CN119812264A - Silicon-carbon negative electrode material and preparation method thereof, secondary battery and electrical equipment - Google Patents
Silicon-carbon negative electrode material and preparation method thereof, secondary battery and electrical equipment Download PDFInfo
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Abstract
本申请提供一种硅碳负极材料及其制备方法、二次电池和用电设备。包括碳纤维和位于所述碳纤维内部的碳包覆硅颗粒，所述碳纤维相互搭接形成层状多孔网状结构，所述硅碳负极材料满足如下关系式：4<a×b×c<15；其中，a cm‑1为硅碳负极材料在拉曼光谱中G峰的半高宽；b为硅碳负极材料的拉曼光谱中的D峰强度与G峰强度的比值；c为硅碳负极材料的泊松比。本申请通过对硅碳负极的结构进行设计，对硅进行碳包覆后，嵌入碳纤维内部，碳纤维进一步搭接形成层状的具有多孔网状的薄膜状结构；同时，合理控制硅碳负极材料的参数满足特定的关系式，能够有效缓解材料的体积膨胀、提高材料的导电性，循环性能和倍率性能都得到提升。The present application provides a silicon-carbon negative electrode material and a preparation method thereof, a secondary battery and an electrical device. It includes carbon fibers and carbon-coated silicon particles located inside the carbon fibers, the carbon fibers overlap each other to form a layered porous mesh structure, and the silicon-carbon negative electrode material satisfies the following relationship: 4<a×b×c<15; wherein a cm ‑1 is the half-width of the G peak in the Raman spectrum of the silicon-carbon negative electrode material; b is the ratio of the D peak intensity to the G peak intensity in the Raman spectrum of the silicon-carbon negative electrode material; and c is the Poisson's ratio of the silicon-carbon negative electrode material. The present application designs the structure of the silicon-carbon negative electrode, and after carbon coating the silicon, it is embedded inside the carbon fibers, and the carbon fibers are further overlapped to form a layered thin film structure with a porous mesh; at the same time, the parameters of the silicon-carbon negative electrode material are reasonably controlled to satisfy a specific relationship, which can effectively alleviate the volume expansion of the material, improve the conductivity of the material, and improve the cycle performance and rate performance.
Description
Technical Field
The application relates to the technical field of negative electrode materials, in particular to a silicon-carbon negative electrode material, a secondary battery and electric equipment.
Background
Lithium ion secondary batteries are the main energy storage devices in the new energy field today. The problem of low capacity of carbon materials as the main commercial negative electrode has limited the development of lithium ion secondary batteries. The silicon cathode has the highest theoretical specific capacity, but the volume expansion of the silicon cathode is up to 300 percent in the charge and discharge process, the intrinsic conductivity of the silicon is low, the huge volume effect in the charge and discharge process can cause the collapse of the electrode material structure and even the stripping from a current collector, so that the electrochemical performance is deteriorated, and the electrode structure of the traditional coating method comprises inert components with very large specific gravity, such as a metal current collector, a conductive agent, a binder and the like, so that the weight of the battery is improved, and the internal resistance is increased.
Therefore, modification and rational design of the negative electrode material of the secondary battery are required to improve the overall properties of the secondary battery, such as conductivity, cycle performance, and rate performance.
Disclosure of Invention
The purpose of the present application is to provide a secondary battery that has excellent cycle performance and rate performance.
In order to achieve the above object, according to a first aspect of the present application, there is provided a silicon-carbon negative electrode material comprising carbon fibers and carbon-coated silicon particles located inside the carbon fibers, wherein the carbon fibers are overlapped with each other to form a layered porous network structure, and the silicon-carbon negative electrode material satisfies the following relationship:
4<a×b×c<15;
Wherein, a cm -1 is half-width of a G peak of the silicon-carbon anode material in a Raman spectrum;
b is the ratio of the D peak intensity to the G peak intensity in the Raman spectrum of the silicon-carbon anode material;
c is the Poisson ratio of the silicon-carbon anode material.
