FeF3 / FeOF thermal battery positive electrode material with heterostructure as well as preparation method and application of FeF3 / FeOF thermal battery positive electrode material
By preparing FeF3/FeOF heterostructure composite cathode materials, the problems of insufficient stability and voltage of thermal battery cathode materials at high temperatures were solved, and the discharge performance of high voltage and high power was improved.
Patent Information
- Application Number
- CN202511183057.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-22
- Publication Date
- 2025-11-18
AI Technical Summary
Existing thermal battery cathode materials have poor stability at high temperatures, low operating voltage, and are prone to no-load failure when the number of cell units increases, making it difficult to meet the requirements of high voltage and high power.
Hydrated iron trifluoride compounds were prepared by solvent method, and FeF3/FeOF heterostructure composite cathode materials were prepared by calcination method. The Schottky heterojunction formed by FeOF and FeF3 promoted electron and ion migration and improved the specific capacity and voltage of the material.
It improves the instantaneous discharge power and specific capacity of the thermal battery, reduces internal resistance, enhances the battery's load-carrying capacity, and solves the problems of insufficient stability and voltage of existing materials at high temperatures.
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Figure CN120978048A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the field of thermal batteries, and particularly relates to a FeF3 / FeOF thermal battery positive electrode material with a heterojunction and a preparation method thereof. BACKGROUND
[0002] A thermal battery is a one-time reserve battery with fast activation and high power. The electrolyte is a solid-state molten salt, which is an ionic insulator at room temperature. The self-heating system is ignited by electric or mechanical activation, the temperature in the battery rises rapidly, the solid-state electrolyte becomes a liquid-state ionic conductor, and the battery enters the working state. Due to its unique working mechanism and the fact that the ionic conductivity of the molten salt electrolyte at high temperature is orders of magnitude higher than that of liquid electrolyte, the thermal battery can provide excellent electrical performance in a short time and is widely used as a starting power source for special equipment. However, as the requirements of equipment increase, the thermal battery is required to have high output power.
[0003] In order to enable the thermal battery to meet the requirements of high voltage and large power discharge, in the past design, the first conventional method is to increase the number of single batteries to ensure the high voltage of the whole battery, and the second conventional method is to increase the number of multiple series of single cells to ensure a high output voltage. However, this method is often limited by the space and height of the equipment, and it is difficult to achieve both. However, as the number of single cells increases, the amount of heating powder also increases, causing the overall heat of the single cell to rise, which easily leads to serious no-load failure problems in the later stage.
[0004] Currently, the positive electrode materials for thermal batteries mainly include transition metal sulfides such as FeS2, FeS, CoS2, NiS2, NiS and ZrS3. Although these materials are relatively cheap, their stability in air or at high temperatures is relatively poor, and their working voltage is relatively low. In addition, in the actual discharge process, the discharge voltage is difficult to maintain constant, decays too fast, and the polarization increases, accompanied by a decrease in the migration rate of electrons and ions. Therefore, a new type of heterostructure material can be prepared to take advantage of the advantages of two materials, and a composite material with higher working voltage and higher specific capacity can be prepared to meet the growing demand. This is also one of the important means to obtain high-voltage and high-performance thermal battery positive electrode materials in the future. SUMMARY
[0005] In order to improve the defects and deficiencies of the existing thermal battery positive electrode materials, the primary purpose of the present application is to provide a FeF3 / FeOF composite positive electrode material with a heterostructure (mass ratio FeF3:FeOF=(0.1-10:10-0.1), which fully utilizes the synergies of the two materials, and the heterostructure material is used in the production and preparation of thermal batteries.
[0006] To achieve the above object, the application adopts the following technical scheme: A preparation method of FeF3 / FeOF composite positive electrode material with a heterostructure, characterized in that it comprises the following steps: (1) dissolving iron salt in an alcohol reagent with an additive; (2) adding prepared ammonium fluoride or ammonium hydrogen fluoride aqueous solution into the above solution system, mixing and stirring, and drying to obtain hydrated iron trifluoride compound; (3) calcining the hydrated iron trifluoride compound under a mixed gas atmosphere composed of argon and oxygen with different humidity and different proportion at a heating rate of 1-20 ℃ / min to 300-800 ℃ for 0.5-6 h, and reducing to room temperature at a cooling rate of 0.5-10 ℃ / min to obtain FeF3 / FeOF composite positive electrode material with a heterostructure and different proportion.
