Double-coated modified carbon fluoride positive electrode material and preparation and application thereof
By performing double coating modification on the surface of fluorinated carbon and using nano-silver and manganese dioxide particle layers, the problems of insufficient rate performance and specific energy characteristics of fluorinated carbon materials were solved, and the high-rate discharge capability and high specific capacity were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WUHAN INSTITUTE OF MARINE ELECTRIC PROPULSION (THE 712TH RESEARCH INSTITUTE OF CHINA STATE SHIPBUILDING CORP LTD)
- Filing Date
- 2025-06-04
- Publication Date
- 2026-06-09
Smart Images
Figure CN120637479B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium primary battery technology, and in particular to a double-coated modified fluorinated carbon cathode material and its preparation and application. Background Technology
[0002] Lithium primary batteries are a type of lithium primary battery that uses metallic lithium as the negative electrode. They can only be used once and cannot be recharged. Among the many lithium primary battery systems, lithium / carbon fluoride batteries have the highest theoretical specific energy (reaching 2180Wh / kg), a wide temperature range (-40℃~80℃), high safety, and long storage life, and are widely used in deep space exploration and underwater equipment.
[0003] However, due to the poor conductivity and slow electrochemical reaction kinetics of fluorocarbon materials, severe polarization occurs at high discharge rates, accompanied by voltage hysteresis and a low voltage plateau, hindering capacity utilization and severely limiting their widespread application in practical engineering. To address these drawbacks, researchers have employed various strategies for modification, including physical and chemical methods such as doping, coating, and hybrid cathodes. However, existing improvement schemes offer limited improvement in rate performance and may even result in capacity loss.
[0004] Therefore, a solution is needed that can significantly improve the rate performance of fluorocarbons while maintaining the high-quality specific energy characteristics of fluorocarbon materials. Summary of the Invention
[0005] In view of this, this application provides a dual-coated modified fluorinated carbon cathode material and its preparation and application, which is used to solve the problem of how to simultaneously improve the rate performance and specific capacity of fluorinated carbon materials.
[0006] To achieve the above technical objectives, this application adopts the following technical solution:
[0007] In a first aspect, this application provides a double-coated modified fluorinated carbon cathode material, which includes a hydrophilic modified fluorinated carbon matrix, a layer of nano-silver particles coated on the surface of the hydrophilic modified fluorinated carbon matrix, and a layer of manganese dioxide particles coated on the surface of the nano-silver particles.
[0008] Preferably, the total mass of the nano-silver particles and manganese dioxide particles is 5-15% of the mass of the double-coated modified fluorinated carbon cathode material; the mass ratio of nano-silver particles to manganese dioxide particles is (1-1.5):1.
[0009] Preferably, the mass of the silver nanoparticles is 0.5-5% of the total mass of the hydrophilic modified fluorinated carbon matrix loaded with silver nanoparticles.
[0010] Secondly, this application provides a method for preparing a double-coated modified fluorinated carbon cathode material, comprising the following steps:
[0011] S1. Fluorocarbon is mixed with an alkaline solution and subjected to a reflux reaction to obtain a hydrophilic modified fluorocarbon matrix;
[0012] S2. Disperse the hydrophilic modified fluorinated carbon matrix, silver source, and reducing agent in water and carry out a hydrothermal reaction to obtain hydrophilic modified fluorinated carbon coated with nano-silver particles;
[0013] S3. The hydrophilic modified fluorinated carbon and manganese source coated with nano-silver particles are dispersed in water and subjected to a secondary hydrothermal reaction to obtain a double-coated modified fluorinated carbon cathode material.
[0014] Preferably, the concentration of the alkaline solution is 3-6 mol / L, and the alkaline solution includes an aqueous solution of NaOH and / or KOH in ethanol; the ratio of carbon fluoride to alkaline solution is 1 g: (100-150) ml.
[0015] Preferably, the silver source includes silver nitrate, and the reducing agent includes one or more of polyvinylpyrrolidone, glucose, ascorbic acid, formaldehyde, and hydrazine hydrate.
[0016] Preferably, the temperature of the first hydrothermal reaction is 120-150℃, and the time of the first hydrothermal reaction is 3h-6h.
[0017] Preferably, the manganese source is a mixture of potassium permanganate and manganese sulfate; the mass ratio of potassium permanganate to manganese sulfate is (1.5-2):1; the mass ratio of hydrophilic modified fluorinated carbon coated with nano-silver particles to the manganese source is 1:(0.5-1.5).
[0018] Preferably, the secondary hydrothermal reaction temperature is 140-180℃ and the secondary hydrothermal reaction time is 12-16h.
