A magnesium battery electrolyte containing an amine additive, a preparation method and a magnesium metal secondary battery
Patent Information
- Application Number
- CN202510476839.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-16
- Publication Date
- 2026-10-23
AI Technical Summary
[0004]本发明的目的在于以解决镁金属二次电池中电解液与正负极之间兼容性差的问题，提供一种含胺类添加剂的镁电池电解液、制备方法及镁金属二次电池
[0023]1.本发明利用胺类添加剂与镁离子的强配位作用，改变电解液中镁离子的溶剂化结构，提高电解液的还原稳定性，从而减缓了镁盐和溶剂与镁金属负极的进一步反应，提升了电解液与镁金属负极之间的界面兼容性，从而大幅提高镁金属二次电池的循环性能。
Smart Images
Figure CN122968436A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery technology, specifically relating to a magnesium battery electrolyte containing amine additives, its preparation method, and a magnesium metal secondary battery. Background Technology
[0002] Among numerous novel battery technologies, magnesium metal rechargeable batteries have gradually gained attention due to their abundant raw material resources. Magnesium metal, when used as an anode material, possesses advantages such as high volumetric capacity and high safety, making it an ideal metallic anode material. However, magnesium metal anodes are easily passivated in conventional electrolyte systems, hindering reversible metal deposition / dissolution reactions on the anode side. Furthermore, the high desolvation energy of solvated magnesium ions in magnesium electrolytes results in slow electrochemical reaction kinetics at the positive and negative electrode interfaces, significantly limiting the practical performance of magnesium metal rechargeable batteries. Therefore, developing novel magnesium electrolyte systems with high positive and negative electrode compatibility and rapid interfacial electrochemical reaction kinetics is crucial for the development of magnesium metal rechargeable batteries. Introducing small amounts of additives into magnesium electrolytes can effectively regulate magnesium ion transport performance and significantly influence the interfacial chemical composition and properties of the electrodes. Lee et al. effectively reduced the water content in the Mg(TFSI)2-based magnesium electrolyte by introducing heptamethyldisilazane as an additive, and consumed the Mg(OH)2 passivation layer on the magnesium metal surface, thereby improving the reversibility of the magnesium deposition / dissolution process (ACS Appl. Mater. Interfaces 2019, 11, 1, 517-524). Li et al. successfully constructed a more stable negative electrode / electrolyte interface and improved the cycle stability of magnesium batteries by introducing a small amount of magnesium borohydride salt as an additive into the Mg[B(hfip)4]2-based magnesium electrolyte (ACS Appl. Mater. Interfaces 2021, 13, 28, 33123-33132). However, the magnesium electrolyte additives reported so far generally have disadvantages such as poor oxidation stability, complex synthesis, and high cost.
[0003] Based on the above considerations, the overall electrochemical performance of magnesium electrolytes can be effectively improved through the design and optimization of electrolyte additives. Therefore, it is necessary to develop an additive system that balances electrochemical performance with reduced magnesium electrolyte costs and is easy to mass-produce, thereby promoting the development and commercial application of magnesium metal secondary batteries. Summary of the Invention
[0004] The purpose of this invention is to solve the problem of poor compatibility between the electrolyte and the positive and negative electrodes in magnesium metal secondary batteries, and to provide a magnesium battery electrolyte containing amine additives, a preparation method, and a magnesium metal secondary battery.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0006] A magnesium battery electrolyte containing amine additives, wherein the electrolyte is a magnesium salt or an organic solvent, and the additives are added to the electrolyte, wherein the additives are one or more of gaseous amines or solid amines.
[0007] The additive accounts for 0.5% to 10% of the mass of the magnesium battery electrolyte, and the water content in the electrolyte is less than 20 ppm.
[0008] The additive is one or more of ammonia, ammonia borane, methylamine, dimethylamine, trimethylamine, ethylamine, and tetrabutylammonium bromide.
[0009] The magnesium salt is one or more of bis(trifluoromethanesulfonyl)imide magnesium, magnesium trifluoromethanesulfonate, and magnesium tetra(hexafluoroisopropyl)borate; the molar concentration of the magnesium salt in the electrolyte is 0.1–2 mol / L;
[0010] The organic solvent is one or a mixture of several of the following: tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, acetonitrile, valerate, trimethyl phosphate, triethyl phosphate, dimethyl sulfoxide, sulfolane, dipropyl sulfone, and dibutyl sulfone.
[0011] Preferably, the amine additive is ammonia borane, the magnesium salt is magnesium bis(trifluoromethanesulfonyl)imide, and the solvent is diethylene glycol dimethyl ether.
[0012] A method for preparing a magnesium battery electrolyte containing amine additives, comprising the following steps:
[0013] (1) Under anhydrous and oxygen-free conditions, dissolve the magnesium salt in the organic solvent at the specified molar concentration and stir for 2 to 10 hours until the solution is clear and uniform.
[0014] (2) Add additives to the above solution under stirring until the electrolyte is stirred evenly to obtain magnesium battery electrolyte containing amine additives.
