Negative electrode material and manufacturing method, battery and electric device

Abstract

The present application discloses a negative electrode material and a method for producing the same, a battery, and an electric device. The negative electrode material includes porous carbon, which contains iron and / or sulfur, and the pores of the porous carbon contain an active material. By these means, the present application achieves a negative electrode material with good electrical conductivity, small volume expansion, and high surface activity, resulting in a battery with high capacity, excellent rate performance, and excellent cycle performance. In one embodiment, the negative electrode material contains 50 to 3000 ppm of iron and / or 100 to 1500 ppm of sulfur.

Description

[Technical Field]

[0001] This application relates to the technical field of battery materials, particularly negative electrode materials and methods of manufacture, batteries, and electrical devices. [Background technology]

[0002] With the rapid development of society today, people's needs for new green energy sources and high-performance energy storage devices are increasing. Batteries, as a new generation of green energy storage and conversion devices, have been widely applied in fields such as portable electronic devices and powered vehicles. Batteries include a positive electrode material, a negative electrode material, a separator, an electrolyte, and a current collector. Currently, battery negative electrode materials have problems such as volume expansion and low conductivity, which significantly shorten the battery life and reduce battery performance. Therefore, there is a high demand for ways to suppress volume expansion, improve cycle performance, and increase conductivity. Summary of the Invention [Means for solving the problem]

[0003] In view of the above technical problems, the present application provides a negative electrode material, a manufacturing method thereof, a battery, and an electric device, which have good electrical conductivity and a small expansion coefficient, and can realize a battery using the negative electrode material having excellent rate performance, cycle performance, and high capacity.

[0004] In a first aspect, the present application provides a negative electrode material, the negative electrode material including porous carbon, the porous carbon including elemental iron and / or elemental sulfur, and an active material included in the pores of the porous carbon.

[0005] In the technical solution of the embodiment of the present application, the matrix material of the negative electrode material is porous carbon, and the pore structure of the porous carbon can mitigate the volume expansion of the active material and alleviate the problems caused by volume expansion. Furthermore, the porous carbon contains iron, which can improve the conductivity of the porous carbon and the negative electrode material. Iron itself is a good conductor, but iron also has a graphitization catalytic effect at high temperatures, improving the conductivity of the carbon material. That is, the conductivity of the porous carbon and the negative electrode material can be improved. Furthermore, the porous carbon contains sulfur, which can improve the surface activity of the porous carbon material and improve the deposition of the active material. Furthermore, since the radius of a sulfur atom (110 pm) is much larger than the radius of a carbon atom (70 pm), the volume of the micropores in the porous carbon can be effectively increased, providing space for the expansion of the active material. Furthermore, the simultaneous presence of iron and sulfur can increase the capacity and enhance the rate performance of the negative electrode material.

[0006] In some embodiments, the iron content of the negative electrode material is 50 to 3000 ppm. If the iron content is too low, the effect of improving the conductivity of the negative electrode material is small. If the iron content is too high, the gram capacity of the active material is reduced and there is a risk of iron precipitation, which affects the safety performance of the battery material.

[0007] In some embodiments, the sulfur content of the negative electrode material is 100 to 1500 ppm. If the sulfur content is too low, the effect of improving the surface activity of the porous carbon material is low, and if the sulfur content is too high, the volume and content of the micropores of the porous carbon become too large.

[0008] In some embodiments, the porous carbon has an average pore size of 2 to 50 nm. By designing the pore size of the porous carbon, it is possible to contribute to the deposition of the active material and reduce the difficulty of the deposition.

[0009] In some embodiments, the pore volume of the porous carbon is between 0.1 and 2.0 cm 3If the pore volume of the porous carbon is too small, it is not favorable for the active material to deposit inside the porous carbon, and if the pore volume of the porous carbon is too large, the strength of the porous carbon is significantly reduced, and the negative electrode material cannot withstand pressure.

[0010] In some embodiments, the ratio of micropores, mesopores, and macropores in the porous carbon is (5% to 25%):(65 to 90%):(5 to 15%). The pore volume of micropores is small, making it difficult for active material to deposit therein, but they can serve as pre-expansion space. If the micropore content ratio is too high, the volume of the pores that cannot be used becomes too large. If the micropore content ratio is too low, the pre-expansion space becomes insufficient. If the mesopore / macropore content ratio is too high, the strength of the porous carbon significantly decreases, and the negative electrode material cannot withstand pressure. If the mesopore content ratio is too low, it is unfavorable for active material deposition, resulting in too low an effective active material deposition amount. If the macropore content ratio is too low, it is unfavorable for the synthesis of porous carbon materials and is difficult to realize. Controlling the ratio of micropores, mesopores, and macropores in the porous carbon can balance these issues.

[0011] In some embodiments, the active material comprises a silicon-carbon material, the silicon-carbon material comprising nanosilicon particles and nanocarbon particles. By depositing the nanosilicon and nanocarbon within the pores of the porous carbon material and controlling the silicon particles to a small size, the nanosilicon, nanocarbon, and porous carbon are tightly bonded together. The increased silicon content increases the capacity ratio of the anode material, while simultaneously reducing the swelling effect of the anode material and improving the cycle performance of the battery.

[0012] In the technical solution of the embodiment of the present application, by depositing nanosilicon particles and nanocarbon particles in the pores of the porous carbon material, the size of the nanosilicon particles can be effectively controlled, and the nanosilicon and nanocarbon are uniformly distributed in the pores of the porous carbon, which effectively improves the conductivity of the negative electrode material and further ensures the expansion space of the nanosilicon, thereby further reducing the expansion of the negative electrode material.

[0013] In some embodiments, the nanosilicon particles have a particle size of 10 nm or less. Reducing the size of the nanosilicon particles can improve the cyclability of the negative electrode material, reduce local stress in the negative electrode material, and increase the structural stability of the negative electrode material during charging and discharging.

[0014] In some embodiments, the nanocarbon particles have a particle size of 30 nm or less. Reducing the particle size of the carbon nanoparticles improves the nanoscale mixing of the nanosilicon and nanocarbon, contributing to improved conductivity of the negative electrode material.

[0015] In some embodiments, the mass ratio of silicon to carbon in the negative electrode material is Si:C=(20-55):(40-75). The limited silicon content allows the negative electrode material to have a high capacity, and the limited carbon content can promote the effective formation of porous carbon and effectively isolate the nanosilicon particles that will be deposited later.

[0016] In some embodiments, the mass ratio of silicon, carbon, and oxygen in the negative electrode material is Si:C:O = (20-55):(40-75):(0.5-5). Limiting the oxygen content can improve the flexibility of the porous carbon and the connection stability between the porous carbon and nanosilicon.

