Lithium carbon fluoride battery electrolyte and use
By introducing high-concentration nitrate additives and nitrogen crown ether solvents into the electrolyte of lithium fluorocarbon batteries, the problems of low current density and high polarization in lithium fluorocarbon batteries have been solved, thereby improving the battery's energy density and discharge performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2024-12-03
- Publication Date
- 2026-06-05
AI Technical Summary
The electrolyte formulation in existing lithium fluoride carbon batteries results in low current density and high polarization during discharge, which affects the battery's energy density and rate performance.
A high concentration of nitrate additives is introduced into the electrolyte of lithium fluoride carbon batteries to form a protective layer to suppress the side reactions between metallic lithium and the solvent. Azacrown ether solvent is used to promote the dissolution of high concentration of nitrates and improve the Li+ transport rate.
It significantly reduces polarization during battery discharge, increases battery energy density and discharge voltage plateau, and improves battery performance.
Smart Images
Figure BDA0005169508080000061 
Figure BDA0005169508080000071
Abstract
Description
Technical Field
[0001] This application relates to a lithium fluorinated carbon battery electrolyte and its application, belonging to the field of lithium / fluorinated carbon primary battery technology. Background Technology
[0002] With technological advancements in mobile communications, aerospace, transportation, and military equipment, the development of various high-energy-density power batteries has become an urgent need for national economic development. Due to the light weight and negative electrode potential of lithium metal, the development of lithium primary batteries with lithium as the negative electrode has received considerable attention. Lithium primary batteries mainly include lithium-manganese dioxide (Li / MnO2), lithium-sulfur dioxide (Li / SO2), lithium-thionyl chloride (Li / SOCl2), and lithium-carbon fluoride (Li / CF2). x Battery systems such as Li / CF2. Compared with other galvanic cells, Li / CF2... x The battery has the highest theoretical specific energy (2180 Wh / kg), while Li / CF x Batteries also offer advantages such as high safety, stable discharge voltage, and environmental friendliness, making them particularly suitable as power sources for instrumentation equipment used in unmanned or enclosed environments. Examples include pacemakers, missile ignition systems, radio transmitters, and underwater electronic detectors. Their application potential is especially significant as a power source for long-range military reconnaissance and personal communication systems carried by soldiers.
[0003] As a crucial component of batteries, the electrolyte solution's physicochemical properties play a vital role in the performance of battery materials. Therefore, developing electrolyte materials compatible with fluorinated carbon materials is of paramount importance. Currently, the electrolytes used in lithium-fluorinated carbon batteries mainly follow the lithium-manganese dioxide battery system. A typical formulation is: LiBF4 as the electrolyte, and propylene carbonate and dimethyl ethylene glycol as the solvent. However, batteries using this electrolyte formulation exhibit low current density and high polarization during discharge. Therefore, there is an urgent need to develop a suitable electrolyte for Li / CF4 batteries. x The electrolyte in the battery system is used to improve the battery's energy density and rate performance. Summary of the Invention
[0004] The purpose of this application is to provide a lithium fluoride carbon battery electrolyte and its application. By introducing a high-concentration nitrate additive into the lithium fluoride carbon battery electrolyte, a protective layer is formed on the surface of the lithium metal anode. This protective layer not only inhibits the side reactions between metallic lithium and the solvent, but also accelerates the reaction of Li... + The transmission effect significantly reduces polarization during battery discharge. Furthermore, the nitrogen-containing crown ethers in the lithium fluoride battery electrolyte promote the dissolution of high-concentration nitrates (above 5%) and the dissolution of lithium fluoride in the positive electrode during discharge, thereby reducing battery polarization, significantly increasing the voltage plateau during discharge, and improving the battery's energy density.
