High temperature electrolyte for carbon fluoride / manganese dioxide composite positive electrode lithium primary battery and its preparation method
Patent Information
- Application Number
- CN202610877449.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-17
- Publication Date
- 2026-08-28
AI Technical Summary
[0005]本发明是要解决现有的氟化碳/二氧化锰复合正极锂一次电池高温下容量衰减速度快的技术问题，而提供一种用于氟化碳/二氧化锰复合正极锂一次电池的高温电解液及其制备方法
[0016] I. The present invention uses LiBF4 and LiClO4 as lithium salts for the electrolyte, which effectively ensures that the electrolyte has higher thermal stability at high temperature, while effectively suppressing the dissolution and side reactions of the composite cathode material at high temperature; the dual salt system can help regulate the unique solvation structure, reduce the number of "free" solvent molecules that are easy to react at high temperature, and fundamentally suppress side reactions.
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Figure CN122659166A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of lithium metal battery technology, specifically relating to a high-temperature electrolyte for a primary lithium battery with a fluorinated carbon / manganese dioxide composite cathode. Background Technology
[0002] Energy plays a vital role in modern society, with non-renewable energy sources such as coal and oil forming a significant portion of the current energy structure. However, increasing energy demand has led to a declining global energy reserve. Furthermore, the use of energy derived from fossil fuels releases substantial amounts of pollutants, far exceeding environmental limits. More importantly, greenhouse gas emissions (such as CO2) have caused irreversible negative impacts on the global climate and have resulted in frequent ecological and environmental problems, which are highly detrimental to the sustainable development of human society. The challenges posed by energy and environmental issues have spurred the development of the concept of clean energy and highlighted the urgent need for its global development. Currently, successfully developed and applied clean energy sources include ocean energy, solar energy, bioenergy, geothermal energy, and hydropower. The rapid development of science and technology has demanded "on-demand" energy, leading to the emergence of energy storage systems with green and clean characteristics. Moreover, against the backdrop of "carbon peaking and carbon neutrality," large-capacity energy storage technology is also promoting the development of new energy sources. Among various energy storage systems, electrochemical energy storage has gradually become a leader in energy storage technology due to its high specific energy, low cost, and excellent environmental performance. Lithium-ion batteries, in particular, have attracted widespread attention because their raw materials are green and clean, and they do not pollute the environment during use. Furthermore, lithium-ion batteries also possess advantages such as high energy density, long lifespan, high operating voltage, and a wide service temperature range, making them highly promising for both military equipment and civilian applications. In the context of a low-carbon society, the active exploration of lithium-ion batteries has profound significance for promoting global development.
[0003] In recent years, the rapid development of aerospace, military, drilling, and other fields has led to an increasing demand for electrical energy sources with high specific energy, high safety, and long storage life. This is evident in applications such as orbital transfer vehicles, individual soldier systems, and drones, which has brought renewed attention to lithium / carbon fluoride primary batteries with their superior specific energy. Researchers are exploring the use of fluorocarbon materials and CF2... x Extensive research has been conducted on the composite materials with other materials, discharge mechanisms, and performance. Significant progress has been made in both research and industrial applications of fluorinated carbon materials and lithium / fluorinated carbon batteries, particularly in Li / CF4 batteries. x Batteries generate significant heat and expand considerably during high-rate discharge; therefore, further improvements in Li / CF2 ratio are needed. xThe battery exhibits high rate capability. It consists of three parts: a high-energy-density fluorinated carbon cathode, a lithium metal anode with the lowest electrode potential (-3.04V vs. SHE), and an organic electrolyte. Fluorinated carbon (CF4) is the primary component. x The theoretical energy density of the material (x=1) reaches 2180 Wh / kg, the highest among existing solid-state lithium primary batteries. Furthermore, the battery boasts advantages such as high specific capacity, stable discharge, wide operating temperature range, and good safety performance. Due to the high chemical stability of fluorinated carbon materials, the battery's capacity loss rate is less than 0.5% per year, resulting in a long storage life. Besides improving battery energy density and storage life, the power source also needs to be able to deliver short-duration, high-current pulse discharges to provide high instantaneous power for rapid response in military equipment. However, as the fluorination process proceeds, the hybridization of carbon in the material changes from sp2 to sp3, and a large number of stable CF covalent bonds are formed. This directly affects the electronic conductivity of fluorinated carbon materials, resulting in poor rate performance of lithium / fluorinated carbon batteries. Conversely, reducing the fluorine content directly impacts battery capacity. Therefore, the focus of lithium primary battery research is on developing novel composite cathode material systems with high energy density and the ability to achieve short-duration pulse discharges.
