Negative electrode material, negative electrode sheet, secondary battery and electrical device

Abstract

The present application provides a negative electrode material, a negative electrode slurry, a negative electrode sheet, a secondary battery, and an electrical device. The negative electrode material includes a negative electrode active material and a lithium dendrite-consuming material. The lithium dendrite-consuming material is located on at least a portion of the surface of the active material, and the oxidation potential of the lithium dendrite-consuming material is ≥1V. By introducing the lithium dendrite-consuming material into the negative electrode material, when lithium dendrites are generated, the lithium dendrite-consuming material can react with the lithium dendrites to prevent further growth of the lithium dendrites, thereby effectively preventing the occurrence of lithium precipitation.

Description

Technical Field

[0001] The present application relates to the technical field of secondary batteries, and in particular to a negative electrode material, a negative electrode plate, a secondary battery, and an electrical device. Background Art

[0002] During the use of lithium-ion batteries, lithium ions are deintercalated from the positive electrode and then intercalated into the negative electrode. When lithium ions intercalate into the negative electrode, lithium dendrites may form on the negative electrode surface, a problem known as lithium plating. This plating can adversely affect the battery's cycling performance. Lithium dendrites may even pierce the separator, causing contact between the positive and negative electrodes and potentially leading to safety hazards such as combustion or explosion. Therefore, preventing lithium plating in batteries is crucial to maintaining their cycling performance. Summary of the Invention

[0003] The present application provides a negative electrode material, including a negative electrode active material and a lithium dendrite-consuming material, wherein the lithium dendrite-consuming material is located on at least a portion of the surface of the active material, and the oxidation potential of the lithium dendrite-consuming material is ≥1V.

[0004] In the above-mentioned negative electrode materials, by introducing the lithium dendrite-consuming material, when lithium dendrites are generated, the lithium dendrite-consuming material can react with the lithium dendrites to prevent further growth of the lithium dendrites, thereby effectively avoiding the occurrence of lithium plating. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 Schematic diagram of a secondary battery according to one embodiment of the present application.

[0006] Figure 2 yes Figure 1 FIG. 1 is an exploded view of a secondary battery according to an embodiment of the present application.

[0007] Figure 3 Schematic diagram of a battery module according to one embodiment of the present application.

[0008] Figure 4 Schematic diagram of a battery pack according to one embodiment of the present application.

[0009] Figure 5 yes Figure 4 An exploded view of a battery pack according to an embodiment of the present application is shown.

[0010] Figure 6 FIG. 1 is a schematic diagram of an electrical device using a secondary battery according to an embodiment of the present application as a power source.

[0011] Figure 7 Schematic diagram of the structure of the negative electrode material according to one embodiment of the present application.

[0012] Description of reference numerals:

[0013] 1. Battery pack; 2. Upper box; 3. Lower box; 4. Battery module; 5. Secondary battery; 51. Shell; 52. Electrode assembly; 53. Top cover assembly; 6. Negative electrode active material; 7. Lithium dendrite consumable material; 8. Polymer coating. DETAILED DESCRIPTION

[0014] Below, the embodiments of the battery assembly, battery cell, secondary battery and electrical device of the present application are described in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0015] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0016] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0017] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0018] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0019] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0020] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true or present, and B is false or absent; A is false or absent, and B is true or present; or both A and B are true, or both A and B are present.

[0021] Unless otherwise specified, in this application, the terms "positive electrode sheet" and "positive electrode sheet" have the same meaning and can be used interchangeably. The terms "negative electrode sheet" and "negative electrode sheet" have the same meaning and can be used interchangeably. The terms "diaphragm" and "separator" have the same meaning and can be used interchangeably.

[0022] An embodiment of the present application provides a negative electrode material, comprising a negative electrode active material and a lithium dendrite-consuming material, wherein the lithium dendrite-consuming material is located on at least a portion of the surface of the negative electrode active material, and the oxidation potential of the lithium dendrite-consuming material is ≥1 V. In the negative electrode material of this embodiment, by introducing the lithium dendrite-consuming material, when lithium dendrites are generated, the lithium dendrite-consuming material can react with the lithium dendrites to avoid further growth of the lithium dendrites, thereby effectively avoiding the occurrence of lithium precipitation. It can be understood that the lithium dendrite-consuming material refers to a material that can react with lithium dendrites and consume the lithium dendrites.

[0023] Furthermore, the negative electrode material in this embodiment is applied to a lithium-ion battery, and the oxidation potential of the lithium dendrite-consuming material is ≥1V, which can effectively consume metallic lithium dendrites, reduce the accumulation of dead lithium, reduce battery polarization, improve the battery's cycle capacity, and further improve the battery's cycle performance.

[0024] Furthermore, when the lithium dendrite-consuming material reacts with the lithium dendrites, the lithium dendrites can be converted into lithium ions. On the one hand, the generated lithium ions can continue to circulate in the battery to improve the battery's cycle performance. On the other hand, the generated lithium ions can participate in the construction of the SEI film, which is beneficial to maintaining the stability of the battery.

[0025] Furthermore, when the negative electrode material in this embodiment is applied to a lithium-ion battery, the lithium plating phenomenon is well avoided, thereby effectively improving the cycle performance of the battery.