As an embodiment of the application, the peak outlet position of the D peak of the silicon-carbon anode material in the raman spectrum is 1300cm -1～1380cm-1.
As an embodiment of the application, the peak position of the G peak of the silicon-carbon anode material in the raman spectrum is 1520cm -1～1590cm-1.
As an embodiment of the application, the silicon carbon negative electrode material satisfies 10cm -1≤a≤25cm-1.
As an embodiment of the application, the silicon-carbon anode material satisfies that b is more than or equal to 0.6 and less than or equal to 1.5.
As an embodiment of the application, the silicon-carbon anode material meets 0<c less than or equal to 0.5.
According to the embodiment of the application, the silicon accounts for 2-15% of the weight of the silicon-carbon anode material.
According to the embodiment of the application, based on the silicon-carbon anode material, the weight ratio of the carbon fiber is 35-78%.
According to the embodiment of the application, based on the silicon-carbon anode material, the weight ratio of the carbon coating layer in the carbon-coated silicon particles is 20-50%.
The second aspect of the application also provides a preparation method of the silicon-carbon anode material of the first aspect of the application, which comprises the following steps:
uniformly mixing a silicon source and a first carbon source in a solvent, adding a second carbon source, uniformly mixing to form a colloid precursor solution, and preparing the silicon-carbon anode material after electrostatic spinning film forming and carbonization of the colloid precursor solution;
the first carbon source is a polar carbon-containing macromolecule to form a carbon coating layer in the carbon-coated silicon particles, and the second carbon source is a precursor polymer for forming carbon fibers.
As an embodiment of the present application, the first carbon source includes at least one of epoxy resin, cellulose, polyvinylidene fluoride.
As an embodiment of the present application, the second carbon source includes at least one of polyvinylpyrrolidone, polyvinyl alcohol, and polyacrylonitrile.
In a third aspect of the present application, there is provided a secondary battery comprising a positive electrode tab, an electrolyte, a separator, and a negative electrode tab comprising a negative electrode current collector and a negative electrode active material layer comprising the silicon-carbon negative electrode material according to the first aspect of the present application disposed on at least one surface of the negative electrode current collector.
In a fourth aspect of the present application, there is also provided an electric device, where the electric device includes the secondary battery according to the third aspect of the present application.
Compared with the prior art, the invention has the beneficial effects that:
According to the application, the structure of the silicon-carbon negative electrode is designed, after silicon is coated with carbon, the carbon fiber is embedded into the silicon-carbon negative electrode, and the carbon fiber is further lapped to form a layered film-like structure with a porous net shape, meanwhile, parameters (such as the ratio of D peak intensity to G peak intensity, half-width of G peak and Poisson's ratio) of the silicon-carbon negative electrode material in Raman spectrum are reasonably controlled to meet a specific relational expression, so that the volume expansion of the material can be effectively relieved, the conductivity of the material is improved, and the cycle performance and the multiplying power performance are improved.
Detailed Description
For a better description of the objects, technical solutions and advantages of the present application, the present application will be further described with reference to the following specific examples, which are not intended to limit the present application in any way. The following description of the embodiments of the present application will be made clearly and completely, and it is apparent that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
In the application, the technical characteristics described in an open mode comprise a closed technical scheme composed of the listed characteristics and also comprise an open technical scheme comprising the listed characteristics.
In the present application, the numerical ranges are referred to as continuous, and include the minimum and maximum values of the ranges, and each value between the minimum and maximum values, unless otherwise specified. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. Further, when multiple range description features or characteristics are provided, the ranges may be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to include any and all subranges subsumed therein.
The reagents or apparatus used in the present application are conventional products commercially available without the manufacturer's knowledge.
