A phosphorus-carbon-silver composite material, a preparation method and application thereof

Abstract

The application discloses a phosphorus-carbon-silver composite material and a preparation method and application thereof, and belongs to the field of lithium ion battery negative electrode materials. The preparation method comprises the following steps: S1, preparing a mixed solution containing a carbon material, a silver source, black phosphorus and a reducing agent; and S2, performing a solvothermal reaction on the mixed solution to obtain a phosphorus-carbon-silver composite material; wherein in the step S2, the temperature of the solvothermal reaction is 60-140 DEG C, and the time is 3-24 hours. The method has simple preparation steps, is favorable for improving production efficiency, and is more suitable for industrialization. On the other hand, the prepared phosphorus-carbon-silver composite material has excellent electrochemical performances such as electrical conductivity, charge and discharge cycle and rate performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium ion battery negative electrode materials, and more particularly relates to a phosphorus-carbon-silver composite material and a preparation method and application thereof. BACKGROUND

[0002] Lithium ion batteries are one of the widely used energy storage devices at present, and have advantages such as high energy density and green environmental protection. In order to further improve the performance of lithium ion batteries, including service life, fast charging, high and low temperature performance, etc., the optimization of negative electrode materials is very important. The negative electrode material currently used in lithium ion batteries is graphite, but the low theoretical capacity (372 mAh / g) of graphite negative electrode cannot meet the demand of energy development.

[0003] Phosphorus is widely available, and the theoretical lithium storage capacity of elemental phosphorus as a lithium ion battery negative electrode material is as high as 2596 mAh / g, which is much higher than that of graphite negative electrode. It is a research hotspot for the next generation of lithium ion battery negative electrode materials. Black phosphorus, as one of the allotropes of phosphorus, has a high lithium ion diffusion efficiency, and is an ideal negative electrode material for achieving high energy density and fast charging performance of lithium ion batteries. However, pure black phosphorus as a negative electrode material has poor electrical conductivity and large volume change during charging and discharging. The combination of black phosphorus and carbon material can improve the problems of poor electrical conductivity and volume expansion. At present, the method of combining black phosphorus and carbon material is mostly ball milling, which is complex and cumbersome. For example, a Chinese patent with publication number CN115172711A discloses a black phosphorus-carbon composite material and a preparation method and application thereof, but in the patent, the method of combining black phosphorus and carbon material is that amorphous red phosphorus and conductive carbon material are ball milled under a protective atmosphere, and then molded, high-temperature and high-pressure reacted to obtain a black phosphorus-carbon composite material. This process is relatively complicated and has low production efficiency.

[0004] Therefore, there is a need for a simple method for preparing a black phosphorus-carbon composite material. SUMMARY

[0005] 1. Problem to be solved

[0006] In view of the problem of complicated operation in the process of combining black phosphorus and carbon material in the prior art lithium ion battery negative electrode material, a phosphorus-carbon-silver composite material and a preparation method thereof are provided. A phosphorus-carbon-silver composite material with excellent electrical conductivity, charge-discharge cycling and rate performance is also provided.

[0007] 2. Technical solution

[0008] In order to solve the above problems, the technical scheme adopted by the application is as follows:

[0009] In a first aspect, the application provides a preparation method of a phosphorus-carbon-silver composite material:

[0010] S1. preparing a mixed solution containing carbon material, silver source, black phosphorus, reducing agent;

[0011] S2. performing a solvothermal reaction on the mixed solution to obtain a phosphorus-carbon-silver composite material.

[0012] It should be noted that in the prior art, the process of preparing a lithium ion battery negative electrode material phosphorus-carbon composite mainly adopts a ball milling method, which is complicated to operate and uses a ball mill device with a large weight and volume. The preparation method described in the present application can obtain a phosphorus-carbon-silver composite material with higher purity. The preparation steps of the composite material are simple, which can not only improve the production efficiency, but also does not require the use of heavy equipment such as a ball mill, and is more suitable for industrialization.

[0013] On the other hand, the ball milling method is a physical mixing method, which is easy to introduce dust and impurities caused by abrasion of the grinding balls. The preparation method described in the present application avoids this problem, and the purity of the mixed solution is higher, which is beneficial to ensure the quality and electrochemical performance of the prepared phosphorus-carbon-silver composite material.

[0014] Further, in step S2, the temperature of the solvothermal reaction is 60-140℃, and the time is 3-24h.

