Method for manufacturing phosphorus-doped silicon-based composite cathode material and its product and application

Abstract

The present invention discloses a method for manufacturing a phosphorus-doped silicon-based composite cathode material, comprising the steps of: (1) sufficiently mixing a phosphorus source gas, a carbon source gas, and a silicon source gas at room temperature under an inert atmosphere to obtain a mixed gas; wherein, when the total volume of the mixed gas is calculated as 100%, the volume share of the phosphorus source gas is 0.1 to 3.0%, the volume share of the carbon source gas is 15 to 28%, and the remainder is silicon source gas; (2) injecting the mixed gas into an immersion furnace containing a base material and obtaining an intermediate product through thermal immersion; and (3) performing carbon cladding treatment on the intermediate product and, again, obtaining a phosphorus-doped silicon-based composite cathode material through post-treatment. The present invention discloses a method for manufacturing a phosphorus-doped silicon-based composite cathode material, wherein a lithium-ion battery obtained by assembling the cathode material obtained by manufacturing possesses excellent circulation stability, while simultaneously possessing high reversible capacity and initial Coulomb efficiency.

Description

Technology Field

[0001] The present invention relates to the technical field of lithium battery negative electrode materials, and in particular, to a method for manufacturing a phosphorus-doped silicon-based composite negative electrode material and the product and application thereof. Background Technology

[0002] Silicon is the best option to replace graphite. As the second most abundant element in the Earth's crust, silicon is environmentally friendly and possesses a very high theoretical capacity (4200 mAh / g). However, if violent volume changes occur during the lithium insertion / extraction process, severe adverse effects occur, significantly reducing cycling stability. Compared to silicon monolithic materials, silicon dioxide materials exhibit significantly reduced volume expansion during lithium insertion and still possess a relatively high theoretical specific capacity (>2000 mAh / g); however, the initial Coulomb efficiency of silicon dioxide is excessively low (lower than 76%), limiting its wider range of applications; compared to silicon dioxide, commercially available silicon carbon products have the characteristics of high initial efficiency and high capacity, but their cycling performance is far inferior to that of silicon dioxide; therefore, manufacturing silicon-based anode materials with high capacity, high initial efficiency, and excellent cycling performance is an urgent matter to be addressed.

[0003] A Chinese patent document with application publication number CN 107623118 A disclosed a method for manufacturing a phosphorus-doped porous carbon cathode material with improved initial Coulomb efficiency. The method involves using monomorphic red phosphorus as a phosphorus source to disperse an organic carbon source in water to form a slurry, then uniformly mixing it with red phosphorus, drying it, placing it in a sealed tank filled with a protective atmosphere for calcination, and subsequently performing further calcination in a pipe-type furnace under an inert atmosphere to produce a phosphorus-doped porous carbon cathode material. The technical solution claimed that using phosphorus as a doping element can improve the reversible specific weight of the carbon material and significantly improve the initial Coulomb efficiency of the material. Although the manufacturing method disclosed in the technical solution is simple, the use of liquid and solid mixtures cannot guarantee doping uniformity, which will affect the consistency of the manufacturing method; furthermore, the initial Coulomb efficiency of the material obtained by the method is only 71% at best, which cannot satisfy market demand.

[0004] Chinese patent document with application publication number CN 113809311 A discloses a phosphorus-doped and soft carbon-clad silicon-based lithium-ion anode material and a method for manufacturing the same and its application. A phosphorus-doped silicon dioxide material is obtained by using a compound containing a phosphorus gas source or a compound containing phosphorus with a high boiling point as a doping material, and by allowing a gas phase mixing reaction between the vapor of the doping material and preheated silicon source vapor to proceed at 1200 to 1700°C for 1 to 24 hours; wherein, the silicon source vapor is a mixed gas of silicon vapor and silicon dioxide vapor; the phosphorus-doped silicon dioxide material is cooled to room temperature, the material is discharged, crushed, and sieved, analysis and testing are performed on the sieved material, and carbon cladding is performed on the material in which the doping uniformity satisfies a preset condition to obtain a phosphorus-doped silicon-based lithium-ion anode material. The above technical method obtains a lithium-ion battery anode material with uniform bulk phase doping by conducting a gas phase mixing reaction between a phosphorus-containing material, silicon vapor, and silicon oxide vapor, thereby ensuring sufficient contact between the reactants. The obtained material possesses higher cycle stability and simultaneously exhibits superior consistency. However, the phosphorus-doped silicon anode material obtained by this method has an initial efficiency of only 80.6% at most, lacking distinct product advantages. Furthermore, the above technical method is very energy-intensive; specifically, the temperature required to preheat silicon and silicon dioxide to form vapor must reach at least 1350°C, the gas phase mixing reaction must be carried out at a high temperature of 1200 to 1700°C, and the subsequent carbon cladding step must also be carried out at a high temperature of 800 to 1000°C. Therefore, the above technical method is not suitable for large-scale industrial production. The problem to be solved