[0017] In some embodiments, the particle diameter Dv50 of the negative electrode material is 3 to 8 μm, the porosity of the negative electrode material is 5 to 30%, and the specific surface area of ​​the negative electrode material is 5.0 m 2 / g or less. By limiting the particle size of the anode material, it is possible to reduce the problems of poor cycling due to too small a particle size and poor conductivity due to too large a particle size. Ensuring sufficient porosity ensures sufficient space for expansion of the silicon material during charging, mitigating expansion and improving the cycling performance of the anode material. If the specific surface area (BET) is too large, it will affect the performance of the material, and if it is too small, it will be difficult to achieve with porous carbon materials.

[0018] In a second aspect, the present application provides a battery comprising a positive electrode plate, a separator, and a negative electrode plate, wherein the separator is located between the positive electrode plate and the negative electrode plate to provide isolation, the negative electrode plate comprises a negative electrode material and a negative electrode current collector, and the negative electrode material comprises the negative electrode material according to any one of the above claims.

[0019] The battery of the present application includes the negative electrode material provided by the present application, and therefore has at least the same advantages as the negative electrode material.

[0020] In a third aspect, the present application provides an electrical device comprising a battery according to any one of the above claims.

[0021] The electrical device of the present application includes the battery provided by the present application, and therefore has at least the same advantages as the battery.

[0022] In a fourth aspect, the present application provides a method for producing an anode material, the method comprising the steps of: providing a porous carbon precursor comprising a carbon precursor, and an iron precursor and / or a sulfur precursor; processing the porous carbon precursor to obtain porous carbon; and depositing an active material in the pores of the porous carbon to obtain the anode material according to any one of the above aspects.

[0023] In some embodiments, the step of depositing an active material in the pores of the porous carbon includes depositing nanosilicon particles and nanocarbon particles in the pores of the porous carbon by vapor-phase codeposition, wherein the volume ratio of silicon source gas to carbon source gas in the silicon-carbon codeposition is 6:1 or greater. Codeposition allows for more uniform deposition of the nanosilicon particles and nanocarbon particles. However, a low volume ratio of silicon source gas to carbon source gas results in excessive carbon deposition, which impacts the silicon-carbon codeposition and the gram capacity of the negative electrode material. A high volume ratio of silicon source gas to carbon source gas results in excessively low carbon deposition, which prevents effective isolation of nanosilicon growth and ineffective improvement of the conductivity of the negative electrode material.

[0024] In some embodiments, the silicon source gas concentration in the silicon-carbon codeposition gas source is 5% to 80%. If the silicon source gas concentration is too low, the deposition time will be long, which is detrimental to improving manufacturing efficiency. If the silicon source gas concentration is too high, it will increase manufacturing safety risks and cause nanosilicon to easily agglomerate, which will affect the silicon-carbon codeposition.

[0025] In some embodiments, the silicon source gas comprises one or more of monosilane, disilane, trisilane, monochlorosilane, dichlorosilane, and trichlorosilane, and the carbon source gas comprises one or more of methane, ethane, butane, propane, ethylene, propylene, butylene, and acetylene.

[0026] In some embodiments, the iron precursor comprises one or more of ferric chloride, ferric nitrate, ferric sulfate, iron carbonyl, and ferrocene, and the sulfur precursor comprises one or more of hydrogen sulfide (HS), thiophene, thiophene compounds, thiols, thiophenols, and thioethers.

[0027] In some embodiments, the method further includes forming a carbon coating layer on the porous carbon by vapor deposition, wherein the deposition gas for the vapor deposition is a mixture of C2H2 and N2, the volume ratio of C2H2 is 2% to 20%, the gas flow rate is 100 to 300 mL / min, the reaction temperature is 800 to 1000°C, and the deposition reaction time is 0.5 to 2 hours. The provision of the carbon coating layer can improve the conductivity of the negative electrode material.

[0028] The above description is merely an outline of the technical solution of the present application, and in order to make the technical solution of the present application more clearly understood, it can be implemented according to the content of the specification, and the above and other objectives, features and advantages of the present application more obvious and understandable, the following provides specific embodiments of the present application. [Brief explanation of the drawings]

[0029] Various other advantages and benefits will become apparent to those skilled in the art after reading the following detailed description of the preferred embodiments. The drawings are for the purpose of illustrating the preferred embodiments only and are not to be construed as limiting the present application. Furthermore, like reference numerals represent like elements in all drawings. [Figure 1] 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application. [Figure 2] 1 is an exploded structural schematic diagram of a battery according to some embodiments of the present application; [Figure 3] 1 is an exploded structural schematic diagram of a battery cell according to some embodiments of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0030] The following detailed description of the embodiments of the technical solution of the present application will be given with reference to the drawings. The following embodiments are merely for the purpose of more clearly illustrating the technical solution of the present application, and are therefore used as examples only, and should not be used to limit the scope of protection of the present application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. The terms used herein are only for describing specific examples and are not intended to limit the present application. The terms "comprises," "has," and any variations thereof in the specification, claims, and description of the drawings of this application are intended to cover the non-exclusive "comprises."

[0032] In the description of the embodiments of the present application, technical terms such as "first," "second," etc. are used only to distinguish different objects, and should not be understood as indicating or implying relative importance, or the number, specific order, or primary-subordinate relationship of the indicated technical features. In the description of the embodiments of the present application, unless otherwise clearly and specifically limited, "plurality" means two or more.

[0033] When an "embodiment" is mentioned in this specification, it means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. Appearances of this phrase in various places in the specification do not necessarily all refer to the same embodiment, nor are they mutually exclusive, separate, or alternative embodiments to other embodiments. Those skilled in the art can explicitly and implicitly understand that the embodiments described in this specification can be combined with other embodiments.

[0034] In the description of the embodiments of the present application, the term "and / or" merely describes the relationship between related objects and indicates that three relationships may exist. For example, A and / or B can represent three cases: A alone, a combination of A and B, and B alone. In addition, the character " / " in this specification generally indicates that the related objects before and after it are in an "or" relationship.

[0035] In describing the examples of the present application, the term "plurality" refers to two or more (including two); similarly, "groups" refers to two or more (including two groups); and "plurality" refers to two or more (including two).

[0036] In recent years, to meet the need for multifunctionality in products, people have increasingly placed higher demands on battery performance, such as lifespan, safety, and capacity. Lithium-ion batteries have been widely used due to their advantages of high voltage, light weight, long cycle life, no memory effect, and high safety. Lithium-ion batteries include a positive electrode material, a negative electrode material, a separator, an electrolyte, and a current collector. The negative electrode material for commercially available lithium-ion batteries can be graphite or silicon. However, graphite has a low theoretical specific capacity and cannot meet the needs of high-energy density devices. Silicon, as a negative electrode material, has advantages such as high specific capacity, high safety, and abundant raw material supply, and is recognized as a new high-performance negative electrode material for lithium-ion batteries. However, as a negative electrode material, silicon causes a large volume expansion of the lithium alloy in the battery during charging and discharging, significantly shortening battery life. Furthermore, as a semiconductor, silicon has relatively low conductivity and a slow electron transfer rate. Therefore, there is a high demand for ways to suppress volume expansion, improve cycle performance, and increase conductivity.