[0015] The temperature can be specifically 60-140℃, 70-140℃, 80-140℃, 90-140℃, 100-140℃, 110-140℃, 120-140℃, or 130-140℃.

[0016] The time can be specifically 3-4h, 3-6h, 3-8h, 3-10h, 3-12h, 3-14h, 3-16h, 3-18h, 3-20h, or 3-24h.

[0017] It should be noted that controlling the temperature and time of the solvothermal reaction within the above range is beneficial to uniformly modifying Ag nanoparticles to the surface of the material to improve the electrical conductivity of the phosphorus-carbon-silver composite material, and is also beneficial to forming a cross-linked structure between the carbon material and the black phosphorus to inhibit the volume expansion of the black phosphorus during the cycling process, thereby preparing a phosphorus-carbon-silver composite material with excellent electrochemical performance.

[0018] If the reaction temperature is lower than 60℃, it may result in poor reaction effect and affect the performance of the prepared composite material. If the reaction temperature is higher than 140℃, the rapid volatilization of the solvent at high temperature may accelerate the volatilization of the reducing agent, resulting in a decrease in the reducing agent in the reaction system and affecting the uniformity of the reaction. In addition, some reactants or solvents may decompose at a temperature exceeding their thermal stability, producing by-products, affecting the purity of the material, and even causing damage to the structure of the material.

[0019] Preferably, in step S2, the reaction temperature of the solvothermal reaction is 100-140℃, and the time is 3-10h.

[0020] It should be noted that in the prior art, the ball milling method is mainly used in the process of preparing the lithium ion battery negative electrode material phosphorus-carbon composite, which is complicated and needs 12-24h of ball milling time, and the efficiency is low.

[0021] In the preparation method, the compounding of the composite material only needs 10h or less, greatly improving the production efficiency and being conducive to industrialization.

[0022] Further, in step S1, the mass ratio of silver to black phosphorus in the silver source is 1:10-1:1.

[0023] Further, in step S1, the mass ratio of the carbon material to black phosphorus is 1:10-1:1.

[0024] Further, in step S1, the mass ratio of the reducing agent to black phosphorus is 10:1-100:1.

[0025] It should be noted that controlling the mass ratio of the silver source to black phosphorus, the carbon material to black phosphorus, and the reducing agent to black phosphorus within the above range is conducive to controlling the reduction of silver ions to generate Ag nanoparticles and uniformly modifying the surface of the carbon material to improve the conductivity, and is also conducive to forming a cross-linked structure between the carbon material and black phosphorus to inhibit the volume expansion and volume change during the cycling process of black phosphorus, so that the prepared phosphorus-carbon-silver composite material has excellent electrochemical properties such as electrical conductivity, charge-discharge cycling, and rate performance.

[0026] Further, in step S1, the carbon material includes one, two, or two or more of carbon nanotubes, carbon black, and graphite powder.

[0027] Further, in step S1, the silver source includes one or both of silver nitrate and silver fluoride.

[0028] Further, the silver source is added in the form of an aqueous silver nitrate solution, a silver ammonia solution, or an aqueous silver fluoride solution.

[0029] It should be noted that the silver source has good solubility in the above solution, and adding the silver source in the form of the above solution can improve the dispersibility of the silver source in the mixed solution, so that the silver ions are fully reduced and the distribution of the Ag nanoparticles obtained by reduction is more uniform.

[0030] Further, the molar concentration of silver in the aqueous silver nitrate solution, the silver ammonia solution, or the aqueous silver fluoride solution is 0.01-0.1mol / L.

[0031] It should be noted that controlling the molar concentration of silver in the silver nitrate aqueous solution, silver ammine solution or silver fluoride aqueous solution in the above range is conducive to reducing silver ions to Ag nanoparticles under the temperature and conditions of the above solvothermal reaction and reducing the occurrence of side reactions.

[0032] Preferably, the silver nitrate aqueous solution is prepared and used immediately.

[0033] Further, in step S1, the reducing agent includes one or both of N,N-dimethylformamide (DMF) and sodium borohydride.

[0034] It should be noted that DMF has good solubility and affinity for a variety of substances, can mix carbon materials, silver sources and black phosphorus to form a uniform slurry, avoiding agglomeration; can also promote the reduction of metallic silver ions through a reduction reaction, acting as a reducing agent; and forms good interactions with carbon materials, etc., which is conducive to preparing phosphorus-carbon-silver composite materials with excellent electrochemical properties such as electrical conductivity and cycle performance.

