Li / CFx battery electrolyte containing cyclic organic molecule additive
By adding cyclic organic molecules as additives to the lithium/fluorinated carbon battery electrolyte, the polarization problem of lithium/fluorinated carbon battery during discharge is solved, which significantly improves the battery's high-rate performance and voltage platform, and reduces battery heat production.
Patent Information
- Application Number
- CN202311707148.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-12
- Publication Date
- 2025-06-13
Smart Images
Figure BDA0004606549770000021 
Figure BDA0004606549770000061 
Figure FDA0004606549710000011
Abstract
Description
Technical Field
[0001] The present application relates to an electrolyte for a Li / CFx battery, belonging to the field of primary lithium / carbon fluoride batteries. Background Art
[0002] With the technological progress in fields such as mobile communication, aerospace, transportation, and military equipment, the development of various high specific energy power batteries has also become an urgent need for the development of the national economy. Due to the characteristics of light mass and negative electrode potential of metallic lithium, the development of lithium primary batteries with lithium as the negative electrode has received great attention. Lithium primary batteries mainly include lithium-manganese dioxide (Li / MnO 2 ), lithium-sulfur dioxide (Li / SO 2 ), lithium-thionyl chloride (Li / SOCl 2 ), and lithium-carbon fluoride (Li / CF x ) and other battery systems. Compared with other primary batteries, the Li / CF x battery has the highest theoretical specific energy value (2180 W·h / kg). At the same time, the Li / CF x battery also has advantages such as high safety, stable discharge voltage, and environmental friendliness. Especially in space applications such as satellites, spacecraft, space stations, deep space exploration (Mars, asteroids) landers, upper stages, and orbital transfer vehicles, as well as in individual soldier systems, unmanned aerial vehicles, etc., in addition to requiring the weight of each component to be as light as possible to increase the payload, the power supply is also required to be able to discharge at a large current and provide a high power to meet the rapid response of military equipment. However, due to the poor intrinsic conductivity of the positive electrode material carbon fluoride and the slow electrode kinetic process, a large polarization occurs during the discharge process of the lithium / carbon fluoride primary battery, resulting in the lithium / carbon fluoride battery being limited to discharging at a low rate and having a voltage lag at the initial stage of discharge; at the same time, a large amount of heat dissipation occurs during the discharge process, affecting the performance of the battery, severely restricting the application of the lithium / carbon fluoride battery. Developing an electrolyte suitable for the Li / CF x battery system is a more effective method to improve the high-rate performance of the battery. Summary of the Invention
[0003] The purpose of the present application is to add a cyclic organic molecule additive to the electrolyte, so that it undergoes a reduction reaction at the carbon fluoride electrode during the discharge process of the lithium / carbon fluoride battery to form organic lithium and inorganic lithium compounds, which combine with the discharge product lithium fluoride of carbon fluoride to form vacancies along the grain boundaries between different materials, providing a channel for the transmission of Li+, thereby reducing polarization and significantly improving the high-rate performance of the battery.
[0004] In one aspect of the present application, there is provided an electrolyte for a Li / CF x battery, the Li / CF xThe battery electrolyte includes: a lithium salt, an ester solvent, an ether solvent, and an additive;
[0005] The additive is a cyclic organic molecule.
[0006] Optionally, the cyclic organic molecule is selected from at least one of the structures represented by Formulas a to e;
[0007]
[0008] Optionally, the mass fraction of the cyclic organic molecule in the Li / CF x battery electrolyte is 0.5% to 20%.
[0009] Optionally, the mass fraction of the cyclic organic molecule in the Li / CF x battery electrolyte is independently selected from any value of 0.5%, 1%, 2%, 5%, 10%, 15%, 20% or any range value between any two of the above.
[0010] Optionally, in the Li / CF x battery electrolyte, the concentration of the lithium salt is 0.5 mol / L to 3 mol / L.
[0011] Optionally, in the Li / CF x battery electrolyte, the concentration of the lithium salt is 1 mol / L.
[0012] Optionally, the concentration of the lithium salt is independently selected from any value of 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L or any range value between any two of the above.