[0037] To address these technical challenges, prior art has employed coating techniques, such as coating a carbon substrate with a catalyst, vapor-depositing a pre-treated substrate with a gas mixture containing a carbon source and a silicon source, and then carbonizing the substrate with a graphitized carbon source to obtain a silicon-carbon anode material. This silicon-carbon anode material can, to some extent, improve the process compatibility of anode plate and battery manufacturing, reduce volume expansion, and extend cycle life. However, the silicon content of this silicon-carbon anode material is limited to the coating layer, with a silicon content of ≤25%, meaning that the capacity of the silicon-carbon material is low, significantly limiting its practical application. Furthermore, the high synthesis temperature of the crystalline carbon layer in this silicon-carbon material leads to silicon grain growth, resulting in excessive local silicon expansion and particle rupture, which in turn leads to poor cycle performance. On the other hand, the synthesis process of this silicon-carbon material is too complicated, and the bonding strength between the matrix and the coating layer, and between the coating layers, is weak, which deteriorates the cycle performance of this silicon-carbon material in actual application.

[0038] The battery disclosed in the embodiments of the present application can be used in various energy storage systems that use the battery as a power source or an energy storage element. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, a power tool, an electric motorcycle, an electric car, a boat, a spacecraft, etc. The electric toy may include a game console, an electric car toy, an electric propulsion boat toy, an electric plane toy, or other stationary or mobile electric toy, and the spacecraft may include an airplane, a rocket, a space shuttle, a spaceship, etc.

[0039] In the following embodiment, for ease of explanation, a case will be described in which an electric device according to an embodiment of the present invention is a vehicle 1000 as an example.

[0040] Referring to FIG. 1, FIG. 1 is a structural schematic diagram of a vehicle 1000 provided by some embodiments of the present application. The vehicle 1000 may be a gasoline-powered vehicle, a gas-powered vehicle, or a new energy vehicle, and the new energy vehicle may be a battery electric vehicle, a hybrid electric vehicle, an extended-range electric vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000, for example, the battery 100 can be an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, to meet the operating power needs of the vehicle 1000 during starting, navigation, and driving.

[0041] In some embodiments of the present application, the battery 100 can be used not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, providing driving power to the vehicle 1000 in place of, or in place of, gasoline or natural gas.

[0042] Referring to FIG. 2, FIG. 2 is an exploded structural schematic diagram of a battery 100 provided according to some embodiments of the present application. The battery 100 includes a box 10 and battery cells 20 housed within the box 10. The box 10 is used to provide a housing space for the battery cells 20, and the box 10 can adopt various structures. In some embodiments, the box 10 can include a first portion 11 and a second portion 12, which cover each other and together define a housing space for housing the battery cells 20. The second part 12 may have a hollow structure that is open at one end, and the first part 11 may have a plate-like structure, with the first part 11 covering the open side of the second part 12 so that the first part 11 and the second part 12 together define the storage space, and the first part 11 and the second part 12 may both have a hollow structure that is open at one end, with the open side of the first part 11 covering the open side of the second part 12. Of course, the box 10 formed by the first part 11 and the second part 12 may have various shapes such as a cylinder or a rectangular parallelepiped.

[0043] The battery 100 may include a plurality of battery cells 20, and the plurality of battery cells 20 may be connected in series, parallel, or series-parallel, and a series-parallel connection includes both series and parallel connections of the plurality of battery cells 20. The plurality of battery cells 20 may be directly connected in series, parallel, or series-parallel, and then the entire battery cell 20 may be housed in the housing 10. Of course, the battery 100 may also be formed by first connecting the plurality of battery cells 20 in series, parallel, or series-parallel to form a battery module, and then connecting the plurality of battery modules in series, parallel, or series-parallel to form a whole and housed in the housing 10. The battery 100 may further include other structures, for example, the battery 100 may further include bus bar members for achieving electrical connection between the plurality of battery cells 20.

[0044] Each battery cell 20 may be a secondary battery or a primary battery, and may be, but is not limited to, a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery. The battery cells 20 may be cylindrical, flat, rectangular, or have other shapes.

[0045] Referring to Figure 3, Figure 3 is an exploded structural schematic diagram of a battery cell 20 provided in some embodiments of the present application. The battery cell 20 is the smallest unit constituting a battery. As shown in Figure 3, the battery cell 20 includes an end cap 21, a case 22, a cell assembly 23, and other functional components.

[0046] The end cap 21 refers to a member that covers the opening of the case 22 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the end cap 21 can be adapted to fit the shape of the case 22, but is not limited thereto. Alternatively, the end cap 21 can be made of a material (e.g., aluminum alloy) with a certain hardness and strength. In this way, the end cap 21 is less likely to be distorted when pressed or impacted, allowing the battery cell 20 to have higher structural strength and improved safety performance. The end cap 21 may be provided with a functional member such as an electrode terminal 21a. The electrode terminal 21a can be used to electrically connect with the cell assembly 23 to output or input electrical energy from or to the battery cell 20. In some embodiments, the end cap 21 may further be provided with a pressure reducing mechanism for reducing the internal pressure of the battery cell 20 when the internal pressure or temperature reaches a threshold. The end cap 21 may be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, or plastic, and the embodiments of the present application are not particularly limited thereto. In some embodiments, an insulating member may be further provided inside the end cap 21, and the insulating member may be used to isolate the end cap 21 from the electrical connection members inside the case 22 so as to reduce the risk of short circuits. Illustratively, the insulating member may be made of plastic, rubber, or the like.

[0047] The case 22 is an assembly that mates with the end cap 21 to form an internal environment for the battery cell 20. The formed internal environment can be used to house the cell assembly 23, electrolyte, and other components. The case 22 and the end cap 21 may be separate components, or an opening can be formed in the case 22 and the end cap 21 can cover the opening to form the internal environment for the battery cell 20. Without being limited thereto, the end cap 21 and the case 22 may be integrated. Specifically, the end cap 21 and the case 22 may first form a common connection surface before other components are inserted into the case. If the interior of the case 22 needs to be packaged, the end cap 21 covers the case 22. The housing 22 may have various shapes and dimensions, such as a rectangular parallelepiped, cylindrical, or hexagonal prism. Specifically, the shape of the case 22 can be determined depending on the specific shape and dimensions of the cell assembly 23. The case 22 may be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, or plastic, and the embodiments of the present application are not particularly limited thereto.

[0048] The cell assembly 23 is a component where the electrochemical reaction occurs in the battery cell 100. One or more cell assemblies 23 may be contained within the case 22. The cell assembly 23 is typically formed by winding or stacking positive and negative electrode plates, with a separator typically provided between the positive and negative electrode plates. The portions of the positive and negative electrode plates containing active material form the main body of the cell assembly, while the portions of the positive and negative electrode plates without active material form tabs 23a, respectively. The positive and negative electrode tabs may be jointly located at one end of the main body, or may be located at both ends of the main body. During the charge and discharge process of the battery, the positive and negative electrode active materials react with the electrolyte, and the tabs 23a are connected to electrode terminals to form a current circuit.

