Negative electrode, battery cell, single battery and electric equipment

Abstract

The invention discloses a negative electrode, a battery cell, a single battery and electric equipment. The material consists of a current collector, an electron conducting layer, a uniform induction layer, a volume buffer layer or not, and an ion / electron transport layer or not. Wherein the electronic conducting layer is the key to reduce the internal resistance of the whole battery, can inhibit the corrosion of the current collector, and is more beneficial to the introduction of the second uniform induction layer; the uniform induction layer is used for inducing uniform deposition of lithium and inhibiting lithium dendrites; the volume buffer layer is mainly a porous structure-containing buffer layer; the ion / electron transmission layer is mainly used for transmitting ions and electrons, the transmission layer can bear an ion-electron mixed transmission layer at the same time, and when the transmission layer only transmits ions, lithium ions are more deviated to be deposited in the volume buffer layer, so that the safety is higher; when the lithium-ion battery has ion-electron mixed transmission, lithium ions may be deposited between the volume buffer layer and the electrolyte layer. The negative electrode material can be applied to non-negative electrode structures of liquid, solid and alkali metal battery systems.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of a negative electrode, an electric core, a single battery and an electric device, and particularly relates to a negative electrode-free, an electric core, a single battery and an electric device, and a preparation method and application thereof. BACKGROUND

[0002] Lithium ion batteries have been widely used in portable electronic devices, new energy vehicles, smart grids and other fields due to their high energy density, long cycle life, low self-discharge rate and no memory effect. However, the energy storage density of the current commercial graphite-based lithium ion battery is relatively low, which is difficult to meet the application requirements of long endurance in the fields of electric flight platforms, aerospace and special equipment.

[0003] The energy density of a lithium ion battery mainly depends on the specific capacity, average working voltage and active material surface load of the positive and negative electrode materials. As a key material, the negative electrode plays a crucial role in improving the cycle life performance of energy storage batteries. Silicon-based negative electrodes (~4200 mAh / g) and metal lithium negative electrodes (~3860 mAh / g) are the most popular next-generation high-energy-density lithium battery negative electrode materials, aiming to replace or surpass traditional graphite negative electrodes (~372 mAh / g). However, the volume expansion of silicon negative electrodes and metal lithium negative electrodes is >300% and 100%, respectively, which restricts their commercialization process. In addition, the metal lithium negative electrode is difficult to commercialize due to its lithium dendrite problem.

[0004] In recent years, negative electrode-free has become a promising negative electrode material. Negative electrode-free sodium ion batteries refer to the omission of the traditional negative electrode material in the battery structure, and only the current collector is used as the negative electrode. During the charging process, the sodium ions released from the positive electrode will deposit on the current collector to form a sodium metal negative electrode. During discharging, the deposited sodium metal will return to the positive electrode side.

[0005] In the prior art, for example, Ag nanoparticles are coated on a stainless steel current collector and copper or copper current collector with conductive carbon and binder PVDF in the article Nat Energy 5, 299-308 (2020). It is found that when preparing a sulfide full solid-state battery, the sulfide electrolyte will react with the copper current collector to generate CuS2, which corrodes the copper current collector. Therefore, a stainless steel current collector is used as the core material. On the other hand, Ag-C nanocomposite electrodes are used to replace metal lithium as the negative electrode of the battery. The dissolution of Ag in Li reduces the overpotential of the deposition of metal lithium on the current collector, thereby effectively regulating the deposition-stripping process of metal lithium, thereby giving the full battery a longer electrochemical life. In this technical solution, Ag is not deposited on the current collector or substrate, and the electronic conductivity of the stainless steel current collector is lower than that of the copper current collector.

[0006] In addition, a negative electrode current collector, a battery cell, a battery, and a power utilization device are disclosed in Chinese Patent Publication No. CN120261584A. The negative electrode current collector includes a substrate and an alloy layer on at least one side of the substrate. The alloy layer includes a first metal element and a second metal element. The substrate includes a third metal element. The nucleation overpotential of the elemental form of the second metal element is less than the nucleation overpotential of the elemental form of the first metal element. The nucleation overpotential of the lithium metal of the elemental form of the first metal element is greater than or equal to 0.10 V. The nucleation overpotential of the elemental form of the second metal element is less than the nucleation overpotential of the elemental form of the third metal element. The core is to prepare two elements that can form an alloy with lithium on the current collector, which cannot inhibit volume expansion, and there is no electronic conductive layer.

[0007] In Chinese Patent Publication No. CN1117199254A, a current collector and a composite coating are used. The current collector is a copper foil current collector. The composite coating includes conductive carbon, active nanoparticles, a binder, and a solvent. The active nanoparticles are one or more of Si, Sn, Au, and Ag. The particle size of the active nanoparticles ranges from 10 to 200 nm. The negative electrode sheet of the present application contains active nanoparticles, which have a significantly lower nucleation energy barrier with respect to Li. In the lithium extraction and insertion cycle, Li inserted on the negative electrode side will tend to preferentially deposit around the active metal nanoparticles, providing more stable cycle performance. This patent does not have a uniform induction layer, but simply deposits the nanoparticles combined with lithium on the current collector side, especially when Si and Sn are used as nanoparticles. It is impossible to deposit on the surface of the current collector or conductive carbon coating after combining with lithium.

[0008] In Chinese Patent Publication No. CN117936922A, a composite structure and its preparation method and application are disclosed. The composite structure includes a current collector, a metal lithium deposition induction material, a conductive carbon layer, and a solid electrolyte layer. The current collector has a porous structure, and the metal lithium deposition induction material is located in the porous structure of the current collector. The conductive carbon layer is located on both sides of the surface of the current collector with the metal lithium deposition induction material, and the solid electrolyte layer is located on the surface of the conductive carbon layer. The composite structure of the present application reserves a metal lithium deposition space in the three-dimensional current collector, constructs a metal lithium deposition induction material layer, and realizes the precise induction of metal lithium deposition behavior. In combination with the construction of the conductive carbon layer and the solid electrolyte layer, the problem of dendrite formation without a negative electrode, the continuous side reaction with the electrolyte, and the volume effect of metal lithium deposition can be solved, which helps to improve the initial efficiency, cycle performance, and rate performance of the battery. The porous current collector used in this patent uses the pores of the current collector to relieve volume expansion. In addition, the induction layer is on the surface of the conductive carbon, and lithium deposition will only deposit on the surface of the induction, not in the porous current collector.