[0035] For example, when the reducing agent is sodium borohydride, the silver source can be in the form of a silver nitrate aqueous solution, silver ammine solution or silver fluoride aqueous solution.

[0036] Further, in step S1, the black phosphorus includes one, two or more of black phosphorus nanosheets, black phosphorus quantum dots and black phosphorus powder.

[0037] It should be noted that the above black phosphorus material can form a cross-linked structure with the above carbon material. Black phosphorus has a high theoretical specific capacity and can provide more charge storage sites; has a certain electronic conductivity, which helps to improve the electrical conductivity of the composite material and reduce the resistance during battery charging and discharging.

[0038] Further, in step S1, the pH value of the mixed solution is also adjusted to 5.4-6.4.

[0039] It should be noted that adjusting the pH value to 5.4-6.4 is conducive to improving the dispersibility of the carbon material in the reducing agent, such as DMF, maintaining the stability of the carbon material, and promoting the interaction and combination of the carbon material with silver nanoparticles and black phosphorus, so as to improve the electrical conductivity and charge-discharge cycle and rate performance of the phosphorus-carbon-silver composite material.

[0040] Further, nitric acid can be used to adjust the pH value to 5.4-6.4.

[0041] For example, the pH value can be adjusted to 5.4-6.4 after the mixed solution is prepared.

[0042] Preferably, in step S1, the carbon material is carbon nanotubes, the silver source is silver nitrate, the black phosphorus is black phosphorus nanosheets, and the reducing agent is DMF.

[0043] It should be noted that, based on the reduction reaction of silver nitrate and DMF (reducing agent), the Ag nanoparticles are uniformly modified to the surface of the CNT, which can improve the conductivity of the composite material, and the addition of CNT can fix the cross-linked black phosphorus nanosheet to construct a phosphorus-carbon composite structure, that is, form a cross-linked structure, which inhibits the volume expansion and volume change in the black phosphorus cycle process, and improves the charge-discharge cycle and rate performance of the composite material.

[0044] On the other hand, the black phosphorus nanosheet can be compounded with metal silver, which can improve the energy density and power density of the battery.

[0045] Further, step S1 is specifically:

[0046] The carbon material is added to the reducing agent and stirred uniformly, and the pH value is adjusted to 5.4-6.4;

[0047] Then, the silver source is added and stirred for 30-60 min;

[0048] Then, the black phosphorus is added and stirred until it is uniformly dispersed.

[0049] Further, the stirring can be magnetic stirring.

[0050] Further, in step S2, the post-treatment is further included after the solvothermal reaction.

[0051] The post-treatment includes cooling, washing and drying in sequence.

[0052] It should be noted that the cooling process in the post-treatment helps to stabilize the composite material to maintain good performance; the purpose of washing is to remove the surface-attached residues to improve the purity of the material, which is beneficial to the subsequent use of the material to prepare a battery negative electrode; and the purpose of the drying process is to remove the solvent to prevent the residual solvent from affecting the application effect of the material.

[0053] Further, the cooling can be cooling to room temperature.

[0054] The washing can be washing with ethanol and acetone.

[0055] The drying temperature is 80-150 DEG C, and the time is 30 min-60 min.

[0056] The drying can be vacuum drying.

[0057] The application also provides a phosphorus-carbon-silver composite material prepared by the preparation method of the above-mentioned phosphorus-carbon-silver composite material.

[0058] Further, the phosphorus-carbon-silver composite material comprises black phosphorus, carbon material and silver nanoparticles,

[0059] The silver nanoparticles are attached to the surface of the carbon material, and the black phosphorus forms a cross-linked structure with the carbon material.

[0060] It should be noted that in the phosphorus-carbon-silver composite material, the silver nanoparticles are uniformly attached to the surface of the carbon material, which improves the conductivity of the composite material; wherein "the silver nanoparticles are uniformly attached to the surface of the carbon material" means that on the carbon nanotube, the arrangement of the silver nanoparticles presents a relatively dispersed and consistent particle size state, that is, the spacing, density or quantity distribution between the particles has no significant local deviation or aggregation phenomenon;

[0061] A phosphorus-carbon composite structure is also constructed, the carbon material plays a fixing and cross-linking role on the black phosphorus, forming a cross-linked structure, which can obviously alleviate the volume change of the black phosphorus during the charging and discharging process of the battery.

