Resin material as well as preparation method and application thereof

Abstract

The invention provides a resin material and a preparation method and application thereof, and relates to the technical field of batteries, the resin material comprises spherical resin particles, the surface contains rough and smooth areas, and the ratio of the sum of the areas of the smooth areas to the surface area of the smooth particles with the same diameter is defined as a smooth coefficient. The average value of the smoothness coefficients of the spherical resin particles in the resin material, namely the smoothness coefficient S1, is 0.0-80.0%. The resin material can be prepared by adding resin, a roughening agent and an optional curing agent into water containing an emulsifier and carrying out solid-liquid separation after the reaction is finished. A spherical carbon material with a rough surface can be obtained by carbonizing the resin material, and a spherical silicon-carbon composite material with a rough surface can be prepared by taking the carbon material as a framework and is used for a negative electrode and a battery; the problem that in the prior art, the circulation stability of spherical silicon-carbon negative electrode particles is poor due to the fact that active substances are prone to being separated from electric contact in the charging and discharging circulation of the lithium ion secondary battery can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and relates to a resin material, a preparation method thereof and an application thereof. Background Art

[0002] With the development of the new energy industry, the actual specific capacity of graphite anodes has approached its theoretical value (372 mAh / g), but it still cannot well meet the demand for energy density. Silicon materials have become the preferred alternative materials for lithium-ion battery anodes due to their high theoretical specific capacity (3579 mAh / g at room temperature) and low voltage platform (~0.4 V vs . Li / Li + ).

[0003] However, as the anode of lithium-ion batteries, silicon-based materials have serious volume expansion-shrinkage effects during charge and discharge processes. The volume expansion rate in the fully lithiated state can reach 300%. At the same time, silicon also has the problem of low conductivity. These problems seriously affect the cycle performance and rate performance of silicon anodes. Depositing silicon into a porous carbon skeleton to prepare a silicon-carbon composite material can use the carbon skeleton with a low expansion rate to limit the expansion of silicon and increase its conductivity. Among them, spherical carbon skeletons have high application potential in the field of silicon-carbon electrodes due to their good isotropy, high mechanical strength, high tap density, etc. However, in the process of lithium insertion and extraction of the silicon@ordinary smooth surface spherical carbon skeleton composite material, the composite material particles are easily detached from the binder due to volume shrinkage and expansion, resulting in disconnection of electrical contact, thereby reducing the cycle stability of the battery and shortening the service life, which limits its industrial application. How to effectively solve the problem of easy disconnection of electrical contact of spherical silicon-carbon anode materials and greatly improve their service life is a research hotspot of spherical silicon-carbon anode materials at present.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] One object of the present invention is to provide a resin material, the resin material is a spherical material and has a rough surface, so as to solve the problems of smooth surface and low surface area of existing spherical resin materials.

[0006] Another object of the present invention is to provide a preparation method of the above resin material.

[0007] A third object of the present invention is to provide a carbon material, the carbon material is a spherical material and has a rough surface, so as to solve the problem of low contact surface between existing smooth spherical carbon material particles.

[0008] A fourth object of the present invention is to provide a silicon-carbon composite material, so as to solve the problem of poor cycle stability caused by easy disconnection of electrical contact of active substances in the charge and discharge cycles of spherical silicon-carbon anode particles in the prior art.

[0009] A fifth object of the present invention is to provide a negative electrode.

[0010] A sixth object of the present invention is to provide a battery.

[0011] In order to achieve the above objects of the present invention, the following technical solutions are specifically adopted: In a first aspect, the present invention provides a resin material, the resin material includes spherical resin particles, and the smoothness coefficient S 1 of the resin material is 0.0 to 80.0%; the smoothness coefficient S 1 of the resin material is defined as the average value of the smoothness coefficients of the spherical resin particles in the resin material; the smoothness coefficient of the spherical resin particles is defined as the ratio of the sum of the smooth area of the spherical resin particles to the surface area of the smooth particles with the same diameter.

[0012] Further, the smoothness coefficient S 1 of the resin material is 0.0 to 10.0%; preferably, the smoothness coefficient S 1 of the resin material is 0.0 to 5.0%.

[0013] Further, the particle size d V50 of the resin material is 2 to 100 μm; preferably, the particle size d V50 of the resin material is 3 to 30 μm.

[0014] Further, the particle size distance of the resin material is 0.4 to 2.0; preferably, the particle size distance of the resin material is 0.4 to 1.2.

[0015] Further, the degree of curing of the resin material is 70.0 to 100.0%; preferably, the degree of curing of the resin material is 80.0 to 100.0%.

[0016] Further, the char residue rate of the resin material is 10.0 to 70.0%; preferably, the char residue rate of the resin material is 40.0 to 60.0%.

[0017] In a second aspect, the present invention provides a method for preparing a resin material, the preparation method includes the following steps: Step S1, preparing a uniform emulsifier dispersion; Step S2, adding resin, a roughening agent and an optional curing agent into the emulsifier dispersion obtained in step S1, continuously stirring at a constant temperature until the reaction ends, and obtaining a resin material through solid-liquid separation; the resin material is a spherical resin material with a rough surface.

[0018] Further, the roughening agent comprises one or more of aniline oligomers, lignosulfonates, sulfonated asphalt, polystyrene sulfonic acid, or surfactant Tween-20.

[0019] Further, the mass fraction of the roughening agent in the resin is 1.0% - 50.0%, preferably, the mass fraction of the roughening agent in the resin is 10.0 - 30.0%.

[0020] Further, the resin comprises one or more of thermoplastic phenolic resin, thermosetting phenolic resin, urea-formaldehyde resin, epoxy resin, or polystyrene resin; or, the resin comprises one or more of the precursors of thermoplastic phenolic resin, the precursors of thermosetting phenolic resin, the precursors of urea-formaldehyde resin, the precursors of epoxy resin, or the precursors of polystyrene resin.

[0021] Further, the emulsifier is a surfactant, preferably, the surfactant includes one or more of sodium dodecylbenzenesulfonate, polyvinyl alcohol, sodium octadecyl, polyethylene glycol, guar gum, sodium carboxymethyl cellulose, F-II type emulsifier, or sodium caseinate.

[0022] Further, the curing agent includes one or more of hexamethylenetetramine, p-toluenesulfonic acid, ethylenediamine, paraformaldehyde, aniline, hydrochloric acid, formaldehyde, boric acid, or propylene carbonate.

[0023] Further, the temperature of the reaction is 60 - 98 °C, preferably, the temperature of the reaction is 85 - 98 °C.

[0024] In a third aspect, the present invention provides a carbon material, the carbon material comprises spherical carbon particles, and the smoothness coefficient S 2 of the carbon material is 0.0 - 80.0%; the smoothness coefficient S 2 of the carbon material is defined as the average value of the smoothness coefficients of the spherical carbon particles in the carbon material; the smoothness coefficient of the spherical carbon particles is defined as the ratio of the sum of the smooth area of the spherical carbon particles to the surface area of a smooth particle with the same diameter.

[0025] Further, the smoothness coefficient S 2 of the carbon material is 0.0 - 10.0%; preferably, the smoothness coefficient S 2 of the carbon material is 0.0 - 5.0%.

[0026] Further, the specific surface area of the carbon material is 200 - 2500 m 2 / g, preferably, the specific surface area of the carbon material is 1000 - 2000 m 2 / g.

[0027] Further, the pore volume of the carbon material is 0.1~1.5 cm 3 / g. Preferably, the pore volume of the carbon material is 0.5~1.2 cm 3 / g.

[0028] Further, the carbon material is obtained by carbonizing a resin material, and the resin material is the resin material described in the first aspect of the present invention, or the resin material obtained according to the preparation method of the resin material described in the second aspect.

[0029] Further, after carbonization, activation and / or de-functionalization treatment is also included.

