comparative Example 1

[0176] Using phenolic resin as a carbon source, the temperature was raised to 1400℃ at a rate of 5℃ / min under a nitrogen atmosphere and held for 12h. The material was then crushed by ball milling to obtain a hard carbon material with a Dv50 of 6±0.5μm, which was used as a carbonaceous material.

[0177] Comparative Example 2

[0178] Phenolic resin was used as carbon source, and the temperature was raised to 1400℃ at a rate of 5℃ / min under nitrogen atmosphere, and then the temperature was kept for 12h. The hard carbon material with Dv50 of 6±0.5μm was obtained by ball milling. The hard carbon material was soaked in 1mol / L perchloric acid aqueous solution for 48h, and then the carbonaceous material was obtained by washing and drying. The mass ratio of the dry weight of the hard carbon material to the perchloric acid aqueous solution was 0.1.

[0179] Production of secondary battery

[0180] The carbonaceous material, conductive agent carbon black (Super P), binder styrene-butadiene rubber, and thickening agent sodium carboxymethyl cellulose were mixed in a weight ratio of 96:1:1:2 in a proper amount of solvent deionized water to form a negative electrode slurry. The negative electrode slurry was coated on both surfaces of the negative electrode current collector copper foil, and then the negative electrode sheet was obtained by drying and cold pressing.

[0181] The positive electrode active material NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, conductive carbon black, and polyvinylidene fluoride were mixed in a weight ratio of 96:2.5:1.5, and a proper amount of solvent NMP was added to obtain a positive electrode slurry. The positive electrode slurry was coated on both surfaces of the positive electrode current collector aluminum foil, and then the positive electrode sheet was obtained by drying and cold pressing.

[0182] Ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent, and then NaPF6 was added to the organic solvent to prepare an electrolyte with a concentration of 1mol / L.

[0183] A polypropylene film with a thickness of 12μm was used as a separator film, and the positive electrode sheet and the negative electrode sheet prepared above were placed in order with the separator film in the middle to play a separating role. Then, an electrode assembly was obtained by winding. The electrode assembly was placed in an outer package, and then the electrolyte prepared above was injected after drying. After vacuum packaging, standing, formation, and capacity processes, a secondary battery was obtained.

[0184] Performance test

[0185] (1) Secondary battery 25℃ cycle performance test

[0186] The secondary battery was charged at 1 C constant current to 4.0 V, then charged at constant voltage to 0.05 C, and then discharged at 1 C constant current to 1.5 V after 5 min of rest, which was one charge-discharge cycle process. The discharge capacity at this time was the discharge capacity after the first cycle of the secondary battery. The above charge-discharge cycle was repeated until the discharge capacity decreased to 80% of the discharge capacity after the first cycle, and the number of cycles of the secondary battery at this time was recorded.

[0187] (2) Secondary battery 45 °C cycle performance test

[0188] The secondary battery was charged at 1 C constant current to 4.0 V, then charged at constant voltage to 0.05 C, and then discharged at 1 C constant current to 1.5 V after 5 min of rest, which was one charge-discharge cycle process. The discharge capacity at this time was the discharge capacity after the first cycle of the secondary battery. The above charge-discharge cycle was repeated until the discharge capacity decreased to 80% of the discharge capacity after the first cycle, and the number of cycles of the secondary battery at this time was recorded.

[0189] (3) Secondary battery 25 °C rate performance test

[0190] The secondary battery was charged at 0.33 C constant current to 4.0 V, then charged at constant voltage to 0.05 C, and then discharged at 0.33 C constant current to 1.5 V after 5 min of rest, which was one charge-discharge cycle process. The discharge capacity at this time was the discharge capacity of the secondary battery at 0.33 C.

[0191] The secondary battery was charged at 1 C constant current to 4.0 V, then charged at constant voltage to 0.05 C, and then discharged at 1 C constant current to 1.5 V after 5 min of rest, which was one charge-discharge cycle process. The discharge capacity at this time was the discharge capacity of the secondary battery at 1 C.

[0192] The ratio of the discharge capacity of the secondary battery at 1 C to the discharge capacity of the secondary battery at 0.33 C was used to represent the rate performance of the secondary battery.