[0005] The present invention was created to solve the above problems existing in the prior art, and its purpose is to provide a method for manufacturing a phosphorus-doped silicon-based composite cathode material. The method for manufacturing the phosphorus-doped silicon-based composite cathode material has low energy consumption during production and high product uniformity during production, and above all, the lithium-ion battery obtained by assembling the manufactured cathode material has excellent circulation stability, while also having high reversible specific capacity and initial Coulomb efficiency. means of solving the problem

[0006] The specific technical plan is as follows.

[0007] A method for manufacturing a phosphorus-doped silicon-based composite cathode material comprises the following steps:

[0008] Step (1) sufficiently mix phosphorus source gas, carbon source gas and silicon source gas at room temperature under an inert atmosphere to obtain a mixed gas;

[0009] When the total volume of the above mixed gas is calculated as 100%, the volume share of the phosphorus source gas is 0.1 to 3.0%, the volume share of the carbon source gas is 15 to 28%, and the remainder is the silicon source gas;

[0010] Step (2) Inject the above mixed gas into an immersion furnace containing a base material, and obtain an intermediate product through thermal immersion;

[0011] Step (3) performing carbon cladding treatment on the intermediate product, and then, through post-treatment, obtaining the phosphorus-doped silicon-based composite cathode material; is included.

[0012] The present invention discloses a method for manufacturing a phosphorus-doped silicon-based composite cathode material, wherein gaseous hydrogen phosphide at room temperature is used as a silicon source, a gaseous carbon source is separately added, and a mixed gas is obtained by mixing it with the gaseous silicon source at room temperature, and during a gas phase deposition reaction process, carbon and phosphorus each perform a bonding action with the silicon source material, and thermal decomposition and dehydrogenation are carried out; and finally, the phosphorus-doped silicon-based composite cathode material is obtained by manufacturing through a carbon cladding treatment.

[0013] The following technical features were discovered from the experimental results. That is, in the present manufacturing method, doping of phosphorus atoms can significantly reduce the average grain size of the silicon primary crystal grains; and through the introduction of a gaseous carbon source, doping of carbon atoms can cooperate with the doped carbon atoms, which helps decompose the phosphorus source gas and promotes doping of the phosphorus source, and when both are simultaneously blended with the silicon source gas, the phosphorus-doped silicon-based composite cathode material produced at the end through the above series of processes possesses excellent circulation stability, reversible specific capacity, and initial Coulomb efficiency.

[0014] The following technical characteristics were discovered from the experimental results. That is, when using only phosphorus source gas in combination with silicon source gas, or using only carbon source gas in combination with silicon source gas, the aforementioned cooperative action cannot be achieved in either case.

[0015] The following technical features were discovered from the results of further experiments. Even if a combination of three sources—namely, phosphorus source gas, carbon source gas, and silicon source gas—is used, if the volume ratio of the three sources is not within the aforementioned limited range, it is still not possible to manufacture a lithium-ion battery that combines excellent circulation stability, high reversible capacity, and initial Coulomb efficiency.

[0016] In step (1),

[0017] The above source gas is selected from phosphine;

[0018] The carbon source gas is selected from alkaline gases capable of decomposing at 400 to 800°C; preferably, it is selected from ethylene, propylene, acetylene, etc.

[0019] The above silicon source gas is selected from one or more of silane, dichlorodihydrosilane, trichlorohydrosilane, and silicon tetrachloride.

[0020] In step (2),

[0021] The total flow rate of the above mixed gas is 0.1 to 50 L / min; preferably, 20 to 50 L / min; more preferably, 25 to 30 L / min.

[0022] The above base material is selected from one or more of hard carbon, electrically conductive carbon black, carbon nanotubes, and graphene; the mass of the added base material accounts for 0.1 to 20.0 wt% of the total mass of the final product.

[0023] Preferably, the D50 of the base material is smaller than 200 nm.

[0024] The temperature of the above heat immersion is 400 to 800℃.