[0015] Trace amounts of water in the organic solvents and amine gases are removed using molecular sieves activated at 400°C for 8 hours; trace amounts of water in the magnesium salts and solid amine additives are removed using vacuum heating at 60–125°C for 24–48 hours.
[0016] In step (2), after adding the additive, the water content in the system is controlled to be less than 20 ppm. When the additive is a gas, the solution is blown into the air through the tube inserted in step (1), and the solution is stirred.
[0017] When the additive is solid or contains liquid, weigh the corresponding amount of additive and add it to the solution obtained in step (1) under stirring, and then mix and stir for 2-10 hours until the solution is uniform.
[0018] An application of the magnesium battery electrolyte containing amine additives, and the application of the electrolyte in the preparation of magnesium metal secondary batteries.
[0019] A magnesium metal secondary battery, wherein the electrolyte in the magnesium battery is the magnesium battery electrolyte.
[0020] The magnesium metal secondary battery includes a negative electrode shell, a negative electrode sheet, an electrolyte, a separator, a positive electrode sheet, a gasket, a spring sheet, and a positive electrode shell.
[0021] The positive electrode is a slurry of positive electrode active materials prepared in a certain proportion and coated onto an aluminum current collector. The active materials include MnO2, TiS2, V2O5, VS4, Mo6S8, and Mg. x Various active materials such as Mn[Fe(CN)6] and MgMnSiO4.
[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:
[0023] 1. This invention utilizes the strong coordination between amine additives and magnesium ions to change the solvation structure of magnesium ions in the electrolyte, thereby improving the reduction stability of the electrolyte. This slows down the further reaction between magnesium salts and solvents and the magnesium metal anode, enhances the interfacial compatibility between the electrolyte and the magnesium metal anode, and thus significantly improves the cycle performance of magnesium metal secondary batteries.
[0024] 2. The introduction of amine additives in this invention not only significantly improves the compatibility between the electrolyte and the magnesium metal anode, but also effectively improves the reaction kinetics on the cathode side, thereby greatly improving the energy density and long-cycle stability of the magnesium metal secondary battery.
[0025] 3. The raw materials used in this invention are readily available, inexpensive, and have high production efficiency. The preparation technology is compatible with existing secondary battery preparation equipment, which facilitates industrialization and application. Attached Figure Description
[0026] Figure 1 Constant current charge-discharge curves of magnesium-copper half-cells using the electrolyte in Example 1;
[0027] Figure 2 Constant current charge-discharge curves of magnesium-copper half-cells using the electrolyte in Example 2;
[0028] Figure 3 Constant current charge-discharge curves of magnesium-copper half-cells using the electrolyte in Example 3;
[0029] Figure 4 Constant current charge-discharge curves of magnesium-copper half-cells using the electrolyte in Example 4;
[0030] Figure 5 Constant current charge-discharge curves of magnesium-copper half-cells using the electrolyte in Example 5;
[0031] Figure 6 The constant current charge-discharge curves of the electrolyte in Comparative Example 1 for magnesium-copper half-cells are shown.
[0032] Figure 7 The constant current charge-discharge curves of the electrolyte in Comparative Example 2 for magnesium-copper half-cells are shown.
[0033] Figure 8 The constant current charge-discharge curves of the electrolyte in Comparative Example 3 for magnesium-copper half-cells are shown.
[0034] Figure 9 This is a charge-discharge curve of the magnesium metal secondary battery described in Example 5 of this application at a current density of 80 mA / g;
[0035] Figure 10 This is a charge-discharge curve of the magnesium metal secondary battery described in Comparative Example 3 of this application at a current density of 80 mA / g. Detailed Implementation
[0036] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
[0037] Example 1
[0038] The magnesium electrolyte of this embodiment includes a magnesium salt, an organic solvent, and an electrolyte additive. The magnesium salt is magnesium bis(trifluoromethanesulfonyl)imide, with a concentration of 0.5 mol / L. The solvent is diethylene glycol dimethyl ether. The electrolyte additive is ammonia borane, with a weight percentage of 2% wt. The preparation method is as follows:
[0039] (1) Diethylene glycol dimethyl ether was treated with activated 4A molecular sieve for 48 h, bis(trifluoromethanesulfonyl)imide magnesium salt was dried under vacuum at 120 °C for 24 h, and ammonia borane was dried under vacuum at 50 °C for 12 h.
[0040] (2) Under anhydrous and oxygen-free conditions, dissolve the magnesium salt treated in step (1) in the treated solvent according to the specified molar concentration, and stir for 10 hours until the solution is clear and uniform.
[0041] (3) Add the dried ammonia borane to the clear and uniform solution in step (2) under stirring according to the above ratio, and continue stirring at 500 rpm for 5 hours until the additive is dissolved uniformly to obtain a magnesium battery electrolyte containing amine additives.
[0042] Example 2
[0043] The magnesium electrolyte of this embodiment includes a magnesium salt, an organic solvent, and an electrolyte additive. The magnesium salt is magnesium bis(trifluoromethanesulfonyl)imide, with a concentration of 0.5 mol / L. The solvent is diethylene glycol dimethyl ether. The electrolyte additive is ammonia borane, with a weight percentage of 5% wt. The preparation method is as follows:
[0044] (1) Diethylene glycol dimethyl ether was treated with activated 4A molecular sieve for 48 h, bis(trifluoromethanesulfonyl)imide magnesium salt was dried under vacuum at 120 °C for 24 h, and ammonia borane was dried under vacuum at 50 °C for 12 h.
