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

Abstract

The application belongs to the technical field of ion batteries, and particularly relates to a lead-carbon composite material and a preparation method and application thereof. The preparation method comprises the following steps: grinding and tabletting a lead source and a carbon source, and roasting the tabletted tablet to obtain the lead-carbon composite material; the lead source comprises at least one of lead citrate, lead acetate, lead chloride and lead oxalate; and the carbon source comprises at least one of polyvinylpyrrolidone, carboxymethyl cellulose, glucose and sucrose. The lead-carbon composite material has a three-dimensional porous structure formed by metal lead particles embedded in a carbon skeleton, and the carbon skeleton can effectively alleviate the volume expansion generated in the alloying process of metal lead and metal sodium in the charging and discharging process, so as to improve the conductivity and electrochemical performance of the material.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ion batteries, and particularly relates to a lead-carbon composite material and a preparation method and application thereof. BACKGROUND

[0002] The information disclosed in this Background section is for the purpose of increasing the understanding of the background of the present application and therefore it not to be taken as an acknowledgement or any form of suggestion that it forms prior art of any form to the present application.

[0003] Sodium-ion batteries are considered as the most potential substitutes for lithium-ion batteries due to their abundant resources, low price and high energy density, and have attracted extensive attention and research in recent years. The negative electrode material is responsible for providing a low potential redox couple, which is very important in battery applications. At present, the negative electrode materials of sodium-ion batteries mainly include carbon-based, titanium-based organic and alloy-based negative electrode materials. The common carbon-based materials have poor sodium storage performance, and the titanium-based compound organic materials have low capacity, which results in low energy density of the battery; and the alloy-based materials have attracted extensive attention due to their high specific capacity and relatively low reaction electrode potential. Among them, lead has a low potential (about 0.1 V) and a high specific capacity and density. However, before and after the sodium is deintercalated, the material has a large volume change, which leads to material pulverization and loss of point contact with the current collector, thereby causing the specific capacity of the battery to rapidly decay at a large rate and the cycle performance to be poor. SUMMARY

[0004] In order to solve the problems in the prior art, the present application provides a lead-carbon composite material and a preparation method and application thereof. The lead-carbon composite material has a three-dimensional porous structure formed by metal lead particles embedded in a carbon skeleton, and the carbon skeleton can effectively alleviate the volume expansion caused by the alloying process of metal lead and metal sodium during the charging and discharging process, thereby improving the electrical conductivity and electrochemical performance of the material.

[0005] In order to achieve the above-mentioned purpose, the present application is realized by the following technical scheme:

[0006] In a first aspect, the present application provides a preparation method of a lead-carbon composite material, comprising the following steps:

[0007] Grinding and tabletting a lead source and a carbon source, and then roasting the tabletted piece to obtain the lead-carbon composite material;

[0008] The lead source comprises at least one of lead citrate, lead acetate, lead chloride and lead oxalate;

[0009] The carbon source comprises at least one of polyvinylpyrrolidone, carboxymethyl cellulose, glucose and sucrose.

[0010] In a second aspect, the present application provides a lead-carbon composite material, which is obtained by the preparation method as described in the first aspect, and has a three-dimensional porous structure formed by embedding metal lead particles in a carbon skeleton.

[0011] In a third aspect, the present application provides an application of the lead-carbon composite material as described in the second aspect in preparing a sodium ion battery.

[0012] In a fourth aspect, the present application provides a sodium ion battery negative material, wherein the active component of the sodium ion battery negative material is the lead-carbon composite material as described in the second aspect.

[0013] In a fifth aspect, the present application provides a sodium ion battery, which comprises the sodium ion battery negative material as described in the fourth aspect.

[0014] The beneficial effects achieved by one or more technical solutions of the present application are as follows:

[0015] In the present application, the lead source and the carbon source are uniformly ground according to different weight ratios and pressed into a sheet. The carbon source wrapped on the generated lead particles can effectively prevent the product from self-igniting in the air after calcination. In addition, the carbon source has a binding effect, which can effectively bind the materials together during the carbonization process to form a three-dimensional porous structure. At the same time, the in-situ carbon-coated lead nanoparticles provide an effective buffer layer for the volume expansion of the active material, improving the electrical conductivity of the material. The lead-carbon composite material as the sodium ion battery negative material has superior rate performance and cycle stability.

[0016] The preparation method of the present application is simple and practical, easy to popularize, and the sheet pressing can not only prevent the powder from flying during calcination to reduce pollution, but also increase the material yield. Therefore, the present application has application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0017] The drawings constituting a part of the specification of the present application are used to provide further understanding of the present application, and the schematic embodiments of the present application and the description thereof are used to explain the present application, and do not constitute an improper limitation on the present application.