[0007] The application first prepares hydrated iron trifluoride compound by a solvent method, introduces oxygen source by using water and oxygen without chemical hazards, and then prepares FeF3 / FeOF composite positive electrode material with a heterostructure by a calcination method.
[0008] The heterojunction material of the FeF3 / FeOF composite positive electrode material can reduce the internal resistance of the positive electrode material, improve the voltage of the single battery, and enhance the load capacity of the battery.
[0009] Further, the iron salt in step (1) is one of soluble in aqueous solution, such as ferric nitrate nonahydrate, ferric chloride hexahydrate, and potassium ferricyanide.
[0010] Further, the additive in step (1) is one or more of ethylene glycol, polyethylene glycol, stearic acid, oleic acid, oleylamine, cetyltrimethylammonium bromide, and sodium dodecyl sulfate.
[0011] Further, the alcohol reagent in step (1) is a mixed solvent of ethanol and n-butanol with a volume ratio of 1-10:1.
[0012] Further, the humidity of the mixed atmosphere in step (3) is controlled by adjusting the flow rate of the gas flowing through the wide-mouth bottle containing deionized water, adjusting the amount of water entering the tube furnace, and adjusting the flow rate of the gas in the range of 5 SCCM to 45 SCCM.
[0013] Further, the calcination temperature in step (3) is 350-600°C, and the time is 1-5h.
[0014] Further, the heating rate in step (3) is 5-20°C / min, and the cooling rate is 0.5-5°C / min.
[0015] The FeF3 / FeOF composite anode material with a heterogeneous structure prepared by the above method can be used as an anode material for thermal batteries or other alkali metal batteries. Compared with the prior art, the present application has the following advantages and beneficial effects: (1) The present application first uses a hydrate as a raw material to prepare a FeF3 / FeOF composite anode material with a heterogeneous structure through a calcination process. The preparation method is simple, the equipment requirements are relatively low, no rare metals are used, the atomic utilization rate is high, and the raw material cost is relatively low, which is conducive to actual production.
[0016] (2) The FeF3 / FeOF composite anode material prepared by the present application is composed of nanometer and micrometer small particles, which is more conducive to electronic conduction and ensures the thermal stability of the material.
[0017] (3) The control of the FeF3 / FeOF component in the composite anode material can adjust the ratio of FeF3 and FeOF by changing the moisture and oxygen content during the calcination process, further control the discharge voltage and specific capacity of the anode material, and is the key to realizing the high-voltage and long-life characteristics of the composite material.
[0018] (4) The FeF3 / FeOF composite anode material with a heterogeneous structure obtained by reasonable component control and structure design has high working voltage and excellent discharge specific capacity in thermal batteries. BRIEF DESCRIPTION OF DRAWINGS
[0019] Figure 1 The XRD pattern of the sample thermal battery anode material obtained in Example 3 of the present application.
[0020] Figure 2 The SEM pattern of the sample thermal battery anode material obtained in Example 3 of the present application.
[0021] Figure 3 The discharge curve of the FeF3 / FeOF anode prepared in Example 1 of the present application at a current density of 50 mA / cm 2 .
[0022] Figure 4 The FeF3 / FeOF anode prepared in Example 2 of the present application has a discharge curve at 50 mA / cm 2
[0023] Figure 5 The FeF3 / FeOF anode prepared in Example 3 of the present application has a discharge curve at 50 mA / cm 2
[0024] Figure 6 The FeF3 / FeOF anode prepared in Example 3 of the present application has a discharge curve at 100 mA / cm 2
[0025] Figure 7 The FeF3 / FeOF anode prepared in Example 4 of the present application has a discharge curve at 50 mA / cm 2 DETAILED DESCRIPTION
[0026] The present application will be described in further detail by the following examples and drawings, but the embodiments of the present application are not limited to them.