[0019] Thirdly, this application provides an application of a double-coated modified fluorinated carbon cathode material in the preparation of lithium primary batteries.
[0020] The beneficial effects of this application are as follows: By uniformly coating the surface of fluorinated carbon with silver particles that have good conductivity and manganese dioxide with an appropriate loading, this application effectively improves the ionic conductivity and electronic conductivity of the fluorinated carbon cathode material, significantly enhances the high-rate discharge capability of the fluorinated carbon battery, and maintains a high specific capacity. Attached Figure Description
[0021] Figure 1 The discharge curves of the fluorinated carbon batteries in Example 1 and the control group at a 15C rate are shown.
[0022] Figure 2 The discharge curves of the fluorinated carbon batteries in Example 1 and the control group at a rate of 30C are shown. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0024] This application provides a double-coated modified fluorinated carbon cathode material, which includes a hydrophilic modified fluorinated carbon matrix, a layer of silver nanoparticles coated on the surface of the hydrophilic modified fluorinated carbon matrix, and a layer of manganese dioxide particles coated on the surface of the silver nanoparticles.
[0025] In this application, silver particles with good conductivity and manganese dioxide with appropriate loading are uniformly coated on the surface of fluorinated carbon, which effectively improves the ionic conductivity and electronic conductivity of the fluorinated carbon cathode material, significantly enhances the high-rate discharge capability of the fluorinated carbon battery and maintains a high specific capacity.
[0026] In some embodiments, the total mass of the silver nanoparticles and manganese dioxide particles is 5-15% of the mass of the double-coated modified fluorinated carbon cathode material; the mass ratio of the silver nanoparticles to the manganese dioxide particles is (1-1.5):1.
[0027] In some embodiments, the mass of the silver nanoparticles is 0.5-5% of the total mass of the hydrophilic modified fluorinated carbon matrix loaded with silver nanoparticles.
[0028] This application provides a method for preparing a double-coated modified fluorinated carbon cathode material, comprising the following steps:
[0029] S1. Fluorocarbon is mixed with an alkaline solution and subjected to a reflux reaction to obtain a hydrophilic modified fluorocarbon matrix;
[0030] S2. Disperse the hydrophilic modified fluorinated carbon matrix, silver source, and reducing agent in water and carry out a hydrothermal reaction to obtain hydrophilic modified fluorinated carbon coated with nano-silver particles;
[0031] S3. The hydrophilic modified fluorinated carbon and manganese source coated with nano-silver particles are dispersed in water and subjected to a secondary hydrothermal reaction to obtain a double-coated modified fluorinated carbon cathode material.
[0032] This application involves sequential surface activation and double coating of fluorinated carbon to simultaneously improve the rate performance and specific capacity of the fluorinated carbon material. The specific process is as follows:
[0033] Step S1 is a surface activation process. After activation with a high-concentration strong alkaline solution, the fluorine content on the surface of the fluorinated carbon material is reduced, which improves its hydrophilicity and is beneficial to the subsequent coating steps. Step S2 is a primary coating process. Fluorinated carbon material with a certain load of conductive silver nanoparticles on its surface is obtained by adjusting the raw material dosage ratio. That is, hydrophilic modified fluorinated carbon coated with silver nanoparticles. Step S3 is a secondary coating process. Through a secondary hydrothermal reaction, manganese dioxide particles are continuously coated on the surface of the hydrophilic modified fluorinated carbon material coated with silver nanoparticles.
[0034] In some embodiments, the concentration of the alkaline solution is 3-6 mol / L, and the alkaline solution includes an aqueous solution of NaOH and / or KOH in ethanol; the ratio of carbon fluoride to alkaline solution is 1 g: (100-150) ml; the temperature of the reflux condensation treatment is 50-80℃, and the reflux condensation time is ≥12 h.
[0035] In some embodiments, the silver source includes silver nitrate, and the reducing agent includes one or more of polyvinylpyrrolidone, glucose, ascorbic acid, formaldehyde, and hydrazine hydrate.
[0036] In some embodiments, the temperature of the first hydrothermal reaction is 120-150℃, and the time of the first hydrothermal reaction is 3h-6h; the ratio of fluorocarbon material to water is 1g:(100-600)ml.
[0037] In some embodiments, the manganese source is a mixture of potassium permanganate and manganese sulfate; the mass ratio of potassium permanganate to manganese sulfate is (1.5-2):1; the mass ratio of hydrophilic modified fluorinated carbon coated with nano-silver particles to the manganese source is 1:(0.5-1.5).
[0038] In some embodiments, the secondary hydrothermal reaction temperature is 140-180℃, and the secondary hydrothermal reaction time is 12-16h; the ratio of hydrophilic modified fluorinated carbon coated with nano-silver particles to water is 1g:(100-600)ml.
