Lithium-carbon monofluoride primary battery electrolyte and lithium-carbon monofluoride primary battery
By optimizing the electrolyte composition of lithium fluorocarbon batteries and using functional additives and electrolyte lithium salts, the problems of poor conductivity and electrode expansion in lithium fluorocarbon batteries under high-rate conditions have been solved, resulting in reduced internal resistance and improved self-discharge, thus expanding their application range.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHANGJIAGANG GUOTAI HUARONG NEW CHEM MATERIALS CO LTD
- Filing Date
- 2024-12-03
- Publication Date
- 2026-06-05
AI Technical Summary
Lithium-carbon fluoride primary batteries suffer from poor conductivity at high rates, and the deposition of discharge products leads to electrode volume expansion and blockage of lithium-ion liquid phase diffusion channels. In addition, the high cost of the electrolyte limits their application.
An electrolyte containing functional additives such as boron trifluoride pyridine, dimethyl boron trifluoride carbonate, and dipyrrole methylene boron difluoride, combined with lithium electrolyte salts such as lithium tetrafluoroborate and lithium perchlorate and specific organic solvents, is used to optimize the electrolyte composition in order to improve conductivity and form a stable SEI film.
It significantly reduces the internal resistance of lithium fluorocarbon batteries, improves self-discharge and rate performance, expands the range of applications, and enhances battery stability and low-temperature discharge performance.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium primary battery technology, specifically to a lithium fluoride carbon primary battery electrolyte and a lithium fluoride carbon primary battery. Background Technology
[0002] Lithium-fluorinated carbon (CFCC) primary batteries currently boast the highest energy density among battery systems, reaching an actual specific energy of 650 Wh / kg (0.01C discharge). Their operating voltage is around 2.5V, with a wide operating temperature range of -20 to 130°C. They exhibit low self-discharge and a storage life exceeding 10 years. CFCC primary batteries use fluorinated carbon as the positive electrode and metallic lithium as the negative electrode. The electrolyte is a mixed organic solvent containing lithium tetrafluoroborate or lithium perchlorate. Their structure is similar to that of lithium manganese dioxide batteries. During discharge, conductive carbon is generated, increasing the battery's conductivity and thus improving its discharge plateau and efficiency.
[0003] The CF bonds formed during the preparation of fluorinated carbon materials cause some carbon atoms in the carbon skeleton to be conjugated sp... 2 Hybridization transforms into non-conjugated sp 3 Hybridization reduces the conductivity of fluorinated carbon materials, limiting the application of Li / CF2. x Application of batteries under high-rate conditions; the reason that limits the rate performance of fluorinated carbon batteries is that during the discharge process, the discharge product LiF will continuously deposit on the surface of the positive electrode material, causing electrode volume expansion and blockage of lithium ion liquid phase diffusion channels.
[0004] Fluorinated carbon has low density and low conductivity, strong hydrophobicity, complex manufacturing process, and expensive batteries. It also generates a lot of heat during high-current discharge, causing significant battery volume expansion, which limits its application.
[0005] Compared to lithium secondary batteries, lithium primary batteries have a greater emphasis on high specific energy discharge characteristics. Therefore, the exploration of electrolytes is a key research direction. By regulating the electrolyte to make it compatible with fluorinated carbon cathode materials, its energy density can be maximized.
[0006] CN116314895A discloses that the discharge platform, discharge capacity, and energy density of a lithium fluoride carbon primary battery containing boron trifluoride-pyrazine in the electrolyte are significantly higher than those of a lithium fluoride carbon primary battery without boron trifluoride-pyrazine in the electrolyte. However, research has found that the performance of lithium fluoride carbon primary batteries still needs further improvement. Summary of the Invention
[0007] The purpose of this invention is to provide a lithium fluoride carbon primary battery electrolyte and a lithium fluoride carbon primary battery with better performance.
[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0009] The first aspect of the present invention provides a lithium fluoride carbon primary battery electrolyte, comprising an electrolyte lithium salt, a functional additive, and an organic solvent, wherein the functional additive comprises one or more of pyridine boron trifluoride, boron trifluoride dimethyl carbonate, and dipyrrole methylene boron difluoride.
[0010] According to some specific embodiments, the total mass of any one or more of the following—boron trifluoride pyridine, dimethyl boron trifluoride carbonate, and dipyrrole methylene boron difluoride—accounts for 0.05% to 2% of the total mass of the electrolyte, for example, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, etc.
[0011] According to some specific embodiments, the functional additive also includes other additives, which are one or more of vinyl sulfate, 1,3-propanesulfonyl lactone, butyl phosphoric anhydride, tris(trimethylsilane) phosphate, and tris(trimethylsilane) borate.