[0193] According to the test results in Table 1, when the O element content A tested by X-ray photoelectron spectroscopy and the O element content B tested by elemental analysis of the carbonaceous material satisfy A / B≥3 and 5 wt%≤A≤20 wt%, the cycle performance and rate performance of the secondary battery can be significantly optimized.

[0194] The carbonaceous material provided by the present application is obtained by wet grinding treatment of the hard carbon material provided by Comparative Example 1, so that a suitable amount of oxygen-containing functional groups can be introduced on the surface of the hard carbon material provided by Comparative Example 1. The inventors of the present application found in the research process that, during charging (i.e. before the formation of SEI film), negative charges can be enriched on the oxygen-containing functional groups on the surface of the carbonaceous material, so that the ester organic solvent in the electrolyte can be induced to decompose rapidly, and thus the content of organic components in the SEI film can be increased. The organic components in the SEI film have higher flexibility, which can improve the anti-deformation ability of the SEI film, so that it can remain stable during long-term cycling, thereby reducing the consumption of active ions during cycling; the organic components in the SEI film can improve the ionic conductivity on the negative electrode side, and also can avoid the reduction and precipitation of active ions on the negative electrode side during cycling; the O atoms on the surface of the carbonaceous material can also participate in the formation of the SEI film, which is beneficial to improve the adhesion of the SEI film on the surface of the carbonaceous material particles, and is beneficial to the high stability of the SEI film during long-term cycling, so that the consumption of active ions during cycling can be reduced. Therefore, the secondary battery using the carbonaceous material provided by the present application can have greatly improved cycle performance and rate performance. The test results of Examples 1-16 also show that when the carbonaceous material further satisfies 6≤A / B≤9.2, 10wt%≤A≤16wt% and 1.5wt%≤B≤3wt%, the optimization effect on the cycle performance and rate performance of the secondary battery is better.

[0195] Comparative Example 2 also can introduce oxygen-containing functional groups on the surface of the hard carbon material provided by Comparative Example 1 by using the oxidative solution immersion method, but the amount of oxygen-containing functional groups introduced is less, so that the optimization effect on the cycle performance and rate performance of the secondary battery is not obvious.

[0196] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having the same technical idea and playing the same role and effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, within the scope of the main idea of the present application, various modifications of the embodiments that can be thought of by those skilled in the art, and other ways constructed by combining part of the components of the embodiments are also included in the scope of the present application.

[0197]

Claims

1. A carbonaceous material, wherein, The carbonaceous material has an O content measured by X-ray photoelectron spectroscopy, denoted as A, and an O content measured by elemental analysis, denoted as B. The carbonaceous material satisfies A / B≥3 and 5wt%≤A≤20wt%. In the Raman spectrum of the carbonaceous material, I d / I g The value is 0.90-1.25, I d This indicates that the Raman displacement is within 1350 ± 50 cm. -1 The d-peak intensity within the range, I g This indicates that the Raman displacement is within 1580±50cm. -1 The intensity of the g peak within the range.

2. The carbonaceous material according to claim 1, wherein, 3 ≤ A / B ≤ 10; and / or, 5wt% ≤ A ≤ 16wt%.

3. The carbonaceous material according to claim 2, wherein, 6 ≤ A / B ≤ 9.2; and / or, 10wt% ≤ A ≤ 16wt%.

4. The carbonaceous material according to claim 1 or 2, wherein, 1.5wt% ≤ B ≤ 6wt%.

5. The carbonaceous material according to claim 4, wherein, 1.5wt% ≤ B ≤ 3wt%.

6. The carbonaceous material according to any one of claims 1-3, wherein, The specific surface area of ​​the carbonaceous material is ≤10m². 2 / g.

7. The carbonaceous material according to claim 6, wherein, The specific surface area of ​​the carbonaceous material is 0.1 m². 2 / g-10m 2 / g.

8. The carbonaceous material according to claim 1, wherein, The carbonaceous material includes multiple nanoporous structures.

9. The carbonaceous material according to claim 1, wherein, In the Raman spectrum of the carbonaceous material, I d / I g For example, 0.95-1.10; and / or, The interlayer spacing of the (002) crystal plane of the carbonaceous material is ≥0.37 nm; and / or, In the X-ray diffraction spectrum of the carbonaceous material, the 2θ value corresponding to the (002) crystal plane peak is between 22° and 24°.