[0027] In the examples of the present application, the specific conditions not mentioned are carried out according to the conventional conditions or the conditions recommended by the manufacturers. The raw materials, reagents, etc. used without mentioning the manufacturers are all the conventional products that can be purchased in the market.
[0028] Example 1, a preparation method of FeF3 / FeOF composite anode material with a heterogeneous structure, as follows: 13.55 g of iron trichloride hexahydrate is dissolved in 50 ml of a mixed solution of ethanol and 5 ml of oleic acid and 5 ml of polyethylene glycol is added, then 15 g of ammonium fluoride is dissolved in 20 ml of deionized water and slowly added to the above solution. After continuous mechanical stirring for 20 min, it is dried in an oven at 80℃ for 5 h and cooled to room temperature. The obtained product is placed in a tube furnace, and the gas flow rate of argon is set to 45 SCCM and the gas flow rate of oxygen is set to 5 SCCM. The temperature is raised to 500℃ at a rate of 20℃ / min, then kept for 1 h, and then cooled to room temperature at a rate of 2℃ / min, then sealed and stored, to obtain a FeF3 / FeOF composite anode material with a heterogeneous structure.
[0029] Example 2, a preparation method of FeF3 / FeOF composite anode material with a heterogeneous structure, as follows: Potassium ferricyanide 16.5 g was dissolved in a mixture of 80 ml ethanol and 8 ml oleylamine and 5 ml polyethylene glycol was added. Ammonium fluoride 13 g was dissolved in 10 ml deionized water and slowly added into the above solution. The solution was stirred for 20 min and then dried in an oven at 80 °C for 5 h and cooled to room temperature. The product was transferred into a tube furnace and the flow rate of argon was set to 40 SCCM and the flow rate of oxygen was set to 10 SCCM. The temperature was increased to 500 °C at a rate of 20 °C / min and then held for 2 h and then decreased to room temperature at a rate of 2 °C / min and sealed to obtain a FeF3 / FeOF composite positive electrode material with a heterogeneous structure.
[0030] Example 3, a method for preparing a FeF3 / FeOF composite positive electrode material with a heterogeneous structure, as follows: Iron nitrate nonahydrate 20.2 g was dissolved in a mixture of 100 ml ethanol and 10 ml ethylene glycol and 5 ml polyethylene glycol was added. Ammonium fluoride 13 g was dissolved in 20 ml deionized water and slowly added into the above solution. The solution was stirred for 20 min and then dried in an oven at 80 °C for 5 h and cooled to room temperature. The product was transferred into a tube furnace and the flow rate of argon was set to 35 SCCM and the flow rate of oxygen was set to 15 SCCM. The temperature was increased to 500 °C at a rate of 20 °C / min and then held for 2 h and then decreased to room temperature at a rate of 2 °C / min and sealed to obtain a FeF3 / FeOF composite positive electrode material with a heterogeneous structure.
[0031] Example 4, a method for preparing a FeF3 / FeOF composite positive electrode material with a heterogeneous structure, as follows: Iron nitrate nonahydrate 20.2 g was dissolved in a mixture of 100 ml ethanol and 2 g cetyltrimethylammonium bromide and 5 ml polyethylene glycol was added. Ammonium fluoride 13 g was dissolved in 15 ml deionized water and slowly added into the above solution. The solution was stirred for 20 min and then dried in an oven at 80 °C for 5 h and cooled to room temperature. The product was transferred into a tube furnace and the flow rate of argon was set to 30 SCCM and the flow rate of oxygen was set to 20 SCCM. The temperature was increased to 500 °C at a rate of 20 °C / min and then held for 2 h and then decreased to room temperature at a rate of 2 °C / min and sealed to obtain a FeF3 / FeOF composite positive electrode material with a heterogeneous structure.
[0032] Physical characterization (taking Example 3 as an example): Figure 1 For the XRD pattern of Example 3, it can be seen that the first, second and fourth peaks from left to right are characteristic peaks of FeOF, and the third and fifth peaks are characteristic peaks of FeF3, which can prove that the FeF3 / FeOF heterojunction composite material is successfully synthesized.Figure 2 The microstructure of Example 3 is composed of small particles with a diameter of 100-200 nm, and is accompanied by partial agglomeration.