[0013] Optionally, the lithium salt is selected from at least one of LiPF6, LiBF4, LiClO 4 , LiAsF6, LiBOB, LiODFB, LiFSI, LiTFSI.
[0014] Optionally, the ester 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, isobutyl acetate.
[0015] Optionally, the volume fraction of the ester solvent in the Li / CF x battery electrolyte is 10% to 50%.
[0016] Optionally, the volume fraction of the ester solvent in the Li / CF x battery electrolyte is 30%.
[0017] Optionally, the ester solvent in the Li / CF x The volume fraction of the battery electrolyte is independently selected from any value among 10%, 60%, 30%, 40%, 50% or any range value between any two of the above.
[0018] Optionally, the ether solvent is selected from at least one of ethylene glycol dimethyl ether, tetrahydrofuran, dioxolane, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, hydrofluoroether, perfluorobutyl methyl ether, and ethyl perfluorobutyl ether.
[0019] Optionally, the ether solvent in the Li / CF x The volume fraction of the battery electrolyte is 50% - 90%.
[0020] Optionally, the ether solvent in the Li / CF x The volume fraction of the battery electrolyte is 70%.
[0021] Optionally, the ether solvent in the Li / CF x The volume fraction of the battery electrolyte is independently selected from any value among 50%, 60%, 70%, 80%, 90% or any range value between any two of the above.
[0022] The beneficial effects that can be produced by this application include:
[0023] By adding a cyclic organic molecule to the electrolyte, a reduction reaction occurs at the carbon fluoride electrode during the discharge process of the lithium / carbon fluoride battery to form organolithium and inorganic lithium compounds, which combine with the discharge product lithium fluoride of carbon fluoride to form vacancies along the particle boundaries between different materials, providing a channel for the transport of Li+, thereby reducing polarization, significantly improving the high-rate performance of the battery, increasing the voltage platform, and reducing the heat generation of the battery. Specific embodiments
[0024] The following describes this application in detail with reference to the embodiments, but this application is not limited to these embodiments.
[0025] Unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels.
[0026] Embodiment 1
[0027] The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the Li / CF x battery electrolyte is 1 mol / L; the solvent is a mixture of propylene carbonate and dioxolane with a volume ratio of 1:2
[0028] The additive is In the Li / CF xThe mass fraction in the battery electrolyte is 2%;
[0029] The carbon fluoride electrode is prepared as follows: carbon fluoride, conductive carbon black, and binder are mixed in a mass ratio of 8:1:1 and dissolved in an appropriate amount of N-methylpyrrolidone and mixed evenly. Then, it is coated into an electrode film with a thickness of 0.15 mm using a wet film coater, dried in vacuum, and cut into electrode sheets with a diameter of 14 mm using a slicing machine. Weigh and calculate the mass of the active material. At the same time, a lithium sheet is used as the negative electrode, Celgard 2500 is used as the separator, 100 μL of electrolyte is added, and a button battery is assembled in a glove box filled with argon. Then, the assembled battery is subjected to electrochemical tests. At the same time, monitor the battery temperature change.
[0030] The test results are shown in Table 1.
[0031] Example 2
[0032] The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the Li / CF x battery electrolyte is 1 mol / L; the solvent is a mixture of propylene carbonate and dioxolane with a volume ratio of 1:2;
[0033] The additive is In the Li / CF x battery electrolyte, the mass fraction is 2%;
[0034] The test results are shown in Table 1.
[0035] Example 3
[0036] The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the Li / CF x battery electrolyte is 1 mol / L; the solvent is a mixture of propylene carbonate and dioxolane with a volume ratio of 1:2;
[0037] The additive is In the Li / CF x battery electrolyte, the mass fraction is 5%;
[0038] The test method is the same as that in Example 1;
[0039] The test results are shown in Table 1.
[0040] Example 4
[0041] The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the Li / CF x battery electrolyte is 1 mol / L; the solvent is a mixture of propylene carbonate and dioxolane with a volume ratio of 1:2;
[0042] The additive is In the Li / CF x the mass fraction in the battery electrolyte is 10%;
[0043] The testing method is the same as that in Example 1;
[0044] The test results are shown in Table 1.