10. The carbonaceous material according to claim 9, wherein, The interlayer spacing of the (002) crystal plane of the carbonaceous material is 0.37nm-0.42nm.

11. The carbonaceous material according to claim 1, wherein, The carbonaceous material satisfies at least one of the following conditions (1) to (4): (1) The volumetric particle size Dv50 of the carbonaceous material is 3μm-15μm; (2) The volumetric particle size Dv90 of the carbonaceous material is 8μm-30μm; (3) The compacted density of the carbonaceous material under a force of 50,000 N is 0.92 g / cm³. 3 -1.05g / cm 3 ; (4) The tap density of the carbonaceous material is 0.80 g / cm³. 3 -0.95g / cm 3 .

12. The carbonaceous material according to claim 11, wherein, The carbonaceous material satisfies at least one of the following conditions (1) to (4): (1) The volumetric particle size Dv50 of the carbonaceous material is 4μm-6μm; (2) The volumetric particle size Dv90 of the carbonaceous material is 9μm-12μm; (3) The compacted density of the carbonaceous material under a force of 50,000 N is 0.95 g / cm³. 3 -1.02g / cm 3 ; (4) The tap density of the carbonaceous material is 0.85 g / cm³. 3 -0.90g / cm 3 .

13. A method for preparing a carbonaceous material, comprising the following steps: S10, providing raw materials, wherein the raw materials include hard carbon materials; S20, grinding the raw materials with a grinding media and an oxidizing solution in a grinding mill; S30, washing and drying the product obtained from the grinding to obtain a carbonaceous material, wherein... The carbonaceous material has an O content measured by X-ray photoelectron spectroscopy, denoted as A, and an O content measured by elemental analysis, denoted as B. The carbonaceous material satisfies A / B≥3 and 5wt%≤A≤20wt%. In the Raman spectrum of the carbonaceous material, I d / I g The value is 0.90-1.25, I d This indicates that the Raman displacement is within 1350 ± 50 cm. -1 The d-peak intensity within the range, I g This indicates that the Raman displacement is within 1580±50cm. -1 The intensity of the g peak within the range.

14. The method according to claim 13, wherein, In S20, The dry weight ratio of the raw material to the mass of the grinding media is ≤1; and / or, The dry weight ratio of the raw material to the oxidizing solution is ≤0.6; and / or, The concentration of the oxidizing solution is ≥0.1 mol / L; and / or, The grinding time is 1 hour to 24 hours.

15. The method according to claim 14, wherein, In S20, The dry weight ratio of the raw material to the mass of the grinding media is 0.2-1; and / or, The dry weight ratio of the raw material to the oxidizing solution is 0.1-0.6; and / or, The concentration of the oxidizing solution is 0.1 mol / L to 10 mol / L; and / or, The grinding time is 4h-16h.

16. The method according to claim 13, wherein, In S20, the solute in the oxidizing solution includes one or more selected from nitric acid, sulfuric acid and perchloric acid, and the solvent includes water.

17. The method according to claim 13, wherein, In S20, the grinding speed is 100rpm-1200rpm.

18. The method according to claim 13, wherein, In S20, the grinding instrument includes a ball mill.

19. The method according to claim 13, wherein, In S20, the total volume ratio of all materials in the grinder is 1 / 5 to 3 / 4, based on the volumetric capacity of the grinder.

20. The method according to claim 13, wherein, In S10, the volumetric particle size Dv50 of the raw material is 3μm-15μm; and / or, In S10, the volumetric particle size Dv90 of the raw material is 8μm-30μm.

21. The method according to claim 20, wherein, In S10, the volumetric particle size Dv50 of the raw material is 4μm-6μm; and / or, In S10, the volumetric particle size Dv90 of the raw material is 9μm-12μm.

22. The method according to claim 13, wherein, The raw material is prepared by the following method: the carbon source is heated to 1000℃-1600℃ at a rate of ≤10℃ / min under a protective gas atmosphere and held at that temperature for 1h-24h, and then crushed to obtain the raw material.

23. A secondary battery, comprising a negative electrode, said negative electrode comprising the carbonaceous material according to any one of claims 1-12 or the carbonaceous material prepared by the method according to any one of claims 13-22.

24. An electrical device comprising the secondary battery of claim 23.

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