[0049] According to some embodiments of the present application, there is provided a negative electrode material, the negative electrode material including porous carbon, the porous carbon including iron element and / or sulfur element, and an active material included in the pores of the porous carbon.

[0050] Porous carbon refers to carbon materials with different pore structures. Porous carbon can be biomass porous carbon or resin porous carbon. Different pore structures allow different molecules / ions to enter the pores. Porous carbon can also serve as a matrix material to provide a matrix for the deposition and adhesion of active materials.

[0051] In some embodiments, an active material is deposited in the pores of the porous carbon. The active material may be one or more of a silicon-carbon material, an aluminum-containing material, a tin-containing material, or an antimony-containing material. Furthermore, the silicon-carbon material includes nanosilicon particles and nanocarbon particles, and the resulting negative electrode material is a composite material of nanosilicon, nanocarbon, and porous carbon. The nanosilicon / nanocarbon / porous carbon are tightly bound together, enhancing the structural stability of the negative electrode material.

[0052] Nanosilicon is nanoscale amorphous silicon, and nanocarbon is nanoscale carbon particles, such as carbon black. The nanosilicon and nanocarbon particles are layered and blended together and uniformly deposited in the pores of the porous carbon.

[0053] In this embodiment of the present application, by depositing nanosilicon particles and nanocarbon particles in the pores of the porous carbon material, the size of the nanosilicon particles can be effectively controlled, and the nanosilicon and nanocarbon are uniformly distributed in the pores of the porous carbon, which effectively improves the conductivity of the negative electrode material and further ensures the expansion space of the nanosilicon, thereby further reducing the expansion effect of the negative electrode material.

[0054] In some embodiments, the average pore size of the porous carbon is 2 to 50 nm, preferably 20 to 30 nm, specifically 5 nm, 8 nm, 13 nm, 19 nm, 26 nm, 33 nm, 41 nm, 49 nm, etc. Designing the pore size of the porous carbon can contribute to the deposition of the active material and reduce the difficulty of the deposition.

[0055] In some embodiments, the nanosilicon particles have a particle size of 10 nm or less, such as 1 nm, 2.5 nm, 3 nm, 4.2 nm, 6 nm, 7.3 nm, 8 nm, 9 nm, etc. Reducing the size of the nanosilicon particles improves the cycling performance of the anode material, reduces local stress in the silicon-carbon composite (i.e., the anode material), and contributes to increasing the structural stability of the anode material during charging and discharging.

[0056] In some embodiments, the nanocarbon particles have a particle size of 30 nm or less, such as 3 nm, 5 nm, 9 nm, 11 nm, 14 nm, 17 nm, 22 nm, 28 nm, etc. Reducing the particle size of the carbon nanoparticles improves the nanoscale mixing of nanosilicon and nanocarbon, contributing to improved conductivity of the negative electrode material.

[0057] In some embodiments, the porous carbon includes elemental iron and / or elemental sulfur.

[0058] The iron and / or sulfur elements are distributed in the matrix of the porous carbon and may be added during the manufacturing process of the porous carbon.

[0059] In one embodiment, the porous carbon may be a resin porous carbon, and iron and / or sulfur elements may be added to a resin precursor for producing the resin porous carbon so that the produced porous carbon contains iron and / or sulfur elements.

[0060] Specifically, an iron source and / or a sulfur source and a resin precursor are mixed together, and the mixture is then treated to produce porous carbon containing elemental iron and / or elemental sulfur.

[0061] The iron source may be one or more of ferric chloride, ferric nitrate, ferric sulfate, iron carbonyl, and ferrocene, and the sulfur source may be one or more of hydrogen sulfide (HS), thiophene, thiophene compounds, thiols, thiophenols, and thioethers.

[0062] In this embodiment, iron can improve the conductivity of the porous carbon and the negative electrode material. Iron itself is a good conductor, and iron has a graphitization catalytic effect at high temperatures, improving the conductivity of the carbon material. Sulfur can improve the surface activity of the porous carbon material and improve the deposition of nanosilicon and nanocarbon. In addition, the radius of a sulfur atom (110 pm) is much larger than the radius of a carbon atom (70 pm), which effectively increases the volume and content of micropores in the porous carbon, ensuring more expansion space for the negative electrode material.

[0063] In some embodiments, the iron content of the porous carbon is 50 to 3000 ppm, and may be 100 ppm, 200 ppm, 300 ppm, 600 ppm, 1000 ppm, 1700 ppm, 2200 ppm, 2800 ppm, etc. If the iron content is too low, the improvement effect on the conductivity of the negative electrode material is low, while if the iron content is too high, the gram capacity of the negative electrode material is reduced and there is a risk of iron precipitation, which affects the safety performance of the battery.

[0064] In some embodiments, the content of elemental sulfur in the porous carbon is 100 to 1500 ppm. Specifically, it may be 150 ppm, 210 ppm, 360 ppm, 530 ppm, 690 ppm, 820 ppm, 970 ppm, 1450 ppm, etc. If the sulfur content is too low, the effect of improving the surface activity of the porous carbon material will be low, and if the sulfur content is too high, the volume of the micropores in the porous carbon will be too large.

[0065] In some embodiments, the mass ratio of silicon to carbon in the negative electrode material is Si:C = (20-55):(40-75), specifically 22:43, 27:56, 35:62, 43:69, 54:71, etc. The limited silicon content allows the negative electrode material to have a high capacity, while the limited carbon content promotes the effective formation of porous carbon and effectively isolates the nanosilicon particles that will be deposited later.

[0066] In some embodiments, the mass ratio of silicon, carbon, and oxygen in the negative electrode material is Si:C:O = (20-55):(40-75):(0.5-5). Specific examples include 22:43:0.6, 27:56:1.3, 35:62:2.8, 43:69:3.7, and 54:71:4.6. Limiting the oxygen content can improve the flexibility of the porous carbon and the stability of the connection between the porous carbon and the nanosilicon and nanocarbon.

[0067] In some embodiments, the pore volume of the porous carbon is between 0.1 and 2.0 cm 3 / g. Specifically, 0.2 cm 3 / g, 0.34cm 3 / g, 0.41cm 3 / g, 0.5cm 3 / g, 0.63cm 3 / g, 0.7cm 3 / g, 0.85cm 3 / g, 0.97cm 3 / g, 1.07cm 3 / g, 1.27cm 3 / g, 1.47cm 3 / g, 1.67cm 3 / g, 1.87cm 3 / g, 1.97cm 3 / g, etc. If the pore volume of the porous carbon is too small, it is disadvantageous for the deposition of nanosilicon and nanocarbon inside the porous carbon, and if the pore volume of the porous carbon is too high, the strength of the porous carbon is significantly reduced, and the negative electrode material cannot withstand pressure.

