A method for preparing a silver nanoparticle-containing positive electrode material for lithium-carbon fluoride batteries

Abstract

The application discloses a preparation method of silver nanoparticle-containing positive electrode material for lithium carbon fluoride batteries, and belongs to the technical field of lithium carbon fluoride batteries. The preparation method of the silver nanoparticle-containing positive electrode material comprises the following steps: dispersing carbon fluoride in a solvent, then adding silver salt, uniformly stirring, and continuously stirring under ultraviolet light to obtain silver nanoparticle-modified carbon fluoride material; adding a binder into water, uniformly stirring, then adding a mixture of the silver nanoparticle-modified carbon fluoride material and carbon material, uniformly stirring, and wet grinding to obtain a mixed slurry; coating and drying the mixed slurry to obtain the silver nanoparticle-containing positive electrode material. The silver nanoparticle-containing positive electrode material can be used for preparing lithium carbon fluoride batteries, and can effectively improve the performance of the lithium carbon fluoride batteries.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium-carbon fluoride batteries, in particular to a preparation method of a silver nanoparticle-containing positive electrode material for lithium-carbon fluoride batteries. BACKGROUND

[0002] Lithium-carbon fluoride batteries are a new type of lithium-ion battery, also known as Li-CFx batteries, which use carbon fluoride (CFx) as the positive electrode material, lithium metal or graphite as the negative electrode material, and lithium salt solution as the electrolyte. The advantages of lithium-carbon fluoride batteries include high energy density, longer cycle life, lower self-discharge rate, and wider operating temperature range, etc., and have wide application prospects in some specific application fields such as medical devices, sensors, and wireless devices. However, lithium-carbon fluoride batteries also have some challenges such as high cost, capacity decay, and safety issues, which need further research and improvement. The porous thick positive electrode material obtained by research can effectively improve the overall energy density of lithium-carbon fluoride batteries at high rates, but at high rates, the rate performance of lithium-carbon fluoride soft-pack batteries prepared by thick electrodes will decrease. SUMMARY

[0003] The purpose of the present application is to provide a preparation method of a silver nanoparticle-containing positive electrode material for lithium-carbon fluoride batteries to solve the problems existing in the prior art.

[0004] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0005] One of the technical solutions of the present application: a preparation method of silver nanoparticle-modified carbon fluoride material, comprising the following steps:

[0006] (1) Disperse carbon fluoride in a solvent, stir uniformly, then add silver salt, continue to stir uniformly, and obtain a mixed solution;

[0007] (2) Place the mixed solution under ultraviolet light and continue to stir, after stirring, centrifuge, wash, and repeat the steps of centrifugation and washing 3 times, and dry to obtain the silver nanoparticle-modified carbon fluoride material.

[0008] Preferably, in step (1), the stirring time is 10-60 min; the solvent is composed of ethanol and water; the mass ratio of carbon fluoride, ethanol, and water is 1:(2-5):(10-20); the silver salt includes silver nitrate; the amount of silver salt is 1-15% of the mass of carbon fluoride.

[0009] Silver nitrate can be decomposed by light, and under the irradiation of ultraviolet lamp, silver nitrate can be reduced to silver nanoparticles and uniformly deposited on carbon fluoride.

[0010] Preferably, in step (2), the stirring time is 10-60 min; the centrifugal speed is 3000-8000 r / min, and the time is 1-10 min; the drying specifically comprises: first pre-drying in a 60-100℃ air drying oven for 60-120 min, and then drying in a 60-100℃ vacuum drying oven for 480-640 min.

[0011] More preferably, the drying specifically comprises: first pre-drying in a 80℃ air drying oven for 120 min, and then drying in a 80℃ vacuum drying oven for 480 min.

[0012] The second technical solution of the present application is a silver nanoparticle modified carbon fluoride material prepared by the above preparation method.