[0009] The negative electrode, the battery cell, the single battery and the electric device provided by the scheme are provided with a current collector, an electron conductive layer, a uniform induction layer, a volume buffer layer which can or can not be contained, and an ion / electron transmission layer which can or can not be contained. The electron conductive layer is the key to reducing the overall battery internal resistance, can also inhibit the corrosion of the current collector (sulfide electrolyte corrosion of the current collector, and LiFSi and LiTFSi corrosion of the current collector), and is more conducive to the introduction of the second uniform induction layer due to the existence of the electron conductive layer. The uniform induction layer is used for inducing uniform lithium deposition and inhibiting lithium dendrites. The volume buffer layer is mainly a pore structure buffer layer. The ion transmission layer is mainly used for transmitting ions, and the ion transmission layer can also carry an ion-electron mixed transmission layer. The negative electrode material can be applied to the negative electrode-free structure of the liquid, solid and alkali metal battery system. SUMMARY

[0010] The purpose of the present application is to provide a negative electrode structure and its battery cell and electric device. By constructing an electron conductive layer on the surface of the current collector, the overall battery internal resistance is reduced, the corrosion of the current collector is inhibited, and the introduction of the second uniform induction layer is more conducive. Further introducing the uniform induction layer for inducing uniform lithium deposition, forming an alloy with lithium or producing a lithium compound to inhibit lithium dendrites. Further constructing a volume buffer layer on the surface of the uniform induction layer to solve the volume expansion when lithium is deposited on the surface. Finally, the volume buffer layer can be mixed with the ion transmission layer. The ion transmission layer can be designed to transmit ions and electrons at the same time, or only transmit ions. When it only transmits ions, lithium ions are more likely to be deposited in the volume buffer layer, which is safer. When it has ion-electron mixed transmission, lithium ions may be deposited between the volume buffer layer and the electrolyte layer, which is generally safe. When it only has electron transmission, lithium ions are only deposited on the surface of the electrolyte and the buffer layer, which is the least safe.

[0011] A negative electrode structure and its battery cell and electric device are provided. By constructing an electron conductive layer on the surface of the current collector, the internal resistance is reduced, and then a uniform induction layer is constructed to improve lithium deposition and inhibit lithium dendrites. Then a volume buffer layer is constructed to improve the volume expansion after lithium deposition. Finally, a transmission layer is constructed to solve the problem of ion transmission and electron transmission.

[0012] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0013] In the first aspect, the present application provides a negative electrode, a battery cell and its battery cell and electric device. The material is provided with a current collector, an electron conductive layer, a uniform induction layer, a volume buffer layer which can or can not be contained, and an ion / electron transmission layer which can or can not be contained.

[0014] As a specific technical solution, the thickness of the current collector of the negative electrode material: 0 < thickness of the current collector ≤ 30 μm, specifically can be 30, 20, 10, 5, 1, and also can be any numerical proportion among them.

[0015] In addition, as a specific technical solution, the thickness of the conductive agent layer of the negative electrode material: 0 < thickness of the electron conductive layer ≤ 5 μm, specifically can be 5, 4, 3, 2, 1, 0.5, 0.1, and also can be any numerical proportion among them.

[0016] As a specific technical solution, the thickness of the uniform induction layer of the negative electrode material: 0 < thickness of the uniform induction layer ≤ 5 μm, specifically can be 5, 4, 3, 2, 1, 0.5, 0.1, 0.001, and also can be any numerical proportion among them.

[0017] As a specific technical solution, the thickness of the buffer layer of the negative electrode material: 0 < thickness of the volume buffer layer ≤ 50 μm, specifically can be 50, 40, 30, 20, 10, 5, 1, 0.1, and also can be any numerical proportion among them.

[0018] In the second aspect, the application provides a preparation method of the composite material, comprising the following steps:

[0019] S1, coating the conductive slurry on the current collector, the coating thickness is controlled to be ≤ 5 μm, and the dried product is reserved;

[0020] S2, depositing a uniform induction layer on the conductive current collector by using a nano thin film preparation process, wherein the nano thin film preparation process includes but is not limited to electron beam evaporation, magnetron sputtering, pulsed laser deposition (PLD), low pressure chemical vapor deposition (LPCVD), plasma enhanced chemical vapor deposition (PECVD), chemical vapor deposition (CVD), and atomic layer deposition (ALD); and the elements of the deposited induction layer are as described in claim 4.

[0021] S3, preparing a volume buffer layer: when the battery system is a liquid battery, the material described in claim 5 is prepared with a binder and a solvent in a certain proportion, and then coated on the surface of S2 and dried to obtain a negative electrode-free material, and then further assembled into a battery; when the battery system is a solid-state battery, the material described in claim 5 is prepared with a solid-state electrolyte and a binder in a certain proportion, and then coated on the surface of S2 and dried to obtain a negative electrode-free material, and then further assembled into a battery with a positive electrode (liquid or solid positive electrode).

[0022] As a specific technical solution, the conductive agent slurry in the preparation method S1 of the negative electrode can use commercial conductive slurry, such as independently prepared conductive agent a + binder b = 100, 0 < a ≤ 99, 1 ≤ b ≤ 50; solid content ≤ 50%; wherein a can be 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 98 or any value therein; wherein b can be 2, 5, 10, 15, 20, 30, 40, 50 or any value therein; the solid content can be 1%, 5%, 10%, 15%, 20%, 30%, 40%, 50% or any value therein.

[0023] As a specific technical solution, the nano-thin film deposition process in the preparation method S2 of the negative electrode takes the magnetron sputtering process as an example: the material prepared in S1 is placed in a magnetron sputtering instrument, first vacuumized to ensure that the vacuum degree is ≤ 5*10 -3 Pa, in an inert gas atmosphere, the working gas pressure is between 0.1-10 Pa, the sputtering power is between 100-400 W; the distance between the target material and the substrate is controlled to be 10-100 mm, and the deposition thickness is controlled by controlling the deposition time; wherein the working gas pressure is more preferably between 0.3-0.6 Pa, too high (> 1 Pa) reduces the deposition rate, too low (< 0.1 Pa) causes unstable sputtering; the distance between the target material and the substrate is more preferably 50-70 mm, too close causes uneven film thickness, too far reduces the deposition rate; the sputtering power is more preferably between 200-300 W; too low sputtering power deposits slowly, too high sputtering power may cause overheating or "poisoning" of the target material; the sputtering threshold of the silicon target (about 150 eV) needs to be matched. The inert gas can be one or more of nitrogen, argon, etc.).