[0068] In some embodiments, the ratio of micropores, mesopores, and macropores in the porous carbon is (5% to 25%):(65 to 90%):(5 to 15%), and may be specifically 6%:68%:7%, 10%:73%:9%, 13%:81%:10%, 19%:85%:13%, 24%:89%:15%, etc.

[0069] Depending on the pore size, pores can be divided into three types: macropores (pore diameter > 50 nm), mesopores (intermediate pores) (pore diameter 2 nm ≤ 50 nm), and micropores (pore diameter < 2 nm). If the pore volume of micropores is too small, nanosilicon particles cannot easily deposit within them, but they can serve as pre-expansion space. If the micropore content ratio is too high, the volume of unused pores will be too large. If the micropore content ratio is too low, the pre-expansion space will be insufficient. If the mesopore / macropore content ratio is too high, the strength of the porous carbon will decrease and the anode material will not be able to withstand pressure. If the mesopore content ratio is too low, silicon deposition will be unfavorable, resulting in a low effective silicon deposition rate. If the macropore content ratio is too low, porous carbon synthesis will be unfavorable. Controlling the ratio of micropores, mesopores, and macropores in porous carbon can balance these issues.

[0070] In some embodiments, the particle size Dv50 of the negative electrode material is 3 to 8 μm. Dv50 is the particle size corresponding to the cumulative volume percentage of the material reaching 50%. Specifically, it may be 3.3 μm, 3.9 μm, 4.2 μm, 4.8 μm, 5.5 μm, 6 μm, 7 μm, 7.4 μm, etc. By limiting the particle size of the negative electrode material, it is possible to reduce the problems of poor cycling due to a particle size that is too small and poor conductivity due to a particle size that is too large.

[0071] In some embodiments, the porosity of the negative electrode material is 5 to 30%, such as 8%, 12%, 15%, 18%, 23%, 26%, or 28%. Ensuring a high porosity ensures sufficient space for the silicon material to expand during charging, mitigating expansion and improving the cycle performance of the negative electrode material.

[0072] In some embodiments, the specific surface area of ​​the negative electrode material is 5.0 m 2 / g or less. The specific surface area refers to the total area per unit mass of a material. Specifically, 0.5m 2 / g, 1.3m 2 / g, 1.8m 2 / g, 2.5m 2 / g, 3.2m 2 / g, 4.5m 2 / g, etc. If the specific surface area (BET) is too large, it will affect the performance of the negative electrode material, and if it is too small, it will be disadvantageous for the formation of porous carbon.

[0073] In the above embodiment, the anode material provided by the present application contains nanosilicon / nanocarbon in the pores of the porous carbon material of the anode material, which effectively controls the size of the silicon particles, controls the silicon particles to a small range, and realizes a tight bond between the nanosilicon / nanocarbon / porous carbon, thereby improving the structural stability of the anode material. The anode material also achieves a high silicon doping ratio, which allows the anode material to achieve high capacity while also having small volume expansion and excellent cycle performance. Furthermore, the anode material further contains iron and sulfur elements, which allows the anode material to further have good electrical conductivity and small volume expansion, resulting in the anode material having excellent rate performance and cycle performance.

[0074] According to some embodiments of the present application, the present application further provides a negative electrode plate, which includes a negative electrode material and a negative electrode current collector, and the negative electrode material includes any one of the negative electrode materials described above.

[0075] According to some embodiments of the present application, the present application further provides a battery, the battery including a positive electrode plate, a separator, and a negative electrode plate, the separator being located between the positive electrode plate and the negative electrode plate to provide isolation, and the negative electrode plate including any one of the negative electrode plates described above.

[0076] According to some embodiments of the present application, the present application further provides an electric device, which includes a battery according to any one of the above technical solutions for providing electric energy to the electric device.

[0077] The electrical device may be any one of the appliances or systems to which the above-mentioned batteries are applied.

[0078] According to some embodiments of the present application, the present application further provides a method for manufacturing a negative electrode material, the method for manufacturing a negative electrode material including the steps of providing porous carbon and depositing an active material in the pores of the porous carbon to obtain the negative electrode material according to any one of the above claims.

[0079] Specifically, the porous carbon may be biomass porous carbon or resin porous carbon.

[0080] In one embodiment, providing the porous carbon comprises providing a porous carbon precursor comprising a carbon precursor, and an iron precursor and / or a sulfur precursor, and processing the porous carbon precursor to obtain the porous carbon.

[0081] The iron precursor includes one or more of ferric chloride, ferric nitrate, ferric sulfate, carbonyl iron, and ferrocene, the sulfur precursor includes one or more of hydrogen sulfide (HS), thiophene, thiophene compounds, thiols, thiophenols, and thioethers, and the carbon precursor includes one or more of furan resin, urea resin, melamine resin, phenolic resin, epoxy resin, polymethyl methacrylate resin, and polyacrylonitrile.

[0082] In this embodiment, the iron precursor, sulfur precursor and resin precursor are mixed, so that the iron and sulfur can be uniformly distributed in the porous carbon matrix, resulting in more uniform electrical conductivity.

[0083] Specifically, the iron source solution and sulfur source solution are added to the resin precursor solution and stirred to be uniformly dispersed to obtain mixed solution A. The mixing ratio of the iron source, sulfur source, and resin precursor is adjusted according to the requirements of the material design.

[0084] Mixed solution A is placed in an oven at 70 to 140°C and temporarily hardened for 3 to 12 hours, and the hardened material is then crushed to obtain powder B.

[0085] Powder B is placed in an oven, protected by nitrogen, and completely cured at 150-220°C for 8-20 hours to obtain Powder C.

[0086] Powder C is placed in a high-temperature furnace, protected by nitrogen, and carbonized at 900 to 3000°C for 2 to 4 hours to form porous carbon powder D.

[0087] In one embodiment, an active material including nanosilicon particles and nanocarbon particles is deposited in the pores of the porous carbon, and a specific method includes depositing the nanosilicon particles and nanocarbon particles in the pores of the porous carbon by vapor-phase co-deposition, which allows the nanosilicon particles and nanocarbon particles to be deposited more uniformly.

[0088] Specifically, silicon-carbon deposition is performed on powder D by chemical vapor deposition. The volume ratio of the silicon source gas to the carbon source gas for the silicon-carbon codeposition is adjusted, and the concentration of the silicon source gas can be adjusted by diluting it with at least one of N2, H2, and Ar. The flow rate of the mixed gas is 100-1000 mL / min, the reaction temperature is 400-1000 °C, and the deposition reaction time is 2-10 h. This step yields the final product, nanosilicon / nanocarbon / porous carbon composite material E.