[0030] In a fourth aspect, the present invention provides a silicon-carbon composite material, which comprises a carbon material and silicon nanoparticles, and the silicon nanoparticles are located in the pores of the carbon material; the silicon-carbon composite material comprises spherical silicon-carbon particles, and the smoothness coefficient S of the silicon-carbon composite material 3 is 0.0~80.0%; the smoothness coefficient S of the silicon-carbon composite material 3 is defined as the average value of the smoothness coefficients of the spherical silicon-carbon particles in the silicon-carbon composite material; the smoothness coefficient of the spherical silicon-carbon particles is defined as the ratio of the sum of the smooth areas of the spherical silicon-carbon particles to the surface area of a smooth particle with the same diameter; The carbon material in the silicon-carbon composite material comprises the carbon material described in the third aspect of the present invention.

[0031] Further, the smoothness coefficient S of the silicon-carbon composite material 3 is 0.0~10.0%; preferably, the smoothness coefficient S of the silicon-carbon composite material 3 is 0.0~5.0%.

[0032] Further, the silicon-carbon composite material is obtained by chemical vapor deposition of a silicon-containing precursor on the carbon material at 150~1000 °C; preferably, the silicon-containing precursor is selected from one or more of silane, disilane, trisilane, halogenated silane, polysilane, silafluorene and its derivatives, or silafuorene and its derivatives; And / or, a heteroatom-containing precursor is introduced during the chemical vapor deposition process; the heteroatom-containing precursor includes at least one of an oxygen-containing precursor, a carbon-containing precursor, a nitrogen-containing precursor, a phosphorus-containing precursor, a sulfur-containing precursor, a boron-containing precursor, etc.; further preferably, the manner in which the silicon-containing precursor and the heteroatom-containing precursor contact the porous substrate includes: the silicon-containing precursor and the heteroatom-containing precursor alternately contact the porous substrate; or, the silicon-containing precursor and the heteroatom-containing precursor simultaneously contact the porous substrate; or, the silicon-containing precursor and a mixed gas containing the silicon-containing precursor and the heteroatom-containing precursor alternately contact the porous substrate; further preferably, the silicon-containing precursor continuously contacts the porous substrate, and the heteroatom-containing precursor is intermittently introduced during this process.

[0033] Furthermore, the silicon-carbon composite material further includes a coating layer on the surface of the silicon-carbon composite material; preferably, the material of the coating layer is selected from at least one of a solid electrolyte, a conductive polymer, a carbonaceous material, a metal, an alloy, a metal oxide, a metal hydroxide, a halogen-containing compound, a nitrogen-containing compound, a phosphorus-containing compound, a boron-containing compound, or a sulfur-containing compound; further preferably, the material of the coating layer is a carbonaceous material.

[0034] In a fifth aspect, the present invention provides a negative electrode, the negative electrode includes a negative electrode active material, and the negative electrode active material includes the silicon-carbon composite material described in the fifth aspect of the present invention.

[0035] In a sixth aspect, the present invention provides a battery, the battery includes a positive electrode, a negative electrode, a separator, and an electrolyte, and the negative electrode includes the silicon-carbon composite material described in the fifth aspect of the present invention.

[0036] Compared with the prior art, the present invention has the following beneficial effects: The resin material provided by the present invention has a smoothness coefficient S 1 of 0.0 to 80.0%, which can effectively increase the direct contact area between particles and between particles and other substances (such as binders, adsorbates, etc.).

[0037] The preparation method of the resin material provided by the present invention is simple. Compared with general resin balls, only a small amount of roughening agent needs to be added, and the cost is controllable.

[0038] The carbon material provided by the present invention has a smoothness coefficient S 2 of 0.0 to 80.0%, and also has a rough surface, which is beneficial to better play its role in applications in the fields of catalysts, porous carriers, hard carbon precursors, graphite precursors, capacitive carbon, adsorbents, and drug carriers.

[0039] The silicon-carbon composite material provided by the present invention is obtained by depositing silicon using the carbon material provided by the present invention as a substrate. Due to the silicon-carbon composite smoothness coefficient S 3is 0.0 to 80.0%, so the effective contact area between it and the binder is greatly increased, solving the technical problem that spherical silicon-carbon anode particles are prone to detachment from electrical contact during the charge and discharge cycles of secondary batteries; improving the cycle stability of the spherical silicon-carbon composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0041] Figure 1 It is a scanning electron microscope image of the spherical resin material with a rough surface provided in Example 1 of the present invention; Figure 2 It is a scanning electron microscope image of the spherical resin material with a rough surface provided in Example 4 of the present invention; Figure 3 It is a scanning electron microscope image of the spherical resin material with a smooth surface provided in Comparative Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0042] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meanings and scopes of the terms should be clear. However, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or extrinsic definition. In this application, unless otherwise stated, the use of "or" means "and / or". In addition, the use of the term "comprising" and other forms is non-limiting.

[0043] Unless otherwise specified, the methods and techniques of the present invention are generally carried out according to conventional methods well known in the art and as described in various general and more specific references, which are cited and discussed throughout this specification.

[0044] The first aspect of the present invention provides a resin material, characterized in that the resin material comprises spherical resin particles, and the smoothness coefficient S of the resin material 1 is 0.0 to 80.0%; the smoothness coefficient S of the resin material 1 is defined as the average value of the smoothness coefficients of the spherical resin particles in the resin material; the smoothness coefficient of the spherical resin particles is defined as the ratio of the sum of the smooth area of the spherical resin particles to the surface area of a smooth particle of the same diameter.

[0045] The present invention defines that, on a spherical particle, the ratio of the maximum area of a certain continuous surface to the surface area of a smooth particle with the same diameter is greater than or equal to 0.01%, and this continuous surface is a smooth area; the ratio of the maximum area of a certain continuous surface to the surface area of a smooth particle with the same diameter is less than 0.01%, and this continuous surface is a rough area. If the ratio of the maximum area of all continuous surfaces on a spherical particle to the surface area of a smooth particle with the same diameter is less than 0.01%, then the smoothness coefficient of this spherical particle is 0; if there is only one continuous surface on a spherical particle whose ratio of the maximum area to the surface area of a smooth particle with the same diameter is 0.01%, and the ratios of the maximum areas of all other continuous surfaces to the surface area of a smooth particle with the same diameter are less than 0.01%, then the smoothness coefficient of this spherical particle is 0.01%.

[0046] For a spherical particle, there are two cases: In the first case, the rough areas and smooth areas on the spherical particle are evenly distributed. Here, "evenly" includes two meanings. First, the areas of different smooth areas on the spherical particle are similar. Second, the regional distribution of the smooth areas on the spherical particle is uniform. For example, there is no spherical particle that is half smooth and half rough; In the second case, the distribution of the rough areas and smooth areas on the spherical particle is uneven. In contrast to the even distribution, on an uneven spherical particle, there is only one smooth area, or there are multiple smooth areas of different sizes at the same time.

[0047] The smoothness coefficient S of the spherical particle is obtained by analyzing the SEM image through image analysis software. Randomly select n (n≥20) particles and number them from 1 to n in sequence. The smooth areas of each particle are numbered from 1 to m in sequence, and its smoothness coefficient: S

[0048] where, A ij The area of the j-th smooth area of the i-th sphere, in μm 2 ; D i is the diameter of the i-th sphere, in μm.

[0049] The resin material provided by the present invention includes spherical resin particles, and the smoothness coefficient S of the resin material 1 is the average value of the smoothness coefficients of the spherical resin particles therein. Therefore, its value can be between 0.0 and 80.0%, which can effectively increase the direct contact area between particles and between particles and other substances (such as binders, adsorbates, etc.). In some embodiments, the smoothness coefficient S of the resin material 1May be, but not limited to, 0.0%, 0.01%, 5.0%, 10.0%, 15.0%, 20.0%, 25.0%, 30.0%, 35.0%, 40.0%, 45.0%, 50.0%, 55.0%, 60.0%, 65.0%, 70.0%, 75.0% or 80.0%, or may be any value between 0.0 and 80.0%. Preferably, the smoothness coefficient S of the resin material 1 is 0.0 - 10.0%; More preferably, the smoothness coefficient S of the resin material 1 is 0.0 - 5.0%.

[0050] In some embodiments, the particle size of the resin material d V50 is 2 - 100 μm.

[0051] Among them, the particle size of the resin material d V50 May be, but not limited to, 2 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm, or may be any value between 2 and 100 μm. Preferably, the particle size of the resin material d V50 is 3 - 30 μm.