[0024] As a specific technical solution, when the battery system is a liquid battery, the material described in claim 5 is prepared with a binder and a solvent in a certain proportion in the preparation method S3 of the negative electrode, wherein the proportion is pore-containing material c + binder d = 100, 0 < c ≤ 99, 1 ≤ d ≤ 50; solid content ≤ 50%; wherein c can be 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 98 or any value therein; wherein d can be 2, 5, 10, 15, 20, 30, 40, 50 or any value therein; the solid content can be 1%, 5%, 10%, 15%, 20%, 30%, 40%, 50% or any value therein.

[0025] As a specific technical solution, in the preparation method S3 of the negative electrode, when the battery system is a solid-state battery, the material described in claim 5 is prepared with a solid-state electrolyte and a binder in a certain proportion. The ratio of the pore-containing material e, the solid-state electrolyte f, and the binder g is e+f+g=100, 0≤e≤99, 0≤f≤30, 0≤g≤30; the solid content is ≤50%. Specifically, e can be 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 99, or any value therein; f can be 2, 5, 10, 15, 20, 30, or any value therein; g can be 2, 5, 10, 15, 20, 30, or any value therein; the solid content can be 1%, 5%, 10%, 15%, 20%, 30%, 40%, 50%, or any value therein. The solvent can be one or a combination of water, NMP, DMF, DMAC, methanol, acetonitrile, dichloromethane, isopropanol, n-butanol, tetrahydrofuran, chloroform, ethanol, and ethyl acetate.

[0026] In a third aspect, the application also provides a negative electrode, a battery cell, and a battery monomer, and the application of the negative electrode material prepared by the preparation method of the battery monomer and the power equipment in a battery, which includes any one of a lithium ion battery, a solid-state battery, and a semi-solid-state battery.

[0027] Compared with the prior art, a small amount of silicon is uniformly deposited in the pore-containing carbon structure material, lithium is uniformly deposited in the pore-containing carbon structure material during charging and discharging, and the problems of lithium dendrite and volume expansion are improved. Then, the carbon coating layer is used to improve the electronic conductivity of the material and improve the kinetics; the enhanced conductive material can be contained or not contained to further improve the electronic conductivity of the material and improve the kinetics; the coating layer of other elements except carbon can be contained or not contained, which is mainly used to improve the electrical performance. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0029] Figure 1 Negative electrode structure schematic diagram DETAILED DESCRIPTION

[0030] The technical solutions of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0031] In the examples and comparative examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are commercially available unless otherwise specified.

[0032] The present application will be described in further detail below by means of specific examples and with reference to the accompanying drawings.

[0033] Example 1

[0034] This embodiment provides a negative electrode, an electrode core, and a battery cell and a power utilization device, wherein the thickness of the copper current collector is about 6 μm, the thickness of the conductive agent coating is about 1 μm, the uniform induction layer element is Si, the thickness of the induction layer is 100 nm, and the thickness of the volume buffer layer is about 30 μm. The preparation method of the negative electrode material is as follows:

[0035] S1, prepare a slurry with a solid content of about 15% by mixing 60 parts of conductive agent SP, 40 parts of adhesive PVDF, and solvent NMP; coat the slurry on the copper current collector with a coating thickness controlled to be ≤1 μm, and dry it for standby use;

[0036] S2, deposit a uniform induction layer Si film on the conductive current collector by using a magnetron sputtering process; place the material prepared in S1 in a magnetron sputtering instrument, first vacuumize to ensure that the vacuum degree is ≤5*10 -3 Pa, under an argon gas atmosphere, the working gas pressure is 0.4 Pa, and the sputtering power is between 255 W; the distance between the target material and the substrate is controlled to be 50 mm, and the deposition thickness is controlled to be 100 nm by controlling the deposition time;

[0037] S3, prepare a volume buffer layer: dissolve PVDF in NMP solvent to prepare a glue solution with a solid content of 10% for standby use; dissolve PEO solid-state electrolyte and lithium salt (LiTFSI) in NMP solution with EO:LiTFSI=18:1 to prepare a polymer solid-state electrolyte glue solution with a solid content of 20%; prepare a slurry with a solid content of 10% by mixing the porous carbon with 5% silicon, conductive agent CNT, PVDF glue solution, and solid-state electrolyte glue solution in a mass ratio of 70:2:5:23; coat the slurry on the surface of S2 with a thickness of 30 μm, dry it, and match it with a solid-state battery positive electrode to form a full solid-state battery (NCM811:LPSC:PTFE:=80:19:1).

[0038] Example 2

[0039] The embodiment provides a negative electrode, an electric core and a battery monomer and a power utilization equipment preparation method, wherein the thickness of the copper current collector is about 6 microns, the thickness of the conductive agent coating is about 1 micron, the uniform induced layer element is Si, the thickness of the induced layer is 100 nanometers, and the thickness of the volume buffer layer is about 20 microns. The preparation method of the negative electrode material is as follows:

[0040] S1, the conductive agent SP 60 parts, the adhesive PVDF 40 parts, and the solvent NMP are prepared into a slurry with a solid content of about 15%; the slurry is coated on the copper current collector, the coating thickness is controlled to be less than or equal to 1 micron, and the slurry is dried for standby;

[0041] S2, a uniform induced layer Si film is deposited on the conductive current collector by using a magnetron sputtering process, the material prepared in S1 is placed in a magnetron sputtering instrument, vacuum is first extracted to ensure that the vacuum degree is less than or equal to 5*10 -3 Pa, in an argon gas atmosphere, the working gas pressure is 0.4 Pa, the sputtering power is 255 W, the distance between the target material and the substrate is controlled to be 50 mm, and the deposition thickness is controlled to be 100 nm by controlling the deposition time;

[0042] S3, a volume buffer layer is prepared: PVDF is dissolved in NMP solvent to prepare a glue solution with a solid content of 10% for standby; PEO solid-state electrolyte and lithium salt (LiTFSI) are dissolved in NMP solution to prepare a polymer solid-state electrolyte glue solution with a solid content of 20%; porous carbon with 5% silicon, conductive agent CNT, PVDF glue solution and solid-state electrolyte glue solution are prepared into a slurry with a solid content of 10% according to a mass ratio of 70:2:5:23; the slurry is coated on the surface of S2 with a thickness of 20 microns, and dried to match a solid-state battery positive electrode to form a full solid-state battery (NCM811:LPSC:PTFE:=80:19:1).