[0005] According to one aspect of this application, a lithium fluorinated carbon battery electrolyte is provided, the lithium fluorinated carbon battery electrolyte comprising a lithium salt, a solvent, and a NO3-containing compound. - additive;
[0006] The solvents include high dielectric constant solvents, ether solvents, and azirocro ether solvents;
[0007] The NO3-containing - The additive is selected from at least one of lithium nitrate, copper nitrate, ammonium nitrate, potassium nitrate, sodium nitrate, barium nitrate, zinc nitrate, lead nitrate, nickel nitrate, magnesium nitrate, calcium nitrate, strontium nitrate, and cesium nitrate;
[0008] The NO3-containing - The additive has a mass fraction of 5% to 20% in the lithium fluoride carbon battery electrolyte.
[0009] Optionally, the mass fraction of the additive is independently selected from any value of 5%, 10%, 12%, 15%, 18%, 20%, or a range between any two of the above.
[0010] Preferably, the NO3-containing - The additive has a mass fraction of 10-15% in the lithium fluoride carbon battery electrolyte.
[0011] Optionally, the lithium salt is selected from at least one of LiPF6, LiBF4, LiClO4, LiAsF6, LiBOB, LiODFB, LiFSI, and LiTFSI.
[0012] Optionally, the concentration of the lithium salt is 0.5 to 3 mol / L.
[0013] Optionally, the concentration of the lithium salt is independently selected from any value among 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, and 3 mol / L, or a range between any two of the above values.
[0014] Optionally, the concentration of the lithium salt is 1 to 1.5 mol / L.
[0015] Optionally, the high dielectric constant solvent is selected from at least one of ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, methyl acetate, ethyl acetate, n-butyl acetate, and isobutyl acetate.
[0016] Optionally, the ether solvent is selected from at least one of ethylene glycol dimethyl ether, tetrahydrofuran, 1,3-dioxane, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, hydrofluoroether, perfluorobutyl methyl ether, and ethyl perfluorobutyl ether.
[0017] Optionally, the azacrown ether solvent is selected from at least one of aza-15-crown ether-5 and diaza-18-crown ether-6.
[0018] Optionally, the volume ratio of high dielectric constant solvent: ether solvent: azacrown ether solvent is 20-40:30-70:5-30.
[0019] Preferably, the volume ratio of high dielectric constant solvent: ether solvent: azacrown ether solvent is 20-40:30-70:10-20.
[0020] According to another aspect of this application, the application of the above-mentioned lithium fluorinated carbon battery electrolyte in a lithium fluorinated carbon battery is provided, wherein the lithium fluorinated carbon battery further includes a fluorinated carbon positive electrode, a lithium negative electrode, and a separator.
[0021] The beneficial effects that this application can produce include:
[0022] High-concentration nitrates in the electrolyte form a protective layer on the surface of the lithium metal anode. This protective layer not only inhibits the side reactions between lithium metal and the solvent, but also accelerates Li+ transport, thereby significantly reducing polarization during battery discharge. In addition, the nitrogen crown ethers in the electrolyte can promote the dissolution of high-concentration nitrates, increase the ion transport number of the electrolyte, and simultaneously increase the Li+ transport rate in the cathode material. Furthermore, it can also promote the dissolution of lithium fluoride in the cathode during battery discharge, thereby reducing battery polarization and significantly increasing the voltage plateau during battery discharge, thus improving the battery's energy density. Detailed Implementation
[0023] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0024] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0025] The analysis method in the embodiments of this application is as follows:
[0026] Electrochemical testing methods and conditions for lithium fluoride carbon batteries: The battery is discharged to 1V at a rate of 0.1C at 25℃.
[0027] Example 1
[0028] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate, 1,3-dioxane and diaza-18-crown ether-6, in a volume ratio of 30:50:20; the lithium nitrate mass fraction is 5%.
[0029] Fluorinated carbon electrodes were prepared as follows: Fluorinated carbon, conductive carbon black, and a binder (PVDF) in a mass ratio of 8:1:1 were dissolved in an appropriate amount of N-methylpyrrolidone and mixed thoroughly. The mixture was then coated into an electrode film with a thickness of 0.15 mm using a wet film preparation device. After vacuum drying, the film was cut into electrode sheets with a diameter of 14 mm using a slicer. The weight of the active material was then measured and calculated. Simultaneously, a lithium sheet was used as the negative electrode, Celgard 2500 was used as the separator, and 100 μL of electrolyte was added. The cells were assembled into button cells in an argon-filled glove box, and then electrochemical tests were performed on the assembled cells.