[0026] Optionally, the oxidation potential of the lithium dendrite-consuming material is ≥1.5 V. Optionally, the oxidation potential of the lithium dendrite-consuming material is ≥2 V. Optionally, the oxidation potential of the lithium dendrite-consuming material is ≥2.5 V. Optionally, the oxidation potential of the lithium dendrite-consuming material is 1 V to 3 V.

[0027] It is understood that the oxidation potential of the lithium dendrite-consuming material can be obtained by querying the redox potential table.

[0028] In this application, oxidation potential is a well-known concept in the art. Specifically, oxidation potential is tested by the following method.

[0029] Oxidation potential test method for lithium dendrite consumable materials:

[0030] 1. Select a single-sided electrode with no creases or scratches on the surface, punch out a small disc with a diameter of 14 mm, and use it as the negative electrode to assemble a button half-cell. The electrolyte is a 1M LiPF6 ethylene carbonate (EC) / diethyl carbonate (DEC) (volume ratio 3:7) electrolyte with the addition of the lithium dendrite consumable material to be tested. The amount of additive is 0.05 mol / L. The positive electrode shell is an aluminum-plated shell. The electrode includes a current collector and a film layer. The current collector is a 6μm copper foil. The film layer includes the negative electrode active material artificial graphite, conductive agent carbon black, binder styrene butadiene rubber and CMC-Na in a mass ratio of 96:1.0:1.5:1.5.

[0031] 2. Assemble the electrochemical workstation with a buckle battery, connect the voltage line and current line of the working electrode together as the positive electrode, and connect the voltage line, current line and white reference line of the counter electrode together as the negative electrode; then connect them to the positive and negative electrodes of the buckle battery respectively.

[0032] 3. The test process is as follows: let it rest for 2 hours, then charge it to 1V at a constant current. Then scan it at a rate of 0.5mV / s over a range of 1-5V. According to the current-voltage curve analysis, the voltage at which the slope begins to rise is the oxidation potential of the lithium dendrite-consuming material.

[0033] In some embodiments, the mass ratio of the lithium dendrite-consuming material to the negative electrode active material is 0.01:1 to 0.1:1. Alternatively, the mass ratio of the lithium dendrite-consuming material to the negative electrode active material is 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1, etc. If the amount of the lithium dendrite-consuming material is too small, it is difficult to effectively inhibit the formation of lithium dendrites. If the mass of the lithium dendrite-consuming material is too large, the proportion of the negative electrode active material may be reduced, which is not conducive to improving the energy density of the negative electrode material.

[0034] Optionally, the Dv50 of the lithium dendrite consumable material is 10 nm to 1000 nm. For example, the Dv50 of the lithium dendrite consumable material is 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, etc. Further optionally, the Dv50 of the lithium dendrite consumable material is 50 nm to 500 nm.

[0035] It is understood that in this application, Dv50 refers to the particle size corresponding to the 50% cumulative particle size distribution in the volume cumulative distribution curve. Its physical meaning is that particles with a smaller (or larger) size account for 50%. As an example, Dv50 can be conveniently measured using a laser particle size analyzer, such as the Mastersizer 2000E laser particle size analyzer from Malvern Instruments Ltd. in the UK, with reference to GB / T 19077-2016 Particle Size Distribution Laser Diffraction Method.

[0036] As some selected examples of lithium dendrite-consuming materials, the lithium dendrite-consuming materials include at least one of phosphorus pentoxide, lithium polysulfide, iron oxide, iodine and its compounds, titanium disulfide, metallocene, phenothiazine, phenazine, thianthrene, triphenylamine, triphenylphosphine, metalloporphyrin, piperidine oxide and tetrathiafulvalene. Alternatively, the lithium dendrite-consuming materials include at least one of phosphorus pentoxide, lithium polysulfide, iron trioxide, iron tetroxide, iodine, tin iodide, titanium disulfide, ferrocene, 10-methylphenothiazine, 5,10-dimethyldihydrophenazine, thianthrene, tri[(diethylamino)phenyl]amine, bis(4-methoxyphenyl)phenylphosphine, tetraphenylcobaltporphyrin, 2,2,6,6-tetramethylpiperidinoxide (tempo) and tetrathiafulvalene. Alternatively, the lithium polysulfide includes at least one of Li2S8, Li2S6, and Li2S4.

[0037] As some examples of negative electrode active materials, the negative electrode active material includes at least one of graphite, hard carbon, soft carbon, silicon-based materials, tin-based materials, and lithium titanate. Alternatively, the negative electrode active material includes at least one of graphite, silicon powder, and silicon oxide. It is understood that graphite can be divided into artificial graphite and natural graphite based on the crystal formation method.

[0038] Optionally, the Dv50 of the negative electrode active material is 3 μm to 25 μm. For example, the Dv50 of the negative electrode active material is 3 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, etc.

[0039] In some embodiments, the negative electrode material further includes a polymer coating layer; the polymer coating layer is coated on at least a portion of the surface of the lithium dendrite consumable material. By introducing the polymer coating layer into the negative electrode material, on the one hand, the position of the lithium dendrite consumable material in the negative electrode active material can be fixed by coating the polymer coating layer, which is beneficial for the lithium dendrite consumable material and the negative electrode active material to maintain a relatively stable positional relationship, thereby helping the lithium dendrite consumable material to play a stable role. On the other hand, the coating of the polymer coating layer can play a good protective role on the lithium dendrite consumable material, preventing the lithium dendrite consumable material from entering the electrolyte and interacting with the electrolyte to cause unnecessary consumption, thereby restricting the effect of the lithium dendrite consumable material. For example, when the electrolyte in the battery is an electrolyte, the polymer coating layer can effectively prevent the lithium dendrite consumable material from entering the electrolyte, so that the lithium dendrite consumable material can maintain a relatively stable content in the negative electrode material, thereby maintaining a good inhibitory effect on the lithium precipitation phenomenon.