[0012] Further, the other additives constitute 0.05% to 5% of the total mass of the electrolyte, for example, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, or 2.1%. 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5%, etc.
[0013] Furthermore, the other additives are two or more combinations of vinyl sulfate, 1,3-propanesulfonyl lactone, butyl phosphoric anhydride, tris(trimethylsilane) phosphate, and tris(trimethylsilane) borate.
[0014] Furthermore, the other additives are three or more of the following: vinyl sulfate, 1,3-propanesulfonyl lactone, butyl phosphoric anhydride, tris(trimethylsilane) phosphate, and tris(trimethylsilane) borate.
[0015] According to some specific embodiments, the electrolyte lithium salt is any one or more of lithium tetrafluoroborate, lithium perchlorate, and lithium di(trifluoromethanesulfonyl)imide.
[0016] According to some more specific embodiments, the electrolyte lithium salt is lithium tetrafluoroborate.
[0017] According to some other, more specific embodiments, the electrolyte lithium salt is lithium tetrafluoroborate, and one or more of lithium perchlorate and lithium bis(trifluoromethanesulfonyl)imide.
[0018] Furthermore, the molar mass of the lithium tetrafluoroborate is 70% or more of the total mass of the electrolyte lithium salt.
[0019] According to some specific embodiments, the concentration of the electrolyte lithium salt is 0.01–2 mol / L, for example, 0.01 mol / L, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2 mol / L, etc. Further, the concentration of the electrolyte lithium salt is 0.5–1.5 mol / L.
[0020] According to some specific embodiments, the organic solvent is one or more selected from ethylene carbonate, propylene carbonate, γ-butyrolactone, ethylene glycol dimethyl ether, sulfolane, 1,3-dioxolane, and 1,2-dimethoxyethane.
[0021] According to some specific embodiments, the organic solvent accounts for 1% to 95% of the total mass of the electrolyte. Further, the organic solvent accounts for 50% to 95% of the total mass of the electrolyte, for example, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, etc.
[0022] This invention improves the rate performance of batteries by using functional additives to dissolve lithium fluoride generated during the discharge process. On the other hand, by optimizing the solvent and adding lithium salts and functional additives, the electrolyte conductivity can be improved while forming a stable SEI film, thereby enhancing battery stability.
[0023] A second aspect of the present invention provides a lithium fluoride carbon primary battery, comprising a positive electrode, a negative electrode and an electrolyte, wherein the electrolyte is the electrolyte as described above.
[0024] According to some specific embodiments, the active component of the positive electrode is fluorinated carbon or a mixture of fluorinated carbon and manganese dioxide; the active component of the negative electrode is metallic lithium.
[0025] According to some specific embodiments, the lithium fluoride primary battery is in the shape of a button, cylindrical, square, or pouch.
[0026] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:
[0027] The electrolyte of this invention can significantly reduce the internal resistance of lithium fluoride carbon batteries, improve the problem of high self-discharge during storage of lithium batteries, and significantly improve the rate performance of lithium batteries. Detailed Implementation
[0028] The present invention will be further described below with reference to embodiments. However, the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific applications, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.
[0029] Unless otherwise specified, the reagents, instruments, etc. used in the following examples and comparative examples are all commercially available products commonly used in the art, or can be prepared using conventional methods in the art. In this invention, unless otherwise specified, all contents are mass contents, "%" is mass percentage, and parts are parts by mass.
[0030] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the ranges, the endpoint values of the ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. The terms "optional" and "discretionary" mean that they may or may not be included (or may or may not be present).
[0031] To provide a more intuitive comparison of the effects of the electrolyte, the following comparative examples and embodiments all use lithium fluoride carbon cylindrical CR123A batteries.
[0032] Comparative Example 1
[0033] The organic solvents are propylene carbonate and dimethyl ethylene glycol (mass ratio of 30:70); the electrolyte lithium salt is lithium tetrafluoroborate, and the concentration of the lithium salt is 1 mol / L.
[0034] Comparative Example 2
[0035] The organic solvent is propylene carbonate, ethylene glycol dimethyl ether, and 1,3-dioxolane (in a mass ratio of 20:30:50); the electrolyte lithium salt is lithium perchlorate, and the concentration of the lithium salt is 1 mol / L.
[0036] Comparative Example 3
[0037] The organic solvents are propylene carbonate, ethylene glycol dimethyl ether, and 1,3-dioxolane (in a mass ratio of 40:20:40); the electrolyte lithium salt is lithium di(trifluoromethanesulfonyl)imide (LiN(CF3SO2)2), and the concentration of the lithium salt is 0.8 mol / L.
