Lithium / carbon fluoride battery electrolyte and application thereof
By modifying the ferrocene molecules, introducing electron-delivery groups, reducing their redox potential, and applying them in lithium/fluorinated carbon battery electrolytes, the problem of high heat generation of lithium/fluorinated carbon battery discharge is solved, and the battery performance and safety improvement is achieved.
Patent Information
- Application Number
- CN202311709655.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-12
- Publication Date
- 2025-06-13
AI Technical Summary
Lithium/fluorinated carbon batteries produce significant heat during discharge, which affects the design, use and safety of the battery pack. Existing research mainly reduces heat production by optimizing the preparation of fluorinated carbon materials, but the effect is limited and there is a lack of effective heat reduction methods.
By modifying the ferrocene molecules, electron-delivery groups, such as amino groups, alkoxy groups, ester groups and alkyl groups, the redox potential of ferrocene is reduced, so that it acts as a homogeneous catalyst in the electrolyte, interacts with fluoride carbons, regulates its reduction process, and converts the solid-solid reaction to liquid-solid reaction, thereby reducing polarization phenomena and discharge heat generation.
It significantly reduces the heat production during discharge of carbon fluoride batteries, improves the discharge capacity and rate performance of the batteries, enables the batteries to have high energy density and high power characteristics, and improves safety performance.
Smart Images
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Abstract
Description
Technical Field
[0001] The present application relates to an electrolyte for a lithium / carbon fluoride battery and its application, 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 primary lithium batteries with lithium as the negative electrode has received great attention. Primary lithium 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 theoretical specific energy value of the Li / CF x battery is the highest (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, and is particularly suitable as a power source for instrument equipment used in unmanned or enclosed environments. Such as cardiac pacemakers, missile ignition systems, radio transmitters, underwater electronic detectors, etc., especially as a communication power source for military long-range reconnaissance and soldiers to carry with them, with great application potential. However, the heat generation during the discharge process of lithium / carbon fluoride batteries is obvious, directly affecting the design, use, safety of the battery pack, and the design of the power supply system. Most current research is to reduce heat generation by optimizing the preparation of carbon fluoride materials, but the conditions are not easy to control and the obtained materials have poor consistency. It is urgent to seek more effective methods to reduce battery heat generation. Among them, developing an electrolyte suitable for the Li / CF x battery system is a more effective method to improve the battery energy density, rate performance, and reduce battery heat generation. At present, there is little research on reducing the heat generation of Li / CF x batteries by improving the electrolyte, almost none, and it is worthy of in-depth study. Summary of the Invention
[0003] The purpose of the present application is to modify ferrocene molecules by introducing electron-donating groups, including amino groups, alkoxy groups, ester groups, and alkyl groups, thereby reducing the redox potential of ferrocene. As a homogeneous catalyst in the electrolyte, it acts with carbon fluoride to regulate its reduction process to achieve the purpose of accelerating the conversion, converting the solid-solid reaction of the battery into a liquid-solid reaction, thereby reducing the polarization phenomenon and significantly reducing the heat generation during the discharge of carbon fluoride batteries.
[0004] In one aspect of the present application, a lithium / carbon fluoride battery electrolyte is provided. The lithium / carbon fluoride battery electrolyte comprises: a lithium salt, an ester solvent, and a ferrocene derivative;
[0005] The ferrocene derivative has a structure shown in Formula I;
[0006]
[0007] wherein, R is selected from at least one of NH 2 , C n H 2n+1 O, COOH, C n H 2n+1 , and 2 ≤ n ≤ 5.
[0008] Optionally, the mass fraction of the ferrocene derivative in the lithium / carbon fluoride battery electrolyte is 0.5% to 10%.
[0009] Optionally, the mass fraction of the ferrocene derivative in the lithium / carbon fluoride battery electrolyte independently selects any value from 0.5%, 1%, 2%, 4%, 6%, 8%, 10% or a range value between any two of the above.
[0010] Optionally, the lithium salt is selected from at least one of LiPF6, LiBF4, LiClO 4 , LiAsF6, LiBOB, LiODFB, LiFSI, LiTFSI.
[0011] Optionally, the lithium salt is LiClO 4 .
[0012] 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.
[0013] Optionally, in the lithium / carbon fluoride battery electrolyte, the concentration of the lithium salt is 0.5 mol / L to 3 mol / L.
[0014] Optionally, the concentration of the lithium salt is 1 mol / L.
[0015] Optionally, the concentration of the lithium salt independently selects any value from 0.5 mol / L, 1 mol / L, 1.2 mol / L, 2 mol / L, 3 mol / L or a range value between any two of the above.