[0004] Li / CF x The primary battery discharge mechanism is as follows: During discharge, solvated lithium ions enter the interlayer of fluorinated carbon, generating a ternary mesophase CF. x Li x :S y (S is the solvent co-intercalated with lithium ions). This compound then spontaneously decomposes into C, LiF, and the solvent, releasing the solvent back into the organic electrolyte. The entire process is irreversible, causing the battery open-circuit voltage to drop from 4.5V to 3V~3.5V, while generating a large amount of heat during the reaction. CF x The discharge product LiF generated during the discharge process is an electronically and ionicly insulating material. As the discharge progresses, LiF continuously coats the positive electrode, affecting its power characteristics. Because CF... x The material's inherent low electronic conductivity and unique electrochemical reaction mechanism make Li / CF x Primary batteries suffer from poor rate discharge performance, slow instantaneous response, poor wide-temperature adaptability (low-temperature voltage hysteresis and high-temperature heat release), and volume expansion. Due to CF... x The material has very stable physicochemical properties and is effective against CF. xStructural modification of materials through doping is difficult; typically, mixing and coating methods are used to modify the cathode, which can significantly improve its discharge voltage and other performance characteristics. Manganese dioxide (MnO2) has higher electronic conductivity and has attracted much attention due to its high discharge voltage plateau and high discharge rate, making Li / MnO2 batteries perform well in various applications, especially suitable for devices requiring high voltage and high current density. It is considered a cost-effective material for reducing battery voltage hysteresis. Furthermore, Li / MnO2 batteries exhibit excellent low-temperature performance and low heat generation characteristics, demonstrating good environmental adaptability. However, MnO2 as a cathode active material also has certain drawbacks, such as low actual mass energy density, short storage life, and high self-discharge rate. MnO2 and CF2 can be combined... x Composites are used to leverage the advantages of both materials and compensate for their respective shortcomings. However, combining MnO2 and CF... x Even after composite processing, the materials still suffer from low storage life and high self-discharge rate. Designing a suitable electrolyte is one of the most convenient strategies to improve the self-discharge rate of fluorinated carbon / manganese dioxide composite cathode lithium primary batteries. Furthermore, electrolyte design for practical battery systems offers significant advantages in terms of repeatability and ease of large-scale manufacturing. Therefore, developing a high-temperature electrolyte suitable for fluorinated carbon / manganese dioxide composite cathode lithium primary batteries is essential. Summary of the Invention
[0005] The present invention aims to solve the technical problem of rapid capacity decay in existing carbon fluoride / manganese dioxide composite cathode lithium primary batteries at high temperatures, and provides a high-temperature electrolyte for carbon fluoride / manganese dioxide composite cathode lithium primary batteries and its preparation method.
[0006] The high-temperature electrolyte for a carbon fluoride / manganese dioxide composite cathode lithium primary battery of the present invention is composed of lithium salt, ester solvent, ether solvent and additives;
[0007] The lithium salt is a mixture of lithium tetrafluoroborate (LiBF4) and lithium perchlorate (LiClO4) or a mixture of lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4) and lithium bis(fluorosulfonyl)imide (LiFSI), and the molar concentration of the lithium salt in the high-temperature electrolyte is 1~1.3 mol / L.
[0008] The ester solvent is one or a mixture of two of propylene carbonate (PC) and ethylene carbonate (EC);
[0009] The ether solvent is one or a mixture of two of ethylene glycol dimethyl ether (DME) and 1,3-dioxane (DOL);
[0010] The volume ratio of the ester solvent to the ether solvent is (1~3):(1~3);
[0011] The additive is one or a mixture of several of 1,3-dimethyl-1,3-diphenyl-1,3-divinyldisiloxane (DK244), succinic anionyl (SN), and 1,3,6-hexanetrionitrile (HTN);
[0012] The additive is 1% to 5% of the total mass of the high-temperature electrolyte.
[0013] This invention also provides a method for preparing the above-mentioned high-temperature electrolyte for a carbon fluoride / manganese dioxide composite cathode lithium primary battery, comprising the following steps:
[0014] Under an inert atmosphere, ester solvents and ether solvents are thoroughly mixed to obtain a mixed solvent; lithium salt is then added to the mixed solvent and dispersed evenly; after adding additives, the mixture is thoroughly mixed to obtain a high-temperature electrolyte.