[0030] The test results are shown in Table 1.
[0031] Example 2
[0032] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate, 1,3-dioxane and diaza-18-crown ether-6, in a volume ratio of 30:50:20; the lithium nitrate mass fraction is 10%.
[0033] The test results are shown in Table 1.
[0034] Example 3
[0035] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate, 1,3-dioxane and diaza-18-crown ether-6, in a volume ratio of 30:50:20; the lithium nitrate mass fraction is 15%.
[0036] The test results are shown in Table 1.
[0037] Example 4
[0038] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate, 1,3-dioxane and diaza-18-crown ether-6 in a volume ratio of 30:50:20; the lithium nitrate mass fraction is 20%.
[0039] The test results are shown in Table 1.
[0040] Example 5
[0041] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of methyl acetate, 1,3-dioxane and diaza-18-crown ether-6 in a volume ratio of 30:50:20; the lithium nitrate mass fraction is 10%.
[0042] Example 6
[0043] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of n-butyl acetate, 1,3-dioxane and diaza-18-crown ether-6 in a volume ratio of 30:50:20; the lithium nitrate mass fraction is 10%.
[0044] Example 7
[0045] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate, 1,3-dioxane and diaza-18-crown ether-6 in a volume ratio of 30:65:5; the lithium nitrate mass fraction is 10%.
[0046] Example 8
[0047] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate, 1,3-dioxane and diaza-18-crown ether-6 in a volume ratio of 30:60:10; the lithium nitrate mass fraction is 10%.
[0048] Example 9
[0049] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate, 1,3-dioxane and diaza-18-crown ether-6 in a volume ratio of 30:40:30; the lithium nitrate mass fraction is 10%.
[0050] Example 10
[0051] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate, 1,3-dioxane and aza-15-crown ether-5 in a volume ratio of 30:50:20; the lithium nitrate mass fraction is 10%.
[0052] Comparative Example 1
[0053] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate, 1,3-dioxane and diaza-18-crown ether-6, in a volume ratio of 30:50:20; the lithium nitrate mass fraction is 2%;
[0054] Fluorinated carbon electrodes were prepared as follows: Fluorinated carbon, conductive carbon black, and a binder (PVDF) in a mass ratio of 8:1:1 were dissolved in an appropriate amount of N-methylpyrrolidone and mixed thoroughly. The mixture was then coated into an electrode film with a thickness of 0.15 mm using a wet film preparation device. After vacuum drying, the film was cut into electrode sheets with a diameter of 14 mm using a slicer. The weight of the active material was then measured and calculated. Simultaneously, a lithium sheet was used as the negative electrode, Celgard 2500 was used as the separator, and 100 μL of electrolyte was added. The cells were assembled into button cells in an argon-filled glove box, and then electrochemical tests were performed on the assembled cells.
[0055] The test results are shown in Table 1.
[0056] Comparative Example 2
[0057] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate, 1,3-dioxane and 18-crown ether-6 in a volume ratio of 30:50:20; the lithium nitrate mass fraction is 10%.
[0058] The test results are shown in Table 1.
[0059] Comparative Example 3
[0060] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate and 1,3-dioxane in a volume ratio of 30:70; the mass fraction of lithium nitrate is 10%.
[0061] The test results are shown in Table 1.
[0062] Comparative Example 4
[0063] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate, 1,3-dioxane and diaza-18-crown ether-6, in a volume ratio of 30:50:20.
[0064] The test results are shown in Table 1.
[0065] Comparative Example 5
[0066] The electrolyte lithium salt is LiFSI, and the concentration of lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate, 1,3-dioxane and aza-12-crown ether-4, in a volume ratio of 30:50:20; the lithium nitrate mass fraction is 10%.
[0067] The test results are shown in Table 1.