[0043] Embodiment 3

[0044] The embodiment provides a negative electrode, an electric core and a battery monomer and a power utilization equipment preparation method, wherein the thickness of the copper current collector is about 6 microns, the thickness of the conductive agent coating is about 1 micron, the uniform induced layer element is Si, the thickness of the induced layer is 100 nanometers, and the thickness of the volume buffer layer is about 15 microns. The preparation method of the negative electrode material is as follows:

[0045] S1, the conductive agent SP 60 parts, the adhesive PVDF 40 parts, and the solvent NMP are prepared into a slurry with a solid content of about 15%; the slurry is coated on the copper current collector, the coating thickness is controlled to be less than or equal to 1 micron, and the slurry is dried for standby;

[0046] S2, depositing a uniform induced layer of Si thin film on the above conductive current collector using a magnetron sputtering process, placing the material prepared in S1 in a magnetron sputtering instrument, first vacuumizing to ensure that the vacuum degree is ≤5*10 -3 Pa, under an argon gas atmosphere, a working gas pressure of 0.4 Pa, and a sputtering power of 255 W; the distance between the target material and the substrate is controlled to be 50 mm, and the deposition thickness is controlled by controlling the deposition time.

[0047] S3, preparing a volume buffer layer: dissolving PVDF in NMP solvent to prepare a glue solution with a solid content of 10% for standby; dissolving PEO solid-state electrolyte and lithium salt (LiTFSI) in NMP solution with EO:LiTFSI=18:1 to prepare a polymer solid-state electrolyte glue solution with a solid content of 20%; preparing a slurry with a solid content of 10% by mixing the porous carbon deposited with 5% silicon, the conductive agent CNT, the PVDF glue solution, and the solid-state electrolyte glue solution in a mass ratio of 70:2:5:23; coating the above slurry on the surface of S2 with a thickness of 15 μm, and drying to match with the positive electrode of the solid-state battery (NCM811:LPSC:PTFE:=80:19:1) to form a full solid-state battery.

[0048] Example 4

[0049] The embodiment provides a negative electrode, a battery cell, and a battery cell and a power utilization device preparation method, wherein the thickness of the copper current collector is approximately 6 μm, the thickness of the conductive agent coating is approximately 1 μm, the uniform induced layer element is Sn, the thickness of the induced layer is 100 nm, and the thickness of the volume buffer layer is approximately 20 μm. The preparation method of the negative electrode material is as follows:

[0050] S1, preparing a slurry with a solid content of about 15% by mixing 60 parts of conductive agent SP, 40 parts of adhesive PVDF, and solvent NMP; coating on the copper current collector with a coating thickness controlled to be ≤1 μm, and drying for standby;

[0051] S2, depositing a uniform induced layer of Sn thin film on the above conductive current collector using a magnetron sputtering process, placing the material prepared in S1 in a magnetron sputtering instrument, first vacuumizing to ensure that the vacuum degree is ≤5*10 -3 Pa, under an argon gas atmosphere, a working gas pressure of 0.4 Pa, and a sputtering power of 255 W; the distance between the target material and the substrate is controlled to be 50 mm, and the deposition thickness is controlled by controlling the deposition time.

[0052] S3, preparing a volume buffer layer: dissolving PVDF in NMP solvent to prepare a glue solution with a solid content of 10%; dissolving PEO solid-state electrolyte and lithium salt (LiTFSI) in NMP solution with EO:LiTFSI=18:1 to prepare a polymer solid-state electrolyte glue solution with a solid content of 20%; preparing a slurry with a solid content of 10% by mixing porous carbon deposited with 5% silicon, conductive agent CNT, PVDF glue solution, and solid-state electrolyte glue solution at a mass ratio of 70:2:5:23; coating the above slurry on the surface of S2 to a thickness of 20 μm, and drying to match a solid-state battery anode to form a full solid-state battery (NCM811:LPSC:PTFE:=80:19:1).

[0053] Example 5

[0054] The present embodiment provides a negative electrode, a battery cell, and a battery cell and a power utilization device preparation method, wherein the copper current collector has a thickness of about 6 μm, the conductive agent coating has a thickness of about 1 μm, the uniform induction layer element is Ag, the induction layer has a thickness of 100 nm, and the volume buffer layer has a thickness of about 20 μm. The preparation method of the negative electrode material is as follows:

[0055] S1, preparing a slurry with a solid content of about 15% by mixing 60 parts of conductive agent SP, 40 parts of adhesive PVDF, and solvent NMP; coating on a copper current collector with a coating thickness controlled to be ≤1 μm, and drying to prepare a material for standby;

[0056] S2, depositing a uniform induction layer Ag film on the above conductive current collector by using a magnetron sputtering process; placing the material prepared in S1 in a magnetron sputtering instrument, first vacuumizing to ensure that the vacuum degree is ≤5*10 -3 Pa, under an argon gas atmosphere, the working gas pressure is 0.4 Pa, and the sputtering power is between 255 W; the distance between the target material and the substrate is controlled to be 50 mm, and the deposition thickness is controlled by controlling the deposition time.

[0057] S3, preparing a volume buffer layer: dissolving PVDF in NMP solvent to prepare a glue solution with a solid content of 10%; dissolving PEO solid-state electrolyte and lithium salt (LiTFSI) in NMP solution with EO:LiTFSI=18:1 to prepare a polymer solid-state electrolyte glue solution with a solid content of 20%; preparing a slurry with a solid content of 10% by mixing porous carbon deposited with 5% silicon, conductive agent CNT, PVDF glue solution, and solid-state electrolyte glue solution at a mass ratio of 70:2:5:23; coating the above slurry on the surface of S2 to a thickness of 20 μm, and drying to match a solid-state battery anode to form a full solid-state battery (NCM811:LPSC:PTFE:=80:19:1).