[0089] In one embodiment, the volume ratio of silicon source gas to carbon source gas for silicon-carbon codeposition is 6:1 or greater. Alternatively, it may be 7:1 to 40:1, specifically 8:1, 13:1, 17:1, 21:1, 29:1, 33:1, 38:1, 43:1, etc. If the volume ratio of silicon source gas to carbon source gas is too low, the amount of carbon deposition will be too high, affecting the silicon-carbon codeposition and the gram capacity of the silicon-carbon composite. If the volume ratio of silicon source gas to carbon source gas is too high, the amount of carbon deposition will be too low, preventing effective isolation of nanosilicon growth and ineffective improvement of the electrical conductivity of the silicon-carbon composite.

[0090] In one embodiment, at least one of N2, H2, and Ar is introduced to dilute the silicon source gas and the carbon source gas, so that the silicon source gas concentration in the silicon-carbon codeposition gas source can be 5% to 80%. Specifically, it can be 8%, 10%, 18%, 25%, 31%, 43%, 57%, 65%, 78%, etc. If the silicon source gas concentration is too low, the deposition time will be longer, which is detrimental to improving manufacturing efficiency. If the silicon source gas concentration is too high, it will increase manufacturing safety risks and cause nanosilicon to easily aggregate, which will affect the silicon-carbon codeposition.

[0091] In some embodiments, the silicon source gas comprises one or more of monosilane, disilane, trisilane, monochlorosilane, dichlorosilane, and trichlorosilane, and the carbon source gas comprises one or more of methane, ethane, butane, propane, ethylene, propylene, butylene, and acetylene.

[0092] In some embodiments, the method further includes forming a carbon coating layer on the porous carbon by vapor deposition, wherein the deposition gas for the vapor deposition is a mixture of C2H2 and N2, the volume ratio of C2H2 is 2% to 20%, the gas flow rate is 100 to 300 mL / min, the reaction temperature is 800 to 1000°C, and the deposition reaction time is 0.5 to 2 hours. The provision of the carbon coating layer can improve the conductivity of the negative electrode material.

[0093] In the above embodiment, in the method for producing an anode material provided by the present application, iron and sulfur elements are uniformly distributed in the porous carbon matrix, thereby achieving more uniform conductivity; nanosilicon particles and nanocarbon particles are more uniformly deposited by vapor-phase co-deposition; an appropriate volume ratio of silicon source gas to carbon source gas increases the gram capacity of the silicon-carbon composite material, effectively improving the conductivity of the silicon-carbon composite material; inert gas is introduced into the silicon-carbon co-deposition gas source to dilute it and control the concentration of the silicon source gas in the silicon-carbon co-deposition gas source, contributing to improved production efficiency and safety; and the provision of a carbon coating layer can increase the conductivity of the silicon-carbon anode material.

[0094] In the above embodiment, the present application provides a negative electrode material in which nanosilicon / nanocarbon are co-deposited in the pores of a porous carbon material, effectively controlling the size of the silicon particles, achieving small particle size control, and achieving a tight nanosilicon / nanocarbon / porous carbon bond, resulting in a stable material structure. The material also achieves a high silicon doping ratio, resulting in high capacity of the negative electrode material, while also having small expansion and excellent cycle performance. Furthermore, the negative electrode material contains Fe and S elements, and by achieving nanoscale mixing of nanosilicon and nanocarbon and element doping, the negative electrode material also has good electrical conductivity and small expansion, resulting in excellent rate and cycle performance.

[0095] The beneficial effects of the present invention will be further explained below in conjunction with examples.

[0096] In order to clarify the technical problems, technical solutions, and beneficial effects of the embodiments of the present application, the present application will be described in more detail below with reference to the embodiments and drawings. Obviously, the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and does not limit the present application and its applications in any way. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without any creative effort fall within the scope of protection of the present application.

[0097] 1. Fabrication of porous carbon Predetermined proportions of iron source material, sulfur source material, and resin material were weighed. In this example, ferrocene was selected as the iron source material, hydrogen sulfide was selected as the sulfur source material, and phenolic resin was selected as the resin material. Mixture A was obtained after dissolving. Mixture A was placed in an oven to pre-cure at a temperature of 80°C and a pre-cure time of 10 hours. The pre-cure material was then crushed to obtain powder B. Powder B was then placed in an oven, protected by nitrogen, and fully cured at a temperature of 160°C and a pre-cure time of 15 hours to obtain powder C. Powder C was then placed in a high-temperature furnace, protected by nitrogen, and carbonized at a temperature of 1000°C and a carbonization time of 4 hours to form porous carbon powder D. Table 1 lists the characteristic parameters for each example and comparative example.

[0098] 2. Preparation of silicon-carbon anode materials Powder D was co-deposited with silicon and carbon by chemical vapor deposition to obtain a silicon-carbon anode material. The volume ratio of the silicon source gas to the carbon source gas for the silicon-carbon co-deposition was adjusted to 30:1, and the concentration of the silicon source gas was adjusted to 30%. In this example, monosilane was selected as the silicon source gas, and acetylene was selected as the carbon source gas.

[0099] 3. Battery manufacturing 1) Manufacturing of negative electrode plates Negative electrode slurry: The silicon-carbon negative electrode materials prepared in each of the above examples and comparative examples, artificial graphite, binders styrene butadiene rubber (SBR), binder polypropylene acid (PAA), dispersant (CMC-Na), conductive carbon black (Super-P, SP), and carbon nanotubes (CNT) were mixed in a weight ratio of 10%:85%:2%:1%:1%:0.7%:0.3% in an appropriate amount of deionized water with sufficient stirring to prepare a negative electrode slurry. The negative electrode slurry was applied to the surface of the copper foil of the negative electrode current collector, dried, and cold-pressed to obtain a negative electrode plate.

[0100] 2) Manufacturing of positive electrode plates Positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), the conductive agent Super P, and the binder PVDF were mixed in a mass ratio of 96.5:1.5:2 in an appropriate amount of NMP with sufficient stirring to form a positive electrode slurry. The positive electrode slurry was then applied to the surface of the aluminum foil positive electrode current collector, dried, cold pressed, and slit, after which a positive electrode plate was obtained.

[0101] 3) Separator A PP / PE composite separator was used.

[0102] 4) Electrolyte Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1, and then LiPF6 was uniformly dissolved in the solution to obtain an electrolyte solution with a LiPF6 concentration of 1 mol / L.

[0103] 5) Battery assembly The positive electrode plate, separator, and negative electrode plate were stacked in this order and wound up to obtain an electrode assembly. The electrode assembly was then placed in an outer casing, and the prepared electrolyte solution was added. After undergoing processes such as packaging, standing, chemical formation, and aging, a secondary battery was obtained.