[0062] Further, the particle size of the silver nanoparticles is 10-100 nm.

[0063] It should be noted that the particle size of the silver nanoparticles is within the above range, which is conducive to the composite material having excellent conductivity; and is also conducive to improving the structural stability of the composite material.

[0064] The application also provides a lithium ion battery negative electrode, the negative electrode comprising the phosphorus-carbon-silver composite material prepared by the above preparation method or the phosphorus-carbon-silver composite material.

[0065] It should be noted that due to the phosphorus-carbon-silver composite material, the lithium ion battery negative electrode has excellent electrical conductivity, charging and discharging cycle and rate performance.

[0066] 3. Beneficial effects

[0067] Compared with the prior art, the beneficial effects of the application are:

[0068] (1) The phosphorus-carbon-silver composite material provided by the application is prepared by a solvothermal method, which has the advantages of mild reaction conditions, simple operation, simple equipment and easy scaling up compared with traditional ball milling processes.

[0069] (2) The phosphorus-carbon-silver composite material provided by the application introduces silver nanoparticles, which helps to improve the conductivity of the composite material, and a phosphorus-carbon composite structure is also constructed, the carbon material plays a fixing role on the black phosphorus, forming a cross-linked structure, which inhibits the volume expansion of the black phosphorus during the cycling process, so that it has excellent charging and discharging cycle and rate performance of the electrochemical performance. BRIEF DESCRIPTION OF DRAWINGS

[0070] Figure 1 is a TEM image of the Ag-CNT-BP composite material 1 in Example 1 of the application;

[0071] Figure 2 is a TEM image of Ag-CNT-BP composite 1 in Example 1 of the present invention;

[0072] Figure 3 is an X-ray diffraction pattern of Ag-CNT-BP composite 1 in Example 1 of the present invention;

[0073] Figure 4 is a graph of electrochemical cycling performance of lithium ion half-cell assembled with Ag-CNT-BP composite 1 in Example 1 of the present invention;

[0074] Figure 5 is a graph of electrochemical rate capability of lithium ion half-cell assembled with Ag-CNT-BP composite 1 in Example 1 of the present invention. DETAILED DESCRIPTION

[0075] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains; the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0076] As used herein, the term "about" is used to provide flexibility to a numerical range endpoint by providing support for a somewhat greater or lesser inclusion of the numerical value as explicitly stated or reasonably to be expected within the production and testing of the invention. The extent to which concreteness is relaxed is dependent on the discernability of the numerical values to be modified.

[0077] As used herein, the term "one, two or more of A, B, or C" explicitly includes only A, only B, only C, and their respective combinations.

[0078] Concentrations, amounts, and other numerical data can be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be construed as having been followed to the rightmost significant figure of the numerical value that immediately precedes such range format. However, this range format is not to be construed as a representation that the numerical values are continuous within the stated range. To the contrary, specific numerical values within the described range are specifically contemplated in this disclosure. The stated range format will thus only be used for the sake of brevity.

[0079] The application will be further described in connection with specific examples. The following examples are only some of the embodiments of the application, but not all. Unless otherwise specified, all the devices and raw materials in the application are commercially available goods commonly used in the art. Unless otherwise specified, the methods in the examples are conventional methods in the art.

[0080] Unless otherwise specified, the specific conditions in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are conventional products that can be commercially available.

[0081] In the embodiments of the application, the CNT is a C301993 product purchased from Aldrich Company; the DMF is a D112004 product purchased from Aldrich Company; and the BP nanosheet (black phosphorus nanosheet) is an XF2077723-14-0 product purchased from Xianfeng Nanometer Company.

[0082] Example 1

[0083] The embodiment provides a preparation method of an Ag-CNT-BP composite material, which comprises the following steps.

[0084] 100 mL of deionized water was added to a 200 mL small beaker, and 1.6987 g of AgNO3 was added while being magnetically stirred by a magnetic stirrer, and stirred until completely dissolved to obtain a colorless and uniform silver nitrate solution (0.1 mol / L).