[0025] In step (3),

[0026] The above intermediate product undergoes crushing, grading, and demagnetization, followed by carbon cladding treatment;

[0027] Preferably, the particle size concentration (SPAN value) of the intermediate product after grinding, grading, and demagnetization is ≤1.5 and the average particle size is ≤10 μm; more preferably, the SPAN value is ≤1.2.

[0028] In step (3),

[0029] The above carbon cladding treatment is selected from one or more of gas phase carbon cladding, liquid phase carbon cladding, and solid phase carbon cladding.

[0030] The carbon source used for the above gas phase carbon cladding is an alkyl gas, for example, ethylene, propylene, acetylene, etc., and the specific carbon cladding process uses conventional technical means in the field of technology.

[0031] The carbon source used for the above liquid carbon cladding is a carbon-containing polymer, for example, liquid epoxy resin, petroleum residue, liquid bitumen, etc., and the detailed carbon cladding process utilizes conventional technical means in the art.

[0032] The carbon source used by the above-mentioned solid carbon cladding is bitumen, and the specific carbon cladding process utilizes conventional technical means in the field of technology.

[0033] The temperature of the carbon cladding treatment above is selected from 600 to 1000°C; customized adjustments are made depending on the type of carbon source used.

[0034] In step (3),

[0035] The above post-processing includes dispersion and sieving, and all specific operations are conventional technical means in this field. For example, the dispersion method utilizes spiral dispersion.

[0036] Preferably, the mesh number used by the above-mentioned body is 100 to 800 mesh.

[0037] Based on the above process and raw materials, preferably,

[0038] The mixed gas of step (1) has a volume share of phosphorus source gas of 0.5 to 3.0%, a volume share of carbon source gas of 15 to 25%, and the remainder is silicon source gas;

[0039] More preferably,

[0040] The above mixed gas has a volume share of phosphorus source gas of 0.5 to 1.5%, a volume share of carbon source gas of 15 to 25%, and the remainder is silicon source gas;

[0041] More preferably, in the above mixed gas, the phosphorus source gas, carbon source gas and silicon source gas are sufficiently mixed at room temperature in a volume ratio of 1.5:25:73.5.

[0042] Most preferably, the silicon source is selected from trichlorohydroxysilane, and as found through experiments, a lithium-ion battery obtained by assembling a phosphorus-doped silicon-based composite cathode material finally manufactured using trichlorohydroxysilane as the silicon source again under the more preferred volume ratio reaches the most desirable state for cyclic stability, reversible capacity, and initial Coulomb efficiency.

[0043] The present invention further discloses a phosphorus-doped silicon-based composite cathode material prepared according to the above method.

[0044] The present invention further discloses the application of a phosphorus-doped silicon-based composite cathode material prepared according to the above method in a lithium-ion battery, and as found through experiments, a lithium-ion battery obtained by assembling using the cathode material has excellent cyclic stability and combines high reversible capacity and initial Coulomb efficiency. Effects of the invention

[0045] Compared to the prior art, the present invention achieves the following beneficial effects.

[0046] The method for manufacturing a phosphorus-doped silicon-based composite cathode material disclosed in the present invention uses phosphorus source gas, carbon source gas, and silicon source gas as raw materials, and the manufacturing process is simple, controllable, and energy-efficient, making it suitable for industrial production.

[0047] A lithium-ion battery obtained by assembling a phosphorus-doped silicon composite cathode material manufactured according to the present invention has excellent cycle stability, with a capacity retention rate of over 80% after 100 cycles and reaching up to 88%; a capacity retention rate of over 70% after 500 cycles and reaching up to 75.5%, and possesses high reversible specific capacity (higher than 1800 mAh / g) and initial Coulomb efficiency (not lower than 90%). Brief explanation of the drawing

[0048] FIG. 1 is an SEM image of the intermediate product prepared in Example 1; FIGS. 2 to 4 are distribution maps of Si, C, and P elements within the image range shown in FIG. 1, respectively; FIG. 5 is an SEM image of the phosphorus-doped silicon-based composite cathode material prepared in Example 1; Figure 6 is a TEM image of the phosphorus-doped silicon-based composite cathode material prepared in Example 1. Specific details for implementing the invention

[0049] Hereinafter, specific embodiments of the present invention will be further described by combining the present embodiments. The specific embodiments described herein are intended only to explain and interpret the present invention, and are not intended to limit the invention.

[0050] Example 1

[0051] Step (1) A mixed gas is obtained by thoroughly mixing phosphine, ethylene, and methylsilane at room temperature in a volume ratio of 1.5:25:73.5 under an argon gas atmosphere.