[0040] It is understood that the polymer coating layer can allow lithium ions to pass through. Alternatively, when the electrolyte in the battery is an electrolyte, the polymer coating layer can allow the electrolyte to pass through.

[0041] In some embodiments, the polymer coating extends to the surface of the negative electrode active material. Alternatively, the polymer coating entirely covers the lithium dendrite-consuming material and extends to the surface of the negative electrode active material. Further, optionally, the polymer coating entirely covers the lithium dendrite-consuming material and the negative electrode active material. In this case, the negative electrode active material and the lithium dendrite-consuming material can maintain a more stable structure.

[0042] It can be understood that the polymer coating layer extending to the surface of the negative electrode active material means that the polymer coating layer extends from the surface of the lithium dendrite consuming material to the surface of the negative electrode active material, which is beneficial to further improve the bonding effect between the lithium dendrite consuming material and the negative electrode active material.

[0043] See also Figure 7, which shows the structure of the negative electrode material in one embodiment of the present application. In the negative electrode material, the negative electrode material includes a negative electrode active material 6, a lithium dendrite consumable material 7 and a polymer coating layer 8. The lithium dendrite consumable material 7 is located on the surface of the negative electrode active material 6, and the polymer coating layer 8 covers the lithium dendrite consumable material 7 and the negative electrode active material 6 as a whole. In the negative electrode material, the negative electrode active material 6 and the lithium dendrite consumable material 7 have a stable structure, and the lithium dendrite consumable material 7 can stably exist on the surface of the negative electrode active material 6. When the negative electrode material is used in a lithium-ion battery, the electrode liquid infiltrates the polymer coating layer and contacts the lithium dendrite consumable material 7. When no lithium dendrites appear, the lithium dendrite consumable material 7 remains unchanged. When lithium dendrites are generated, the lithium dendrite consumable material 7 can react with the lithium dendrites to convert the lithium dendrites into lithium ions. The lithium ions formed by the transformation of lithium dendrites can continue to circulate in the battery on the one hand, and on the other hand, can participate in the construction of the SEI film to further improve the performance of the battery. It can be understood that Figure 7 The main purpose is to show the structure of the negative electrode material, and it does not limit the content of the negative electrode active material, lithium dendrite consumption material, and the thickness of the polymer coating layer in the negative electrode material.

[0044] In some embodiments, the thickness of the polymer coating layer is 0.1 μm to 10 μm. Alternatively, the thickness of the polymer coating layer is 0.1 μm, 0.2 μm, 0.5 μm, 0.8 μm, 1 μm, 1.5 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc. Further optionally, the thickness of the polymer coating layer is 1 μm to 10 μm.

[0045] In some embodiments, the polymer coating has a degree of swelling of ≥110%. Optionally, the polymer coating has a degree of swelling of 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, 210%, 220%, 250%, etc. Further optionally, the polymer coating has a degree of swelling of 110% to 200%.

[0046] It can be understood that the swelling degree of the polymer coating layer refers to the ratio of the volume after swelling to the volume before swelling when the polymer of the polymer coating layer adsorbs solvent molecules in the solvent to reach swelling equilibrium.

[0047] Alternatively, the swelling degree of the polymer coating can be tested by scraping the polymer coating onto a glass plate, taking a 1 cm x 1 cm piece of the polymer film, measuring its thickness with a vernier caliper or micrometer, and calculating its volume as V1. The polymer film is then immersed in pure dimethyl carbonate for 12 hours. After removal, the length, width, and height of the polymer film are measured, and the volume is calculated as V2. Swelling degree C = (V2 / V1) × 100%.

[0048] In some embodiments, the polymer of the polymer coating layer includes at least one of polyacrylic acid, poly(vinylidene fluoride-co-hexafluoropropylene), polyacrylonitrile, polyvinylidene fluoride, polyethylene oxide, polyacetylene, polyparaphenylene, polypyrrole, polythiophene, polyaniline, and polyphenylene vinylene. Optionally, the polymer coating layer may be formed by a conductive polymer to further improve the electrical performance of the battery.

[0049] Optionally, the weight average molecular weight of the polymer in the polymer coating layer is 10,000 to 150,000.

[0050] Another embodiment of the present application provides a method for preparing a negative electrode material. The method for preparing the negative electrode material comprises the following steps: mixing a negative electrode active material and a lithium dendrite consumable material. By mixing, the lithium dendrite consumable material can be adsorbed on at least a portion of the surface of the negative electrode active material to form a negative electrode material comprising the negative electrode active material and the lithium dendrite consumable material. It is understandable that the selection and dosage of the negative electrode active material and the lithium dendrite consumable material and other characteristics can be selected accordingly in the content of the above-mentioned negative electrode material, and will not be repeated here.

[0051] In some embodiments, after mixing the negative electrode active material and the lithium dendrite-consuming material, the method further includes forming a polymer coating layer on at least a portion of the surface of the lithium dendrite-consuming material.