The first aspect of the application provides a silicon-carbon negative electrode material, which comprises carbon fibers and carbon-coated silicon particles positioned in the carbon fibers, wherein the carbon fibers are mutually overlapped to form a layered porous network structure, and the silicon-carbon negative electrode material meets the following relational expression:
4<a×b×c<15;
Wherein, a cm -1 is half-width of a G peak of the silicon-carbon anode material in a Raman spectrum;
b is the ratio of the D peak intensity to the G peak intensity in the Raman spectrum of the silicon-carbon anode material;
c is the Poisson ratio of the silicon-carbon anode material.
According to the application, the structure of the silicon-carbon negative electrode is designed, after silicon is coated with carbon, the carbon fiber is embedded into the silicon-carbon negative electrode, and the carbon fiber is further lapped to form a layered film-like structure with a porous net shape, meanwhile, parameters (such as the ratio of D peak intensity to G peak intensity, half-width of G peak and Poisson's ratio) of the silicon-carbon negative electrode material in Raman spectrum are reasonably controlled to meet a specific relational expression, so that the volume expansion of the material can be effectively relieved, the conductivity of the material is improved, and the cycle performance and the multiplying power performance are improved.
The silicon-carbon negative electrode material is in a fiber membranous shape, wherein a carbon fiber matrix can be used as a part of a negative electrode active material and can be used as a current collector, so that the silicon-carbon negative electrode material can be used as a negative electrode piece after being tabletted, and is not required to be loaded on the surface of a metal current collector.
In some embodiments, the silicon carbon anode material has a D peak with a peak out position of 1300cm -1～1380cm-1 in the raman spectrum.
In some embodiments, the silicon carbon anode material has a G peak with a peak out position of 1520cm -1～1590cm-1 in the raman spectrum.
In some embodiments, the silicon carbon anode material satisfies 10cm -1≤a≤25cm-1. In the application, a (the unit is cm -1) represents the half-width of a G peak in a Raman spectrum of the silicon-carbon anode material, namely the difference between two wavelengths corresponding to half of the intensity of the G peak. The half-height width a is related to the defect concentration and disorder degree of the hard carbon material in the silicon-carbon negative electrode material, specifically, the defect concentration of the hard carbon material can influence the obstruction of solid phase migration of lithium ions in the hard carbon material so as to influence the dynamic performance of the hard carbon material, and meanwhile, the disorder degree of the hard carbon material reflects the capacity of the silicon-carbon negative electrode material to a certain extent. When the G peak intensity a of the silicon-carbon anode material is within the range, the defect concentration and the disorder degree of the carbon material are moderate, and the lithium ion secondary battery using the silicon-carbon anode material as the anode active substance has more excellent initial coulombic efficiency and cycle rate performance. The value of a can be any value or a range between any two values in 10.5cm -1、11.0cm-1、14.5cm-1、16.2cm-1、18.3cm-1、25.0cm-1, and is more preferably 12cm -1≤a≤20cm-1.
In some embodiments, the silicon-carbon anode material satisfies that b is more than or equal to 0.6 and less than or equal to 1.5, and more preferably is more than or equal to 0.8 and less than or equal to 1.2, and the value of b can be any one value or a range between any two values of 0.75, 0.99, 1.05, 1.31, 1.39 and 1.50. b=id/IG represents the defect concentration of the silicon-carbon anode material, and is the ratio of the D-peak intensity (represented by ID) to the G-peak intensity (represented by IG) of the silicon-carbon anode material in the raman spectrum. The value of b is in the proper range, the silicon-carbon anode material has proper defect concentration, the active reaction site is moderate, the contradiction between the side reaction and the lithium storage capacity of the lithium ion secondary battery in the charge and discharge process can be well balanced, and the battery has the first-circle coulomb efficiency and long cycle life.