[0052] Step (2) A mixed gas is introduced at a flow rate of 25 L / min for a total gas volume, and 100 grams of hard carbon microspheres with a D50 of approximately 100 nm are introduced into an immersion furnace set to a temperature of 500°C. Gas is continuously introduced until the surface of the hard carbon microsphere particles continuously forms a core and grows, and the immersion is performed to form a phosphorus-doped silicon carbon immersion layer. The gas injection maintenance time is 10 h.

[0053] Step (3) The immersion furnace is cooled to lower the temperature, and after the material is discharged from the furnace, it undergoes crushing and grading treatment to obtain uniform particles with a D50 smaller than 5 μm and a SPAN value smaller than 1.2, and then undergoes magnetic treatment to obtain an intermediate product.

[0054] Step (4) The intermediate product is introduced into a chemical gas phase immersion furnace under an argon gas atmosphere, heated to 800°C at a rate of 5°C / min, and acetylene gas is injected at a flow rate of 1L / min to carry out gas phase decomposition to clad carbon, and the amount of clad carbon is controlled to account for 4 wt% of the total mass of the final product. After the immersion is finished, the temperature is lowered to room temperature, the material is removed, and dispersion and sieving are carried out to obtain a phosphorus-doped silicon-based composite cathode material.

[0055] FIG. 1 is a mapping image of the intermediate product prepared in step (3) of the present embodiment and a distribution map of Si element (Fig. 2), C element (Fig. 3) and P element (Fig. 4) within the range of the image. As can be seen by referring to FIG. 2 to FIG. 4, the intermediate product prepared in the present embodiment has already been successfully doped with two elements, namely C element and P element, and the two elements are uniformly dispersed in the intermediate product.

[0056] Figure 5 is an SEM image of the final product manufactured in this embodiment, and as can be seen by referring to the figure, the final product manufactured in this embodiment is a regular sphere and has a relatively uniform distribution of diameters.

[0057] Figure 6 is a TEM drawing of the final product manufactured in this embodiment, and as can be seen by referring to the drawing, the cathode material manufactured in this embodiment has a uniform carbon layer clad on its surface.

[0058] Example 2

[0059] The manufacturing process is almost identical to Example 1, and the only distinguishing difference is that the volume ratio of hydrogen phosphide, ethylene, and methylsilane in step (1) is replaced with 3:15:82.

[0060] Example 3

[0061] The manufacturing process is almost identical to Example 1, and the only distinguishing difference is that the volume ratio of hydrogen phosphide, ethylene, and methylsilane in step (1) is replaced with 0.5:25:74.5.

[0062] Comparative Example 1

[0063] The manufacturing process is almost identical to Example 1, and the only distinguishing difference is that the volume ratio of hydrogen phosphide, ethylene, and methylsilane in step (1) is replaced with 5:25:70.

[0064] Comparison Example 2

[0065] The manufacturing process is almost identical to Example 1, and the only distinguishing difference is that in step (1), only ethylene and methyl silane with a volume ratio of 25:75 are added and mixed to obtain a mixed gas.

[0066] Comparison Example 3

[0067] The manufacturing process is almost identical to Example 1, and the only distinguishing difference is that the volume ratio of hydrogen phosphide, ethylene, and methylsilane in step (1) is replaced with 2:30:68.

[0068] Comparison Example 4

[0069] The manufacturing process is almost identical to Example 1, and the only distinguishing difference is that the volume ratio of hydrogen phosphide, ethylene, and methylsilane in step (1) is replaced with 2:13:85.

[0070] Comparative Example 5

[0071] The manufacturing process is almost identical to Example 1, and the distinguishing difference is that in step (1), only hydrogen phosphide and methyl silane with a volume ratio of 2:98 are added and mixed to obtain a mixed gas.

[0072] Example 4

[0073] Step (1) Hydrogen phosphide, propylene, and dichlorodihydrosilane are sufficiently mixed at room temperature in a volume ratio of 1.5:25:73.5 under an argon gas atmosphere to obtain a mixed gas.

[0074] Step (2) A mixed gas is introduced at a flow rate of 30 L / min for a total gas volume, and 100 grams of graphene microspheres with a D50 of approximately 100 nm are introduced into an immersion furnace set to a temperature of 400°C. Gas is continuously introduced until the surface of the graphene microsphere particles continuously forms a core and grows, and the immersion is performed to form a phosphorus-doped silicon carbon immersion layer. The gas introduction maintenance time is 13 h.