[0052] Optionally, forming the polymer coating layer on at least a portion of the surface of the lithium dendrite-consuming material includes: mixing a mixture of the negative electrode active material and the lithium dendrite-consuming material with a polymer slurry to obtain a mixed solution; and removing a solvent from the mixed solution. Furthermore, optionally, the solvent from the polymer slurry is removed by drying.

[0053] It is understandable that the polymer slurry includes a polymer and a solvent. The polymer can be selected from the above-mentioned negative electrode materials and will not be described in detail here.

[0054] In some embodiments, the mass ratio of polymer to solvent in the polymer slurry is 1:10 to 1:100. Alternatively, the mass ratio of polymer to solvent is 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, etc. Further optionally, the solvent in the polymer slurry includes at least one of acetonitrile, acetone, ethylene glycol, and N-methylpyrrolidone.

[0055] Another embodiment of the present application provides a negative electrode slurry, which includes the negative electrode material or the negative electrode material prepared by the method for preparing the negative electrode material, and a solvent.

[0056] Another embodiment of the present application provides a method for preparing a negative electrode slurry, which comprises mixing the above-mentioned negative electrode material or the negative electrode material prepared by the above-mentioned method for preparing the negative electrode material with a solvent.

[0057] Optionally, the negative electrode slurry further includes at least one of a binder, a conductive agent and a thickener.

[0058] Another embodiment of the present application provides a negative electrode plate, which includes a current collector and a negative electrode film layer located on at least one surface of the current collector, wherein the negative electrode film layer includes the above-mentioned negative electrode material or the negative electrode material prepared by the above-mentioned method for preparing the negative electrode material.

[0059] Another embodiment of the present application provides a method for preparing a negative electrode sheet. The method comprises the following steps: transferring a slurry containing the aforementioned negative electrode material or a negative electrode material prepared using the aforementioned method to at least one surface of a current collector and curing the slurry to form a negative electrode film layer on the corresponding surface of the current collector. Optionally, the transfer is performed by coating.

[0060] Another embodiment of the present application provides a method for preparing a negative electrode sheet. The method comprises the following steps: transferring the negative electrode slurry to at least one surface of a current collector and curing the slurry to form a negative electrode film layer on the corresponding surface of the current collector. Optionally, the transfer is performed by coating.

[0061] Another embodiment of the present application provides a method for preparing a negative electrode plate. The method for preparing the negative electrode plate comprises the following steps: transferring a slurry containing a negative electrode active material and a lithium dendrite consumable material to at least one surface of a current collector and solidifying it, forming an intermediate layer on the corresponding surface of the current collector, and transferring a polymer slurry to the surface of the intermediate layer and solidifying it to form a negative electrode film layer on the corresponding surface of the current collector. Optionally, the transfer method is coating. In this preparation method, when the slurry containing a negative electrode active material and a lithium dendrite consumable material is transferred to at least one surface of the current collector and solidified, the interaction between the negative electrode active material and the lithium dendrite consumable material forms a structure in which the lithium dendrite consumable material is located on the surface of the negative electrode active material. After the polymer slurry is transferred to the intermediate surface, the polymer penetrates into the pores of the intermediate layer to form a polymer coating layer. After the obtained negative electrode plate is applied to the battery, the occurrence of lithium plating can be effectively avoided. It can be understood that the negative electrode active material, the lithium dendrite consumable material and the polymer can be selected accordingly from the content of the above-mentioned negative electrode materials, and will not be repeated here.

[0062] Another embodiment of the present application provides a secondary battery, which includes the above-mentioned negative electrode sheet or a negative electrode sheet prepared by the above-mentioned method for preparing a negative electrode sheet.

[0063] Optionally, the secondary battery further comprises an electrolyte, and the concentration of the lithium dendrite consumable material in the electrolyte is ≤100mmol / L. Optionally, the concentration of the lithium dendrite consumable material in the electrolyte is ≤90mmol / L. Optionally, the concentration of the lithium dendrite consumable material in the electrolyte is ≤80mmol / L. Optionally, the concentration of the lithium dendrite consumable material in the electrolyte is ≤60mmol / L. Optionally, the concentration of the lithium dendrite consumable material in the electrolyte is ≤40mmol / L. Optionally, the concentration of the lithium dendrite consumable material in the electrolyte is ≤20mmol / L. Optionally, the concentration of the lithium dendrite consumable material in the electrolyte is ≤10mmol / L. Optionally, the concentration of the lithium dendrite consumable material in the electrolyte is 0.

[0064] The present application also provides a secondary battery, which includes the above-mentioned positive electrode sheet or a positive electrode sheet prepared by the above-mentioned method for preparing the positive electrode sheet.

[0065] The present application also provides a battery module, which includes the aforementioned secondary battery.

[0066] The present application also provides a battery pack, which includes the aforementioned secondary battery or the aforementioned battery module.

[0067] The present application also provides an electrical device, which includes at least one of the aforementioned secondary battery, the aforementioned battery module, and the aforementioned battery pack.

[0068] Hereinafter, the secondary battery will be described with reference to the relevant drawings.

[0069] Typically, a secondary battery consists of a positive electrode, a negative electrode, an electrolyte, and a separator. During the battery's charge and discharge processes, active ions are inserted and removed between the positive and negative electrodes. The electrolyte conducts ions between the positive and negative electrodes. The separator, located between the positive and negative electrodes, primarily prevents short circuits between the positive and negative electrodes while allowing ions to pass through.