[0058] Example 6

[0059] The embodiment provides a negative electrode, an electric core and a battery monomer and a power utilization equipment preparation method thereof, wherein the thickness of the copper current collector is about 6 mu m, the thickness of the conductive agent coating is about 1 mu m, the uniform induced layer element is Sb, the thickness of the induced layer is 100 nm, and the thickness of the volume buffer layer is about 20 mu m. The preparation method of the negative electrode material is as follows:

[0060] S1, the conductive agent SP 60 parts, the adhesive PVDF 40 parts, and the solvent NMP are prepared into a slurry with a solid content of about 15%; the slurry is coated on the copper current collector, the coating thickness is controlled to be less than or equal to 1 mu m, and the slurry is dried for standby;

[0061] S2, a uniform induced layer Sb film is deposited on the conductive current collector by using a magnetron sputtering process, the material prepared in S1 is placed in a magnetron sputtering instrument, first, vacuum is drawn to ensure that the vacuum degree is less than or equal to 5*10 -3 Pa, under an argon gas atmosphere, the working gas pressure is 0.4 Pa, the sputtering power is 255 W, the distance between the target material and the substrate is controlled to be 50 mm, and the deposition thickness is controlled by controlling the deposition time.

[0062] S3, a volume buffer layer is prepared: PVDF is dissolved in NMP solvent to prepare a glue solution with a solid content of 10% for standby; PEO solid-state electrolyte and lithium salt (LiTFSI) are dissolved in NMP solution to prepare a polymer solid-state electrolyte glue solution with a solid content of 20%; porous carbon with 5% silicon, conductive agent CNT, PVDF glue solution and solid-state electrolyte glue solution are prepared into a slurry with a solid content of 10% according to a mass ratio of 70:2:5:23; the slurry is coated on the surface of S2 with a thickness of 20 mu m, and dried to match a solid-state battery positive electrode to form a full solid-state battery (NCM811:LPSC:PTFE:=80:19:1).

[0063] Embodiment 7

[0064] The embodiment provides a negative electrode, an electric core and a battery monomer and a power utilization equipment preparation method thereof, wherein the thickness of the copper current collector is about 6 mu m, the thickness of the conductive agent coating is about 1 mu m, the uniform induced layer element is Sb, the thickness of the induced layer is 100 nm, and the thickness of the volume buffer layer is about 20 mu m. The preparation method of the negative electrode material is as follows:

[0065] S1, the conductive agent SP 60 parts, the adhesive PVDF 40 parts, and the solvent NMP are prepared into a slurry with a solid content of about 15%; the slurry is coated on the copper current collector, the coating thickness is controlled to be less than or equal to 1 mu m, and the slurry is dried for standby;

[0066] S2, a uniform induced layer Sb film is deposited on the conductive current collector by using a magnetron sputtering process, the material prepared in S1 is placed in a magnetron sputtering instrument, first, vacuum is drawn to ensure that the vacuum degree is less than or equal to 5*10-3 Pa, under argon gas atmosphere, working pressure 0.4 Pa, sputtering power 255 W; the distance between the target material and the substrate is controlled at 50 mm, and the deposition thickness is controlled by controlling the deposition time.

[0067] S3, preparing a volume buffer layer: dissolving PVDF in NMP solvent to prepare a glue solution with a solid content of 10%; dissolving PEO solid-state electrolyte and lithium salt (LiTFSI) in NMP solution with EO:LiTFSI=18:1 to prepare a polymer solid-state electrolyte glue solution with a solid content of 20%; preparing a slurry with a solid content of 10% by mixing the porous carbon with 5% silicon, conductive agent CNT, PVDF glue solution, and solid-state electrolyte glue solution in a mass ratio of 70:2:5:23; coating the above-mentioned slurry on the surface of S2 with a thickness of 20 μm, and drying to match with a solid-state battery positive electrode to form a full solid-state battery (NCM811:LPSC:PTFE:=80:19:1).

[0068] Example 8

[0069] The embodiment provides a negative electrode, a battery cell, and a battery cell and a power utilization device preparation method, wherein the thickness of the copper current collector is approximately 6 μm, the thickness of the conductive agent coating is approximately 1 μm, the uniform induction layer element is Mg, the thickness of the induction layer is 100 nm, and the thickness of the volume buffer layer is approximately 20 μm. The preparation method of the negative electrode material is as follows:

[0070] S1, preparing a slurry with a solid content of about 15% by mixing 60 parts of conductive agent SP, 40 parts of adhesive PVDF, and solvent NMP; coating on the copper current collector with a coating thickness controlled to be ≤1 μm, and drying to prepare a material for standby use;

[0071] S2, depositing a uniform induction layer Mg film on the conductive current collector by using a magnetron sputtering process; placing the material prepared in S1 in a magnetron sputtering instrument, first vacuumizing to ensure that the vacuum degree is ≤5*10 -3 Pa, under argon gas atmosphere, working pressure 0.4 Pa, sputtering power 255 W; the distance between the target material and the substrate is controlled at 50 mm, and the deposition thickness is controlled by controlling the deposition time.

[0072] S3, preparing a volume buffer layer: dissolving PVDF in NMP solvent to prepare a glue solution with a solid content of 10%; dissolving PEO solid-state electrolyte and lithium salt (LiTFSI) in NMP solution with EO:LiTFSI=18:1 to prepare a polymer solid-state electrolyte glue solution with a solid content of 20%; preparing a slurry with a solid content of 10% by mixing porous carbon deposited with 5% silicon, conductive agent CNT, PVDF glue solution, and solid-state electrolyte glue solution at a mass ratio of 70:2:5:23; coating the above slurry on the surface of S2 to a thickness of 20 μm, and drying to match a solid-state battery anode to form a full solid-state battery (NCM811:LPSC:PTFE:=80:19:1).

[0073] Example 9

[0074] The embodiment provides a negative electrode, a battery cell, and a battery cell and a power utilization device preparation method, wherein the thickness of the copper current collector is about 6 μm, the thickness of the conductive agent coating is about 1 μm, the uniform induction layer element is Ge, the thickness of the induction layer is 100 nm, and the thickness of the volume buffer layer is about 20 μm. The preparation method of the negative electrode material is as follows:

[0075] S1, preparing a slurry with a solid content of about 15% by mixing 60 parts of conductive agent SP, 40 parts of adhesive PVDF, and solvent NMP; coating the slurry on a copper current collector with a coating thickness controlled to be ≤1 μm, and drying to prepare a material for standby use;

[0076] S2, depositing a uniform induction layer Ge film on the conductive current collector by using a magnetron sputtering process; placing the material prepared in S1 in a magnetron sputtering instrument; first, vacuumizing to ensure that the vacuum degree is ≤5*10 -3 Pa, in an argon gas atmosphere, the working gas pressure is 0.4 Pa, and the sputtering power is 255 W; the distance between the target material and the substrate is controlled to be 50 mm, and the deposition thickness is controlled by controlling the deposition time.