[0052] In some embodiments, the particle size distance of the resin material is 0.4 - 2.0.

[0053] Among them, the particle size distance of the resin material may be, but not limited to, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8 or 2.0, or may be any value between 0.4 and 2.0. Preferably, the particle size distance of the resin material is 0.4 - 1.2.

[0054] In some embodiments, the degree of cure of the resin material is 70.0 - 100.0%.

[0055] Among them, the degree of cure of the resin material may be, but not limited to, 70.0%, 75.0%, 80.0%, 85.0%, 90.0%, 95.0% or 100.0%, or may be any value between 70.0 and 100.0%. Preferably, the degree of cure of the resin material is 80.0 - 100.0%.

[0056] In some embodiments, the char yield of the resin material is 10.0 - 70.0%.

[0057] Among them, the char yield of the resin material can be, but is not limited to, 10.0%, 15.0%, 20.0%, 25.0%, 30.0%, 35.0%, 40.0%, 45.0%, 50.0%, 55.0%, 60.0%, 65.0% or 70.0%, and can also be any value between 10.0% and 70.0%. Preferably, the char yield of the resin material is 40.0% - 60.0%.

[0058] The second aspect of the present invention provides a preparation method of a resin material, and the preparation method includes the following steps: Step S1, preparing a uniform emulsifier dispersion; Step S2, adding a resin, a roughening agent and an optional curing agent into the emulsifier dispersion obtained in step S1, continuously stirring at a constant temperature until the reaction ends, and obtaining a resin material through solid-liquid separation; the resin material is a spherical resin material with a rough surface.

[0059] This preparation method is simple. Compared with general resin balls, only a small amount of roughening agent needs to be added, and the cost is controllable.

[0060] In some embodiments, the roughening agent includes one or more of aniline oligomer, lignosulfonate, sulfonated asphalt, polystyrene sulfonic acid or surfactant Tween-20.

[0061] Specifically, the roughening agent can be any one of aniline oligomer, lignosulfonate, sulfonated asphalt, polystyrene sulfonic acid or surfactant Tween-20, or can be any two or more of aniline oligomer, lignosulfonate, sulfonated asphalt, polystyrene sulfonic acid or surfactant Tween-20.

[0062] In some embodiments, the mass fraction of the roughening agent in the resin is 1.0% - 50.0%.

[0063] Among them, the mass fraction of the roughening agent in the resin can be, but is not limited to, 1.0%, 5.0%, 10.0%, 15.0%, 20.0%, 25.0%, 30.0%, 35.0%, 40.0%, 45.0% or 50.0%, and can also be any value between 1.0% and 50.0%. Preferably, the mass fraction of the roughening agent in the resin is 10% - 30.0%.

[0064] In some embodiments, the resin includes one or more of a thermoplastic phenolic resin, a thermosetting phenolic resin, a urea-formaldehyde resin, an epoxy resin or a polystyrene resin; or, the resin includes one or more of a precursor of a thermoplastic phenolic resin, a precursor of a thermosetting phenolic resin, a precursor of a urea-formaldehyde resin, a precursor of an epoxy resin or a precursor of a polystyrene resin.

[0065] Specifically, the resin can be any one of thermoplastic phenolic resin, thermosetting phenolic resin, urea formaldehyde resin, epoxy resin or polystyrene resin, or can be any two or more of thermoplastic phenolic resin, thermosetting phenolic resin, urea formaldehyde resin, epoxy resin, polystyrene resin; or the resin can be any one of the precursors of thermoplastic phenolic resin, the precursors of thermosetting phenolic resin, the precursors of urea formaldehyde resin, the precursors of epoxy resin or the precursors of polystyrene resin, or can be any two or more of the precursors of thermoplastic phenolic resin, the precursors of thermosetting phenolic resin, the precursors of urea formaldehyde resin, the precursors of epoxy resin or the precursors of polystyrene resin.

[0066] In some embodiments, the emulsifier includes one or more of sodium dodecyl benzene sulfonate, polyvinyl alcohol, sodium octadecyl, polyethylene glycol, guar gum, sodium carboxymethyl cellulose, F-II type emulsifier or sodium caseinate.

[0067] Specifically, the emulsifier can be any one of sodium dodecyl benzene sulfonate, polyvinyl alcohol, sodium octadecyl, polyethylene glycol, guar gum, sodium carboxymethyl cellulose, F-II type emulsifier or sodium caseinate, or can be any two or more of sodium dodecyl benzene sulfonate, polyvinyl alcohol, sodium octadecyl, polyethylene glycol, guar gum, sodium carboxymethyl cellulose, F-II type emulsifier or sodium caseinate.

[0068] In some embodiments, the curing agent includes one or more of hexamethylenetetramine, p-toluenesulfonic acid, ethylenediamine, paraformaldehyde, aniline, hydrochloric acid, formaldehyde, boric acid or propylene carbonate.

[0069] Specifically, the curing agent can be any one of hexamethylenetetramine, p-toluenesulfonic acid, ethylenediamine, paraformaldehyde, aniline, formaldehyde, boric acid and propylene carbonate, or can be any two or more of hexamethylenetetramine, p-toluenesulfonic acid, ethylenediamine, paraformaldehyde, aniline, hydrochloric acid, formaldehyde, boric acid and propylene carbonate.

[0070] In some embodiments, the temperature of the reaction is 60~98 °C.

[0071] Among them, the temperature of the reaction can be, but is not limited to, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C, 95 °C or 98 °C, or can be any value between 60~98 °C. Preferably, the temperature of the reaction is 85~98 °C.

[0072] The third aspect of the present invention provides a carbon material, the carbon material contains spherical carbon particles, and the smoothness coefficient S of the carbon material 2 is 0.0~80.0%; the smoothness coefficient S of the carbon material 2It is defined as the average value of the smoothness coefficients of the spherical carbon particles in the carbon material; the smoothness coefficient of the spherical carbon particle is defined as the ratio of the sum of the smooth area of the spherical carbon particle to the surface area of a smooth particle with the same diameter.

[0073] The smoothness coefficient S of the carbon material 2 is 0.0 to 80.0%, and it also has a rough surface, which is beneficial to better play its role in applications in the fields of catalysts, porous carriers, hard carbon precursors, graphite precursors, capacitive carbon, adsorbents, and drug carriers.

[0074] Among them, the smoothness coefficient S of the carbon material 2 can be but is not limited to 0.0%, 0.01%, 5.0%, 10.0%, 15.0%, 20.0%, 25.0%, 30.0%, 35.0%, 40.0%, 45.0%, 50.0%, 55.0%, 60.0%, 65.0%, 70.0%, 75.0% or 80.0%, and it can also be any value between 0.0 and 80.0%. Preferably, the smoothness coefficient S of the carbon material 2 is 0.0 to 10.0%; more preferably, the smoothness coefficient S of the carbon material 2 is 0.0 to 5.0%.

[0075] In some embodiments, the specific surface area of the carbon material is 200 to 2500 m 2 / g.

[0076] Among them, the specific surface area of the carbon material can be but is not limited to 200 m 2 / g, 300 m 2 / g, 500 m 2 / g, 700m 2 / g, 900 m 2 / g, 1100 m 2 / g, 1300 m 2 / g, 1500 m 2 / g, 1700 m 2 / g, 1900 m 2 / g, 2100 m 2 / g, 2300m 2 / g or 2500 m 2 / g, and it can also be any value between 200 and 2500 m 2 / g. Preferably, the specific surface area of the carbon material is 1000 to 2000 m 2 / g.

[0077] In some embodiments, the pore volume of the carbon material is 0.1 to 1.5 cm 3 / g.

[0078] Among them, the pore volume of the carbon material can be, but is not limited to, 0.1 cm 3 / g, 0.3 cm 3 / g, 0.5 cm 3 / g, 0.7 cm 3 / g, 0.9 cm 3 / g, 1.1 cm 3 / g, 1.3 cm 3 / g or 1.5 cm 3 / g, and can also be any value between 0.1 and 1.5 cm 3 / g. Preferably, the pore volume of the carbon material is 0.5 - 1.2 cm 3 / g.