[0075] Steps (3) to (4) are exactly the same as in Example 1.

[0076] Example 5

[0077] Step (1) A mixed gas is obtained by thoroughly mixing phosphine, acetylene, and trichlorohydroxysilane at room temperature in a volume ratio of 1.5:25:73.5 under an argon gas atmosphere.

[0078] Step (2) A mixed gas is introduced at a flow rate of 30 L / min for a total gas volume, and 100 grams of electrically conductive carbon black microspheres with a D50 of approximately 100 nm are introduced into an immersion furnace set to a temperature of 800°C. Gas is continuously introduced until the surface of the electrically conductive carbon black microsphere particles continuously forms a core and grows, and the immersion is performed to form a phosphorus-doped silicon carbon deposit layer. The gas injection maintenance time is 5 h.

[0079] Steps (3) to (4) are exactly the same as in Example 1.

[0080] Application example

[0081] The cathode materials prepared in each example and each control example are assembled into a battery, respectively.

[0082] Under a nitrogen gas protection atmosphere, the electrical conductor SuperP, carboxymethylcellulose sodium CMC, and deionized water are sufficiently mixed and dispersed, then the cathode material is added and stirred at 2000 rpm for 10 min, and then the water-based adhesive AONE (purchased from Shenzhen Yanyi New Materials Co., Ltd.) is added and stirred at 2000 rpm for 10 min to obtain a cathode slurry. Here, the mass ratio of the cathode material, the electrical conductor SuperP, the carboxymethylcellulose sodium CMC, and the adhesive AONE (based on dry weight) is 70:15:5:10, and the solid content of the slurry is 15 wt%.

[0083] The above cathode slurry is applied to a collector copper foil, dried at 80°C for 30 minutes under a relative vacuum of -0.1 MPa, and then rolled at room temperature, with an isal density of 9.1 mg / cm² 2 Then, punching is performed to cut the electrode into a wafer with a diameter of 14 mm, thereby manufacturing it into an electrode plate.

[0084] The electrode uses a lithium sheet CR2016 (purchased from Yongxing Industry Equipment Technology Co., Ltd. in Shenzhen) and has a diameter of 16 mm.

[0085] A button-type battery is assembled in a glove box under an argon gas protection atmosphere, and the moisture fraction and oxygen fraction of the glove box are both less than 0.01 ppm. It is assembled in the order of “negative electrode shell-washer-lithium sheet-electrolyte-separator-electrolyte-electrode plate-positive electrode shell,” wherein the electrolyte is composed of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) (EC:EMC:DEC volume ratio = 1:1:1) and contains 1.0 M LiPF6.

[0086] Here, the diameter of the electrode plate is 14 mm, the diameter of the lithium sheet is 16 mm, the diameter of the separator is 19 mm, and the size of the battery housing (positive and negative housings) is 20 mm. The separator is a ceramic-coated separator with a thickness of 12 μm (purchased from Shanghai Enjie New Materials Technology Co., Ltd.). The assembled button-type battery is placed into the mold groove of a hydraulic capping machine (purchased from Shenzhen Kejing Zhida Technology Co., Ltd.) and tightly locked, at 500 kg / cm² 2 Apply greater pressure, then unlock and remove the capped button-type battery.

[0087] When assembling the battery, five button-type batteries are manufactured by conducting experiments for each group, and the data from a total of five groups is tested, and the final performance is the average value of the data from the five groups.

[0088] Performance Test:

[0089] The material phase is analyzed and inspected using Bruker’s XRD-D2 PHASER, and the particle size of the silicon primary crystal grains is tested by calculating using the Scherr formula.

[0090] Test the shape using the Phenom Generation 5 from Thermofisher, USA.

[0091] The carbon content is tested using a high-frequency infrared carbon sulfur analyzer from ELTRA, Germany.

[0092] Phosphorus content is tested using an organic element analyzer from Elementar, Germany.

[0093] Battery cycling performance is tested at the LAND Battery Test System CT2001A facility, and in detail,

[0094] The charge / discharge cycle characteristics of the button-type battery are tested using the LAND test cabinet at 25℃. First, the battery is discharged to 0.005V at 0.1C, then discharged to 0.001V at 0.08C, then discharged to 0.001V at 0.05C, then discharged to 0.001V at 0.02C, and left standing for 10 minutes; then, the battery is charged to 1.5V at 0.1C and left standing for 10 minutes, the charge / discharge capacity after the first cycle is recorded, and the initial Coulomb efficiency is calculated; the battery is cycled 100 times according to the above method, the charge / discharge capacity after 100 cycles is recorded, and the capacity retention rate after 100 cycles is calculated; the test and calculation process for the capacity retention rate after 500 cycles is carried out using the same method, and the test results are shown in Table 1 below.