[0068] Table 1
[0069]
[0070]
[0071] Examples 1-4 demonstrate that increasing the content of LiNO3 additive in the electrolyte can improve the battery's discharge voltage plateau, thereby increasing the battery's discharge specific energy, with an optimal value of 10%-15%. Examples 5 and 6 show that using other high dielectric constant solvents can also result in batteries with high discharge specific energy. Examples 7-9 demonstrate that battery performance is better when the crown ether content is 10%-20%.
[0072] Example 10 illustrates that the battery still exhibits high discharge performance when using azir-15-crown ether-5.
[0073] Examples 1 and 1 (Comparative Example 1) demonstrate that low LiNO3 content is detrimental to battery performance. Examples 2 and 2 (Comparative Example 2) show that using a nitrogen-free crown ether cannot dissolve high concentrations of LiNO3, reducing the battery's discharge voltage and energy density. Examples 2 and 3 (Comparative Example 3) show that the absence of a nitrogen-free crown ether leads to insolubility of lithium nitrate, resulting in poor battery performance. Examples 2 and 4 (Comparative Example 4) demonstrate that an electrolyte without LiNO3 is detrimental to battery performance. Examples 2 and 5 (Comparative Example 5) show that the type of nitrogen-free crown ether has a significant impact on battery performance.
[0074] Unless otherwise specified, all figures appearing in this application specification and claims, such as temperature and time values, should not be construed as absolutely precise values. Due to the standard deviation of measurement techniques, the measured values inevitably contain a certain degree of experimental error.
[0075] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A lithium fluoride carbon battery electrolyte, characterized in that, The lithium fluorinated carbon battery electrolyte includes lithium salt, solvent, and NO3-containing components. - additive; The solvents include high dielectric constant solvents, ether solvents, and azirocro ether solvents; The NO3-containing - The additive has a mass fraction of 5% to 20% in the lithium fluoride carbon battery electrolyte.
2. The lithium fluoride carbon battery electrolyte according to claim 1, characterized in that, The NO3-containing - The additive is selected from at least one of lithium nitrate, copper nitrate, ammonium nitrate, potassium nitrate, sodium nitrate, barium nitrate, zinc nitrate, lead nitrate, nickel nitrate, magnesium nitrate, calcium nitrate, strontium nitrate, and cesium nitrate.
3. The lithium fluoride carbon battery electrolyte according to claim 1, characterized in that, The lithium salt is selected from at least one of LiPF6, LiBF4, LiClO4, LiAsF6, LiBOB, LiODFB, LiFSI, and LiTFSI.
4. The lithium fluoride carbon battery electrolyte according to claim 1, characterized in that, The concentration of the lithium salt is 0.5–3 mol / L; Preferably, the concentration of the lithium salt is 1 to 1.5 mol / L.
5. The lithium fluoride carbon battery electrolyte according to claim 1, characterized in that, The high dielectric constant solvent is selected from at least one of ethylene carbonate, propylene carbonate, diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, methyl acetate, ethyl acetate, n-butyl acetate, and isobutyl acetate.
6. The lithium fluoride carbon battery electrolyte according to claim 1, characterized in that, The ether solvent is selected from at least one of ethylene glycol dimethyl ether, tetrahydrofuran, 1,3-dioxane, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, hydrofluoroether, perfluorobutyl methyl ether, and ethyl perfluorobutyl ether.
7. The lithium fluoride carbon battery electrolyte according to claim 1, characterized in that, The azacrown ether solvent is selected from at least one of aza-15-crown ether-5 and diaza-18-crown ether-6.
8. The lithium fluoride carbon battery electrolyte according to claim 1, characterized in that, The volume ratio of high dielectric constant solvents: ether solvents: azacrown ether solvents is 20-40:30-70:5-30.
9. The lithium fluoride carbon battery electrolyte according to claim 1, characterized in that, The volume ratio of high dielectric constant solvents: ether solvents: azacrown ether solvents is 20-40:30-70:10-20.
10. The application of the lithium fluoride carbon battery electrolyte according to any one of claims 1 to 9 in a lithium fluoride carbon battery, characterized in that, The lithium fluoride carbon battery also includes a fluoride carbon positive electrode, a lithium negative electrode, and a separator.