[0015] Compared with the prior art, the present invention has the following advantages:
[0016] I. The present invention uses LiBF4 and LiClO4 as lithium salts for the electrolyte, which effectively ensures that the electrolyte has higher thermal stability at high temperature, while effectively suppressing the dissolution and side reactions of the composite cathode material at high temperature; the dual salt system can help regulate the unique solvation structure, reduce the number of "free" solvent molecules that are easy to react at high temperature, and fundamentally suppress side reactions.
[0017] 2. Compared with conventional electrolytes, the high-temperature electrolyte of the present invention can effectively suppress the dissolution of manganese ions by forming a stable elastic SEI film containing an organosilicon (silicon from DK244) network at the interface, reduce the increase in internal resistance during high-temperature storage, effectively alleviate the self-discharge of the fluorinated carbon / manganese dioxide composite cathode lithium primary battery, and alleviate the problem of its rapid capacity decay at high temperature.
[0018] Third, the operation steps of the present invention are simple, the equipment used is simple, and it is easy to prepare. Attached Figure Description
[0019] Figure 1 The discharge curves of the fluorinated carbon / manganese dioxide composite cathode lithium primary batteries prepared for Example 1 and Comparative Example 1 at 0.05C before storage;
[0020] Figure 2 The discharge curves of the fluorinated carbon / manganese dioxide composite cathode lithium primary batteries prepared for Example 1 and Comparative Example 1 at 0.05C after being stored at 55°C for 30 days;
[0021] Figure 3 Scanning electron microscope image of the negative electrode of the lithium primary battery with fluorinated carbon / manganese dioxide composite positive electrode prepared for Comparative Example 1 after storage at 55°C for 30 days.
[0022] Figure 4 The negative electrode of the lithium primary battery with fluorinated carbon / manganese dioxide composite positive electrode prepared in Example 1 is a scanning electron microscope image of the negative electrode after being stored at 55°C for 30 days.
[0023] Figure 5 This is a schematic diagram of the structure of the electrolyte prepared in this invention on the SEI surface of the fluorinated carbon / manganese dioxide composite cathode. Detailed Implementation
[0024] Specific Implementation Method 1: This implementation method is a high-temperature electrolyte for a primary lithium battery with a fluorinated carbon / manganese dioxide composite cathode, specifically composed of lithium salt, ester solvent, ether solvent and additives.
[0025] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the lithium salt is a mixture of lithium tetrafluoroborate and lithium perchlorate, or a mixture of lithium tetrafluoroborate, lithium perchlorate, and lithium bis(fluorosulfonyl)imide. Everything else is the same as in Specific Implementation Method One.
[0026] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 2 in that the molar concentration of the lithium salt in the high-temperature electrolyte is 1 mol / L to 1.3 mol / L. Everything else is the same as in Specific Implementation Method 2.
[0027] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the ester solvent is one or a mixture of two of propylene carbonate and ethylene carbonate. Everything else is the same as in Specific Implementation Methods One to Three.
[0028] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Four in that the ether solvent is one or a mixture of two of ethylene glycol dimethyl ether and 1,3-dioxane. Everything else is the same as in Specific Implementation Method Four.
[0029] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Five in that the volume ratio of the ester solvent to the ether solvent is (1~3):(1~3). Everything else is the same as in Specific Implementation Method Five.
[0030] Specific Embodiment Seven: This embodiment differs from Specific Embodiment Six in that the additive is one or a mixture of several of 1,3-dimethyl-1,3-diphenyl-1,3-divinyldisiloxane, butadionitrile, and 1,3,6-hexanetrionitrile. Everything else is the same as in Specific Embodiment Six.
[0031] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Seven in that the additive is 1% to 5% of the total mass of the high-temperature electrolyte. Everything else is the same as in Specific Implementation Method Seven.
[0032] Specific Implementation Method Nine: This implementation method is the preparation method of the high-temperature electrolyte for the fluorinated carbon / manganese dioxide composite cathode lithium primary battery described in Specific Implementation Method One, including the following steps:
[0033] Under an inert atmosphere, ester solvents and ether solvents are thoroughly mixed to obtain a mixed solvent; lithium salt is then added to the mixed solvent and dispersed evenly; after adding additives, the mixture is thoroughly mixed to obtain a high-temperature electrolyte.
[0034] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Nine in that the inert atmosphere is argon. Everything else is the same as in Specific Implementation Method Nine.
[0035] The present invention is verified using the following examples:
[0036] Example 1
[0037] I. Preparation of high-temperature electrolyte:
[0038] In an argon atmosphere, ethylene carbonate (PC) and dimethyl ethylene glycol (DME) were mixed at a volume ratio of 1:1, then LiBF4 and LiClO4 were added and stirred until homogeneous. Finally, DK244 was added to obtain a high-temperature electrolyte.