[0077] S3, preparing a volume buffer layer: dissolving PVDF in NMP solvent to prepare a glue solution with a solid content of 10%; dissolving PEO solid-state electrolyte and lithium salt (LiTFSI) in NMP solution with EO:LiTFSI=18:1 to prepare a polymer solid-state electrolyte glue solution with a solid content of 20%; preparing a slurry with a solid content of 10% by mixing porous carbon deposited with 5% silicon, conductive agent CNT, PVDF glue solution, and solid-state electrolyte glue solution at a mass ratio of 70:2:5:23; coating the above slurry on the surface of S2 to a thickness of 20 μm, and drying to match a solid-state battery anode to form a full solid-state battery (NCM811:LPSC:PTFE:=80:19:1).

[0078] Example 10

[0079] The embodiment provides a negative electrode, an electric core and a battery monomer and a power utilization equipment preparation method thereof, wherein the thickness of the copper current collector is about 6 mu m, the thickness of the conductive agent coating is about 1 mu m, the uniform induced layer element is Ge, the thickness of the induced layer is 100 nm, and the thickness of the volume buffer layer is about 20 mu m. The preparation method of the negative electrode material is as follows:

[0080] S1, the conductive agent SP 60 parts, the adhesive PVDF 40 parts, and the solvent NMP are prepared into a slurry with a solid content of about 15%; the slurry is coated on the copper current collector, the coating thickness is controlled to be less than or equal to 1 mu m, and the slurry is dried for standby;

[0081] S2, a uniform induced layer Ge film is deposited on the conductive current collector by using a magnetron sputtering process, the material prepared in S1 is placed in a magnetron sputtering instrument, first, vacuum is drawn to ensure that the vacuum degree is less than or equal to 5*10 -3 Pa, in an argon gas atmosphere, the working gas pressure is 0.4 Pa, the sputtering power is 255 W, the distance between the target material and the substrate is controlled to be 50 mm, and the deposition thickness is controlled by controlling the deposition time.

[0082] S3, a volume buffer layer is prepared: PVDF is dissolved in NMP solvent to prepare a glue solution with a solid content of 10% for standby; PEO solid-state electrolyte and lithium salt (LiTFSI) are dissolved in NMP solution to prepare a polymer solid-state electrolyte glue solution with a solid content of 20%; porous carbon with 5% silicon, conductive agent CNT, PVDF glue solution and solid-state electrolyte glue solution are prepared into a slurry with a solid content of 10% according to a mass ratio of 70:2:5:23; the slurry is coated on the surface of S2 with a thickness of 20 mu m, and dried to match a solid-state battery positive electrode to form a full solid-state battery (NCM811:LPSC:PTFE:=80:19:1).

[0083] Embodiment 10

[0084] The embodiment provides a negative electrode, an electric core and a battery monomer and a power utilization equipment preparation method thereof, wherein the thickness of the copper current collector is about 6 mu m, the thickness of the conductive agent coating is about 1 mu m, the uniform induced layer element is Ge, the thickness of the induced layer is 100 nm, and the thickness of the volume buffer layer is about 20 mu m. The preparation method of the negative electrode material is as follows:

[0085] S1, the conductive agent SP 60 parts, the adhesive PVDF 40 parts, and the solvent NMP are prepared into a slurry with a solid content of about 15%; the slurry is coated on the copper current collector, the coating thickness is controlled to be less than or equal to 1 mu m, and the slurry is dried for standby;

[0086] S2, a uniform induced layer Si film is deposited on the conductive current collector by using a magnetron sputtering process, the material prepared in S1 is placed in a magnetron sputtering instrument, first, vacuum is drawn to ensure that the vacuum degree is less than or equal to 5*10-3 Pa, under an argon gas atmosphere, working pressure 0.4 Pa, sputtering power 255 W; the distance between the target material and the substrate was controlled at 50 mm, and the deposition thickness was controlled by controlling the deposition time.

[0087] S3, preparing a volume buffer layer: dissolving PVDF in NMP solvent to prepare a glue solution with a solid content of 10% for use; preparing a slurry with a solid content of 25% by mixing the porous carbon deposited with 5% silicon, conductive agent CNT, PVDF glue solution, and solid electrolyte glue solution at a mass ratio of 75:5:20; coating the above slurry on the surface of S2 to a thickness of 20 μm, and after drying, matching with a liquid battery cathode and a separator film to form a battery (high-nickel NCM811: PVDF: SP: CNT = 96.5:2:1.2:0.3).

[0088] Comparative Example 1

[0089] This comparative example provides for the direct deposition of a 100 nm Si thin film on the surface of a current collector 6 μm Cu foil,

[0090] Example 10 is a liquid battery system, and the electrolyte is LiFSi, configured in a 12 mol / L DME solvent, and then diluted to a 3 mol / L electrolyte by TTE, with 5 wt% FEC and 1% LiNO3 film additive, and the separator is a Celgard 2400 polyethylene film; the solid-state battery is tested in a detachable mold battery, and the pressure of the mold is 10 MPa; the electrolyte layer uses LPSC: PTFE = 99.8:0.2 with a refined particle size D50 of 700 nm, and the solid-state battery cathode is (high-nickel NCM811: PVDF: SP: CNT = 96.5:2:1.2:0.3, with a surface capacity of 4 mAh / cm 2 ).

[0091] The battery test charge and discharge interval is 2.5V-4.2V, and the test current size is 0.1C. In addition, the thickness of the electrode sheet is tested as follows: test steps: (1) measure the thickness of the coated and dried negative electrode of the example, and assemble into a button half battery / mold battery; (2) after the battery is charged and lithium is embedded, the electrode sheet is disassembled; (3) the thickness of the embedded electrode sheet is measured again; (4) the difference between the two thickness measurements is the expansion, and the thickness difference / electrode sheet thickness=expansion rate.