[0033] Electrochemical performance test: First, the material synthesized in the above examples is used as a positive electrode material, conductive carbon black, carbon nanotubes and graphene are used as conductive agents, and electrolyte is used as an additive. The positive electrode material: conductive agent: additive = 0.8: 0.1: 0.1 mass ratio is uniformly mixed and pressed into a positive electrode sheet, and is assembled into a single finished battery together with an electrolyte sheet and a LiB negative electrode which have been pressed, and is discharged at 500°C. The test results in the specific examples are as follows Figures 3-7 .
[0034] Figure 3 , Figure 4 , Figure 5 , Figure 7 The positive electrode material prepared from the positive electrode material of Examples 1-4 is tested under the above test conditions at a current density of 50 mA / cm 2 The results show that the potential platform is about 3.0 V, indicating that different precursors can be used to prepare FeF3 / FeOF heterojunction composite materials. In addition, by changing the different gases and gas flow, the ratio of FeF3 / FeOF heterojunction composite materials can be controlled, which is reflected in the capacity of the 3.0 V voltage platform. It can be seen that the capacity of Example 1 remains the largest, about 600 As / g, and the capacities of the other examples change with the change of the gas flow of the roasting gas.
[0035] The above is only an embodiment of the present application, and the specific technical solutions and / or common knowledge of the scheme are not described in detail. It should be noted that for those skilled in the art, without departing from the technical solutions of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application, which will not affect the effect and practicality of the patent. The protection scope of the present application should be subject to the content of its claims, and the specific implementation mode and the like in the specification can be used to explain the content of the claims.
Claims
1. A method for preparing a FeF3 / FeOF composite cathode material with a heterostructure, characterized in that, Includes the following steps: (1) Dissolve the iron salt in an alcohol reagent with additives; (2) Add the prepared aqueous solution of ammonium fluoride or ammonium bifluoride to the above solution system, mix and stir, and dry to obtain hydrated iron trifluoride compound; (3) Hydrated iron trifluoride compounds were calcined at 300~800℃ for 0.5~6h at a heating rate of 1-20℃ / min in a mixed atmosphere of argon and oxygen with different humidity and different proportions, and then cooled to room temperature at a cooling rate of 0.5~10℃ / min to obtain FeF3 / FeOF composite cathode materials with heterostructures and different proportions.
2. The method for preparing a FeF3 / FeOF composite cathode material with a heterostructure according to claim 1, characterized in that: The iron salt mentioned in step (1) is one of the following that is soluble in aqueous solution: ferric nitrate nonahydrate, ferric chloride hexahydrate, and potassium ferricyanide.
3. The method for preparing a FeF3 / FeOF composite cathode material with a heterostructure according to claim 1, characterized in that: The additive mentioned in step (1) is one of ethylene glycol, stearic acid, oleic acid, oleylamine, hexadecyltrimethylammonium bromide, and sodium dodecyl sulfate.
4. The method for preparing a FeF3 / FeOF composite cathode material with a heterostructure according to claim 1, characterized in that: The alcohol reagent mentioned in step (1) is a mixed solvent of ethanol and n-butanol, with a volume ratio of 1 to 10:
1.
5. The method for preparing a FeF3 / FeOF composite cathode material with a heterostructure according to claim 1, characterized in that: In step (3), the humidity and proportion of the mixed atmosphere are controlled by adjusting the gas flow rate through a wide-mouth bottle containing deionized water, thereby adjusting the amount of water entering the tubular furnace. The gas flow rate control range is 5 SCCM to 45 SCCM.
6. The method for preparing a FeF3 / FeOF composite cathode material with a heterostructure according to claim 1, characterized in that: The roasting temperature in step (3) is 350~600℃ and the time is 1~5h.
7. The method for preparing a FeF3 / FeOF composite cathode material with a heterostructure according to claim 1, characterized in that: The calcination heating rate in step (3) is 5~20℃ / min, and the cooling rate is 0.5~5℃ / min.
8. The FeF3 / FeOF composite cathode material with a heterostructure prepared by the method according to any one of claims 1 to 7.
9. The application of the FeF3 / FeOF composite cathode material with heterostructure according to claim 8 in thermal batteries or other alkali metal batteries.