In some embodiments, the silicon carbon negative electrode material satisfies 0<c.ltoreq.0.5, preferably 0.4.ltoreq.c.ltoreq.0.49. c is poisson ratio of the silicon-carbon anode material, is the elastic coefficient of material deformation, and is positively correlated with the bending effect of the material. The silicon-carbon negative electrode material within the Poisson ratio has sufficient flexibility, and in the charging and discharging process of the lithium ion secondary battery, the specific distribution between the carbon fibers and the carbon-coated silicon particles in the silicon-carbon negative electrode material can effectively buffer the volume change of silicon in the charging and discharging process, and the combination of the carbon fibers and the carbon-coated silicon particles also greatly improves the conductivity of the silicon-carbon negative electrode material, so that the cycle performance and the multiplying power performance of the lithium ion secondary battery can be greatly improved. Illustratively, the value of c may be any one of 0.30, 0.35, 0.39, 0.45, 0.48, 0.49, or a range between any two values.
In some embodiments, the silicon accounts for 2-15% of the weight of the silicon-carbon anode material, and may be any one value or a range between any two values of 2%, 10% and 15% by way of example. The silicon element has higher capability of inserting and extracting lithium ions, so that the energy storage capability of the lithium battery can be improved, but the volume of the lithium ion secondary battery can be expanded in the lithium ion extraction process, so that the cycle life and the multiplying power performance of the lithium ion secondary battery are influenced, and the lithium ion secondary battery prepared by the silicon element has higher initial coulombic efficiency and multiplying power performance due to the proper silicon content in the negative electrode material.
In some embodiments, the weight ratio of the carbon coating layer in the carbon-coated silicon particles is 20-50% based on the silicon-carbon anode material, and may specifically be any one value or a range between any two values of 20%, 30% and 50%.
In some embodiments, based on the silicon-carbon anode material, the weight ratio of the carbon fiber is 35-78%, and an exemplary specific value may be any one value or a range between any two values of 35%, 40%, 60%, 78%.
The proportion of the two carbon materials and silicon in the silicon-carbon anode material can influence the structure of the silicon-carbon anode material, especially the coating integrity of the carbon material, so that the cycle performance is influenced. Parameters of the silicon-carbon anode material can be regulated and controlled, and the dosage proportion of each component is controlled within a proper range, so that excellent electrochemical performance of the silicon-carbon anode material can be ensured.
The second aspect of the application provides a preparation method of the silicon-carbon anode material of the first aspect of the application, comprising the following steps:
And after uniformly mixing a silicon source and a first carbon source in a solvent, adding a second carbon source, uniformly mixing to form a colloid precursor solution, and performing electrostatic spinning film formation and carbonization on the colloid precursor solution to obtain the silicon-carbon anode material, wherein the first carbon source is a polar carbon-containing macromolecule to form a carbon coating layer in carbon-coated silicon particles, and the second carbon source is a precursor polymer for forming carbon fibers.
In some embodiments, the first carbon source comprises at least one of epoxy, cellulose, polyvinylidene fluoride. The first carbon source forms a carbon coating in the carbon-coated silicon particles.
In some embodiments, the second carbon source comprises at least one of polyvinylpyrrolidone, polyvinyl alcohol, polyacrylonitrile. The second carbon source may form a carbon fiber matrix.
In some embodiments, the silicon source comprises at least one of silicate, elemental silicon and silicon dioxide, preferably silicate, wherein the silicate has better compatibility with the first carbon source and the second carbon source, and the prepared silicon-carbon anode material has more uniform structure distribution, and the silicate comprises at least one of sodium silicate, lithium silicate, potassium silicate and ammonium silicate.
In some embodiments, the solvent comprises at least one of water, ethanol, N-dimethylformamide, N-dimethylacetamide, ethylene carbonate. Solvents conventional in the art for electrospinning can be used in the present application.
In some embodiments, the mass concentration of the silicon source in the colloidal precursor solution is 1% -20%.
In some embodiments, the parameter of the electrostatic spinning is that the glue pushing speed is 0.1-0.5 mL/h, the spinning distance is 10-20 cm, the spinning voltage is 10-25 kV, and the rotating speed of the collector is 150-300 rpm.
In some embodiments, the carbonization process parameters include a heating rate of 2-10 ℃ per minute, a carbonization temperature of 800-1100 ℃ and a carbonization time of 1-4 hours.