[0079] In some embodiments, the carbon material is prepared by carbonizing a resin material, and the resin material is the resin material described in the first aspect of the present invention, or a resin material prepared according to the preparation method of the resin material described in the second aspect.

[0080] In some embodiments, after carbonization, activation and / or de-functionalization treatment are further included.

[0081] The fourth aspect of the present invention provides a silicon-carbon composite material, which includes a carbon material and silicon nanoparticles, and the silicon nanoparticles are located in the pores of the carbon material; the silicon-carbon composite material includes spherical silicon-carbon particles, and the smoothness coefficient S of the silicon-carbon composite material 3 is 0.0 - 80.00%; the smoothness coefficient S of the silicon-carbon composite material 3 is defined as the average value of the smoothness coefficients of the spherical silicon-carbon particles in the silicon-carbon composite material; the smoothness coefficient of the spherical silicon-carbon particles is defined as the ratio of the sum of the smooth area of the spherical silicon-carbon particles to the surface area of a smooth particle with the same diameter.

[0082] Since the smoothness coefficient S of the silicon-carbon composite is 3 0.0 - 80.0%, the effective contact area between it and the binder is greatly increased, solving the technical problem that spherical silicon-carbon negative electrode particles are easily detached from electrical contact during the charge and discharge cycles of secondary batteries; the cycle stability of the spherical silicon-carbon composite material is improved.

[0083] Among them, the smoothness coefficient S of the silicon-carbon composite material 3It may be, but is not limited to, 0.0%, 0.01%, 5.0%, 10.0%, 15.0%, 20.0%, 25.0%, 30.0%, 35.0%, 40.0%, 45.0%, 50.0%, 55.0%, 60.0%, 65.0%, 70.0%, 75.0% or 80.0%, or may also be any value between 0.0 and 80.0%. Preferably, the smoothness coefficient S of the silicon-carbon composite material 3 is 0.0 to 10.0%; More preferably, the smoothness coefficient S of the silicon-carbon composite material 3 is 0.0 to 5.0%.

[0084] In some embodiments, the carbon material in the silicon-carbon composite material includes the carbon material described in the third aspect of the present invention.

[0085] In some embodiments, the silicon-carbon composite material is obtained by bringing a silicon-containing precursor into contact with the carbon material in a temperature range of 150 °C to 1000 °C. Wherein, the silicon-containing precursor is selected from one or more of silane, disilane, trisilane, halogenated silane, polysilane, silafluorene and its derivatives, or silole and its derivatives. The above-mentioned silicon-containing precursors can be selected according to the needs of different scenarios, and will not be elaborated here.

[0086] In some embodiments, a heteroatom-containing precursor is introduced during the chemical vapor deposition process. The heteroatom-containing precursor includes at least one of an oxygen-containing precursor, a carbon-containing precursor, a nitrogen-containing precursor, a phosphorus-containing precursor, a sulfur-containing precursor or a boron-containing precursor; The contact methods between the silicon-containing precursor and the heteroatom-containing precursor include: the silicon-containing precursor and the heteroatom-containing precursor alternately contacting the porous matrix, the silicon-containing precursor and the heteroatom-containing precursor simultaneously contacting the porous matrix, and the silicon-containing precursor and a mixed gas containing the silicon-containing precursor and the heteroatom-containing precursor alternately contacting the porous matrix; Preferably, the silicon-containing precursor continuously contacts the porous matrix, and at the same time, the heteroatom-containing precursor is intermittently introduced during this process. The above-mentioned heteroatoms can be selected according to the needs of different scenarios, and will not be elaborated here.

[0087] In some embodiments, a coating layer is further provided on the surface of the silicon-carbon composite material. The material of the coating layer is selected from at least one of a solid electrolyte, a conductive polymer, a carbonaceous material, a metal, an alloy, a metal oxide, a metal hydroxide, a halogen-containing compound, a nitrogen-containing compound, a phosphorus-containing compound, a boron-containing compound or a sulfur-containing compound; More preferably, the material of the coating layer is a carbonaceous material. The above-mentioned coating layer can be selected according to the needs of different scenarios, and will not be elaborated here.

[0088] In a fifth aspect, the present invention provides a negative electrode, the negative electrode includes a negative electrode active material, and the negative electrode active material includes the silicon-carbon composite material described in the fifth aspect of the present invention.

[0089] In a sixth aspect, the present invention provides a battery, which includes a positive electrode, a negative electrode, a separator, and an electrolyte. The negative electrode includes the silicon-carbon composite material as described in the fifth aspect of the present invention.

[0090] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0091] 1. Resin material Example 1 This example provides a resin material, and its preparation method is as follows: Step S1, under stirring conditions, polyvinyl alcohol is added to deionized water at 60 °C, and stirred at a constant temperature of 60 °C for 6 h to disperse the emulsifier evenly, obtaining an emulsifier dispersion; Step S2, under stirring conditions, thermoplastic phenolic resin and 1.0% of its mass of aniline oligomer are added to the 60 °C emulsifier dispersion prepared in Step S1, and then a certain proportion of hexamethylenetetramine is added thereto. Stir at a constant temperature of 60 °C for 4 h until the reaction ends. After the reaction solution is naturally cooled to room temperature, it is filtered through a fast qualitative filter paper, rinsed thoroughly with deionized water, and dried in an oven at 60 °C to obtain a spherical resin material with a rough surface.

[0092] The resin material obtained in this example is spherical, with a rough surface, and the smoothness coefficient S 1 is 44.15%, and its scanning electron microscope image is as Figure 1 shown.

[0093] Example 2 This example provides a resin material, and its preparation method is as follows: Step S1, under stirring conditions, polyvinyl alcohol is added to deionized water at 80 °C, and stirred at a constant temperature of 80 °C for 4 h to disperse the emulsifier evenly, obtaining an emulsifier dispersion; Step S2, under stirring conditions, thermoplastic phenolic resin and 5.0% of its mass of aniline oligomer are added to the 80 °C emulsifier dispersion prepared in Step S1, and then a certain proportion of hexamethylenetetramine is added thereto. Stir at a constant temperature of 80 °C for 4 h until the reaction ends. After the reaction solution is naturally cooled to room temperature, it is filtered through a fast qualitative filter paper, rinsed thoroughly with deionized water, and dried in an oven at 60 °C to obtain a spherical resin material with a rough surface.

[0094] Example 3 This example provides a resin material, and its preparation method is as follows: Step S1, under stirring conditions, polyvinyl alcohol was added to deionized water at 85 °C, and stirred at a constant temperature of 85 °C for 4 h to uniformly disperse the emulsifier, obtaining an emulsifier dispersion. Step S2, under stirring conditions, thermoplastic phenolic resin and 10.0% of its mass of aniline oligomer were added to the 85 °C emulsifier dispersion prepared in Step S1, and then a certain proportion of hexamethylenetetramine was added thereto. Stirring was continued at a constant temperature of 85 °C for 4 h until the reaction ended. After the reaction solution was naturally cooled to room temperature, it was filtered through a rapid qualitative filter paper, thoroughly rinsed with deionized water, and dried in an oven at 60 °C to obtain a spherical resin material with a rough surface.

[0095] Example 4 This example provides a resin material, and its preparation method is as follows: Step S1, under stirring conditions, polyvinyl alcohol was added to deionized water at 90 °C, and stirred at a constant temperature of 90 °C for 4 h to uniformly disperse the emulsifier, obtaining an emulsifier dispersion. Step S2, under stirring conditions, thermoplastic phenolic resin and 30.0% of its mass of aniline oligomer were added to the 90 °C emulsifier dispersion prepared in Step S1, and then a certain proportion of hexamethylenetetramine was added thereto. Stirring was continued at a constant temperature of 90 °C for 4 h until the reaction ended. After the reaction solution was naturally cooled to room temperature, it was filtered through a rapid qualitative filter paper, thoroughly rinsed with deionized water, and dried in an oven at 60 °C to obtain a spherical resin material with a rough surface.

[0096] The resin material obtained in this example is spherical, has a rough surface, and the smoothness coefficient S 1 is 0.58%, and its scanning electron microscope image is as Figure 2 shown.