[0045] Example 5
[0046] The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the Li / CF x battery electrolyte is 1 mol / L; the solvent is a mixture of propylene carbonate and dioxolane with a volume ratio of 1:2;
[0047] The additive is in the Li / CF x the mass fraction in the battery electrolyte is 15%;
[0048] The testing method is the same as that in Example 1;
[0049] The test results are shown in Table 1.
[0050] Comparative Example 1
[0051] The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the Li / CF x battery electrolyte is 1 mol / L; the solvent is a mixture of propylene carbonate and dioxolane with a volume ratio of 1:2;
[0052] The carbon fluoride electrode is prepared as follows: carbon fluoride, conductive carbon black, and binder are dissolved in an appropriate amount of N-methylpyrrolidone in a mass ratio of 8:1:1 and mixed evenly. The electrode film with a thickness of 0.15 mm is coated with a wet film coater, vacuum dried, and then cut into electrode sheets with a diameter of 14 mm with a slicing machine, weighed, and the mass of the active material is calculated. At the same time, a lithium sheet is used as the negative electrode, Celgard 2500 is used as the separator, 100 μL of electrolyte is added, and a button battery is assembled in a glove box filled with argon, and then the assembled battery is subjected to electrochemical testing.
[0053] The test results are shown in Table 1.
[0054] Comparative Example 2
[0055] The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the Li / CF x battery electrolyte is 1 mol / L; the solvent is a mixture of propylene carbonate and dioxolane with a volume ratio of 1:2; the mass fraction of vinylene carbonate (VC) is 10%;
[0056] The testing method is the same as that in Comparative Example 1;
[0057] The test results are shown in Table 1.
[0058] Table 1
[0059]
[0060] As can be seen from Table 1, Examples 1 to 5 show that by adding a cyclic organic molecule additive to the electrolyte, its reduction product combines with LiF to provide a channel for the transport of Li+, thereby reducing polarization and significantly improving the high-rate performance of the battery. Examples 2 to 5 show that as the content of the additive increases, the battery rate performance first increases and then decreases, and the performance is the highest when the addition amount is 10%. The performance decreases at 15%, which is due to the change in the Li+ transport effect caused by the difference in the compounding ratio of the additive reduction product and LiF. Comparative Examples 1 and 2 show that without adding a cyclic organic molecule additive, the battery rate performance is very poor.
[0061] The above are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, makes some changes or modifications using the technical content disclosed above, which are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.
Claims
1. A Li / CF x battery electrolyte It is characterized in that The Li / CF x battery electrolyte includes: a lithium salt, an ester solvent, an ether solvent, and an additive; the additive is a cyclic organic molecule.
2. The Li / CF x battery electrolyte It is characterized in that the cyclic organic molecule is selected from at least one of the structures represented by Formulae a to e; 3. The Li / CF x battery electrolyte It is characterized in that The mass fraction of the cyclic organic molecule in the Li / CF x battery electrolyte is 0.5% to 20%.
4. The Li / CF x battery electrolyte It is characterized in that The Li / CF x In the battery electrolyte, the concentration of the lithium salt is 0.5 mol / L to 3 mol / L.
5. The Li / CF x battery electrolyte It is characterized in that The lithium salt is selected from at least one of LiPF6, LiBF4, LiClO 4 , LiAsF6, LiBOB, LiODFB, LiFSI, and LiTFSI.
6. The Li / CF x battery electrolyte, It is characterized in that the ester 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.
7. The Li / CF x battery electrolyte It is characterized in that The volume fraction of the ester solvent in the Li / CF x battery electrolyte is 10% to 50%.
8. The Li / CF x battery electrolyte It is characterized in that the ether solvent is selected from at least one of ethylene glycol dimethyl ether, tetrahydrofuran, dioxolane, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, hydrofluoroether, perfluorobutyl methyl ether, and ethyl perfluorobutyl ether.
9. The Li / CF x battery electrolyte It is characterized in that The volume fraction of the ether solvent in the Li / CF x battery electrolyte is 50% to 90%.