In a third aspect of the application, a secondary battery is provided, wherein the secondary battery comprises the silicon-carbon negative electrode material according to the first aspect of the application, and specifically comprises a positive electrode plate, electrolyte, a separation film and a negative electrode formed by the silicon-carbon negative electrode material according to the first aspect of the application.
The positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer arranged on at least one surface of the positive electrode current collector, wherein the positive electrode active material layer contains a negative electrode active material.
The type of the positive electrode current collector is not particularly limited, and can be selected according to actual requirements.
The positive electrode current collector may include, but is not limited to, metal materials such as aluminum, stainless steel, nickel plating, titanium, tantalum, carbon materials such as carbon cloth and carbon paper, and composite materials formed by polymer and metal layers, and in some embodiments, aluminum foil is preferably used as the positive electrode current collector.
In the present application, the kind of the positive electrode active material is not limited, and may be selected according to practical requirements, for example, the positive electrode active material may be lithium iron phosphate, lithium manganese iron phosphate, or a ternary positive electrode material. The positive electrode active material may further contain a doping element and/or a coating element, which are not particularly required as long as the positive electrode active material can be made more stable.
The positive electrode active material layer further includes at least one of a conductive agent, a binder, and a thickener.
The conductive agent, binder and thickener for battery commonly used in the art can be used in the present application.
In some embodiments, the conductive agent includes, but is not limited to, at least one of graphite, carbon black, acetylene black, ketjen black, carbon nanotubes, graphene.
In some embodiments, the binder includes, but is not limited to, at least one of styrene-butadiene rubber, polyacrylic acid, polyacrylonitrile, polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer.
In some embodiments, the thickener includes, but is not limited to, at least one of sodium carboxymethyl cellulose, lithium carboxymethyl cellulose.
In some embodiments, the kind of solvent used to form the positive electrode slurry and/or the negative electrode slurry is not limited as long as it is a solvent capable of dissolving or dispersing the positive electrode active material, the negative electrode active material, the conductive agent, the binder, and the dispersing agent.
In the secondary battery of the present application, the kind of the separator is not particularly limited and may be selected according to actual needs. The isolating film may be polypropylene film, polyethylene film, polyvinylidene fluoride film, polyurethane film, aramid film or multilayer composite film modified with coating.
In the secondary battery according to the present application, the type of electrolyte is not particularly limited, and may be selected according to actual needs.
In some embodiments, the preparation of the secondary battery comprises the steps of sequentially stacking a positive electrode plate, a separation film and a negative electrode, enabling the separation film to be positioned between the positive electrode and the negative electrode to play a role of separation, winding the separation film into a square bare cell, then loading the bare cell into a cell shell, baking at 65-95 ℃ for water removal, injecting electrolyte, sealing, and carrying out standing, hot-cold pressing, formation, clamping, capacity division and other procedures to obtain the secondary battery.
In some embodiments, the secondary battery may include an outer package, which may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, or the like. The outer package of the secondary battery can also be a soft package, such as a bag-type soft package, and the soft package can be made of one or more of plastics, such as polypropylene, polybutylene terephthalate, polybutylene succinate and the like. The shape of the secondary battery is not particularly limited, and may be cylindrical, square, or any other shape.
In a fourth aspect of the present application, there is provided an electric device comprising the secondary battery as set forth in the third aspect. The electric equipment can be application devices such as vehicles, mobile phones, portable equipment, notebook computers, ships, spacecrafts, electric toys, electric tools and the like. The vehicle may be a new energy vehicle, which may be a pure electric vehicle, a hybrid vehicle, or a range-extended vehicle, etc., the spacecraft may include an airplane, a rocket, a space plane, a spacecraft, etc., the electric toy may include a stationary or mobile electric toy such as a game machine, an electric vehicle toy, an electric ship toy, an electric plane toy, etc., and the electric tool may include a metal cutting electric tool, a grinding electric tool, an assembling electric tool, and a railway electric tool such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator, an electric planer, etc. The embodiment of the application does not limit the device in particular.