[0104] 4. The test methods for the relevant parameters of the negative electrode materials and batteries in the examples and comparative examples of this application are as follows:

[0105] (1) Examination of the pore size and pore volume of micropores, mesopores, and macropores within the porous carbon matrix: The evaluation methods for pore size and pore volume can be referred to GB / T 19587-2017 and GB / T 21650.2-2008. A TriStar II3020 pore size distribution analyzer is used to test the material. At a constant temperature, the adsorbed gas is adsorbed into the material under a series of gradually increasing pressures. The pore size and pore volume distribution of the porous carbon matrix material can be characterized by the graph of the pore size volume at each scale and the corresponding partial pressure, and the average pore size can be calculated.

[0106] The pore volume of the porous carbon obtained in each of the Examples and Comparative Examples was 0.8 cm 3 / g, and the ratio of the contents of micropores, mesopores, and macropores obtained was 20:70:10. Details of the pore sizes of the porous carbons obtained in each of the examples and comparative examples are shown in Table 1.

[0107] (2) Porosity test The true density of the material was obtained by testing using a true density meter (e.g., AccuPyc II 1340 model). Specifically, a certain mass of sample was weighed and placed in the true density tester. The test system was sealed, and helium was introduced according to the procedure. By detecting the gas pressure in the sample chamber and expansion chamber, the real volume Vr could be calculated using Boyle's law (PV = nRT), and the real density ρr = m / Vr. The apparent density of the material was determined by packing a certain mass of powder into a cylindrical mold with an inner diameter of 10 mm and applying a pressure of 200 MPa to obtain the corresponding apparent volume V0 of the powder. The apparent density of the material was then ρ0 = m / V0.

[0108] The material porosity P = 1-ρ0 / ρr × 100%.

[0109] The details of the porosity of the porous carbon obtained in each of the examples and comparative examples are shown in Table 1.

[0110] (3) Specific surface area test The specific surface area (SSA) of the negative electrode material was determined in accordance with GB / T 19587-2017, "Testing the specific surface area of ​​solid materials by the gas adsorption BET method," using a specific surface area tester (e.g., TriStar II3020 model) to measure the amount of gas adsorbed on the solid surface at a constant low temperature and different relative pressures. Based on the Brunauer-Emmett-Teller (BET) multilayer adsorption theory, the amount of monolayer adsorption of the sample was determined, and the specific surface area of ​​the solid was calculated. The specific surface area of ​​the negative electrode material obtained in each example and comparative example was 4.5m 2 / g.

[0111] (4) Volume distribution particle size Dv50 test Dv50 can be obtained by measuring using a laser particle size analyzer (e.g., Malvern Master Size 3000) according to GB / T 19077.1-2016, and the physical definition of Dv50 is the particle size corresponding to the cumulative volume distribution percentage of the material reaching 50%. The Dv50 of the negative electrode materials obtained in each of the examples and comparative examples was 7 μm.

[0112] (5) Average particle size test The particle size of 100 nanosilicon particles and nanocarbon particles can be measured using a transmission electron microscope (e.g., Thermo Fisher F200i S / TEM) (TEM test), and the average particle size can be obtained by averaging the measurements. In the case of irregularly shaped particles, the particle size was determined based on the particle size of the largest particle size. The average particle size of the nanosilicon particles in the negative electrode materials obtained in each example and comparative example was 8 nm, and the average particle size of the nanocarbon particles was 12 nm.

[0113] (6) Element mass ratio test Oxygen content is evaluated using cross-sectional EDS energy spectra in accordance with GB / T 17359-2012, "Quantitative Analysis by Microbeam Analysis Energy Spectrum Method." Specifically, the test powder is placed in an ion polisher (e.g., IB-19500CP model), and under vacuum conditions, argon gas from the ion source is ionized to generate argon ions. After acceleration and focusing, the high-speed argon ions collide with atoms or molecules on the sample surface, achieving ion polishing and cross-sectional detection. The resulting powder cross-section is placed in an energy spectrum analyzer (e.g., OXFORD model), and the oxygen content of each section of the material cross-section is tested. Ten sections are tested and the average value is taken to obtain the oxygen content of the material.

[0114] The silicon content was evaluated using an inductively coupled plasma (ICP) analyzer in accordance with the United States Environmental Protection Agency standard EPA 6010D-2018. Specifically, the test powder was decomposed in a microwave decomposition device (e.g., CEM-Mars6 type), and the resulting solution was introduced into an ICP tester (e.g., ICAP7400 type). The silicon concentration in the material was then compared with that in a standard solution to calculate the silicon content.

[0115] Carbon content was tested using a carbon-sulfur analyzer (e.g., the Dekai HCS-140 Infrared Carbon-Sulfur Analyzer) in accordance with GB / T 20123-2006 / ISO 15350:200. The principle is to heat the sample to high temperature in a high-frequency furnace under oxygen-rich conditions, oxidizing carbon to carbon dioxide. The resulting gas enters an absorption pool, absorbs the corresponding infrared radiation, and converts it into a corresponding signal via a detector, allowing calculation to determine the carbon content of the material. The mass ratio of Si:C:O in the silicon-carbon anode materials obtained in each example and comparative example was 45:50:5.

[0116] [Table 1-1] [Table 1-2]

[0117] (7) Battery cycle performance test Cycle performance test at 45℃: The fabricated secondary battery was charged at a constant current of 1C at a constant temperature of 45°C until the voltage reached 4.25V, then further charged at a constant voltage of 4.25V until the current reached 0.05mA or less, and then allowed to stand for 5 minutes. It was then discharged at a constant current of 1C until the voltage reached 2.5V, and then allowed to stand for 5 minutes. This constitutes one cycle of the charge-discharge process, and the discharge capacity at this time was recorded as the first-cycle discharge capacity of the secondary battery. The secondary battery was subjected to 300 charge-discharge cycles according to the above method, and the discharge capacity at the 300th cycle was recorded.

[0118] The capacity retention rate of the secondary battery after 300 cycles at 45°C, CR45°C (%) = discharge capacity at 300th cycle / discharge capacity at 1st cycle × 100%. Details of the cycle performance of the batteries obtained in each example and comparative example are shown in Table 2.

[0119] Secondary battery plate cycle expansion performance test at 45℃: The thickness of the negative electrode plate of the secondary battery after the cold pressing process was recorded as h0. According to the cycle performance test method for secondary batteries at 45°C described above, the secondary battery was cycled 300 times, charging at a constant current of 1C until the voltage reached 4.25V, and then charging at a constant voltage of 4.25V until the current reached 0.05mA or less, after which the battery was allowed to stand for 5 minutes. The cell was disassembled in a drying room after cycling, and the thickness of the negative electrode plate after 300 cycles was recorded as h300. The expansion rate of the electrode plate of the secondary battery at 45°C during 300 cycles was recorded as Δh300.

[0120] Δh300(%)=(h300-h0) / h0*100%. Details of the expansion performance of the batteries obtained in each example and comparative example are shown in Table 2.