[0092] Table 1 Test data of batteries made from different examples

[0093] Examples Thickness of the current collector Thickness of the conductive agent layer Induction layer Volume buffer layer Discharge capacity mAh / g Volume expansion rate 1 6 1 Si 100 nm 30 μm 195.4 5.2% 2 6 1 Si 100 nm 20 μm 197.2 13.5% 3 6 1 Si 100 nm 15 μm 200.5 27.9% 4 6 1 Sn 100 nm 20 μm 198.2 14.4% 5 6 1 Ag 100 nm 20 μm 197.3 11.8% 6 6 1 Sb 100 nm 20 μm 193.2 15.2% 7 6 1 Bi 100 nm 20 μm 187.2 12.9% 8 6 1 Mg 100 nm 20 μm 186.4 12.3% 9 6 1 Ge 100 nm 20 μm 194.2 14.9% 10 Liquid 6 1 Si 100 nm 20 μm 189.5 13.2% Comparative Example 1 6 \ Si 100 nm 20 μm Comparative Example 2 Si 100 nm 20 μm Comparative Example 3 Si 100 nm 20 μm Comparative Example 4 Si 100 nm 20 μm Comparative Example 5 Si 100 nm 20 μm Comparative Example 6 Si 100 nm 20 μm Comparative Example 7 Si 100 nm 20 μm Comparative Example 8 Si 100 nm 20 μm Comparative Example 9 Si 100 nm 20 μm Comparative Example 10 Si 100 nm 20 μ \ 191.3 92.6%

[0094] As can be seen from Table 1 above, the greater the thickness of the buffer layer, the smaller the volume expansion, but on the other hand, since the buffer layer is all a porous material, its specific surface area is larger, resulting in more SEI film production and lower discharge capacity. As can be seen from Examples 1-3, when the thickness of the buffer layer is 30 μm, the volume expansion is only 5.2%, when the thickness of the buffer layer is reduced to 20 μm, the volume expansion increases to 13.5%, and when the thickness of the buffer layer is further reduced to 15 μm, the volume expansion further increases to 27.9%, and at the same time, due to the reduction of the porous material, the specific capacity is improved. Example 10 is a liquid battery system, since the liquid is more prone to consume SEI film, resulting in lower first discharge capacity, but smaller volume expansion. Examples 4-9 use different induction layers, among which the thickness difference is not large, and the difference in capacity is mainly related to the irreversible phase formed by different alloys, but since the total thickness of the induction layer is very thin, the difference is due to the expansion difference of the alloy phase formed and part of the test error.

[0095] The negative electrode, the battery cell, the single battery and the power equipment provided by the application can be applied to lithium ion batteries, solid-state batteries, semi-solid-state batteries, negative electrode-free batteries and the like.

[0096] The above examples only exemplarily illustrate the concepts and technical solutions of the application, and are not used to limit the application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical idea disclosed by the application should be covered by the claims of the application.

[0097] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. The invention discloses a negative electrode, a battery cell, a single battery and an electrical device, which material is composed of a current collector, an electron conductive layer, a uniform induction layer, which can or can not contain a volume expansion buffer layer, which can or can not contain an ion / electron transport layer; wherein the electron conductive layer is the key to reduce the overall battery resistance, such as used in sulfide full solid-state battery can also alleviate the corrosion of sulfide electrolyte to the current collector; the uniform induction layer is used to induce uniform deposition of lithium, material composition of alloy or compound with lithium, and inhibit lithium dendrite; the volume buffer layer is mainly a porous structure buffer layer; the ion transport layer is mainly used for ion transport, and the ion transport layer can also carry ion and electron mixed transport layer.

2. The method of claim 1, wherein, The current collector includes but is not limited to copper, aluminum, stainless steel, nickel, and composite current collector with polymer sandwich structure, and the polymer includes but is not limited to PET (polyterephthalate), PP (polypropylene), PI (polyimide), PE (polyethylene) and the like; 0 < thickness of the current collector ≤ 30 μm.

3. The method of claim 1, wherein The electron conductive layer is a conductive agent layer, the thickness of the conductive agent layer is 0 < electron conductive layer ≤ 5 μm; the main material of the conductive agent layer can be metal powder conductive agent and inorganic conductive material, wherein the metal powder conductive agent can be one or more of nickel powder, silver powder, copper powder, aluminum powder, tin powder, gold powder and the like, and the D50 particle size is ≤ 2 μm; the inorganic conductive material can be at least one of single-arm, multi-arm carbon nanotube, conductive carbon black, graphene, graphite, conductive graphite, fullerene, VGCF, amorphous carbon, soft carbon, hard carbon or a composite of two or more thereof.

4. According to the claim 1, the uniform induction layer is a material that is easy to form alloy or compound with alkali metal, such as Si, Sn, Sb, Al, Mg, P, Ag, Zn, Se, Te, Bi, B, Ge, Sn-Co-C tin cobalt carbon composite material, Si-Sn composite material and the like, wherein the thickness of the uniform induction layer is 0 < uniform induction layer thickness ≤ 5 μm.

5. The anode of claim 1, which can or can not contain a volume expansion buffer layer, which is mainly a porous structure material or a coating layer for the growth space of lithium deposition, and can effectively inhibit volume expansion; the thickness of the buffer layer: 0 < volume buffer layer thickness < 50 μm, the porous structure material or the coating layer includes at least one of single-arm, multi-arm carbon nanotubes, conductive carbon black, electrospun fibers, graphene, graphite, fullerene, VGCF, amorphous carbon, soft carbon, hard carbon, or a composite coating layer with pores coated with two or more of the above, which can also be carbon cloth, carbon fiber cloth, carbon felt, carbon fiber paper, glass fiber cloth, glass fiber paper, porous carbon, activated carbon, porous material, material surface modified by the element of claim 4, and silicon-deposited porous material, surface-modified porous material, phosphorus-containing porous material, etc. The volume expansion buffer layer can or can not contain, when it contains, it can effectively inhibit volume expansion; when it does not contain, the alkali metal ions released from the positive electrode are directly and uniformly deposited on the induction layer, inhibiting lithium dendrites, but unable to achieve volume expansion inhibition function.