[0070] [Positive electrode]

[0071] The positive electrode sheet includes a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector, wherein the positive electrode film layer includes a positive electrode active material.

[0072] As an example, the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive electrode current collector.

[0073] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector may be formed by forming a metal material on a polymer material substrate. Alternatively, the metal material may include but is not limited to one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. Alternatively, the polymer material substrate may include but is not limited to one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS) and polyethylene (PE).

[0074] In some embodiments, when the secondary battery is a lithium-ion battery, the positive electrode active material may adopt the positive electrode active material for lithium-ion batteries known in the art. As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium transition metal oxides may include but are not limited to at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and their modified compounds. Optionally, lithium cobalt oxide includes LiCoO2. Lithium nickel oxide includes LiNiO2. Lithium manganese oxide includes at least one of LiMnO2 and LiMn2O4. Lithium nickel cobalt manganese oxide includes LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2(NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM 622 ) and LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM 811 ) at least one of. Lithium nickel cobalt aluminum oxide includes LiNi 0.85 Co 0.15 Al 0.05 Examples of olivine-structured lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Optionally, the lithium iron phosphate includes LiFePO4 (LFP). The lithium manganese phosphate includes LiMnPO4.

[0075] In some embodiments, when the secondary battery is a sodium ion battery, the positive electrode active material may adopt the positive electrode active material for sodium ion batteries known in the art. As an example, the positive electrode active material may be used alone or in combination of two or more. Among them, the positive electrode active material may be selected from sodium iron composite oxide, sodium cobalt composite oxide, sodium chromium composite oxide, sodium manganese composite oxide, sodium nickel composite oxide, sodium nickel titanium composite oxide, sodium nickel manganese composite oxide, sodium iron manganese composite oxide, sodium nickel cobalt manganese composite oxide, sodium iron phosphate compound, sodium manganese phosphate compound, sodium cobalt phosphate compound, Prussian blue material, polyanion material, etc., but the present application is not limited to these materials, and the present application may also use other conventionally known materials that can be used as positive electrode active materials for sodium ion batteries. Optionally, sodium iron composite oxide includes NaFeO2. Sodium cobalt composite oxide includes NaCoO2. Sodium chromium composite oxide includes NaCrO2. Sodium manganese composite oxide includes NaMnO2. Sodium nickel composite oxide includes NaNiO2. Sodium nickel titanium composite oxide includes NaNi 1 / 2 Ti 1 / 2 O2. Sodium nickel manganese composite oxide includes NaNi 1 / 2 Mn 1 / 2 O2. Sodium iron manganese composite oxide includes Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2. Sodium nickel cobalt manganese composite oxides include NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2. Sodium iron phosphate includes NaFePO4. Sodium manganese phosphate includes NaMnPO4. Sodium cobalt phosphate includes NaCoPO4. The polyanion material includes at least one of phosphate, fluorophosphate, pyrophosphate and sulfate.

[0076] In some embodiments, the positive electrode film layer may further optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.

[0077] In some embodiments, the positive electrode film layer may further include a conductive agent. For example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0078] In some embodiments, the positive electrode sheet can be prepared by dispersing the components for preparing the positive electrode sheet, such as the positive electrode active material, conductive agent, binder, and any other components, in a solvent to form a positive electrode slurry; coating the positive electrode slurry on a positive electrode current collector, and performing drying, cold pressing, and other processes to obtain the positive electrode sheet. Optionally, the solvent includes N-methylpyrrolidone.

[0079] [Negative electrode]

[0080] The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector, wherein the negative electrode film layer includes a negative electrode active material.

[0081] As an example, the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0082] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer base layer and a metal layer formed on at least one surface of the polymer base material. The composite current collector may be formed by forming a metal material on a polymer base material. Optionally, the metal material includes at least one of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. The polymer material includes at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS) and polyethylene (PE).

[0083] In some embodiments, the negative electrode active material may be a negative electrode active material for a battery that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxides, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0084] In some embodiments, the negative electrode film layer may further include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), carboxymethyl chitosan (CMCS), polyamide-imide (PAI), polyethyleneimine (PEI), polyimide (PI), and poly-tert-butyl acrylate-triethoxyvinylsilane (TBATEVS).

[0085] In some embodiments, the negative electrode film layer may further include a conductive agent, which may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0086] In some embodiments, the negative electrode film layer may further include other additives, such as a thickener. Optionally, the thickener includes sodium carboxymethyl cellulose (CMC-Na).

[0087] In some embodiments, the negative electrode sheet can be prepared by dispersing the aforementioned components for preparing the negative electrode sheet, such as the negative electrode active material, conductive agent, binder, and any other components, in a solvent to form a negative electrode slurry; coating the negative electrode slurry on a negative electrode current collector, and performing drying, cold pressing, and other processes to obtain the negative electrode sheet. Optionally, the solvent includes deionized water.

[0088] [Electrolytes]

[0089] The electrolyte conducts ions between the positive and negative electrodes. This application does not specify the type of electrolyte, and the electrolyte can be selected based on the needs. For example, the electrolyte can be liquid, gel, or solid.

[0090] In some embodiments, the electrolyte is an electrolyte solution, which further includes an electrolyte salt and a solvent.

[0091] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0092] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.

[0093] In some embodiments, the electrolyte may further include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, and additives that improve battery high or low temperature performance.