[0095] Table 1

[0096]

[0097] As can be seen from the changes in phosphorus content and carbon content in Table 1, the method disclosed by the present invention can be manufactured to control the phosphorus content and carbon content in the product. As can be seen by comparing the average particle size of the silicon primary crystal grains in Example 1 and Comparative Examples 2 and 3, the introduction of phosphorus can effectively reduce the average particle size of the silicon primary crystal grains.

[0098] According to the above embodiments, the present invention can be implemented very effectively. Above all, even if modifications or formulas that have no substantial meaning to the present invention are made under the premise based on the above design to solve the same technical problem, since the essence of the technical solution used is still the same as the present invention, this should also be included within the scope of protection of the present invention.

Claims

Claim 1 A method for manufacturing a phosphorus-doped silicon-based composite cathode material, comprising the following steps: Step (1) sufficiently mixing a phosphorus source gas, a carbon source gas, and a silicon source gas at room temperature under an inert atmosphere to obtain a mixed gas; wherein, when the total volume of the mixed gas is calculated as 100%, the volume share of the phosphorus source gas is 0.5 to 1.5%, the volume share of the carbon source gas is 15 to 25%, and the remainder is silicon source gas; Step (2) injecting the mixed gas into an immersion furnace containing a base material and obtaining an intermediate product through thermal immersion; Step (3) performing carbon cladding treatment on the intermediate product and, again, obtaining the phosphorus-doped silicon-based composite cathode material through post-treatment; characterized by comprising the step of manufacturing a phosphorus-doped silicon-based composite cathode material. Claim 2 A method for manufacturing a phosphorus-doped silicon-based composite cathode material according to claim 1, wherein in step (1), the phosphorus source gas is selected from hydrogen phosphide; the carbon source gas is selected from an alkane gas capable of decomposing at 400 to 800°C; and the silicon source gas is selected from one or more of silane, dichlorodihydrosilane, trichlorohydrosilane, and silicon tetrachloride. Claim 3 A method for manufacturing a phosphorus-doped silicon-based composite cathode material according to claim 1, wherein in step (2), the total flow rate of the mixed gas is 0.1 to 50 L / min; the base material is selected from one or more of hard carbon, electrically conductive carbon black, carbon nanotubes, and graphene; and the temperature of the thermal immersion is 400 to 800℃. Claim 4 A method for manufacturing a phosphorus-doped silicon-based composite cathode material according to claim 1, wherein in step (3), the intermediate product undergoes crushing, grading, and demagnetization treatment, and then undergoes carbon cladding treatment; wherein the particle size concentration of the intermediate product undergoing crushing, grading, and demagnetization treatment is ≤ 1.5 and the average particle size is ≤ 10 μm. Claim 5 A method for manufacturing a phosphorus-doped silicon-based composite cathode material, characterized in that, in step (3) above, the carbon cladding treatment is selected from one or more of gas phase carbon cladding, liquid phase carbon cladding, and solid phase carbon cladding; and the temperature of the carbon cladding treatment is selected from 600 to 1000℃. Claim 6 A method for manufacturing a phosphorus-doped silicon-based composite cathode material according to claim 1, wherein in step (3), the post treatment includes dispersion and sieving. Claim 7 A method for manufacturing a phosphorus-doped silicon-based composite cathode material, characterized in that, in any one of claims 1 to 6, in step (1), the mixed gas has a volume share of phosphorus source gas of 0.5 to 3.0%, a volume share of carbon source gas of 15 to 25%, and the remainder is silicon source gas; and in step (2), the total flow rate of the mixed gas is 20 to 50 L / min. Claim 8 A method for manufacturing a phosphorus-doped silicon-based composite cathode material according to claim 7, wherein, in the above mixed gas, the phosphorus source gas, the carbon source gas, and the silicon source gas are sufficiently mixed at room temperature in a volume ratio of 1.5:25:73.5; and the silicon source is selected from trichlorohydroxysilane. Claim 9 Phosphorus-doped silicon-based composite cathode material manufactured by a method according to any one of claims 1 to 6. Claim 10 A lithium-ion battery comprising a phosphorus-doped silicon-based composite cathode material according to claim 9.

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