[0039] The concentrations of LiBF4 and LiClO4 in the high-temperature electrolyte are both 0.5 mol / L, and the volume of DK244 is 3% of the volume of the high-temperature electrolyte.
[0040] II. Performance Testing of Lithium Primary Batteries with Fluorinated Carbon / Manganese Dioxide Composite Cathode:
[0041] A manganese dioxide / fluorocarbon composite material (positive electrode active material) with a mass ratio of 1:9, super P (conductive additive), and PVDF (binder) were slurried at a mass ratio of 8:1:1. The slurry was then coated onto aluminum foil and heated to 70°C. o Dry at C for 8 hours to obtain a manganese dioxide / fluorinated carbon composite positive electrode sheet; cut the positive electrode sheet into small round pieces with a diameter of 1 cm; stack the small round pieces, polyethylene separator, lithium sheet (negative electrode) and nickel foam in the battery case in sequence; and then drop in 40 μL of the high-temperature electrolyte prepared in step one.
[0042] The battery casing was completely sealed to obtain a fluorinated carbon / manganese dioxide composite cathode lithium primary battery. Battery performance was tested at 25ºC, and battery capacity was calculated based on the mass of the cathode. The test results are shown in Table 1.
[0043] Example 2: The difference between this example and Example 1 is that the volume of DK244 in step one is 2% of the volume of the high-temperature electrolyte. Everything else is the same as in Example 1.
[0044] Example 3: The difference between this example and Example 1 is that the volume of DK244 in step one is 1% of the volume of the high-temperature electrolyte. Everything else is the same as in Example 1.
[0045] Example 4: The difference between this example and Example 1 is that in step one, DK244 is replaced with SN, while the amount added remains the same. Everything else is the same as in Example 1.
[0046] Example 5: The difference between this example and Example 4 is that the volume of SN in step one is 2% of the volume of the high-temperature electrolyte. Everything else is the same as in Example 4.
[0047] Example 6: The difference between this example and Example 4 is that the volume of SN in step one is 1% of the volume of the high-temperature electrolyte. Everything else is the same as in Example 4.
[0048] Example 7: The difference between this example and Example 1 is that DK244 is replaced with HTN in step one, while the amount added remains the same. Everything else is the same as in Example 1.
[0049] Example 8: The difference between this example and Example 7 is that the volume of HTN in step one is 2% of the volume of the high-temperature electrolyte. Everything else is the same as in Example 7.
[0050] Example 9: The difference between this example and Example 7 is that the volume of HTN in step one is 1% of the volume of the high-temperature electrolyte. Everything else is the same as in Example 7.
[0051] Example 10: The difference between this example and Example 1 is that in step one, LiBF4 and LiClO4 are replaced with only LiBF4, and the concentration of LiBF4 in the high-temperature electrolyte is 1 mol / L. Everything else is the same as in Example 1.
[0052] Example 11: The difference between this example and Example 1 is that in step one, LiBF4 and LiClO4 are replaced with only LiClO4, and the concentration of LiClO4 in the high-temperature electrolyte is 1 mol / L. Everything else is the same as in Example 1.
[0053] Comparative Example 1: The difference between this example and Example 1 is that DK244 is not added in step one. Everything else is the same as in Example 1.
[0054] Comparative Example 2: The difference between this example and Example 10 is that DK244 is not added in step one. Everything else is the same as in Example 10.
[0055] Comparative Example 3: The difference between this example and Example 11 is that DK244 is not added in step one. Everything else is the same as in Example 11.
[0056] Table 1. High-temperature (55℃) storage performance test
[0057]
[0058] The analysis of Table 1 is as follows:
[0059] (1) According to the data of Examples 1-3 and Comparative Example 1, the high-temperature electrolyte prepared by the present invention can still improve the capacity retention rate of the fluorinated carbon / manganese dioxide composite cathode lithium primary battery even after adding only 1% volume fraction of DK244. The effect is best when the addition amount is 3% (Example 3).
[0060] (2) According to the data of Examples 4-6 and Comparative Example 1, the high-temperature capacity retention rate of the battery was also effectively improved after adding SN. SN inhibited the dissolution of manganese element by coordinating C≡N with Mn on the surface, thus alleviating self-discharge.
[0061] (3) According to the data of Examples 7-9 and Comparative Example 1, the high-temperature capacity retention rate of the battery can be effectively improved after adding HTN. Its mechanism of action is similar to that of SN, which is to inhibit the dissolution of manganese element through the coordination of C≡N and Mn, but the effect is slightly worse.