[0038] Comparative Example 4
[0039] The organic solvent is propylene carbonate, ethylene glycol dimethyl ether, and 1,3-dioxolane (in a mass ratio of 50:20:30); the electrolyte lithium salt is 1 mol / L lithium tetrafluoroborate; and the additive is 1% boron trifluoride-pyrazine, with the following structural formula:
[0040] Example 1
[0041] The organic solvent is propylene carbonate, ethylene glycol dimethyl ether, and 1,3-dioxolane (in a mass ratio of 50:20:30); the electrolyte lithium salt is 1 mol / L lithium tetrafluoroborate; and the additive is 1% pyridine boron trifluoride, with the following structural formula:
[0042] Example 2
[0043] The organic solvents are propylene carbonate, ethylene glycol dimethyl ether, and 1,3-dioxolane (in a mass ratio of 50:20:30); the electrolyte lithium salt is 1 mol / L lithium tetrafluoroborate; and the additive is 1% dipyrrole methylene boron difluoride (CAS: 138026-71-8).
[0044] Example 3
[0045] The organic solvents are propylene carbonate, ethylene glycol dimethyl ether, and 1,3-dioxolane (in a mass ratio of 50:20:30); the electrolyte lithium salt is 1 mol / L lithium tetrafluoroborate; and the additives are 1% boron trifluoride pyridine and 1% vinyl sulfate.
[0046] Example 4
[0047] The organic solvents are propylene carbonate, ethylene glycol dimethyl ether, and 1,3-dioxolane (in a mass ratio of 50:20:30); the electrolyte lithium salt is 1 mol / L lithium tetrafluoroborate; and the additives are 1% boron trifluoride pyridine and 1% 1,3-propane sulpholide.
[0048] Example 5
[0049] The organic solvents are propylene carbonate, ethylene glycol dimethyl ether, and 1,3-dioxolane (in a mass ratio of 50:20:30); the electrolyte lithium salt is 1 mol / L lithium tetrafluoroborate; and the additives are 1% boron trifluoride pyridine and 1% butyl phosphoric anhydride (CAS: 163755-62-2).
[0050] Example 6
[0051] The organic solvents are propylene carbonate, ethylene glycol dimethyl ether, and 1,3-dioxolane (in a mass ratio of 50:20:30); the electrolyte lithium salt is 1 mol / L lithium tetrafluoroborate; and the additives are 2% boron trifluoride pyridine, 1% tris(trimethylsilane) phosphate (CAS: 10497-05-9), 0.1% butyl phosphoric anhydride, and 3% vinyl sulfate.
[0052] Example 7
[0053] The organic solvent is propylene carbonate, ethylene glycol dimethyl ether, and 1,3-dioxolane (in a mass ratio of 50:20:30); the electrolyte lithium salt is 1 mol / L lithium tetrafluoroborate; and the additives are 1% boron trifluoride pyridine and 1% tris(trimethylsilane)borate (CAS: 4325-85-3).
[0054] Example 8
[0055] The organic solvents are propylene carbonate, ethylene glycol dimethyl ether, and 1,3-dioxolane (in a mass ratio of 50:20:30); the electrolyte lithium salts are 0.8 mol / L lithium tetrafluoroborate and 0.2 mol / L lithium di(trifluoromethylsulfonyl)imide; the additives are 1% boron trifluoride pyridine, 1% vinyl sulfate, 3% 1,3-propane sulpholactone, and 1% tri(trimethylsilane)borate.
[0056] Experimental results
[0057] The discharge performance of the battery was tested using a Shenzhen Xinwei battery tester.
[0058] Each comparative example and each embodiment was prepared into an electrolyte according to the formula, and injected into a CR123A type cylindrical lithium fluoride carbon primary battery. Internal resistance test, voltage drop at 60°C, high current pulse discharge and -10°C low temperature discharge test were performed respectively.
[0059] The internal resistance test method is as follows: Under normal temperature conditions, the internal resistance of the battery is directly tested using an internal resistance meter.
[0060] The method for testing voltage drop under 60℃ high temperature is as follows: place the battery in a 60℃ oven for 14 days, then remove the battery and test the voltage change.
[0061] The test method for high-current pulse discharge is as follows: under normal temperature conditions, discharge at a constant current of 3A for 3s, rest for 27s, and cycle until the voltage reaches 1.8V and then stop.
[0062] The test method for low-temperature discharge is as follows: under -10℃ conditions, leave for 24 hours, discharge at a constant current of 20mA, and cutoff voltage of 2.0V.
[0063] The test results for all comparative examples and embodiment examples are shown in Table 1 below.