[0097] Example 5 This example provides a resin material, and its preparation method is as follows: Step S1, under stirring conditions, polyvinyl alcohol was added to deionized water at 95 °C, and stirred at a constant temperature of 95 °C for 3 h to uniformly disperse the emulsifier, obtaining an emulsifier dispersion. Step S2, under stirring conditions, thermoplastic phenolic resin and 40.0% of its mass of aniline oligomer were added to the 95 °C emulsifier dispersion prepared in Step S1, and then a certain proportion of hexamethylenetetramine was added thereto. Stirring was continued at a constant temperature of 95 °C for 4 h until the reaction ended. After the reaction solution was naturally cooled to room temperature, it was filtered through a rapid qualitative filter paper, thoroughly rinsed with deionized water, and dried in an oven at 60 °C to obtain a spherical resin material with a rough surface.

[0098] Example 6 This example provides a resin material, and its preparation method is as follows: Step S1, under stirring conditions, polyvinyl alcohol was added to deionized water at 98 °C, and stirred at a constant temperature of 98 °C for 3 h to uniformly disperse the emulsifier, obtaining an emulsifier dispersion; Step S2, under stirring conditions, thermoplastic phenolic resin and 50.0% of its mass of aniline oligomer were added to the emulsifier dispersion at 98 °C prepared in Step S1, and then a certain proportion of hexamethylenetetramine was added thereto. Stirring was continued at a constant temperature of 98 °C for 4 h until the reaction ended. After the reaction solution was naturally cooled to room temperature, it was filtered through a fast qualitative filter paper, thoroughly rinsed with deionized water, and dried in an oven at 60 °C to obtain a spherical resin material with a rough surface.

[0099] Example 7 This example provides a resin material, and its preparation method is as follows: Step S1, under stirring conditions, polyethylene glycol was added to deionized water at 90 °C, and stirred at a constant temperature of 90 °C for 4 h to uniformly disperse the emulsifier, obtaining an emulsifier dispersion; Step S2, under stirring conditions, urea-formaldehyde resin and 10.0% of its mass of sulfonated asphalt were added to the emulsifier dispersion at 90 °C prepared in Step S1, and then a certain proportion of concentrated hydrochloric acid (37 wt. %) was added thereto. Stirring was continued at a constant temperature of 90 °C for 4 h until the reaction ended. After the reaction solution was naturally cooled to room temperature, it was filtered through a fast qualitative filter paper, thoroughly rinsed with deionized water, and dried in an oven at 60 °C to obtain a spherical resin material with a rough surface.

[0100] Example 8 This example provides a resin material, and its preparation method is as follows: Step S1, under stirring conditions, sodium dodecylbenzenesulfonate was added to deionized water at 90 °C, and stirred at a constant temperature of 90 °C for 4 h to uniformly disperse the emulsifier, obtaining an emulsifier dispersion; Step S2, under stirring conditions, thermosetting phenolic resin and 10.0% of its mass of Tween-20 were added to the emulsifier dispersion at 90 °C prepared in Step S1. Stirring was continued at a constant temperature of 90 °C for 4 h until the reaction ended. After the reaction solution was naturally cooled to room temperature, it was filtered through a fast qualitative filter paper, thoroughly rinsed with deionized water, and dried in an oven at 60 °C to obtain a spherical resin material with a rough surface.

[0101] Example 9 This example provides a resin material, and its preparation method is as follows: Step S1, under stirring conditions, sodium dodecylbenzenesulfonate was added to deionized water at 90 °C, and stirred at a constant temperature of 90 °C for 4 h to uniformly disperse the emulsifier, obtaining an emulsifier dispersion; Step S2, under stirring conditions, add thermosetting phenolic resin and 1.0% of its mass of Tween-20 to the emulsifier dispersion at 90 °C obtained in Step S1, continuously stir at a constant temperature of 90 °C for 4 h until the reaction ends. After the reaction solution is naturally cooled to room temperature, filter it through a rapid qualitative filter paper, wash it thoroughly with deionized water, and dry it in an oven at 60 °C to obtain a spherical resin material with a rough surface.

[0102] Comparative Example 1 This comparative example provides a resin material, which is a commercially available resin microsphere (below 200 mesh); The resin material obtained in this comparative example is spherical and does not have a rough surface. The smoothness coefficient S 1 is 100.0%, and its scanning electron micrograph is as Figure 3 shown.

[0103] 2. Carbon material Example 10 This example provides a carbon material, and its preparation method is as follows: Step S1, provide a spherical resin material, which is the resin particles below 200 mesh obtained by sieving the resin material obtained in Example 1; Step S2, dehydrate the resin material obtained in Step S1 in an inert atmosphere at 200 °C for 1 h, and then heat it to 900 °C at a heating rate of 2 °C / min for pyrolytic carbonization for 2 h to obtain porous carbon 1 particles.

[0104] Example 11 This example provides a carbon material, and its preparation method is as follows: Step S1, provide a spherical resin material, which is the resin particles below 200 mesh obtained by sieving the resin material obtained in Example 2; Step S2, dehydrate the resin material obtained in Step S1 in an inert atmosphere at 200 °C for 1 h, and then heat it to 900 °C at a heating rate of 2 °C / min for pyrolytic carbonization for 2 h to obtain porous carbon 1 particles; Step S3, place the porous carbon 1 particles obtained in Step S2 in H 2 O atmosphere, activate it at 800 °C for 3 h, and naturally cool it to room temperature to obtain porous carbon 2 particles.

[0105] Example 12 This example provides a carbon material, and its preparation method is as follows: Step S1, provide a spherical resin material, which is the resin particles below 200 mesh obtained by sieving the resin material obtained in Example 3; Step S2: The resin material obtained in Step S1 is dehydrated at 200 °C for 1 h in an inert atmosphere, and then pyrolytically carbonized at a heating rate of 2 °C / min to 900 °C for 2 h to obtain porous carbon 1 particles; Step S3: The porous carbon 1 particles obtained in Step S2 are activated in a CO 2 atmosphere at 800 °C for 3 h and naturally cooled to room temperature to obtain porous carbon 2 particles.

[0106] Example 13 This example provides a carbon material, and its preparation method is as follows: Step S1: Provide spherical resin material, which is resin particles with a mesh size below 200 obtained by sieving the resin material obtained in Example 4; Step S2: The resin material obtained in Step S1 is dehydrated at 200 °C for 1 h in an inert atmosphere, and then pyrolytically carbonized at a heating rate of 2 °C / min to 900 °C for 2 h to obtain porous carbon 1 particles; Step S3: The porous carbon 1 particles obtained in Step S2 are activated in an H 2 O atmosphere at 800 °C for 5 h and naturally cooled to room temperature to obtain porous carbon 2 particles.

[0107] Example 14 This example provides a carbon material, and its preparation method is as follows: Step S1: Provide spherical resin material, which is resin particles with a mesh size below 200 obtained by sieving the resin material obtained in Example 5; Step S2: The resin material obtained in Step S1 is dehydrated at 200 °C for 1 h in an inert atmosphere, and then pyrolytically carbonized at a heating rate of 2 °C / min to 900 °C for 2 h to obtain porous carbon 1 particles; Step S3: The porous carbon 1 particles obtained in Step S2 are activated in an H 2 O atmosphere at 800 °C for 6 h and naturally cooled to room temperature to obtain porous carbon 2 particles.

[0108] Example 15 This example provides a carbon material, and its preparation method is as follows: Step S1: Provide spherical resin material, which is resin particles with a mesh size below 200 obtained by sieving the resin material obtained in Example 6; Step S2: The resin material obtained in Step S1 is dehydrated at 200 °C for 1 h in an inert atmosphere, and then pyrolytically carbonized at a heating rate of 2 °C / min to 900 °C for 2 h to obtain porous carbon 1 particles; Step S3: The porous carbon 1 particles obtained in Step S2 are activated in an H 2In an O atmosphere, it was activated at 800 °C for 7 h and naturally cooled to room temperature to obtain porous carbon 2 particles.