[0121] Rate performance test method: At 25°C, the fabricated secondary battery was charged at a constant current of 0.33 C (i.e., the current value at which the theoretical capacity is completely discharged within 3 hours) to a charge cutoff voltage of 4.25 V, then charged at a constant voltage until the current reached 0.05 C, allowed to stand for 5 minutes, and then discharged at a constant current of 0.33 C to a discharge cutoff voltage of 2.5 V, and the actual capacity was recorded as C0.

[0122] The battery was then charged at a constant current of 0.33 C up to the charge cutoff voltage of 4.25 V, then charged at a constant voltage of 0.05 C until the current reached 0.05 C, allowed to stand for 5 min, and then discharged at a constant current of 3 C down to the discharge cutoff voltage of 2.5 V, and the actual capacity was recorded as C3.

[0123] The rate performance of a secondary battery can be characterized as DR = C3 / C0 × 100%. A higher DR value indicates a better rate performance of the material. Details of the rate performance of the batteries obtained in each example and comparative example are shown in Table 2.

[0124] [Table 2]

[0125] As can be seen from the relevant data in Table 2, the batteries of Examples 1 to 15 had a capacity retention rate of 95.6% to 97.5% after 300 cycles at 45°C, a cycle expansion rate Δh300 of 32.6% to 36.4%, and a rate performance DR of 82.1% to 85.9%. The secondary batteries had excellent cycle stability, small volume expansion, and excellent dynamic performance. The negative electrode material of Example 16 had an iron content of 20 ppm and a sulfur content of 30 ppm, and the contents of iron and sulfur elements were very low. The capacity retention rate after 300 cycles at 45°C was 92.3%, a cycle expansion rate Δh300 of 39.1%, and a rate performance DR of 79.8%. The negative electrode material of Example 17 had an iron content of 5000 ppm and a sulfur content of 30 ppm. After 300 cycles at 45°C, the capacity retention was 88.4%, the cycle expansion coefficient Δh300 was 40.5%, and the rate performance DR was 88.9%. The negative electrode material of Example 18 had an iron content of 20 ppm and a sulfur content of 2500 ppm. After 300 cycles at 45°C, the capacity retention was 85.7%, the cycle expansion coefficient Δh300 was 30.7%, and the rate performance DR was 75.2%. The cycle performance, cycle expansion, and dynamic performance of Examples 16-18 were significantly lower than those of Examples 1-15. This indicates that the iron and sulfur content significantly affect the performance of the silicon-carbon negative electrode material. The silicon-carbon negative electrode material has good conductivity, and the resulting secondary batteries exhibit minimal expansion and excellent cycle performance and rate characteristics.

[0126] The above description is merely an embodiment of the present application, and does not limit the patent scope of the present application. The conversion of an equivalent structure or equivalent flow made by using the contents of the specification and drawings of the present application, or the direct or indirect use in other related technical fields, is also included in the patent protection scope of the present application.

Claims

1. 1. A negative electrode material comprising porous carbon, wherein the porous carbon contains iron and / or sulfur elements, and the pores of the porous carbon contain an active material.

2. The content of iron element in the negative electrode material is 50 to 3000 ppm, and / or 2. The negative electrode material according to claim 1, wherein the content of sulfur element in the negative electrode material is 100 to 1500 ppm.

3. 3. The negative electrode material according to claim 1, wherein the porous carbon has an average pore size of 2 to 50 nm.

4. The pore volume of the porous carbon is 0.1 to 2.0 cm ３ The negative electrode material according to any one of claims 1 to 3, characterized in that the anode material has a Cr content of 0.15 / g.

5. 5. The negative electrode material according to claim 1, wherein the porous carbon has a ratio of micropores, mesopores, and macropores of (5% to 25%): (65 to 90%): (5 to 15%).

6. The negative electrode material according to any one of claims 1 to 5, wherein the active material comprises a silicon-carbon material, and the silicon-carbon material comprises nanosilicon particles and nanocarbon particles.

7. The nanosilicon particles have a particle size of 10 nm or less, and / or 7. The negative electrode material according to claim 6, wherein the nanocarbon particles have a particle size of 30 nm or less.

8. 8. The negative electrode material according to claim 6, wherein the mass ratio of silicon element to carbon element in the negative electrode material is Si:C=(20 to 55):(40 to 75).

9. The negative electrode material according to any one of claims 6 to 8, characterized in that the mass ratio of silicon element, carbon element, and oxygen element in the negative electrode material is Si:C:O = (20 to 55): (40 to 75): (0.5 to 5).

10. The particle size Dv50 of the negative electrode material is 3 to 8 μm, and / or the porosity of the negative electrode material is 5 to 30%, and / or The specific surface area of ​​the negative electrode material is 5.0 m ２ The negative electrode material according to any one of claims 1 to 9, characterized in that the Cr content is 0.15 / g or less.

11. A battery comprising a positive electrode plate, a separator, and a negative electrode plate, wherein the separator is located between the positive electrode plate and the negative electrode plate to provide isolation, the negative electrode plate comprises a negative electrode material and a negative electrode current collector, and the negative electrode material comprises the negative electrode material according to any one of claims 1 to 10.

12. An electrical device comprising the battery of claim 11.

13. providing a porous carbon precursor comprising a carbon precursor and an iron precursor and / or a sulfur precursor; treating the porous carbon precursor to obtain porous carbon; and depositing an active material in the pores of the porous carbon to obtain the negative electrode material according to any one of claims 1 to 10.

14. the iron precursor comprises one or more of ferric chloride, ferric nitrate, ferric sulfate, carbonyl iron, ferrocene; and / or The sulfur precursor is hydrogen sulfide (H ２ 14. The method of claim 13, wherein the anode material comprises one or more of the following: thiophene, thiophene compound, thiol, thiophenol, thioether.

15. The step of depositing an active material in the pores of the porous carbon comprises:

15. The method for producing an anode material according to claim 13, further comprising the step of depositing nanosilicon particles and nanocarbon particles in the pores of the porous carbon by vapor-phase co-deposition.

16. The volume ratio of the silicon source gas to the carbon source gas for the silicon-carbon codeposition is 6:1 or more; and / or 16. The method for producing a negative electrode material according to claim 15, wherein the concentration of the silicon source gas in the gas source for silicon-carbon codeposition is 5% to 80%.

17. the silicon source gas comprises one or more of monosilane, disilane, trisilane, monochlorosilane, dichlorosilane, and trichlorosilane; and / or 17. The method for producing an anode material according to claim 15 or 16, wherein the carbon source gas comprises one or more of methane, ethane, butane, propane, ethylene, propylene, butylene, and acetylene.

18. Further comprising forming a carbon coating layer on the porous carbon by vapor deposition; The deposition gas for the vapor phase deposition was C ２ H ２ and N ２ is a mixed gas of C ２ H ２ is 2% to 20%, the flow rate of the introduced gas is 100 to 300 mL / min, the reaction temperature is 800 to 1000 ° C, and the deposition reaction time is 0.5 to 2 h. The method for producing a negative electrode material according to any one of claims 13 to 17.

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