6. The application of claim 1, which can or can not contain an ion / electron mixed transport layer, must contain at least an ion transport layer when applied to a solid-state battery, and can also be an ion-electron mixed transport layer; when applied to a battery containing electrolyte, it can not contain an ion transport layer due to the presence of liquid electrolyte for ion transport; the above-mentioned electrolyte can be a traditional electrolyte with carbonate as solvent, or a high-concentration lithium salt electrolyte with ether solvent as solvent and a partial high-concentration lithium salt electrolyte system; the ion transport layer necessary for the above-mentioned application to a solid-state battery must contain a solid-state electrolyte that can conduct lithium ions, and the ion transport layer can be mixed with the ion-electron transport layer of claim 4 and claim 5 to form an ion-electron transport layer, while also having a buffering effect; the core material of the ion transport layer includes but is not limited to one or more of oxide solid electrolyte, sulfide solid electrolyte, polymer solid electrolyte, halide solid electrolyte; the oxide solid electrolyte includes one or more of garnet type (such as lithium lanthanum zirconium oxide LLZO and its modified system), perovskite type (lithium lanthanum tantalum oxide LLTO and its modified system), mixed polyanion solid (NASICON) type ceramic [including lithium titanium aluminum phosphate (LATP) and its modified system, lithium aluminum germanium phosphate (LAGP)], lithium aluminate, lithium niobate, lithium silicate, lithium titanate, lithium tantalate, lithium tungstate], and its modified system, one or more of which; the sulfide solid electrolyte can be a binary sulfide system composed of Li2S-GeS2, Li2S-P2S5, Li2S-SiS2, Li2S-SnS2, Li2S-SeS2, or a ternary sulfide system of Li2S-MS2-P2S5 (M=Si, Ge, Sn, Al), or one or more of Li2S-P2S5-LiCl (LPSC) and its modified system; the polymer solid electrolyte is mainly composed of polymer matrix, lithium salt and additives, and the ion conduction efficiency is improved by the movement of high molecular chain segments and inorganic fillers.The polymer matrix can be one or more of polyether [containing (—C—O—C—) such as PEO, PPO, PEO-PPO copolymer, PEO-PS copolymer, multi-armed polyether, star-shaped, dendritic polyether, and supramolecular structure polymer synthesized with polyether units], polycarbonate [such as polytrimethylene carbonate, polyethylene carbonate, polycarbonate (PVC, PTMC, PPC), polyacrylonitrile acrylate (PECA), polypropanediamide (PMA)], polyacrylate [especially polyacrylate electrolyte containing ethylene oxide segment in chain end, acrylic acid unit, methyl acrylate, ethyl acrylate, butyl acrylate, and copolymer with other monomers], polyacrylonitrile and its copolymer with other monomers, polysiloxane [polymer containing -Si-O-Si- structure and its polymer with other monomers], polyurethane [polymer containing urethane, allophanate structure], single-ion conductor polymer system, polyvinylidene fluoride (PVDF, PVDF-HFP and its modified system); the above lithium salt can be one or more of lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), and lithium hexafluorophosphate (LiPF6), organic lithium salt is obtained by introducing an electron-withdrawing group on the basis of inorganic lithium salt, common ones are one or more of lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), lithium bis(difluorosulfonyl)imide (LiFSI), and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), lithium nitrate (LiNO3); the inorganic filler can be one or more of alumina, silica, zirconia, titania, magnesia, barium titanate, mica powder, kaolin powder, talc powder, calcium oxide, barium sulfate; when a polymer solid-state electrolyte is used, the interface impedance can be further effectively reduced.

7. The application also discloses a preparation method of the negative electrode-free battery, characterized in that The steps include: S1. Apply conductive paste to the current collector, with a coating thickness controlled to be ≤5 μm, and dry for standby; S2. Deposit a uniform induction layer on the conductive current collector using a nano-thin film preparation process, which includes but is not limited to electron beam evaporation, magnetron sputtering, pulsed laser deposition (PLD), low-pressure chemical vapor deposition (LPCVD), plasma-enhanced chemical vapor deposition (PECVD), chemical vapor deposition (CVD), and atomic layer deposition (ALD); deposit the induction layer elements as described in claim 4; S3. Prepare a volume buffer layer: when the battery system is a liquid battery, prepare the material described in claim 5 with a binder and a solvent in a certain proportion, then coat it on the surface of S2 and dry it to obtain a negative electrode-free material, and then further assemble the battery; when the battery system is a solid-state battery, prepare the material described in claim 5 with a solid-state electrolyte and a binder in a certain proportion, then coat it on the surface of S2 and dry it to obtain a negative electrode-free material, and then further assemble the battery with a positive electrode (liquid or solid positive electrode).

8. The method of claim 7, wherein, In step S1, the conductive paste mainly contains the conductive material described in claim 3, a binder (polyacrylic acid, water-based / oil-based polyurethane, SBR, NBR, PVDF, PVDF-HFP), can or can not contain a dispersant, and can or can not contain a thickening agent (CMC, PVP), etc.

9. The preparation method according to claim 7, characterized in that, The binder in step S3 can be a binder (polyacrylic, water-based polyurethane, SBR, NBR), a dispersant (CMC, PVP), a solvent (water, NMP, DMF, acetone, ethanol, etc.), and the like when the battery system is liquid; when the battery is a solid-state battery, the binder can be preferably a polymer solid-state electrolyte system (as claimed in claim 6) to further reduce the interface impedance, and a small amount of oily binder such as PVDF can be compounded with the polymer electrolyte to enhance the adhesion strength of the buffer layer; wherein the total of the porous material and the binder is 100, 0≤porous material≤99, 1≤binder≤30, and the solid content is≤30; when the battery system is a solid-state battery, the material in claim 5 is compounded with a solid-state electrolyte and a binder in a certain proportion, and then coated on the surface of S2 above and dried to obtain a negative electrode material, and then further assembled into a battery, wherein the total of the porous material, the solid-state electrolyte, and the binder is 100, 0≤porous material≤99, 0≤solid-state electrolyte≤30, and 0≤binder≤50; the solid content is≤50%; the solvent can be one or more of water, NMP, DMF, DMAC methanol, acetonitrile, dichloromethane, isopropanol, n-butanol, tetrahydrofuran, chloroform, ethanol, ethyl acetate; the positive electrode includes a liquid battery positive electrode and a solid-state battery positive electrode; wherein the positive electrode active material includes one or more of lithium iron phosphate, lithium cobaltate, lithium manganate, ternary positive electrode material, cobalt-free positive electrode, lithium-rich manganese positive electrode, lithium nickelate positive electrode material, and the like; when it is a solid-state battery positive electrode, it contains a solid-state electrolyte material in addition to the above-mentioned positive electrode active material, and the solid-state electrolyte material is at least one or more of the materials claimed in claim 6.

10. The application of the negative electrode material of claim 1 or the negative electrode material prepared by the method of any one of claims 1-9 in an electrode sheet, a battery, a battery pack, and an electrical equipment, wherein the battery includes any one of a lithium ion battery, a solid-state battery, and a semi-solid-state battery.

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