[0018] Figure 1 XRD of the lead-carbon composite material prepared for the present application embodiment 1;

[0019] Figure 2 SEM of the lead-carbon composite material prepared for the present application embodiment 1;

[0020] Figure 3 SEM of the lead-carbon composite material prepared for the present application embodiment 1;

[0021] Figure 4The rate performance test chart of the lead-carbon composite material prepared in Example 1 of the present application as a negative material of a sodium ion battery;

[0022] Figure 5 The cycle performance test chart of the lead-carbon composite material prepared in Example 1 of the present application as a negative material of a sodium ion battery;

[0023] Figure 6 The actual photo of the lead material prepared in Comparative Example 1 of the present application;

[0024] Figure 7 The SEM of the lead material prepared in Comparative Example 1 of the present application in partial enlargement;

[0025] Figure 8 The SEM of the lead material prepared in Comparative Example 1 of the present application;

[0026] Figure 9 The rate performance test chart of the lead material prepared in Comparative Example 1 of the present application as a negative material of a sodium ion battery. DETAILED DESCRIPTION

[0027] In a first typical embodiment of the present application, a preparation method of a lead-carbon composite material comprises the following steps:

[0028] The lead source and the carbon source are ground and pressed into a tablet, and the pressed tablet is calcined to obtain the lead-carbon composite material;

[0029] The lead source comprises at least one of lead citrate, lead acetate, lead chloride and lead oxalate;

[0030] The carbon source comprises at least one of polyvinylpyrrolidone, carboxymethyl cellulose, glucose and sucrose.

[0031] The addition of the carbon source effectively prevents the self-ignition of the lead salt after high-temperature calcination in air and reduces the volatilization of lead. After the alloy negative electrode is compounded with the carbon material, the carbon skeleton can effectively alleviate the volume expansion generated in the alloying process of metal lead and metal sodium, thereby improving the electrical conductivity and electrochemical performance of the material.

[0032] In one or more embodiments of the embodiment, the mass ratio of the lead source to the carbon source is 1-5:1.

[0033] In one or more embodiments of the embodiment, the tablet pressing pressure is 5-10 MPa, and the time is 5-10 min.

[0034] In one or more embodiments of the embodiment, the calcination temperature is 800-1300℃, and the calcination holding time is 0.5-5 h.

[0035] In one or more embodiments of the embodiment, the calcination is carried out in an inert atmosphere.

[0036] In one or more embodiments of this embodiment, the inert atmosphere comprises a nitrogen atmosphere or an argon atmosphere.

[0037] In a second typical embodiment of the present application, a lead-carbon composite material is obtained by the preparation method as described in the first typical embodiment, and the lead-carbon composite material has a three-dimensional porous structure formed by embedding metal lead particles in a carbon skeleton.

[0038] In a third typical embodiment of the present application, the application of the lead-carbon composite material as described in the second typical embodiment in the preparation of a sodium ion battery.

[0039] In a fourth typical embodiment of the present application, a sodium ion battery negative electrode material, and the active component of the sodium ion battery negative electrode material is the lead-carbon composite material as described in the second typical embodiment.

[0040] In a fifth typical embodiment of the present application, a sodium ion battery, characterized in that the sodium ion battery comprises the sodium ion battery negative electrode material as described in the fourth typical embodiment.

[0041] In order to enable those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in combination with specific examples and comparative examples.

[0042] Example 1

[0043] 1) Preparation method of lead-carbon composite material

[0044] Step 1: uniformly grind 0.3 g of lead citrate and 0.075 g of PVP to obtain a uniform powder.

[0045] Step 2: transfer the uniform powder obtained in step 1 into a stainless steel tablet press mold, the pressure range is 5-10 MPa, and the pressure is maintained for 5-10 min. Take out the pressed tablet in the mold.

[0046] Step 3: after weighing the tablet pressed in step 2, place the tablet in a porcelain boat, heat it to 1000℃ at a rate of 2℃ / min under an argon atmosphere, maintain the temperature for 1 h, take it out after natural cooling, and grind it to obtain a lead-carbon composite material, which is denoted as Pb@C.

[0047] As shown in Figure 1 , the XRD pattern of the lead-carbon composite material shows a diffraction peak of Pb, indicating that metal lead is successfully loaded on the lead-carbon composite material. As shown in Figure 2 and Figure 3As shown in FIG. 1, SEM observation shows that the lead-carbon composite material presents a three-dimensional porous structure, and the metal lead particles are uniformly distributed on the surface and inside the carbon framework. When the metal lead is used as the negative electrode in a sodium ion battery, an alloying reaction occurs, the volume expands, and the material is prone to pulverization. Therefore, when the material is subjected to rapid charging and discharging at a large rate, the material undergoes a large volume expansion, rapidly generates a large stress, and causes the material to pulverize and fall off, losing point contact with the current collector, resulting in poor large-rate performance. The introduction of the carbon framework can not only improve the electrical conductivity of the material, but also effectively alleviate the volume expansion of lead during the alloying process, maintain the overall framework and morphology of the material, maintain good electrical conductivity, and effectively improve the large-rate performance of the battery.