[0013] The third technical solution of the present application is a preparation method of a silver nanoparticle containing positive electrode material for a lithium-carbon fluoride battery, comprising the following steps:

[0014] A. Put the silver nanoparticle modified carbon fluoride material and the carbon material in a mortar and grind to obtain a mixed powder of the silver nanoparticle modified carbon fluoride material and the carbon material;

[0015] B. Add the binder to water and stir uniformly, then add the mixed powder of the silver nanoparticle modified carbon fluoride material and the carbon material, continue to stir uniformly, and then wet mill to obtain a mixed slurry;

[0016] C. Dry the mixed slurry after coating on the surface of an aluminum foil to obtain the silver nanoparticle containing positive electrode material.

[0017] Preferably, in step A, the grinding time is 30-240 min.

[0018] More preferably, in step A, the grinding time is 120 min.

[0019] Preferably, in step B, the stirring speed is 200-500 r / min, and the time is 10-60 min; the continued stirring speed is 1000 r / min, and the time is 12 h.

[0020] Preferably, in step B, the wet milling time is 10-60 min.

[0021] Preferably, in step B, the mass ratio of the binder, the silver nanoparticle modified carbon fluoride material and the carbon material is (2-10):90:(5-10).

[0022] Preferably, in step C, the coating thickness is 100-500 μm, the rate is 1-10 cm / s, and the temperature is 20-60℃.

[0023] Preferably, in step C, the drying specifically includes: pre-drying in a blower drying oven at a temperature of 60-100°C for 60-120 minutes, and then drying in a vacuum drying oven at a temperature of 60-100°C for 480-640 minutes.

[0024] More preferably, in step C, the drying specifically includes: pre-drying in a forced-air drying oven at 80°C for 120 minutes, and then drying in a vacuum drying oven at 80°C for 480 minutes.

[0025] The fourth technical solution of the present invention: a silver-containing nanoparticle cathode material prepared by the above preparation method.

[0026] The fifth technical solution of the present invention: the application of the above-mentioned silver-containing nanoparticle cathode material in the preparation of lithium fluoride carbon batteries.

[0027] The present invention discloses the following technical effects:

[0028] The silver nanoparticle-containing cathode material of this invention (using silver nanoparticles to surface-modify the active material fluorinated carbon in the cathode material) can be used to prepare lithium fluorinated carbon batteries, effectively improving the performance of lithium fluorinated carbon batteries, such as conductivity, rate performance, high and low temperature discharge performance, voltage plateau during discharge, lithium-ion and electron mass transfer efficiency, and pulse resistance. Furthermore, it can effectively reduce the internal resistance of lithium fluorinated carbon batteries. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a scanning electron microscope (SEM) image of the silver nanoparticle-containing cathode material prepared in Example 1 of the present invention;

[0031] Figure 2 The discharge specific capacity curves of the lithium fluorinated carbon battery assembled with the silver nanoparticle cathode material prepared in Example 1 of the present invention at different temperatures.

[0032] Figure 3 The AC impedance electrochemical characterization test results are shown for the lithium carbon fluoride battery assembled using the silver nanoparticle cathode material prepared in Example 1 of this invention and the cathode material prepared in Example 4.

[0033] Figure 4The image shows the pulse electrochemical characterization test results of the lithium carbon fluoride battery assembled using the cathode materials prepared in Examples 1 and 4 of this invention.

[0034] Figure 5 The discharge specific capacity curves of lithium fluoride carbon batteries assembled using the cathode materials prepared in Examples 1-4 of this invention are shown at 1C.

[0035] Figure 6 The bar chart shows the discharge specific energy of lithium fluoride batteries assembled using the cathode materials prepared in Examples 1-4 of this invention. Detailed Implementation

[0036] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0037] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0039] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0040] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0041] In the following examples, "parts" refers to "parts by weight".

[0042] In a first aspect, the present invention provides a method for preparing a silver nanoparticle-modified fluorinated carbon material, comprising the following steps:

[0043] (1) Disperse fluorinated carbon in a solvent, stir until homogeneous, add silver salt, and continue stirring until homogeneous to obtain a mixed solution;

[0044] (2) Place the mixed solution under ultraviolet light and stir continuously. After stirring, centrifuge, wash, repeat the above steps 3 times, and dry to obtain silver nanoparticle-modified fluorinated carbon material.