[0094] [Isolation film]

[0095] In some embodiments, the secondary battery further includes a separator. The present application has no particular limitation on the type of separator, and any known porous separator with good chemical and mechanical stability can be selected.

[0096] In some embodiments, the material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0097] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator can be formed into an electrode assembly through a winding process or a lamination process.

[0098] In some embodiments, the secondary battery may include an outer packaging that can be used to encapsulate the electrode assembly and the electrolyte.

[0099] In some embodiments, the outer packaging of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. Alternatively, the outer packaging of the secondary battery can be a soft shell, such as a pouch-type soft shell. The soft shell can be made of plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0100] The present application has no particular limitation on the shape of the secondary battery, which can be cylindrical, square or any other shape. For example, Figure 1 The secondary battery 5 is a square structure as an example.

[0101] In some embodiments, reference Figure 2, the outer packaging may include a shell 51 and a cover plate 53. The shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can form an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.

[0102] In some embodiments, secondary batteries can be assembled into a battery module. The number of secondary batteries contained in the battery module can be one or more. The specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

[0103] Figure 3 4 is an example of a battery module. Figure 3 In the battery module 4, the plurality of secondary batteries 5 may be arranged in sequence along the length of the battery module 4. Of course, they may also be arranged in any other manner. The plurality of secondary batteries 5 may further be fixed by fasteners.

[0104] Optionally, the battery module 4 may further include a housing having an accommodation space, and the plurality of secondary batteries 5 are accommodated in the accommodation space.

[0105] In some embodiments, the battery modules described above may also be assembled into a battery pack. The battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art based on the application and capacity of the battery pack.

[0106] Figure 4 and Figure 5 The battery pack 1 is used as an example. Figure 4 and Figure 5 The battery pack 1 may include a battery box and multiple battery modules 4 disposed in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can cover the lower box body 3 and form an enclosed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner in the battery box.

[0107] In addition, the present application also provides an electric device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application. The secondary battery, battery module, or battery pack can be used as a power source for the electric device, and can also be used as an energy storage unit for the electric device. The electric device may include mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc., but is not limited thereto. For example, mobile devices include mobile phones, laptops, etc. Electric vehicles include pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.

[0108] As the electrical device, a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.

[0109] Figure 6 This is an example of an electric device. This device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of the secondary battery, a battery pack or battery module can be used.

[0110] Another example device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is generally required to be lightweight and thin, and may use a secondary battery as a power source.

[0111] Example

[0112] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0113] In Table 1, tempo represents 2,2,6,6-tetramethylpiperidinium oxide. X represents the mass ratio of lithium dendrite-consuming material to active material. PVDF-HFP represents poly(vinylidene fluoride-co-hexafluoropropylene).

[0114] Example 1 to Example 4

[0115] Preparation of negative electrode sheet.

[0116] (1) The negative electrode active material and the lithium dendrite consumption material are stirred and mixed to obtain a mixed material.

[0117] (2) A negative electrode slurry is obtained by mixing a mixture, a conductive agent, a binder and deionized water, wherein the conductive agent is superp, and the binder is a mixture of CMC and SBR in a mass ratio of 1:1.

[0118] (3) The negative electrode slurry is coated on the negative electrode current collector and dried to obtain a negative electrode sheet.

[0119] Among them, the material selection, Dv50 and other characteristics of the negative electrode active material and lithium dendrite consumption material in Examples 1 to 4 are shown in Table 1.

[0120] Example 5

[0121] Preparation of negative electrode sheet.

[0122] (1) The negative electrode active material and the lithium dendrite consumption material are stirred and mixed to obtain a mixed material.

[0123] (2) A negative electrode slurry is obtained by mixing a mixture, a conductive agent, a binder and deionized water, wherein the conductive agent is superp, and the binder is a mixture of CMC and SBR in a mass ratio of 1:1.

[0124] (3) The negative electrode slurry is coated on the negative electrode current collector and dried to form an intermediate layer on the surface of the negative electrode current collector.

[0125] (4) The polymer and acetone solvent are mixed in a mass ratio of 1:10 to obtain a polymer slurry. The polymer slurry is scraped onto the surface of the intermediate layer and dried to remove the solvent in the slurry to obtain a negative electrode sheet.

[0126] Among them, the characteristics of the negative electrode active material, lithium dendrite consumption material, Dv50 and polymer in this embodiment are shown in Table 1.

[0127] Example 6

[0128] Preparation of negative electrode sheet.

[0129] (1) The negative electrode active material and the lithium dendrite consumption material are stirred and mixed to obtain a mixed material.

[0130] (2) A negative electrode slurry is obtained by mixing a mixture, a conductive agent, a binder and deionized water, wherein the conductive agent is superp, and the binder is a mixture of CMC and SBR in a mass ratio of 1:1.

[0131] (3) The negative electrode slurry is coated on the negative electrode current collector and dried to form an intermediate layer on the surface of the negative electrode current collector.

[0132] (4) The polymer and N-methylpyrrolidone solvent are mixed in a mass ratio of 1:10 to obtain a polymer slurry. The polymer slurry is scraped onto the surface of the intermediate layer and dried to remove the solvent in the slurry to obtain a negative electrode sheet.

[0133] Among them, the characteristics of the negative electrode active material, lithium dendrite consumption material, Dv50 and polymer in this embodiment are shown in Table 1.