[0062] (4) Based on the data from Examples 1, 10, 11 and Comparative Examples 1-3, it can be seen that the dual-salt system can give full play to the characteristics of the two lithium salts, generate a more stable SEI film at the interface, ensure interface stability, suppress battery self-discharge, and thus effectively improve capacity retention.
[0063] Figure 1 The discharge curves of the fluorinated carbon / manganese dioxide composite cathode lithium primary batteries prepared in Example 1 and Comparative Example 1 at 0.05C before storage show that the addition of DK244 has no effect on the discharge capacity of the fluorinated carbon / manganese dioxide composite cathode lithium primary batteries before high-temperature storage.
[0064] Figure 2 The discharge curves of the fluorinated carbon / manganese dioxide composite cathode lithium primary batteries prepared in Example 1 and Comparative Example 1 at 0.05C after storage at 55°C for 30 days show that after 30 days of high-temperature storage, the discharge specific capacity of the battery with added DK244 is significantly higher than that of the battery without added DK244, indicating that the addition of DK244 suppresses the self-discharge of the fluorinated carbon / manganese dioxide composite cathode lithium primary battery.
[0065] Figure 3 The image shows the negative electrode of the lithium primary battery with fluorinated carbon / manganese dioxide composite cathode prepared in Comparative Example 1 after storage at 55°C for 30 days. Figure 4The image shows the negative electrode of the fluorinated carbon / manganese dioxide composite positive electrode lithium primary battery prepared in Example 1 after storage at 55°C for 30 days. It can be seen that the corrosion on the surface of the negative electrode of the battery with added DK244 is significantly less than that without added DK244, indicating that the addition of DK244 effectively inhibits the dissolution of manganese ions.
[0066] Figure 5 This is a schematic diagram of the structure of the electrolyte prepared in this invention on the SEI surface of the fluorinated carbon / manganese dioxide composite cathode.
Claims
1. A high-temperature electrolyte for a fluorinated carbon / manganese dioxide composite cathode lithium primary battery, characterized in that... The high-temperature electrolyte is composed of lithium salt, ester solvent, ether solvent and additives.
2. The high-temperature electrolyte for a carbon fluoride / manganese dioxide composite cathode lithium primary battery according to claim 1, characterized in that... The lithium salt is a mixture of lithium tetrafluoroborate and lithium perchlorate, or a mixture of lithium tetrafluoroborate, lithium perchlorate, and lithium bis(fluorosulfonyl)imide.
3. The high-temperature electrolyte for a carbon fluoride / manganese dioxide composite cathode lithium primary battery according to claim 2, characterized in that... The molar concentration of the lithium salt in the high-temperature electrolyte is 1 mol / L to 1.3 mol / L.
4. The high-temperature electrolyte for a carbon fluoride / manganese dioxide composite cathode lithium primary battery according to claim 1, characterized in that... The ester solvent is one or a mixture of two of propylene carbonate and ethylene carbonate.
5. The high-temperature electrolyte for a carbon fluoride / manganese dioxide composite cathode lithium primary battery according to claim 4, characterized in that... The ether solvent is one or a mixture of two of ethylene glycol dimethyl ether and 1,3-dioxane.
6. The high-temperature electrolyte for a primary lithium battery with a fluorinated carbon / manganese dioxide composite cathode according to claim 5, characterized in that... The volume ratio of the ester solvent to the ether solvent is (1~3):(1~3).
7. The high-temperature electrolyte for a primary lithium battery with a fluorinated carbon / manganese dioxide composite cathode according to claim 1, characterized in that... The additive is one or a mixture of several of 1,3-dimethyl-1,3-diphenyl-1,3-divinyldisiloxane, butadionitrile, and 1,3,6-hexanetrionitrile.
8. The high-temperature electrolyte for a primary lithium battery with a fluorinated carbon / manganese dioxide composite cathode according to claim 1, characterized in that... The additive is 1% to 5% of the total mass of the high-temperature electrolyte.
9. The method for preparing a high-temperature electrolyte for a carbon fluoride / manganese dioxide composite cathode lithium primary battery as described in claim 1, characterized in that... The preparation method includes the following steps: Under an inert atmosphere, ester solvents and ether solvents are thoroughly mixed to obtain a mixed solvent; lithium salt is then added to the mixed solvent and dispersed evenly; after adding additives, the mixture is thoroughly mixed to obtain a high-temperature electrolyte.
10. A method for preparing a high-temperature electrolyte for a carbon fluoride / manganese dioxide composite cathode lithium primary battery according to claim 9, characterized in that... The inert atmosphere is argon.