[0109] Example 16 This example provides a carbon material, and its preparation method is as follows: Step S1: Provide a spherical resin material, which is the resin particles with a mesh size below 200 obtained by sieving the resin material obtained in Example 7. Step S2: Dehydrate the resin material obtained in Step S1 in an inert atmosphere at 200 °C for 1 h, and then heat it to 900 °C at a heating rate of 2 °C / min for pyrolytic carbonization for 2 h to obtain porous carbon 1 particles. Step S3: Subject the porous carbon 1 particles obtained in Step S2 to activation treatment in an H 2 O atmosphere at 800 °C for 3 h, and naturally cool to room temperature to obtain porous carbon 2 particles.

[0110] Example 17 This example provides a carbon material, and its preparation method is as follows: Step S1: Provide a spherical resin material, which is the resin particles with a mesh size below 200 obtained by sieving the resin material obtained in Example 8. Step S2: Dehydrate the resin material obtained in Step S1 in an inert atmosphere at 200 °C for 1 h, and then heat it to 900 °C at a heating rate of 2 °C / min for pyrolytic carbonization for 2 h to obtain porous carbon 1 particles. Step S3: Subject the porous carbon 1 particles obtained in Step S2 to activation treatment in an H 2 O atmosphere at 800 °C for 3 h, and naturally cool to room temperature to obtain porous carbon 2 particles.

[0111] Example 18 This example provides a carbon material, and its preparation method is as follows: Step S1: Provide a spherical resin material, which is the resin particles with a mesh size below 200 obtained by sieving the resin material obtained in Example 9. Step S2: Dehydrate the resin material obtained in Step S1 in an inert atmosphere at 200 °C for 1 h, and then heat it to 900 °C at a heating rate of 2 °C / min for pyrolytic carbonization for 2 h to obtain porous carbon 1 particles. Step S3: Subject the porous carbon 1 particles obtained in Step S2 to activation treatment in an H 2 O atmosphere at 800 °C for 3 h, and naturally cool to room temperature to obtain porous carbon 2 particles.

[0112] Comparative Example 2 This example provides a carbon material, and its preparation method is as follows: Step S1: Provide a spherical resin material, which is the resin material obtained in Comparative Example 1. Step S2: Dehydrate the resin material obtained in Step S1 in an inert atmosphere at 200 °C for 1 h, and then heat it to 900 °C at a heating rate of 2 °C / min for pyrolytic carbonization for 2 h to obtain porous carbon 1 particles. Step S3: Place the porous carbon 1 particles obtained in Step S2 in an H 2 O atmosphere, activate at 800 °C for 3 h, and naturally cool to room temperature to obtain porous carbon 2 particles.

[0113] 3. Silicon-carbon composite material Example 19 This example provides a silicon-carbon composite material, and its preparation method is as follows: Step S1: Provide a porous carbon material, which is the carbon material obtained in Example 10. Step S2: Place the porous carbon material obtained in Step S1 in a tube furnace, and heat it from room temperature to 550 °C at 2 °C / min in an N 2 atmosphere; then change to a 20.0% SiH 4 -N 2 mixed gas, and keep it at 550 °C for 2 h in a 20.0% SiH 4 -N 2 mixed atmosphere; change to a 10.0% C 2 H 2 -N 2 mixed gas, and keep it at 600 °C for 0.5 h; naturally cool in an N 2 atmosphere to obtain a silicon-carbon composite material.

[0114] Example 20 This example provides a silicon-carbon composite material, and its preparation method is as follows: Step S1: Provide a porous carbon material, which is the carbon material obtained in Example 11. Step S2: Place the porous carbon material obtained in Step S1 in a tube furnace, and heat it from room temperature to 550 °C at 2 °C / min in an N 2 atmosphere; then change to a 20.0% SiH 4 -N 2 mixed gas, and keep it at 550 °C for 8 h in a 20.0% SiH 4 -N 2 mixed atmosphere; change to a 10.0% C 2 H 2 -N 2 mixed gas, and keep it at 600 °C for 1 h; naturally cool in an N 2 atmosphere to obtain a silicon-carbon composite material.

[0115] Example 21 This example provides a silicon-carbon composite material, and its preparation method is as follows: Step S1: Provide a porous carbon material, which is the carbon material obtained in Example 12; Step S2: Place the porous carbon material obtained in Step S1 in a tubular furnace, and heat it from room temperature to 550 °C at a rate of 2 °C / min in an N 2 atmosphere; then change to a 20.0% SiH 4 -N 2 mixed gas, and keep it at 550 °C for 4 h in a 20.0% SiH 4 -N 2 mixed atmosphere; change to introduce a 10.0% C 2 H 2 -N 2 mixed gas, and keep it at 600 °C for 1 h; cool it naturally in an N 2 atmosphere to obtain the silicon-carbon composite material.

[0116] Example 22 This example provides a silicon-carbon composite material, and its preparation method is as follows: Step S1: Provide a porous carbon material, which is the carbon material obtained in Example 13; Step S2: Place the porous carbon material obtained in Step S1 in a tubular furnace, and heat it from room temperature to 550 °C at a rate of 2 °C / min in an N 2 atmosphere; then change to a 20.0% SiH 4 -N 2 mixed gas, and keep it at 550 °C for 10 h in a 20.0% SiH 4 -N 2 mixed atmosphere; change to introduce a 10.0% C 2 H 2 -N 2 mixed gas, and keep it at 600 °C for 1 h; cool it naturally in an N 2 atmosphere to obtain the silicon-carbon composite material.

[0117] Example 23 This example provides a silicon-carbon composite material, and its preparation method is as follows: Step S1: Provide a porous carbon material, which is the carbon material obtained in Example 14; Step S2: Place the porous carbon material obtained in Step S1 in a tubular furnace, and heat it from room temperature to 550 °C at a rate of 2 °C / min in an N 2 atmosphere; then change to a 20.0% SiH 4 -N 2The mixed gas, with 20.0% SiH 4 -N 2 in the mixed atmosphere is maintained at 550 °C for 10 h; then change to introduce 10.0% C 2 H 2 -N 2 mixed gas, and maintain at 600 °C for 1 h; naturally cool down in the N 2 atmosphere to obtain the silicon-carbon composite material.

[0118] Example 24 This example provides a silicon-carbon composite material, and its preparation method is as follows: Step S1: Provide a porous carbon material, which is the carbon material obtained in Example 15; Step S2: Place the porous carbon material obtained in Step S1 in a tubular furnace, and heat it from room temperature to 550 °C at a rate of 2 °C / min in the N 2 atmosphere; then change to 20.0% SiH 4 -N 2 mixed gas, and maintain at 550 °C for 12 h in the 20.0% SiH 4 -N 2 mixed atmosphere; change to introduce 10.0% C 2 H 2 -N 2 mixed gas, and maintain at 600 °C for 1.5 h; naturally cool down in the N 2 atmosphere to obtain the silicon-carbon composite material.

[0119] Example 25 This example provides a silicon-carbon composite material, and its preparation method is as follows: Step S1: Provide a porous carbon material, which is the carbon material obtained in Example 16; Step S2: Place the porous carbon material obtained in Step S1 in a tubular furnace, and heat it from room temperature to 550 °C at a rate of 2 °C / min in the N 2 atmosphere; then change to 20.0% SiH 4 -N 2 mixed gas, and maintain at 550 °C for 28 h in the 20.0% SiH 4 -N 2 mixed atmosphere; change to introduce 10.0% C 2 H 2 -N 2 mixed gas, and maintain at 600 °C for 2 h; naturally cool down in the N 2 atmosphere to obtain the silicon-carbon composite material.

[0120] Example 26 This example provides a silicon-carbon composite material, and its preparation method is as follows: Step S1: Provide a porous carbon material, which is the carbon material obtained in Example 17; Step S2: Place the porous carbon material obtained in Step S1 in a tube furnace, and heat it from room temperature to 550 °C at a rate of 2 °C / min in an N 2 atmosphere; then change to a 20.0% SiH 4 -N 2 mixed gas, and hold it at 550 °C for 8 h in a 20.0% SiH 4 -N 2 mixed atmosphere; change to introduce a 10.0% C 2 H 2 -N 2 mixed gas, and hold it at 600 °C for 1.5 h; cool it naturally in an N 2 atmosphere to obtain a silicon-carbon composite material.