[0016] Optionally, the volume fraction of the ester solvent in the lithium / carbon fluoride battery electrolyte is 50% to 90%.
[0017] Another aspect of the present application provides an application of the above-mentioned lithium / carbon fluoride battery electrolyte in a lithium / carbon fluoride battery, and the lithium / carbon fluoride battery is pre-charged before use;
[0018] The process of the pre-charging includes: charging the lithium / carbon fluoride battery to 4.2V with a constant current of 0.1mA, and then discharging at a rate of 0.1C.
[0019] The beneficial effects that can be produced by the present application include:
[0020] By modifying ferrocene molecules and introducing electron-donating groups, including amino groups, alkoxy groups, ester groups and alkyl groups, the redox potential of ferrocene is reduced. Its reduction potential is close to the discharge platform potential of carbon fluoride, achieving the purpose of accelerating the conversion of carbon fluoride, converting the solid-solid reaction of the battery into a liquid-solid reaction, thereby reducing the polarization phenomenon and significantly reducing the heat generation during the discharge of the carbon fluoride battery. At the same time, the discharge capacity and discharge rate performance of the battery are improved. The battery has both high energy density and high power characteristics, and better safety performance. Detailed Embodiments
[0021] The present application will be described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0022] Unless otherwise specified, the raw materials in the embodiments of the present application are all purchased through commercial channels.
[0023] Embodiment 1
[0024] Preparation of the lithium / carbon fluoride battery electrolyte: The electrolyte lithium salt is LiClO 4 , the concentration of the lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate and dimethyl carbonate, wherein the volume ratio of propylene carbonate to dimethyl carbonate is 2:3;
[0025] The additive is where R is NH 2 , and its mass fraction is 1% of the electrolyte;
[0026] The carbon fluoride electrode is prepared as follows: The mass ratio of carbon fluoride, conductive carbon black and binder is 8:1:1, which are dissolved in an appropriate amount of N-methylpyrrolidone and mixed evenly. The electrode film with a thickness of 0.15 mm is coated with a wet film preparation device, 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 the 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. At the same time, the temperature change of the battery is monitored.
[0027] Pre - charge the battery: Charge the battery to 4.2V with a constant current of 0.1mA. Then discharge it at a rate of 0.1C.
[0028] The test results are shown in Table 1.
[0029] Example 2
[0030] Preparation of the electrolyte for lithium / carbon monofluoride battery: The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate and dimethyl carbonate, where the volume ratio of propylene carbonate to dimethyl carbonate is 2:3;
[0031] The additive is where R is C 2 H 5 O, and its mass fraction is 1% of the electrolyte;
[0032] The test method is the same as that in Example 1;
[0033] The test results are shown in Table 1.
[0034] Example 3
[0035] Preparation of the electrolyte for lithium / carbon monofluoride battery: The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate and dimethyl carbonate, where the volume ratio of propylene carbonate to dimethyl carbonate is 2:3;
[0036] The additive is where R is COOH, and its mass fraction is 1% of the electrolyte;
[0037] The test method is the same as that in Example 1;
[0038] The test results are shown in Table 1.
[0039] Example 4
[0040] Preparation of the electrolyte for lithium / carbon monofluoride battery: The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate and dimethyl carbonate, where the volume ratio of propylene carbonate to dimethyl carbonate is 2:3;
[0041] The additive is where R is C 3 H 7 , and its mass fraction is 1% of the electrolyte;
[0042] The test method is the same as that in Example 1;
[0043] The test results are shown in Table 1.
[0044] Comparative Example 1
[0045] Preparation of the electrolyte for lithium / carbon monofluoride battery: The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate and dimethyl carbonate, wherein the volume ratio of propylene carbonate to dimethyl carbonate is 2:3; the additive is ferrocene, and its mass fraction is 1% of the electrolyte.
[0046] The carbon monofluoride electrode was prepared as follows: The carbon monofluoride, conductive carbon black, and binder were mixed uniformly in a mass ratio of 8:1:1 in an appropriate amount of N-methylpyrrolidone, and then coated into an electrode film with a thickness of 0.15 mm using a wet film applicator. After vacuum drying, the electrode film was cut into electrode sheets with a diameter of 14 mm using a slicing machine, weighed, and the mass of the active material was calculated. At the same time, a lithium sheet was used as the negative electrode, Celgard 2500 was used as the separator, 100 μL of the electrolyte was added, and a button battery was assembled in a glove box filled with argon. Then, the assembled battery was subjected to electrochemical testing.