[0048] 2) Electrochemical performance test method

[0049] The lead-carbon composite material prepared in Experimental Example 1 was used as the negative active material of the sodium ion battery, polyvinylidene fluoride (PVDF) was used as the binder, Super P was used as the conductive agent, and N-methyl pyrrolidone (NMP) was used as the solvent. The mass ratio of the active material, the binder, and Super P was 8:1:1, and a uniform slurry was formed, which was coated on a copper foil and placed in a vacuum drying box at 80°C for 12 hours, and then cut into an electrode sheet with a diameter of 14 mm. Metallic sodium was used as the working electrode, 1M NaPF6 was dissolved in ethylene glycol dimethyl ether (DME) (100vol%) to form an electrolyte, and a 2032-type sodium ion battery was assembled in an argon-filled glove box, and then tested after standing for 12 hours. The voltage range was 0.01-1.5V.

[0050] As shown in FIG. 2, the rate test results show that the lead-carbon composite material as the negative electrode material of the sodium ion battery exhibits excellent performance and stability at different charging and discharging current densities, and the specific capacity can reach 350mAh / g, and the coulombic efficiency is stable at about 99%. As shown in FIG. 3, the specific capacity and coulombic efficiency of the lead-carbon composite material do not decrease after 300 cycles at a current density of 1A / g. Therefore, the carbon framework provides an effective buffer layer for the volume expansion of the active material, and also improves the electrical conductivity of the material, so that the prepared lead-carbon composite material has excellent rate performance and cycle stability. Figure 4 Figure 5 As shown in FIG. 2, the rate test results show that the lead-carbon composite material as the negative electrode material of the sodium ion battery exhibits excellent performance and stability at different charging and discharging current densities, and the specific capacity can reach 350mAh / g, and the coulombic efficiency is stable at about 99%. As shown in FIG. 3, the specific capacity and coulombic efficiency of the lead-carbon composite material do not decrease after 300 cycles at a current density of 1A / g. Therefore, the carbon framework provides an effective buffer layer for the volume expansion of the active material, and also improves the electrical conductivity of the material, so that the prepared lead-carbon composite material has excellent rate performance and cycle stability.

[0051] Example 2

[0052] The difference from Example 1 is that the temperature in step 3 of the preparation method of the lead-carbon composite material is raised to 800°C.

[0053] Example 3

[0054] The difference from Example 1 is that the temperature in step 3 of the preparation method of the lead-carbon composite material is raised to 1300°C.

[0055] Example 4 ​

[0056] The difference from Example 1 is that the holding time in step 3 of the preparation method of the lead-carbon composite material is 0.5 h.

[0057] Example 5

[0058] The difference from Example 1 is that the holding time in step 3 of the preparation method of the lead-carbon composite material is 5 h.

[0059] Comparative Example 1

[0060] The difference from Example 1 is that no PVP is added as a carbon source, and no tabletting treatment is performed, to obtain a lead material. As shown in FIG. 1, without the addition of a carbon source, the lead source self-ignites to generate yellow PbO. Figure 6

[0061] As shown in FIG. 2 and FIG. 3, although the organic acid radical provides a basic carbon framework after calcination, and has a certain coating and dispersion effect on lead, the morphology of the lead material prepared in this comparative example is an unordered granular accumulation morphology, and the lead particles are accumulated and adhered. Figure 7 Figure 8 As shown in FIG. 4, when the lead material is subjected to a rate test as a negative electrode material for a sodium ion battery, the specific capacity at different current densities decreases with the number of cycles, and the coulombic efficiency cannot be stabilized, indicating that the material cannot avoid the volume expansion and structural damage caused by alloying, and has poor stability.

[0062] As shown in FIG. 4, when the lead material is subjected to a rate test as a negative electrode material for a sodium ion battery, the specific capacity at different current densities decreases with the number of cycles, and the coulombic efficiency cannot be stabilized, indicating that the material cannot avoid the volume expansion and structural damage caused by alloying, and has poor stability. Figure 9

[0063] The above only describes preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.​​​

Claims

1. A method for producing a lead-carbon composite material, characterized by, The method comprises the following steps: Grinding and tabletting a lead source and a carbon source, and roasting the tablet to obtain a lead-carbon composite material; The lead source comprises at least one of lead citrate, lead acetate, lead chloride and lead oxalate; The carbon source comprises at least one of polyvinylpyrrolidone, carboxymethyl cellulose, glucose and sucrose.

2. The production method according to claim 1, wherein The mass ratio of the lead source to the carbon source is 1-5:

1.

3. The production method according to claim 1, wherein The tabletting pressure is 5-10 MPa, and the tabletting time is 5-10 min.

4. The production method according to claim 1, wherein The roasting temperature is 800-1300 ℃, and the roasting holding time is 0.5-5 h.

5. The production method according to claim 1, wherein The roasting is performed in an inert atmosphere.

6. The production method according to claim 5, wherein The inert atmosphere comprises a nitrogen atmosphere or an argon atmosphere.

7. A lead-carbon composite material, characterized by, The lead-carbon composite material obtained by the preparation method of any one of claims 1-6 has a three-dimensional porous structure formed by metal lead particles embedded in a carbon skeleton.

8. Use of the lead-carbon composite material of claim 7 in the preparation of a sodium ion battery.

9. A sodium-ion battery anode material, characterized in that, The active component of the sodium ion battery negative electrode material is the lead-carbon composite material of claim 7.

10. A sodium-ion battery, characterized in that, The sodium ion battery comprises the sodium ion battery negative electrode material of claim 9.

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