[0045] In step (1) of the present invention, the stirring time is 10 to 60 min; the solvent is composed of ethanol and water; the mass ratio of fluorinated carbon, ethanol and water is 1:(2 to 5):(10 to 20); the silver salt includes silver nitrate; the amount of silver salt used is 1 to 15% of the mass of fluorinated carbon.

[0046] Silver nitrate decomposes when exposed to light. Under ultraviolet light, silver nitrate can be reduced to silver nanoparticles, which are then uniformly deposited on fluorinated carbon.

[0047] In step (2) of the present invention, the stirring time is 10 to 60 minutes; the centrifugation speed is 3000 to 8000 r / min and the time is 1 to 10 minutes; the drying specifically includes: first pre-drying in a forced-air drying oven at a temperature of 60 to 100°C for 60 to 120 minutes, and then placing it in a vacuum drying oven at a temperature of 60 to 100°C for 480 to 640 minutes.

[0048] The drying process in this invention specifically includes: pre-drying in a forced-air drying oven at 80°C for 120 minutes, and then drying in a vacuum drying oven at 80°C for 480 minutes.

[0049] The purpose of pre-drying followed by full drying is to prevent cracking of the materials and electrodes during the manufacturing process.

[0050] In a second aspect, the present invention provides a silver nanoparticle-modified fluorinated carbon material prepared by the above-described preparation method.

[0051] In a third aspect, the present invention provides a method for preparing a silver-containing nanoparticle cathode material for lithium fluoride carbon batteries, comprising the following steps:

[0052] A. Place the silver nanoparticle-modified fluorinated carbon material and the carbon material in a mortar and grind them to obtain a mixed powder of the silver nanoparticle-modified fluorinated carbon material and the carbon material.

[0053] B. After adding the binder to water and stirring evenly, add the above-mentioned silver nanoparticle-modified fluorinated carbon material and carbon material mixed powder, continue stirring evenly, and then wet grind to obtain a mixed slurry;

[0054] C. After coating the mixed slurry, dry it to obtain a silver-containing nanoparticle cathode material.

[0055] In step A of the present invention, the grinding time is 30 to 240 minutes, preferably 120 minutes.

[0056] The stirring speed of this invention is 200-500 r / min, and the stirring time is 10-60 min; the stirring speed is continued at 1000 r / min for 12 h.

[0057] In step B of this invention, the wet milling time is 10 to 60 minutes.

[0058] In step B of the present invention, the mass ratio of binder, silver nanoparticle-modified fluorinated carbon material and carbon material is (2-10):90:(5-10).

[0059] In step C of the present invention, the coating thickness is 100-500 μm, the coating speed is 1-10 cm / s, and the temperature is 20-60 °C.

[0060] Using the above coating parameters can prevent electrode detachment and cracking. Coating parameters outside the above range will cause electrode detachment and cracking, seriously affecting performance.

[0061] Binders can improve the stability of the slurry and prevent sedimentation during the slurry preparation process.

[0062] In step C of this invention, the drying process specifically includes: pre-drying in a forced-air drying oven at a temperature of 60–100°C for 60–120 min, and then drying in a vacuum drying oven at a temperature of 60–100°C for 480–640 min. Preferably, the drying process specifically includes: pre-drying in a forced-air drying oven at a temperature of 80°C for 120 min, and then drying in a vacuum drying oven at a temperature of 80°C for 480 min.

[0063] The purpose of pre-drying followed by full drying is to prevent cracking of the materials and electrodes during the manufacturing process.

[0064] In a fourth aspect, the present invention provides a silver-containing nanoparticle cathode material prepared by the above-described preparation method.

[0065] In a fifth aspect, the present invention provides an application of the above-mentioned silver-containing nanoparticle cathode material in the preparation of lithium fluoride carbon batteries.

[0066] Example 1

[0067] A method for preparing silver-containing nanoparticle cathode material for lithium fluoride carbon batteries:

[0068] (1) Disperse 3g of carbon fluoride in a mixed solution of 10mL ethanol and 40mL deionized water. After stirring for 30min, add 0.2361g of silver nitrate (the mass of silver in silver nitrate accounts for 5% of the mass of carbon fluoride, and the mass of silver nitrate accounts for 7.87% of the mass of carbon fluoride) and continue stirring for 30min to obtain a uniform mixed solution.