[0047] The test results are shown in Table 1.
[0048] Comparative Example 2
[0049] Preparation of the electrolyte for lithium / carbon monofluoride battery: The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate and dimethyl carbonate, wherein the volume ratio of propylene carbonate to dimethyl carbonate is 2:3;
[0050] The additive is R is C 2 H 5 O, and its mass fraction is 1% of the electrolyte;
[0051] The test method is the same as that of Comparative Example 1;
[0052] The test results are shown in Table 1.
[0053] Comparative Example 3
[0054] Preparation of the electrolyte for lithium / carbon monofluoride battery: The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate and dimethyl carbonate, wherein the volume ratio of propylene carbonate to dimethyl carbonate is 2:3;
[0055] The additive is R is CH 3 O, and its mass fraction is 1%;
[0056] The test method is the same as that of Comparative Example 1;
[0057] The test results are shown in Table 1.
[0058] Comparative Example 4
[0059] Preparation of the electrolyte for the lithium / carbon monofluoride battery: The electrolyte lithium salt is LiClO 4 , and the concentration of the lithium salt in the electrolyte is 1.2 mol / L; the solvent is a mixture of propylene carbonate and dimethyl carbonate, wherein the volume ratio of propylene carbonate to dimethyl carbonate is 2:3;
[0060] The additive is 1,1-diethylene glycol monomethyl ether ferrocene, and its mass fraction is 1% of the electrolyte;
[0061] The test method is the same as that in Example 1;
[0062] The test results are shown in Table 1.
[0063] Table 1
[0064]
[0065] As can be seen from Table 1, the groups introduced in Example 1 and Example 2 are super strong electron-donating groups, which significantly reduce the reduction potential of ferrocene, and their accelerating effect on the conversion of carbon monofluoride is more significant, thereby reducing the polarization phenomenon and having the best effect on reducing the heat generation during the discharge of the carbon monofluoride battery. At the same time, the battery has higher rate performance and the best performance. The electron-donating groups introduced in Example 3 and Example 4 are weaker than those in Example 1 and Example 2. Therefore, the discharge temperature of the battery is slightly higher and the rate performance is relatively lower. The additive in Comparative Example 1 is ferrocene without introducing any groups, and its effect is poor. Comparative Example 2 only introduces an electron-donating group on one side of the ferrocene structure, and its effect is not as good as symmetrically introducing functional groups in the ferrocene structure (Example 2). This shows that symmetrically introducing electron-donating groups in the ferrocene molecule has a better effect. Compared with Example 1, Comparative Example 3 lacks a methyl group, resulting in poorer performance. From Comparative Example 4, it can be seen that when 1,1-diethylene glycol monomethyl ether ferrocene is added, the battery performance is poor.
[0066] 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 disclosed technical content, which are equivalent to equivalent embodiments and all fall within the scope of the technical solution.
Claims
1. A lithium / carbon fluoride battery electrolyte, characterized in that, the lithium / carbon fluoride battery electrolyte comprises: a lithium salt, an ester solvent and a ferrocene derivative; the ferrocene derivative has the structure shown in Formula I; Among them, R is selected from NH 2 , C n H 2n+1 O, COOH, C n H 2n+1 and at least one of them, 2 ≤ n ≤ 5.
2. The lithium / carbon fluoride battery electrolyte according to claim 1, characterized in that, the mass fraction of the ferrocene derivative in the lithium / carbon fluoride battery electrolyte is 0.5% to 10%.
3. The lithium / carbon fluoride battery electrolyte according to claim 1, characterized in that, The lithium salt is selected from at least one of LiPF6, LiBF4, LiClO 4 , LiAsF6, LiBOB, LiODFB, LiFSI, and LiTFSI.
4. The lithium / carbon fluoride battery electrolyte according to claim 1, 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, isobutyl acetate.
5. The lithium / carbon fluoride battery electrolyte according to claim 1, characterized in that in the lithium / carbon fluoride battery electrolyte, the concentration of the lithium salt is 0.5 mol / L to 3 mol / L.
6. The lithium / carbon fluoride battery electrolyte according to claim 1, characterized in that, the volume fraction of the ester solvent in the lithium / carbon fluoride battery electrolyte is 50% to 90%.
7. An application of the lithium / carbon fluoride battery electrolyte according to any one of claims 1 to 6 in a lithium / carbon fluoride battery, characterized in that, the lithium / carbon fluoride battery is pre-charged before use; the process of the pre-charging includes: charging the lithium / carbon fluoride battery to 4.2V with a constant current of 0.1 mA, and then discharging at a rate of 0.1C.