[0134] Example 7

[0135] Preparation of negative electrode sheet.

[0136] (1) The negative electrode active material and the lithium dendrite consumption material are stirred and mixed to obtain a mixed material.

[0137] (2) A negative electrode slurry is obtained by mixing a mixture, a conductive agent, a binder and deionized water, wherein the conductive agent is superp, and the binder is a mixture of CMC and SBR in a mass ratio of 1:1.

[0138] (3) The negative electrode slurry is coated on the negative electrode current collector and dried to form an intermediate layer on the surface of the negative electrode current collector.

[0139] (4) The polymer and acetone solvent are mixed in a mass ratio of 1:50 to obtain a polymer slurry. The polymer slurry is scraped onto the surface of the intermediate layer and dried to remove the solvent in the slurry to obtain a negative electrode sheet.

[0140] Among them, the characteristics of the negative electrode active material, lithium dendrite consumption material, Dv50 and polymer in this embodiment are shown in Table 1.

[0141] Example 8

[0142] Preparation of negative electrode sheet.

[0143] (1) The negative electrode active material and the lithium dendrite consumption material are stirred and mixed to obtain a mixed material.

[0144] (2) A negative electrode slurry is obtained by mixing a mixture, a conductive agent, a binder and deionized water, wherein the conductive agent is superp, and the binder is a mixture of CMC and SBR in a mass ratio of 1:1.

[0145] (3) The negative electrode slurry is coated on the negative electrode current collector and dried to form an intermediate layer on the surface of the negative electrode current collector.

[0146] (4) The polymer and acetone solvent are mixed in a mass ratio of 1:100 to obtain a polymer slurry. The polymer slurry is scraped onto the surface of the intermediate layer and dried to remove the solvent in the slurry to obtain a negative electrode sheet.

[0147] The characteristics of the negative electrode active material, lithium dendrite consumption material, Dv50, and polymer in this embodiment are shown in Table 1. The mass ratio of silicon oxide to graphite in the negative electrode active material in this embodiment is 1:1.

[0148] Example 9 to Example 30

[0149] Compared with Example 5, the differences between Examples 9 to 30 are that the selection of lithium dendrite consumable materials and / or Dv50 and / or the mass ratio of lithium dendrite consumable materials to negative electrode active materials and / or the polymer coating layer are different, as shown in Table 1.

[0150] Example 31

[0151] Preparation of negative electrode sheet.

[0152] (1) The negative electrode active material and the lithium dendrite consumption material are stirred and mixed to obtain a mixed material.

[0153] (2) The polymer and acetone solvent were mixed in a mass ratio of 1:10 to obtain a polymer slurry. The polymer slurry was mixed with the mixture obtained in (1), and the solvent in the slurry was removed by drying to obtain a negative electrode material.

[0154] (3) The negative electrode material, conductive agent, binder and deionized water obtained in (2) are mixed to obtain a negative electrode slurry, wherein the conductive agent is super p, and the binder is CMC and SBR mixed in a mass ratio of 1:1.

[0155] (4) The negative electrode slurry is coated on the negative electrode current collector and dried to obtain a negative electrode sheet.

[0156] Among them, the characteristics of the negative electrode active material, lithium dendrite consumption material, Dv50 and polymer in this embodiment are shown in Table 1.

[0157] Comparative Example 1 to Comparative Example 2

[0158] Preparation of negative electrode sheet.

[0159] (1) A negative electrode active material, a conductive agent, a binder and deionized water are mixed to obtain a negative electrode slurry, wherein the conductive agent is super P, and the binder is CMC and SBR mixed in a mass ratio of 1:1.

[0160] (2) The negative electrode slurry is coated on the negative electrode current collector and dried to form an intermediate layer on the surface of the negative electrode current collector.

[0161] (4) The polymer and acetone solvent are mixed in a mass ratio of 1:10 to obtain a polymer slurry. The polymer slurry is scraped onto the surface of the intermediate layer and dried to remove the solvent in the slurry to obtain a negative electrode sheet.

[0162] The characteristics of the negative electrode active materials and polymers in Comparative Examples 1 and 2 are shown in Table 1.

[0163] Comparative Example 3

[0164] Preparation of negative electrode sheet.

[0165] (1) A negative electrode active material, a conductive agent, a binder and deionized water are mixed to obtain a negative electrode slurry, wherein the conductive agent is super P, and the binder is CMC and SBR mixed in a mass ratio of 1:1.

[0166] (2) The negative electrode slurry is coated on the negative electrode current collector and dried to obtain a negative electrode sheet.

[0167] The negative electrode active materials in this comparative example are shown in Table 1.

[0168] Preparation of positive electrode sheet.

[0169] The positive electrode active material, PVDF, and conductive carbon were mixed in a mass ratio of 8:1:1, and N-methylpyrrolidone was added and stirred to obtain a positive electrode slurry. The positive electrode slurry was applied to the surface of the positive electrode current collector and dried to obtain a positive electrode sheet. The positive electrode active materials used in the Examples and Comparative Examples are shown in Table 1.

[0170] electrolyte.

[0171] 2% by mass of fluoroethylene carbonate (FEC), 1 mol / L of lithium hexafluorophosphate (LiPF6), solvent ethylene carbonate (EC) and diethyl carbonate (DEC) are uniformly mixed in a volume ratio of 3:7.