[0069] (2) Place the mixed solution under ultraviolet light (300W) and continue stirring for 30 min. After stirring, centrifuge (4000 r / min for 2 min), wash with ethanol, and repeat the centrifugation and washing steps 3 times. Finally, place it in an 80℃ forced-air drying oven for 120 min and then place it in an 80℃ vacuum drying oven for 480 min to obtain fluorinated carbon powder containing silver nanoparticles (fluorinated carbon material modified with silver nanoparticles).

[0070] (3) Weigh the fluorinated carbon powder containing silver nanoparticles and the carbon material powder in a mortar at a mass ratio of 9:1, grind for 120 min to obtain a mixed powder of fluorinated carbon containing silver nanoparticles and carbon material; weigh the binder powder.

[0071] (4) Add a magnetic stir bar and 100 mL of deionized water to a beaker. Start stirring with a magnetic stir bar at a speed of 300 r / min. Slowly add the weighed binder powder (the binder is the thickener CMC, and the mass ratio of the binder to the fluorinated carbon powder containing silver nanoparticles is 10:90) to the beaker. After stirring for 30 min, slowly add the mixed powder of fluorinated carbon containing silver nanoparticles and carbon material. After the mixed powder is completely blended, set the speed of the magnetic stir bar to 1000 r / min and stir for 12 h. Finally, take it out and place it in a mortar and grind it wet for 30 min to obtain a uniformly mixed slurry.

[0072] (5) Use a fully automatic coating machine to perform the coating process, set the coating thickness to 300μm, the speed to 3cm / s, and the temperature to 40℃; after coating, place it in an 80℃ forced-air drying oven for pre-drying for 120min, then place it in an 80℃ vacuum drying oven for drying for 480min, and finally use a die-cutting machine to cut the positive electrode sheet to obtain the silver nanoparticle positive electrode material (positive electrode).

[0073] Example 2

[0074] Same as Example 1, except that the amount of silver nitrate used in step (1) is 0.118g (the mass of silver in silver nitrate accounts for 2.5% of the mass of fluorinated carbon, and the mass of silver nitrate accounts for 3.93% of the mass of fluorinated carbon).

[0075] Example 3

[0076] Same as Example 1, except that the amount of silver nitrate used in step (1) is 0.3541g (the mass of silver in silver nitrate accounts for 7.5% of the mass of fluorinated carbon, and the mass of silver nitrate accounts for 11.80% of the mass of fluorinated carbon).

[0077] Example 4

[0078] Same as Example 1, except that the amount of silver nitrate used in step (1) is 0g (the mass of silver in silver nitrate accounts for 0% of the mass of carbon fluoride).

[0079] Example 5

[0080] Same as Example 1, except that in step (5), the coating thickness is 100 μm, the coating rate is 1 cm / s, and the coating temperature is 20 °C.

[0081] Example 6

[0082] Same as Example 1, except that in step (5), the coating thickness is 500 μm, the coating rate is 10 cm / s, and the coating temperature is 60 °C.

[0083] Example 1

[0084] The microstructure of the silver-containing nanoparticle cathode material prepared in Example 1 at the 50 nm scale (SEM image) is shown below. Figure 1 .

[0085] from Figure 1 As can be seen from the example, in the silver nanoparticle cathode material prepared in Example 1, particulate KB (conductive carbon material, Ketjen Black) is observed loaded on carbon nanotubes, and the size of the silver particles is in the nanometer range.

[0086] The silver-containing nanoparticle cathode material prepared in Example 1 was assembled into a lithium fluoride carbon battery, and discharge specific capacity curves at a constant current of 0.05C were plotted at different temperatures. The results are shown in [Figure 1]. Figure 2 .