The following are specific embodiments of the present application, and the technical solutions of the present application will be further described with reference to the embodiments, but the present application is not limited to these embodiments. The reagents, methods and apparatus employed in the present application, unless otherwise specified, are all conventional in the art.
Example 1
The preparation method of the silicon-carbon anode material specifically comprises the following steps:
weighing raw materials according to the proportion shown in Table 1, respectively adding epoxy resin (namely the first carbon source) and sodium silicate into 66.67wt% ethanol water solution, uniformly mixing, adding polyvinylpyrrolidone (namely the second carbon source), stirring for 30min by ultrasonic, and stirring at normal temperature for 12h to form uniform colloid precursor solution (the mass concentration of sodium silicate in the colloid precursor solution is 1.70 wt%);
Injecting the prepared colloid precursor solution into an injector, setting a gel pushing speed of 0.25mL/h, a spinning distance of 15cm and a spinning voltage of 15kV, carrying out electrostatic spinning at a collector rotating speed of 200rpm, collecting the obtained product, drying at 50 ℃ for 12h in a drying oven, then placing the product into an argon atmosphere tube furnace, heating to 1000 ℃ at 5 ℃ per min, keeping the temperature for 2h, and cooling to room temperature (25+/-5 ℃) to obtain the silicon-carbon anode material, wherein the characterization of the relevant parameters of the obtained silicon-carbon anode material is shown in Table 1 in detail.
Examples 2 to 13, comparative examples 1 to 2
A series of silicon-carbon anode materials are provided, the silicon-carbon anode materials are prepared by referring to the method of the embodiment 1, and the silicon-carbon anode materials with different parameters are obtained by changing the types and the dosage proportion of the raw materials in the embodiment 1, parameters of electrostatic spinning (including spinning distance and the like), carbonization temperature, time and the like, and the parameters of the obtained silicon-carbon anode materials are shown in the table 1 in detail.
Comparative example 3
A silicon carbon negative electrode material is provided, which is prepared by referring to the method of example 1, and is different from example 1 in that an epoxy resin (a first carbon source) is replaced by polyvinylpyrrolidone (a second carbon source) with equal mass, and electrostatic spinning parameters and carbonization temperature are adjusted, so that the relation of the parameters satisfies the calculated value of a×b×c, and the calculated value is the same as that of example 1.
Comparative example 4
A silicon carbon negative electrode material was provided, which was prepared by referring to the method of example 1, and was different from example 1 in that the second carbon source polyvinylpyrrolidone was replaced with an equal mass epoxy resin (first carbon source), i.e., the second carbon source polyvinylpyrrolidone was not added, and the electrospinning parameters and carbonization temperature were adjusted, so that the relation of the parameters was ensured to satisfy the calculated value of axbxc as in example 1.
Comparative example 5
A silicon-carbon anode material is provided, which is prepared by referring to a method of comparative example 3, and is different from comparative example 3 in that the parameters of electrostatic spinning and carbonization temperature are adjusted, and the relation of the parameters is a multiplied by b multiplied by c <4.
Comparative example 6
A silicon-carbon anode material is provided, which is prepared by referring to the method of comparative example 4, and is different from comparative example 3 in that the parameters of electrostatic spinning and carbonization temperature are adjusted, and the relation of the parameters is a multiplied by b multiplied by c >15.