[0039] This application provides the application of a double-coated modified fluorinated carbon cathode material in the preparation of lithium primary batteries.
[0040] The following specific embodiments further illustrate this solution.
[0041] Example 1
[0042] A double-coated modified fluorinated carbon cathode material includes a hydrophilic modified fluorinated carbon matrix, a layer of silver nanoparticles coated on the surface of the hydrophilic modified fluorinated carbon matrix, and a layer of manganese dioxide particles coated on the surface of the silver nanoparticles.
[0043] A method for preparing a double-coated modified fluorinated carbon cathode material includes the following steps:
[0044] S1. Disperse 5g of fluorinated carbon material in a mixture of 600ml concentrated NaOH solution and ethanol, wherein the volume ratio of ethanol to water is 5:1 and the concentration of NaOH solution is 6mol / L. Reflux at 70℃ for 12h to obtain a hydrophilic modified fluorinated carbon matrix.
[0045] S2. 5g of hydrophilic modified fluorinated carbon matrix, 0.08g of silver nitrate, and 10g of glucose reducing agent were uniformly dispersed in 800ml of water. The hydrothermal reaction was carried out at 150℃ for 5 hours to obtain hydrophilic modified fluorinated carbon coated with silver nanoparticles. The mass of the silver nanoparticles was 1.5% of the total mass of the hydrophilic modified fluorinated carbon matrix after loading with silver nanoparticles.
[0046] S3. 4g of nano-silver particles were coated and uniformly dispersed with 0.27g of potassium permanganate and 0.3g of manganese sulfate in 1.5L of deionized water for a second hydrothermal reaction. The temperature was controlled at 160℃ and the hydrothermal reaction time was 16h to obtain a double-coated modified fluorinated carbon cathode material.
[0047] Example 2
[0048] A double-coated modified fluorinated carbon cathode material includes a hydrophilic modified fluorinated carbon matrix, a layer of silver nanoparticles coated on the surface of the hydrophilic modified fluorinated carbon matrix, and a layer of manganese dioxide particles coated on the surface of the silver nanoparticles.
[0049] A method for preparing a double-coated modified fluorinated carbon cathode material includes the following steps:
[0050] S1. Disperse 5g of fluorinated carbon material in a mixture of 500ml of NaOH solution and ethanol, wherein the volume ratio of ethanol to water is 5:1 and the concentration of NaOH solution is 3mol / L. Reflux at 70℃ for 12h to obtain a hydrophilic modified fluorinated carbon matrix.
[0051] S2. 5g of hydrophilic modified fluorinated carbon matrix, 0.04g of silver nitrate, and 10g of glucose reducing agent were uniformly dispersed in 800ml of water. The hydrothermal reaction temperature was 180℃ and the reaction time was 5h to obtain hydrophilic modified fluorinated carbon coated with nano-silver particles.
[0052] S3. Coated with 3g of silver nanoparticles, 0.27g of potassium permanganate, and 0.3g of manganese sulfate, and uniformly dispersed in 1.5L of deionized water, a second hydrothermal reaction was carried out, with the temperature controlled at 160℃ and the hydrothermal reaction time at 16h, to obtain a double-coated modified fluorinated carbon cathode material.
[0053] Comparative Example 1
[0054] A fluorinated carbon cathode material, which is otherwise the same as in Example 1, except that step S1 is not included.
[0055] Comparative Example 2
[0056] A fluorinated carbon cathode material, otherwise the same as in Example 1, except that step S2 is not included.
[0057] Comparative Example 3
[0058] A fluorinated carbon cathode material, otherwise the same as in Example 1, except that step S3 is not included.
[0059] Comparative Example 4
[0060] A fluorinated carbon cathode material is the same as in Example 1, except that the coating order of steps S2 and S3 is reversed.
[0061] Testing and Evaluation
[0062] Fluorinated carbon cathode materials, fluorinated carbon raw materials (control group), PVDF, and SP obtained from different embodiments and comparative examples were vacuum dried in an oven at 120°C for 10 hours. Then, they were mixed evenly in an agate mortar according to the mass ratio of fluorinated carbon:SP:PVDF of 8:1:1. The specific amounts of each component used in each slurry preparation were fluorinated carbon (0.5g), SP (0.0625g), and PVDF (0.0625g). After dry mixing, 1g of NMP was added (in three to four portions), and the mixture was continuously ground in the agate mortar until there were no visible particles and the slurry was uniform. The slurry prepared in the slurry preparation step was coated onto carbon-coated aluminum foil using a 100μm scraper and then transferred to an 80°C forced-air oven to dry for 2 hours. The electrode sheets were then removed and rolled, and then punched into round sheets with a diameter of 10mm using a punching machine. The round sheets were then transferred to a vacuum oven at 100°C to dry for 12 hours before use.