[0085] 0.5 g of CNT was added to 260 mL of DMF, and then stirred, and the pH value was adjusted to 6.0 by nitric acid (nitric acid, 0.01 mol / L). Then 100 mL of the silver nitrate solution (0.1 mol / L) was added, and the whole process was kept stirring, and 3.5 g of BP nanosheet was added after stirring and dispersing for 30 min, and the stirring was continued until the dispersion was uniform. The uniformly dispersed mixed solution was reacted at 120℃ for 12 h, and after the reaction was completed, it was naturally cooled to room temperature, washed with anhydrous ethanol, and the remaining solid was dried at 80℃ under vacuum for 30 min to obtain the Ag-CNT-BP composite material 1.

[0086] Example 2

[0087] The embodiment provides a preparation method of an Ag-CNT-BP composite material, which comprises the following steps.

[0088] The preparation method of the Ag-CNT-BP composite material in the embodiment is basically the same as that in example 1, and the difference is that the mixed solution is reacted at 80℃ for 6 h.

[0089] Finally, the Ag-CNT-BP composite material 2 is obtained.

[0090] Example 3

[0091] The present embodiment provides a preparation method of an Ag-CNT-BP composite material, comprising the following steps:

[0092] The preparation method of the Ag-CNT-BP composite material in the present embodiment is basically the same as that in Example 1, and the only difference is that the mixed solution is reacted at 60°C for 3h.

[0093] Finally, Ag-CNT-BP composite material 3 is obtained.

[0094] Comparative Example 1

[0095] The present embodiment provides a preparation method of a CNT-BP composite material, comprising the following steps:

[0096] 0.5g of CNT was added to 260mL of DMF, and then stirring treatment was performed, after stirring and dispersing for 30min, 3.5g of BP nanosheet was added, and stirring was continued until uniform dispersion. The uniformly dispersed mixed solution was reacted at 120°C for 12h, after the reaction was completed, it was naturally cooled to room temperature, washed with anhydrous ethanol, and the remaining solid was vacuum dried at 80°C for 30min to obtain the CNT-BP composite material.

[0097] The Ag-CNT-BP composite material 1 prepared in Example 1 was subjected to TEM and XRD characterization. The obtained TEM image is shown in Figure 1 、 Figure 2 , wherein the black sheet is the black phosphorus nanosheet, the granular elemental Ag, and the tubular CNT. As can be seen from Figure 1 , the elemental silver is in the form of granules with uniform particle size, and is loaded on the surface of CNT. At the same time, CNT plays a crosslinking role on the black phosphorus nanosheet. As can be seen from the figure, the distribution of elemental silver in the material is uniform. Figure 3 The XRD pattern of the Ag-BP-CNT composite material 1 of Example 1, as can be seen from the diffraction peaks in the figure, there are no other impurity peaks in the material except for BP, elemental silver and CNT, which proves that the purity of the Ag-CNT-BP composite material 1 is very high.

[0098] The composite material prepared in the above examples and comparative examples was used as an active material, and the active material, conductive carbon black, and polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 8:1:1 in a mortar, and then a proper amount of NMP was added and stirred by a homogenizer to obtain a mixed slurry. After coating and rolling by a small coater and a roller, the slurry was dried in a vacuum drying box at 80°C for 12 h, and then sliced by a slicer. The negative electrode sheet was assembled into a lithium ion half battery with a polypropylene (PP) separator, a battery shell CR2032 type button cell shell, metallic lithium, and an electrolyte (1M LiPF6 dissolved in EC:DEC:FEC:VC = 1:1:1:1 (volume ratio)). The cycle and rate performance were tested at room temperature, and the test results are shown in Table 1.

[0099] In combination Figure 4 , when the Ag-CNT-BP composite material 1 of Example 1 was used as a negative electrode material to assemble a lithium ion half battery, the battery had a first circle discharge specific capacity of 1901.6 mAh / g, a charge specific capacity of 1433.4 mAh / g, a first circle coulombic efficiency of 75.4%, a capacity retention rate of 77.2% after 60 cycles, and a coulombic efficiency of 99.2%.

[0100] When the Ag-CNT-BP composite material 1 of Example 1 was used as a negative electrode active material to assemble a lithium ion half battery, the battery had a charge specific capacity of 1106.9 mAh / g after 60 cycles at a current density of 1.0 A / g, and a capacity retention rate of 77.2%, indicating that it had good cycle performance.