Parameters for the silicon carbon anode material:
1) The ratio of each component in the silicon-carbon negative electrode material product can be calculated by a thermal gravity differential heat (TG-DTA) method, the specific calculation method comprises the steps of testing a thermal gravity differential heat curve of the silicon-carbon negative electrode material in an argon atmosphere, calculating the content of the silicon material and the carbon material according to the weight loss curve, and further calculating the content of a carbon fiber matrix and a coated carbon layer according to the ratio of two carbon sources, wherein the specific result is shown in Table 1;
2) In the application, the Raman spectrum test condition of the silicon-carbon anode material is that the material is placed under a Raman spectrometer and is tested at a constant temperature of 25 ℃, the ratio b of the D peak intensity to the G peak intensity of the Raman spectrum of the material is b=I D/IG, wherein I D represents the D peak intensity of the Raman spectrum of the material, the D peak is near the wavelength of the Raman spectrum of 1350cm -1 (in the range of 1300cm -1-1380cm-1 selected in the application), I G represents the G peak intensity of the Raman spectrum of the material, and the G peak is near the wavelength of 1580cm -1 (in the range of 1520cm -1-1590cm-1 selected in the application);
3) Poisson's ratio C, the tensile rate is 50mm/min, the test temperature is room temperature (25+ -5 ℃), and the test results are shown in Table 1.
TABLE 1 parameters of silicon carbon negative electrode materials
The silicon-carbon anode materials provided in the above examples and comparative examples were prepared into batteries, and electrochemical performance tests were performed, and the specific preparation process included the following steps:
preparation of positive electrode plate
The positive electrode active material lithium iron phosphate, the conductive agent acetylene black, the dispersing agent PVP and the binder polyvinylidene fluoride are dispersed in NMP according to the mass ratio of 96:1.2:1:1.8 to prepare slurry, then the slurry is coated on two sides of an aluminum foil, and the positive electrode plate (the surface density is 0.22g/1540.25mm 2) is obtained after baking, rolling and cutting;
Preparation of negative electrode plate
Compacting the silicon-carbon negative electrode active materials prepared in the examples and the comparative examples to obtain a negative electrode plate (the surface density is 0.135g/1540.25mm 2);
Preparation of electrolyte
Mixing EC and DMC according to a volume ratio of 1:1, and then adding lithium hexafluorophosphate into a glove box to prepare electrolyte with a concentration of 1 mol/L;
battery assembly
And sequentially stacking the prepared positive electrode plate, the polyethylene diaphragm and the negative electrode plate, enabling the diaphragm to be positioned between the positive electrode plate and the negative electrode plate, winding to obtain a bare cell, placing the bare cell in an outer packaging shell, vacuum drying, injecting electrolyte, standing, forming, shaping and capacity division to obtain the secondary battery.
The performance of the secondary batteries obtained in the above examples and comparative examples was tested, and specific test items and test methods and results were as follows:
1. And (3) testing the cycle performance:
Placing the secondary battery in a charge-discharge test cabinet, keeping the temperature at 25 ℃, and carrying out internal circulation test at a voltage interval of 2.5-3.65V at a charge rate of 1C and a discharge rate of 1C;
Taking a negative pole piece before and after secondary battery circulation, placing the negative pole piece under a resistance meter to measure the resistance value of the pole piece, recording initial pole piece resistance (rho 0) and pole piece resistance (rho t) after circulation, and calculating the resistance change rate of the negative pole piece= (rho t)-ρ0)/ρ0 is 100%;
2. And (3) multiplying power performance test:
Placing the secondary battery in a charge-discharge test cabinet, keeping the temperature at 25 ℃, charging the secondary battery at 1C, discharging the secondary battery at 1C and 5C, recording the capacity under different multiplying powers after each cycle is 5 circles in a voltage interval of 2.5-3.65V, respectively recording the capacity as C1 and C5, and calculating the capacity retention rate=C5/C1 x 100% under the 5C multiplying power;
3. Bending stiffness is measured by taking a pole piece made of the material, placing the pole piece under a bending test machine, and measuring the bending stiffness of the pole piece according to DIN 53121 or ISO 5628 standard by adopting a 2-point bending test method.