[0063] Secondly, calculate the content of active material. The amount of active material is m = (m1 - m2) × 0.8, where M1 is the weight of the electrode with a diameter of 10 mm and M2 is the weight of the current collector aluminum foil with a diameter of 10 mm.
[0064] Then, the coin cell assembly was performed: using 1 mol / L LiPF6 (a mixed solvent with a volume ratio of EC:DMC:EMC of 1:1:1) as the electrolyte, the cells were assembled in the following order: negative electrode shell, lithium sheet, separator, positive electrode sheet, flat pad, spring pad, and positive electrode shell. Before placing the positive electrode sheet, 50 μL to 100 μL of electrolyte was added. The cells were then sealed using a coin cell sealing machine and left to stand for 12 hours. The discharge curves of different fluorinated carbon batteries at 15C and 30C rates were then tested.
[0065] Figure 1 The discharge curves of the fluorinated carbon batteries in Example 1 and the control group at a 15C rate are shown. Figure 2The discharge curves of the fluorinated carbon batteries in Example 1 and the control group at a rate of 30C are shown.
[0066] The results show that the present application uniformly coats the surface of fluorinated carbon with silver particles with good conductivity and manganese dioxide with appropriate loading, which effectively improves the ionic conductivity and electronic conductivity of the fluorinated carbon cathode material, significantly enhances the high-rate discharge capability of the fluorinated carbon battery and maintains a high specific capacity.
[0067] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.
Claims
1. A double-coated modified fluorinated carbon cathode material, characterized in that, It includes a hydrophilic modified fluorinated carbon matrix, a layer of silver nanoparticles coated on the surface of the hydrophilic modified fluorinated carbon matrix, and a layer of manganese dioxide particles coated on the surface of the silver nanoparticles. The preparation steps of the double-coated modified fluorinated carbon cathode material include: mixing fluorinated carbon with an alkaline solution and carrying out a reflux reaction to obtain a hydrophilic modified fluorinated carbon matrix; then coating with a layer of silver nanoparticles and a layer of manganese dioxide particles. The total mass of the nano-silver particles and the manganese dioxide particles is 5-15% of the mass of the double-coated modified fluorinated carbon cathode material; the mass ratio of the nano-silver particles to the manganese dioxide particles is (1-1.5):
1.
2. The double-coated modified fluorinated carbon cathode material according to claim 1, characterized in that, The mass of the silver nanoparticles is 0.5-5% of the total mass of the hydrophilic modified fluorinated carbon matrix loaded with silver nanoparticles.
3. A method for preparing a double-coated modified fluorinated carbon cathode material as described in any one of claims 1-2, characterized in that, Includes the following steps: Fluorinated carbon was mixed with an alkaline solution and subjected to a reflux condensation reaction to obtain a hydrophilic modified fluorinated carbon matrix. The hydrophilic modified fluorinated carbon matrix, silver source, and reducing agent are dispersed in water and subjected to a hydrothermal reaction to obtain hydrophilic modified fluorinated carbon coated with silver nanoparticles. The hydrophilic modified fluorinated carbon and manganese source coated with the nano-silver particles are dispersed in water and subjected to a secondary hydrothermal reaction to obtain the double-coated modified fluorinated carbon cathode material.
4. The preparation method according to claim 3, characterized in that, The concentration of the alkaline solution is 3-6 mol / L, and the alkaline solution includes an aqueous solution of NaOH and / or KOH in ethanol; the ratio of the amount of fluorinated carbon to the amount of alkaline solution is 1 g: (100-150) ml.
5. The preparation method according to claim 3, characterized in that, The silver source includes silver nitrate, and the reducing agent includes one or more of polyvinylpyrrolidone, glucose, ascorbic acid, formaldehyde, and hydrazine hydrate.
6. The preparation method according to claim 3, characterized in that, The temperature of a single hydrothermal reaction is 120-150℃, and the reaction time is 3-6 hours.
7. The preparation method according to claim 3, characterized in that, The manganese source is a mixture of potassium permanganate and manganese sulfate; the mass ratio of potassium permanganate to manganese sulfate is (1.5-2):1; the mass ratio of the hydrophilic modified fluorinated carbon coated with nano-silver particles to the manganese source is 1:(0.5-1.5).
8. The preparation method according to claim 3, characterized in that, The secondary hydrothermal reaction temperature is 140-180℃, and the secondary hydrothermal reaction time is 12-16h.
9. The application of the double-coated modified fluorinated carbon cathode material as described in any one of claims 1-2 in the preparation of lithium primary batteries.