[0101] The CNT-BP composite material in Comparative Example 1 was prepared by the same steps as above except that silver nitrate was not added. However, the discharge specific capacity of the CNT-BP composite material prepared in Comparative Example 1 was only 574.3 mAh / g, and the charge specific capacity was only 577.2 mAh / g after 60 cycles at a current density of 1.0 A / g, indicating that the Ag nanoparticles effectively improved the electrochemical performance of the phosphorus-carbon-silver composite material.

[0102] In addition, in combination Figure 5 When the composite material of Example 1 was used as a negative electrode active material to assemble a lithium ion half battery, the battery could be charged and discharged at a current density of 0.2-4.0 A / g, and the specific capacity at 4.0 A / g was 373.6 mAh / g, indicating that the Ag-CNT-BP composite material had excellent rate performance. This may be due to the good combination of Ag-CNT and black phosphorus, which improves the conductivity of black phosphorus and effectively suppresses the volume expansion of black phosphorus during charging and discharging.

[0103] In addition, the cycle and rate performance of the Ag-CNT-BP composite 2 and the Ag-CNT-BP composite 3 in Example 2 and Example 3 are lower than that of the Ag-CNT-BP composite 1, which can be due to the incomplete reaction of silver nitrate caused by the reduction in temperature and time of the reduction reaction, and the less silver nanoparticles attached on the CNT, resulting in the decrease of the electrochemical performance of the Ag-CNT-BP composite. Example 2

[0104] Table 1 Performance test of the composite in the examples and comparative examples

[0105]

[0106] Note: The test conditions of the above first cycle discharge specific capacity are: current density: 1.0 A / g; test voltage 0.1-2.5 V.

[0107] The test conditions of the above first cycle charge specific capacity are: current density: 1.0 A / g; test voltage 0.1-2.5 V.

[0108] The test conditions of the above cycle discharge specific capacity are: cycle number: 60 cycles; current density: 1.0 A / g; test voltage 0.1-2.5 V.

[0109] The test conditions of the above cycle charge specific capacity are: cycle number: 60 cycles; current density: 1.0 A / g; test voltage 0.1-2.5 V.

[0110] The above is a schematic description of the present application and its embodiments, which is not restrictive, and the embodiments shown in the examples are only one of the embodiments of the present application, and the actual embodiments are not limited thereto. Therefore, if a person skilled in the art is inspired by it, without departing from the purpose of the present application, similar embodiments and examples of the technical solution can be designed without creativity, which should belong to the protection scope of the present application.

Claims

1. A phosphor carbon Method for the production of a silver composite material, characterized in that S1. preparing a mixed solution containing carbon material, silver source, black phosphorus, reducing agent; S2. subjecting the mixture to a solvothermal reaction to obtain phosphorus carbon silver composites; In step S2, the temperature of the solvothermal reaction is 60-140℃, and the time is 3-24h. In step S1, the mass ratio of the carbon material to the black phosphorus is 1:10-1:

1. The mass ratio of silver to black phosphorus in the silver source is 1:10-1:

1. The mass ratio of the reducing agent to black phosphorus is 10:1-100:

1. The phosphor Carbon The silver composite material comprises black phosphor, carbon material and silver nanoparticles, the silver nanoparticles are attached to the surface of the carbon material, and the black phosphor forms a crosslinked structure with the carbon material. The carbon material is carbon nanotube; the black phosphorus is black phosphorus nanosheet; and the silver nanoparticles are generated by reduction of silver ions.

2. The phosphor of claim 1 carbon Process for the production of silver composites, characterized in that: In step S1, the silver source includes one or both of silver nitrate and silver fluoride. The reducing agent includes one or both of N,N dimethylformamide, sodium borohydride.

3. The phosphor of claim 2 carbon Process for the production of silver composites, characterized in that: In step S1, the pH value of the mixed solution is adjusted to 5.4-6.

4.

4. The phosphor of claim 1 carbon Process for the production of silver composites, characterized in that: In step S1, the silver source is silver nitrate, and the reducing agent is DMF.

5. phosphorus carbon a silver composite, characterized in that The phosphorus according to any one of claims 1 to 4 Carbon The silver composite material is prepared by the preparation method.

6. The phosphor of claim 5 carbon Silver composite material, characterized in that: The particle size of the silver nanoparticles is 10-100nm.

7. A lithium-ion battery anode, characterized by: The negative electrode comprises the phosphor as claimed in any one of claims 5 to 6 Carbon Silver composites.

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