Table 2 results of performance test of negative electrode tabs and batteries prepared in examples and comparative examples
From the above results, it can be seen that:
According to the embodiment and the comparative example, through designing the structure of the silicon-carbon negative electrode, after the silicon is coated with the carbon, the carbon fiber is embedded into the carbon fiber, and the carbon fiber is further lapped to form a layered film-shaped structure with a porous net shape, meanwhile, parameters (such as the ratio of D peak intensity to G peak intensity, the half-width of G peak and the Poisson ratio in Raman spectrum) of the silicon-carbon negative electrode material are reasonably controlled to meet a specific relational expression, so that the volume expansion of the material can be effectively relieved, the conductivity of the material is improved, and the cycle performance and the multiplying power performance are improved.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention may be modified or substituted equally without departing from the spirit and scope of the technical solution of the present invention.
Claims (10)
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160013481A1 (en) * | 2014-07-11 | 2016-01-14 | Oci Company Ltd. | Anode active material for lithium secondary battery and method for preparing same |
| US20160240843A1 (en) * | 2015-02-16 | 2016-08-18 | Shin-Etsu Chemical Co., Ltd. | Negative electrode active material for non-aqueous electrolyte secondary battery, non-aqueous electrolyte secondary battery, and method of producing negative electrode material for a non-aqueous electrolyte secondary battery |
| WO2022188818A1 (en) * | 2021-03-10 | 2022-09-15 | 贝特瑞新材料集团股份有限公司 | Graphite composite material and preparation method therefor, and lithium-ion battery |
| CN115443559A (en) * | 2021-03-19 | 2022-12-06 | 宁德新能源科技有限公司 | Negative electrode material and preparation method thereof, electrochemical device and electronic device |
| CN117038855A (en) * | 2023-08-14 | 2023-11-10 | 广东省豪鹏新能源科技有限公司 | Negative electrode plate, lithium ion battery and electronic device |
| CN118712370A (en) * | 2024-08-27 | 2024-09-27 | 宁波广科新材料有限公司 | Preparation method and application of multi-layer carbon-coated silicon-carbon composite material |
-
2024
- 2024-12-27 CN CN202411984141.1A patent/CN119812264A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160013481A1 (en) * | 2014-07-11 | 2016-01-14 | Oci Company Ltd. | Anode active material for lithium secondary battery and method for preparing same |
| US20160240843A1 (en) * | 2015-02-16 | 2016-08-18 | Shin-Etsu Chemical Co., Ltd. | Negative electrode active material for non-aqueous electrolyte secondary battery, non-aqueous electrolyte secondary battery, and method of producing negative electrode material for a non-aqueous electrolyte secondary battery |
| WO2022188818A1 (en) * | 2021-03-10 | 2022-09-15 | 贝特瑞新材料集团股份有限公司 | Graphite composite material and preparation method therefor, and lithium-ion battery |
| CN115443559A (en) * | 2021-03-19 | 2022-12-06 | 宁德新能源科技有限公司 | Negative electrode material and preparation method thereof, electrochemical device and electronic device |
| CN117038855A (en) * | 2023-08-14 | 2023-11-10 | 广东省豪鹏新能源科技有限公司 | Negative electrode plate, lithium ion battery and electronic device |
| CN118712370A (en) * | 2024-08-27 | 2024-09-27 | 宁波广科新材料有限公司 | Preparation method and application of multi-layer carbon-coated silicon-carbon composite material |
Non-Patent Citations (3)
| Title |
|---|
| YONGHUI YAN ET AL.: "All-in-one asymmetric micro-supercapacitor with Negative Poisson’s ratio structure based on versatile electrospun nanofibers", 《CHEMICAL ENGINEERING JOURNAL》, vol. 433, 14 September 2021 (2021-09-14), pages 1 - 9 * |
| 张晨阳;文越华;赵鹏程;程杰;邱景义;孙艳芝;: "有机碳源对LiTi_2(PO_4)_3/C复合水系负极性能的影响", 高等学校化学学报, no. 06, 10 June 2020 (2020-06-10) * |
| 李肖辉;陈北海;陈干杰;张跃伟;王京;古领先;: "高倍率双层碳包覆硅基复合材料的制备研究", 储能科学与技术, no. 04, 31 December 2020 (2020-12-31) * |
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