[0121] Example 27 This example provides a silicon-carbon composite material, and its preparation method is as follows: Step S1: Provide a porous carbon material, which is the carbon material obtained in Example 18; Step S2: Place the porous carbon material obtained in Step S1 in a tube furnace, and heat it from room temperature to 550 °C at a rate of 2 °C / min in an N 2 atmosphere; then change to a 20.0% SiH 4 -N 2 mixed gas, and hold it at 550 °C for 8 h in a 20.0% SiH 4 -N 2 mixed atmosphere; change to introduce a 10.0% C 2 H 2 -N 2 mixed gas, and hold it at 600 °C for 1.5 h; cool it naturally in an N 2 atmosphere to obtain a silicon-carbon composite material.

[0122] Comparative Example 3 This example provides a silicon-carbon composite material, and its preparation method is as follows: Step S1: Provide a porous carbon material, which is the carbon material obtained in Comparative Example 2; Step S2: Place the porous carbon material obtained in Step S1 in a tube furnace, and heat it from room temperature to 550 °C at a rate of 2 °C / min in an N 2 atmosphere; then change to a 20.0% SiH 4 -N 2 mixed gas, and hold it at 550 °C for 8 h in a 20.0% SiH 4 -N 2 mixed atmosphere; change to introduce a 10.0% C2 H 2 -N 2 The mixed gas was maintained at 600 °C for 1 h; and then cooled naturally in an N 2 atmosphere to obtain the silicon-carbon composite material.

[0123] 4. Testing methods SEM and N 2 adsorption tests are both well-known material characterization means for those skilled in the art, and their specific test conditions will not be elaborated here.

[0124] 4-1. Smoothness coefficient test: The smoothness coefficient S of the resin material 1 was obtained by analyzing the SEM image through image analysis software. Randomly selected n (n≥20) particles were numbered from 1 to n in sequence, and the smooth regions of each particle were numbered from 1 to m in sequence. Its smoothness coefficient: S 1 ; where A ij is the area of the j-th smooth region of the i-th sphere, with the unit of μm 2 ; D i is the diameter of the i-th sphere, with the unit of μm.

[0125] The smoothness coefficient S of the carbon material 2 and the smoothness coefficient S of the silicon-carbon composite material 3 were calculated in the same way.

[0126] 4-2. N 2 adsorption test: The specific surface area A of the carbon material was obtained by multi-point BET calculation, and the calculation result satisfied the intercept C value > 0 and the correlation coefficient R 2 ≥0.9999. The pore volume V was obtained based on the maximum adsorption amount when 2 in the N p / p 0 >0.99, and the average pore diameter D = 4 V / A *1000 (nm).

[0127] 4-3. Si content test: 3.0 g of the silicon-carbon composite material was placed in an oven at 150 °C and dried to constant weight, and the mass m 1 was recorded; the dried composite material was placed in a muffle furnace, heated to 1100 °C and maintained for 2 h, and then cooled and weighed, and the mass m 2 was recorded. The Si content calculation formula: 。

[0128] 4-4. Half-cell test: The silicon-carbon composite materials obtained in Examples 19 to 27 and Comparative Example 3 were subjected to electrochemical performance tests, and the results are shown in Table 3. Using the silicon-carbon composite materials obtained in Examples 19 to 27 and Comparative Example 3 as the negative electrode active materials, negative electrode sheets were prepared respectively. The negative electrode sheets were used to prepare CR2032-type button cells by conventional methods, and the electrical performance of the cells was tested. The LAND battery test system was used to perform charge-discharge tests on the cells.

[0129] (1) Half-cell assembly: Assemble a CR2032-type button cell in a glove box, using a lithium metal sheet as the counter electrode, a polypropylene microporous membrane as the separator, and the electrolyte being LiPF 6 dissolved in a mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC) (volume ratio EC:DEC = 1:1), where the concentration of LiPF 6 is 1 mol / L.

[0130] (2) Cycle specific capacity and first efficiency test: After the CR2032-type button cell was left standing for 6 h, it was discharged at 0.05 C to 0.005 V, and then discharged at 0.01 C to 0.005 V; after standing for 5 min, it was charged at a constant current of 0.05 C to 1.5 V; the first de-lithiation specific capacity at 0.8 V is the 0.8 V specific capacity (or mass specific capacity) of the electrode material, and the ratio of the first de-lithiation capacity at 0.8 V to the first lithium insertion capacity at 1.5 V is the 0.8 V first Coulombic efficiency of the battery.

[0131] 4-5. Full-cell test: Using the silicon-carbon composite materials obtained in Examples 19 to 27 and Comparative Example 3 as the negative electrode active materials, the electrode sheets containing the negative electrode active materials were used to prepare soft-pack batteries by conventional methods and their electrical performance was tested. The soft-pack batteries were prepared in a dehumidifying chamber with a dew point of -45 °C. The LANBTS battery test system was used to perform charge-discharge cycle tests on the batteries, and the results are shown in Table 3. The specific test method is as follows: (1) Fabrication of the positive electrode sheet: The positive electrode active material LiCoO 2 , conductive agent Super P, binder PVDF and solvent NMP were stirred and mixed evenly according to a mass ratio of 92:3:5:150, and then evenly coated on the positive electrode current collector, and then dried at 80 °C to obtain the positive electrode sheet.

[0132] (2)Fabrication of the negative electrode sheet: The negative electrode active material, conductive agent Super P, binder polyacrylic acid, and solvent deionized water are stirred and mixed evenly according to a mass ratio of 95:1:4:120, and then evenly coated on the negative electrode current collector, and then dried at 100 °C to obtain the negative electrode sheet.

[0133] (3)The positive electrode sheet and the negative electrode sheet are stacked in a square shape and separated by a polypropylene separator to form a battery core, which is then encapsulated in an aluminum-plastic bag. The corresponding volume of electrolyte is injected into the aluminum-plastic bag, and after vacuum sealing, the soft-pack battery is obtained. The electrolyte is a mixed solution of EC and DEC of LiPF 6 with a LiPF 6 concentration of 1 mol / L and a volume ratio of EC to DEC of 1:1.

[0134] (4)Formation and grading: The battery after injecting electrolyte and sealing starts to be formed. It is left standing in an incubator at 25 °C for 12 h, then charged at a constant current of 0.02C to 3.3 V, left standing for 30 min, charged at a constant current of 0.025 C to 3.8 V, left standing for 10 min, and charged at a constant current of 0.33 C to 4.2 V; after formation, the battery is evacuated and the air bag is cut, and then graded. It is charged at a constant current of 0.33 C to 4.45 V, left standing for 10 min, discharged at a constant current of 1 C to 3 V, left standing for 10 min, and discharged at a constant current of 0.33 C to 3 V to end the grading. The ratio of the discharge capacity to the charge capacity during the formation and grading of the soft-pack battery is the first efficiency of the battery.

[0135] (5)Cycle test at 25 °C: The battery is placed in an incubator at 25 °C, charged at a constant current of 1 C to 4.45 V, and then charged at a constant voltage of 4.45 V until the current is 0.1 C; after standing for 10 min, it is discharged at a constant current of 1 C to 3.0 V, left standing for 10 min, and the above charging and discharging steps are repeated until the discharge capacity is lower than 80.0% of the discharge capacity of the first cycle and then stopped. At this time, the number of cycle weeks obtained is the cycle life of the soft-pack battery; record the cycle capacity retention rate of 100 cycles.

[0136] 5. Results and analysis of the examples The comparison of the improvement effects of the resin materials in Examples 1 to 9 and Comparative Example 1 is shown in Table 1. The comparison of the improvement effects of the carbon materials obtained in Examples 10 to 18 and Comparative Example 2 is shown in Table 2. The comparison of the improvement effects of the silicon-carbon composite materials obtained in Examples 19 to 27 and Comparative Example 3 is shown in Table 3.