[0087] from Figure 2 As can be seen, the lower the temperature, the worse the discharge performance of the lithium-carbon fluoride battery. At 55℃, the discharge voltage plateau of the lithium-carbon fluoride battery is 2.62V, the discharge specific capacity is 804.0mAh / g, and the discharge specific energy is 2005.8mWh / g. At -10℃, the discharge voltage plateau of the lithium-carbon fluoride battery is 2.22V, the discharge specific capacity is 728.4mAh / g, and the discharge specific energy is 1555.0mWh / g. This demonstrates that silver-containing nanoparticles significantly improve the low-temperature discharge performance of the lithium-carbon fluoride battery.

[0088] The silver nanoparticle-containing cathode material prepared in Example 4 (fluorinated carbon material without silver nanoparticles, Example 4) and Example 1 (silver nanoparticle-containing cathode material, Example 1) were assembled into lithium fluorinated carbon batteries, and the electrochemical characterization of the lithium fluorinated carbon batteries by AC impedance was measured. The results are shown in [Figure 1]. Figure 3 .

[0089] from Figure 3 As can be seen, the EIS curves of the silver nanoparticle-containing cathode electrodes prepared in Example 4 and Example 1 are both a low semicircle reflecting the charge transfer process and a sloping straight line related to the diffusion of lithium ions in the electrode. The semicircle of the lithium fluoride battery prepared using the silver nanoparticle-containing cathode material of Example 1 is smaller than that of the blank sample (Example 4) lithium fluoride battery, indicating that the presence of silver nanoparticles in the lithium fluoride battery reduces the battery resistance and improves the mass transfer efficiency of lithium ions and electrons.

[0090] Example 2

[0091] The cathode material prepared in Example 1 and the cathode material prepared in Example 4 were assembled into a lithium-carbon fluoride battery, and pulse discharge electrochemical characterization tests were performed. The results are shown in [Figure 1]. Figure 4 .

[0092] from Figure 4 As can be seen, the battery's pulse discharge performance has been improved.

[0093] Example 3

[0094] The cathode materials prepared in Examples 1-4 were assembled into lithium-carbon fluoride batteries, and the discharge specific capacity curves at 1C were obtained. The results are shown in [Figure 1]. Figure 5 .

[0095] from Figure 5 As can be seen, the battery's discharge capacity performance has been improved.

[0096] Example of effect 4

[0097] The cathode materials prepared in Examples 1-4 were assembled into lithium-carbon fluoride batteries, and the discharge specific energy was measured. The results are shown in [Figure 1]. Figure 6 .

[0098] from Figure 6 As can be seen, the battery's discharge energy density performance has been improved.

[0099] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing silver nanoparticle-modified fluorocarbon material, characterized by, The method comprises the following steps: carbon fluoride is dispersed in a solvent, then a silver salt is added, stirred uniformly, and placed under 300W ultraviolet light for 30min of continuous stirring to obtain the silver nanoparticle modified carbon fluoride material; the solvent is composed of ethanol and water; the mass ratio of carbon fluoride, ethanol, and water is 1:(2-5):(10-20); the silver salt is silver nitrate; the amount of silver salt is 7.87% or 11.80% of the mass of carbon fluoride.

2. A silver nanoparticle modified carbon fluoride material prepared by the preparation method in claim 1.

3. A method for preparing a silver nanoparticle-containing positive electrode material for a lithium-carbon fluoride battery, characterized by, The method comprises the following steps: a binder is added to water and stirred uniformly, then the mixture of the silver nanoparticle modified carbon fluoride material in claim 2 and carbon material is added, stirred uniformly, and wet ground to obtain a mixed slurry; the mixed slurry is coated and dried to obtain the silver nanoparticle containing positive electrode material.

4. The production method according to claim 3, characterized by, the mass ratio of the binder, silver nanoparticle modified carbon fluoride material, and carbon material is (2-10):90:(5-10).

5. The preparation method according to claim 3, characterized in that, the wet grinding time is 10-60min; the coating thickness is 100-500μm, the rate is 1-10cm / s, and the temperature is 20-60℃.

6. A silver nanoparticle containing positive electrode material prepared by the preparation method in any one of claims 3-5.

7. Use of the silver nanoparticle containing positive electrode material in claim 6 in the preparation of lithium-carbon fluoride batteries.

Images