[0172] Isolation film.

[0173] Use polyethylene isolation film.

[0174] Secondary battery.

[0175] The positive electrode sheet, the separator, and the negative electrode sheet are stacked in this order to form a battery cell, which is then placed in an outer package, injected with electrolyte, and packaged to obtain a secondary battery.

[0176] Formation treatment: The secondary battery was charged to 30% SOC at 0.04C.

[0177] Test Case

[0178] The secondary battery was cycled: charging at 0.33C to 4.0V and discharging at 0.33C to 2.0V. The number of cycles was recorded when the capacity retention rate reached 80%. The test results are shown in Table 1.

[0179] The lithium deposition degree test method is as follows: After charging the battery to 4.0V, disassemble it, remove the negative electrode, cut it, and affix a 50mm*50mm electrode to conductive adhesive. The battery is then analyzed using an electron microscope, and the amount of dendritic lithium metal in selected areas is observed to determine the degree of lithium deposition. In Table 1, "low," "relatively low," and "high" indicate that the degree of lithium deposition gradually increases.

[0180] Table 1

[0181]

[0182]

[0183]

[0184] As can be seen from Table 1, when a lithium dendrite-consuming material is introduced into the negative electrode material, the cycle performance of the battery can be improved. When a lithium dendrite-consuming material and a polymer coating layer are introduced into the negative electrode material, the cycle performance of the battery can be further improved.

[0185] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A negative electrode material, characterized in that It includes a negative electrode active material, a lithium dendrite consumable material and a polymer coating layer, wherein the lithium dendrite consumable material is located on at least a portion of the surface of the negative electrode active material, and the oxidation potential of the lithium dendrite consumable material is ≥1V; the polymer coating layer is coated on at least a portion of the surface of the lithium dendrite consumable material.

2. The negative electrode material according to claim 1, characterized in that The lithium dendrite consumable material satisfies at least one of the following characteristics: (1) The oxidation potential of the lithium dendrite consumable material is 1V to 3V; (2) The mass ratio of the lithium dendrite consumable material to the negative electrode active material is 0.01:1 to 0.1:1; (3) The Dv50 of the lithium dendrite consumable material is 10nm to 1000nm.

3. The negative electrode material according to claim 1, characterized in that The Dv50 of the lithium dendrite consumable material is 50nm to 500nm.

4. The negative electrode material according to claim 1, characterized in that The lithium dendrite consumption material includes at least one of phosphorus pentoxide, lithium polysulfide, iron oxide, iodine and its compounds, titanium disulfide, metallocene, phenothiazine, phenazine, thianthrene, triphenylamine, triphenylphosphine, metalloporphyrin, piperidine oxide and tetrathiafulvalene.

5. The negative electrode material according to claim 1, characterized in that The lithium dendrite-consuming material includes at least one of tin iodide, ferrocene, 10-methylphenothiazine, 5,10-dimethyldihydrophenazine, tris[(diethylamino)phenyl]amine, bis(4-methoxyphenyl)phenylphosphine, tetraphenylcobalt porphyrin and 2,2,6,6-tetramethylpiperidinium oxide.

6. The negative electrode material according to claim 1, characterized in that The negative electrode active material satisfies at least one of the following characteristics: (1) The negative electrode active material includes at least one of graphite, hard carbon, soft carbon, silicon-based material, tin-based material and lithium titanate; (2) The Dv50 of the negative electrode active material is 3 μm to 25 μm.

7. The negative electrode material according to claim 1, characterized in that The negative electrode active material includes at least one of graphite, silicon powder and silicon oxide.

8. The negative electrode material according to any one of claims 1 to 7, characterized in that The polymer coating layer extends to the surface of the negative electrode active material.

9. The negative electrode material according to any one of claims 1 to 7, characterized in that The polymer coating layer integrally covers the lithium dendrite-consuming material and the negative electrode active material.

10. The negative electrode material according to any one of claims 1 to 7, characterized in that The polymer coating layer satisfies at least one of the following characteristics: (1) The thickness of the polymer coating layer is 0.1 μm to 10 μm; (2) The swelling degree of the polymer coating layer is ≥110%; (3) The polymer of the polymer coating layer includes at least one of polyacrylic acid, poly(vinylidene fluoride-co-hexafluoropropylene), polyacrylonitrile, polyvinylidene fluoride, polyethylene oxide, polyacetylene, polyparaphenylene, polypyrrole, polythiophene, polyaniline and polyphenylene vinylene; (4) The weight average molecular weight of the polymer in the polymer coating layer is 10,000 to 150,000.

11. The negative electrode material according to any one of claims 1 to 7, characterized in that The polymer coating layer satisfies at least one of the following characteristics: (1) The thickness of the polymer coating layer is 1 μm to 10 μm; (2) The swelling degree of the polymer coating layer is 110% to 200%.

12. A negative electrode plate, characterized in that: The invention comprises a current collector and a negative electrode film layer located on at least one surface of the current collector, wherein the negative electrode film layer comprises the negative electrode material according to any one of claims 1 to 11.

13. A secondary battery, characterized in that: Including the negative electrode sheet according to claim 12.

14. The secondary battery according to claim 13, wherein: It also includes an electrolyte, and the concentration of the lithium dendrite consumable material in the electrolyte is ≤100mmol / L.

15. An electrical device, characterized in that: The secondary battery according to claim 14 is included.

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