[0137] Table 1 Performance test results of the resin materials in Examples 1 to 9 and Comparative Example 1

[0138] Table 2 Performance test results of the carbon materials obtained in Examples 10 to 18 and Comparative Example 2

[0139] Table 3 Comparison of the improvement effects of the carbon materials obtained in Examples 19 to 27 and Comparative Example 3

[0140] In Examples 10 to 18 and Comparative Example 2, the resin materials of Examples 1 to 9 and Comparative Example 1 were respectively used as carbon precursors, and were subjected to carbonization, optional activation, and optional de-functionalization treatments to obtain carbon materials. In Examples 19 to 27 and Comparative Example 3, the carbon materials of Examples 10 to 18 and Comparative Example 2 were respectively used as substrates for silicon deposition to obtain silicon-carbon composite materials. As can be seen from Table 1, the resin materials provided in Examples 1 to 9 all exhibited the characteristics of a rough surface after adding a certain amount of roughening agent during the preparation process; for the same resin raw material, as the addition ratio of the roughening agent increased, the smoothness coefficient S 1 gradually decreased; Figure 1 , Figure 2 and Figure 3 are the SEM images of Example 1, Example 4, and Comparative Example 1 respectively. It can be seen that compared with Example 1 and Example 4, Comparative Example 1 is a commercially available resin microsphere, and there is no rough area on the surface of its particles. It can be seen that the present invention can realize the surface roughening modification of spherical resin carbon materials by adding a roughening agent.

[0141] As can be seen from Table 2, after the resin materials of Examples 1 to 9 were subjected to carbonization, optional activation, and optional de-functionalization treatments, the smoothness coefficient S of the prepared carbon materials 2 was slightly larger than that of the corresponding resin materials S 1 , indicating that high-temperature carbonization, activation, and de-functionalization treatments would slightly increase the surface smoothness of the carbon materials described in Examples 10 to 18; the carbon material of Comparative Example 2 was obtained by carbonizing, optionally activating, and optionally de-functionalizing commercially available resin microspheres, and there was no rough area on its surface.

[0142] The silicon-carbon composite materials of Examples 19 to 27 and Comparative Example 3 used the porous carbon materials provided by the present invention as substrates, and their rough surfaces could greatly increase the effective contact area with the binder. As can be seen from Table 3, compared with Comparative Example 3, the smoothness coefficients of the silicon-carbon composite materials of Examples 19 to 27 were all between 0.0% and 80.0%. Therefore, the cycle stability of Examples 19 to 27 was better than that of Comparative Example 3, and their 100-cycle capacity retention rates were all above 95.0%.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A resin material, characterized in that: The resin material comprises spherical resin particles, and the smoothness coefficient S1 of the resin material is 0.0~80.0%; the smoothness coefficient S1 of the resin material is defined as the average value of the smoothness coefficients of the spherical resin particles in the resin material; the smoothness coefficient of the spherical resin particles is defined as the ratio of the sum of the smooth area of ​​the spherical resin particles to the surface area of ​​smooth particles with the same diameter.

2. The resin material according to claim 1, characterized in that The smoothness coefficient S1 of the resin material is 0.0~10.0%; and / or, the particle size of the resin material d V50 2~100 μm; And / or, the particle size of the resin material is 0.4-2.0; And / or, the curing degree of the resin material is 70.0-100.0%; And / or, the carbon residue rate of the resin material is 10.0-70.0%.

3. A method for preparing a resin material, characterized in that: The preparation method comprises the following steps: Step S1, preparing a uniform emulsifier dispersion; Step S2, adding the resin, the roughening agent and the optional curing agent to the emulsifier dispersion obtained in step S1, stirring at a constant temperature until the reaction is completed, and obtaining the resin material through solid-liquid separation; The resin material is a spherical resin material with a rough surface.

4. The preparation method according to claim 3, characterized in that: The roughening agent comprises one or more of aniline oligomer, lignin sulfonate, sulfonated asphalt, polystyrene sulfonic acid or surfactant Tween-20; And / or, the mass fraction of the roughening agent in the resin is 1.0% to 50.0%.

5. The preparation method according to claim 3, characterized in that: The resin comprises one or more of a thermoplastic phenolic resin, a thermosetting phenolic resin, a urea-formaldehyde resin, an epoxy resin or a polystyrene resin; or, the resin comprises one or more of a precursor of a thermoplastic phenolic resin, a precursor of a thermosetting phenolic resin, a precursor of a urea-formaldehyde resin, a precursor of an epoxy resin or a precursor of a polystyrene resin; and / or, the emulsifier is a surfactant, and the surfactant includes one or more of sodium dodecylbenzene sulfonate, polyvinyl alcohol, sodium octadecyl, polyethylene glycol, guar gum, sodium carboxymethyl cellulose, F-II type emulsifier or sodium caseinate; and / or, the curing agent comprises one or more of hexamethylenetetramine, p-toluenesulfonic acid, ethylenediamine, paraformaldehyde, aniline, hydrochloric acid, formaldehyde, boric acid or propylene carbonate; And / or, the reaction temperature is 60-98°C.

6. A carbon material, characterized in that The carbon material comprises spherical carbon particles, and the smoothness coefficient S2 of the carbon material is 0.0~80.0%; the smoothness coefficient S2 of the carbon material is defined as the average value of the smoothness coefficients of the spherical carbon particles in the carbon material; the smoothness coefficient of the spherical carbon particles is defined as the ratio of the sum of the smooth region areas of the spherical carbon particles to the surface area of ​​smooth particles with the same diameter.

7. The carbon material according to claim 6, characterized in that The smoothness coefficient S2 of the carbon material is 0.0-10.0%; And / or, the specific surface area of ​​the carbon material is 200-2500 m 2 / g; And / or, the pore volume of the carbon material is 0.1-1.5 cm 3 / g.

8. The carbon material according to claim 6, characterized in that The carbon material is obtained by carbonizing a resin material, and the resin material is the resin material according to claim 1 or 2, or a resin material obtained by the preparation method according to any one of claims 3 to 5.

9. The carbon material according to claim 8, characterized in that The carbonization may further include activation and / or defunctionalization treatment.

10. A silicon-carbon composite material, characterized in that: The silicon-carbon composite material comprises a carbon material and silicon nanoparticles, wherein the silicon nanoparticles are located in the pores of the carbon material; The silicon-carbon composite material comprises spherical silicon-carbon particles, and the smoothness coefficient S3 of the silicon-carbon composite material is 0.0-80.0%; the smoothness coefficient S3 of the silicon-carbon composite material is defined as the average value of the smoothness coefficients of the spherical silicon-carbon particles in the silicon-carbon composite material; the smoothness coefficient of the spherical silicon-carbon particles is defined as the ratio of the sum of the smooth area of ​​the spherical silicon-carbon particles to the surface area of ​​smooth particles with the same diameter; The carbon material includes the carbon material according to any one of claims 6 to 9.

11. The silicon-carbon composite material according to claim 10, characterized in that: The smoothness coefficient S3 of the silicon-carbon composite material is 0.0-10.0%.

12. The silicon-carbon composite material according to claim 10, characterized in that: The silicon-carbon composite material is obtained by chemical vapor deposition of a silicon-containing precursor on the carbon material at 150-1000°C; the silicon-containing precursor is selected from one or more of monosilane, disilane, trisilane, halosilane, polysilane, silole and its derivatives or silanol and its derivatives.

13. The silicon-carbon composite material according to claim 12, characterized in that: A heteroatom-containing precursor is introduced into the chemical vapor deposition process; the heteroatom-containing precursor includes at least one of an oxygen-containing precursor, a carbon-containing precursor, a nitrogen-containing precursor, a phosphorus-containing precursor, a sulfur-containing precursor or a boron-containing precursor.

14. The silicon-carbon composite material according to claim 10, characterized in that: The silicon-carbon composite material also includes a coating layer located on the surface of the silicon-carbon composite material; the material of the coating layer is selected from at least one of a solid electrolyte, a conductive polymer, a carbonaceous material, a metal, an alloy, a metal oxide, a metal hydroxide, a halogen-containing compound, a nitrogen-containing compound, a phosphorus-containing compound, a boron-containing compound or a sulfur-containing compound.

15. A negative electrode, characterized in that The negative electrode comprises a negative electrode active material, and the negative electrode active material comprises the silicon-carbon composite material according to any one of claims 10 to 14.

16. A battery, characterized in that The battery comprises a positive electrode, a negative electrode, a separator and an electrolyte, and the negative electrode comprises the silicon-carbon composite material according to any one of claims 10 to 14.

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