[0064] Table 1
[0065]
[0066]
[0067] The comparison of data from the various embodiments and comparative examples in Table 1 shows that the electrolyte formulation of this invention can significantly improve the internal resistance of lithium fluoride carbon batteries, reduce battery self-discharge under high-temperature storage, and improve power characteristics and low-temperature discharge performance. Furthermore, comparisons of Examples 1 and 2 and Comparative Example 4 demonstrate that the addition of pyridine boron trifluoride and dipyrrole methylene boron difluoride is more effective than the addition of boron trifluoride-pyrazine.
[0068] This invention, through the selection and combination of the aforementioned electrolyte lithium salt, functional additives, and organic solvents, produces an electrolyte that, after being injected into a lithium fluoride carbon battery, simultaneously meets the requirements for room temperature discharge and high-rate discharge performance. The added lithium tetrafluoroborate, lithium perchlorate, and lithium di(trifluoromethanesulfonyl)imide exhibit high ionic conductivity. The addition of functional additives such as pyridine boron trifluoride and dipyrrole methylene boron difluoride can dissolve the discharge product lithium fluoride that clogs the positive electrode interface during discharge, improving the battery's conductivity, significantly reducing the internal resistance of the lithium fluoride carbon battery, alleviating the problem of high self-discharge during lithium battery storage, and significantly improving the rate performance of the lithium battery. The addition of vinyl sulfate, 1,3-propane sulpholactone, butyl phosphoric anhydride, tris(trimethylsilane) phosphate, and tris(trimethylsilane) borate can participate in the formation of an SEI film on the lithium metal surface, improving high-temperature performance and reacting with moisture in the electrolyte, thus improving the overall battery performance. Therefore, this electrolyte system effectively expands the application range of lithium fluoride carbon primary batteries and has broad application prospects in the future of lithium fluoride carbon batteries.
[0069] The present invention has been described in detail above, with the aim of enabling those skilled in the art to understand and implement the invention. However, this description should not be construed as limiting the scope of protection of the invention. All equivalent changes or modifications made in accordance with the spirit and essence of the invention should be included within the scope of protection of the invention.
Claims
1. A lithium fluoride carbon primary battery electrolyte, comprising an electrolyte lithium salt, functional additives, and an organic solvent, characterized in that: The functional additives include any one or more of boron trifluoride pyridine, dimethyl boron trifluoride carbonate, and dipyrrole methylene boron difluoride.
2. The lithium fluoride carbon primary battery electrolyte according to claim 1, characterized in that: The total mass of any one or more of pyridine boron trifluoride, boron trifluoride dimethyl carbonate, and dipyrrole methylene boron difluoride accounts for 0.05 to 2% of the total mass of the electrolyte.
3. The lithium fluoride carbon primary battery electrolyte according to claim 1, characterized in that: The functional additive also includes other additives, which are one or more of vinyl sulfate, 1,3-propanesulfonyl lactone, butyl phosphoric anhydride, tris(trimethylsilane) phosphate, and tris(trimethylsilane) borate.
4. The lithium fluoride carbon primary battery electrolyte according to claim 3, characterized in that: The other additives account for 0.05% to 5% of the total mass of the electrolyte.
5. The lithium fluoride carbon primary battery electrolyte according to claim 3, characterized in that: The other additives are two or more of the following: vinyl sulfate, 1,3-propanesulfonyl lactone, butyl phosphoric anhydride, tris(trimethylsilane) phosphate, and tris(trimethylsilane) borate.
6. The lithium fluoride carbon primary battery electrolyte according to claim 5, characterized in that: The other additives are three or more of the following: vinyl sulfate, 1,3-propanesulfonyl lactone, butyl phosphoric anhydride, tris(trimethylsilane) phosphate, and tris(trimethylsilane) borate.
7. The lithium fluoride carbon primary battery electrolyte according to claim 1, characterized in that: The electrolyte lithium salt is any one or more of lithium tetrafluoroborate, lithium perchlorate, and lithium di(trifluoromethanesulfonyl)imide; the concentration of the electrolyte lithium salt is 0.01 to 2 mol / L.
8. The lithium fluoride carbon primary battery electrolyte according to claim 1, characterized in that: The organic solvent is one or more selected from ethylene carbonate, propylene carbonate, γ-butyrolactone, ethylene glycol dimethyl ether, sulfolane, 1,3-dioxolane, and 1,2-dimethoxyethane; the organic solvent accounts for 1 to 95% of the total mass of the electrolyte.
9. A lithium-carbon fluoride primary battery, comprising a positive electrode, a negative electrode, and an electrolyte, characterized in that: The electrolyte is the electrolyte according to any one of claims 1 to 8.
10. The lithium fluoride carbon primary battery according to claim 9, characterized in that: The active component of the positive electrode is fluorinated carbon or a mixture of fluorinated carbon and manganese dioxide; the active component of the negative electrode is metallic lithium.