[0045] (2) Under anhydrous and oxygen-free conditions, dissolve the magnesium salt treated in step (1) in the treated solvent according to the specified molar concentration, and stir for 10 hours until the solution is clear and uniform.
[0046] (3) Add the dried ammonia borane to the clear and uniform solution in step (2) under stirring according to the above ratio, and continue stirring at 500 rpm for 5 hours until the additive is dissolved uniformly to obtain a magnesium battery electrolyte containing amine additives.
[0047] Example 3
[0048] The magnesium electrolyte of this embodiment includes a magnesium salt, an organic solvent, and an electrolyte additive. The magnesium salt is magnesium bis(trifluoromethanesulfonyl)imide with a concentration of 0.5 mol / L. The solvent is diethylene glycol dimethyl ether. The electrolyte additive is ammonia gas, which is continuously ventilated at a gas flow rate of 2 ml / min for 4 hours and has a weight percentage of 0.5% wt in the electrolyte.
[0049] The preparation method is as follows:
[0050] (1) Diethylene glycol dimethyl ether was treated with activated 4A molecular sieve for 48h, and bis(trifluoromethanesulfonyl)imide magnesium salt was dried under vacuum at 120℃ for 24h. Ammonia gas needed to be treated with 4A molecular sieve before being introduced into the electrolyte.
[0051] (2) Under anhydrous and oxygen-free conditions, dissolve the magnesium salt treated in step (1) in the solvent after treatment according to the specified molar concentration, and stir for 10 hours until the solution is clear and uniform.
[0052] (3) Under the above-mentioned solution stirring state, the solution is blown into the solution through the tube inserted in step (2), and the solution is stirred evenly to obtain magnesium battery electrolyte containing amine additives.
[0053] Example 4
[0054] The magnesium electrolyte of this embodiment includes a magnesium salt, an organic solvent, and an electrolyte additive. The magnesium salt is magnesium trifluoromethanesulfonate with a concentration of 0.2 mol / L; the solvent is ethylene glycol dimethyl ether; and the electrolyte additive is ammonia borane with a weight percentage of 5% wt.
[0055] The preparation method is as follows:
[0056] (1) Diethylene glycol dimethyl ether was treated with activated 4A molecular sieve for 48 h, magnesium trifluoromethanesulfonate was dried under vacuum at 120 °C for 24 h, and ammonia borane was dried under vacuum at 50 °C for 12 h.
[0057] (2) Under anhydrous and oxygen-free conditions, dissolve the magnesium salt treated in step (1) in the treated solvent according to the specified molar concentration, and stir for 10 hours until the solution is clear and uniform.
[0058] (3) Add the dried ammonia borane to the clear and uniform solution in step (2) under stirring according to the above ratio, and continue stirring at 500 rpm for 5 hours until the additive is dissolved uniformly to obtain a magnesium battery electrolyte containing amine additives.
[0059] Example 5
[0060] The magnesium electrolyte of this embodiment includes a magnesium salt, an organic solvent, and an electrolyte additive. The magnesium salt is magnesium tetra(hexafluoroisopropyl)borate with a concentration of 0.5 mol / L. The solvent is diethylene glycol dimethyl ether. The electrolyte additive is ammonia borane with a weight percentage of 5% wt.
[0061] The preparation method is as follows:
[0062] (1) Diethylene glycol dimethyl ether was treated with activated 4A molecular sieve for 48 h, magnesium tetra(hexafluoroisopropyl)borate was dried under vacuum at 80 °C for 24 h, and ammonia borane was dried under vacuum at 50 °C for 12 h.
[0063] (2) Under anhydrous and oxygen-free conditions, dissolve the magnesium salt treated in step (1) in the treated solvent according to the specified molar concentration, and stir for 10 hours until the solution is clear and uniform.
[0064] (3) Add the dried ammonia borane to the clear and uniform solution in step (2) under stirring according to the above ratio, and continue stirring at 500 rpm for 5 hours until the additive is dissolved uniformly to obtain a magnesium battery electrolyte containing amine additives.
[0065] Comparative Example 1
[0066] This comparative magnesium electrolyte includes a magnesium salt and an organic solvent. The magnesium salt is magnesium bis(trifluoromethanesulfonyl)imide with a concentration of 0.5 mol / L. The solvent is ethylene glycol dimethyl ether.
[0067] The preparation method is as follows:
[0068] (1) Diethylene glycol dimethyl ether was treated with activated 4A molecular sieve for 48 h, and bis(trifluoromethanesulfonyl)imide magnesium salt was dried under vacuum at 120 °C for 24 h.
[0069] (2) Under anhydrous and oxygen-free conditions, dissolve the magnesium salt treated in step (1) in the treated solvent according to the specified molar concentration, and stir for 10 hours until the solution is clear and uniform.
[0070] Comparative Example 2
[0071] This comparative magnesium electrolyte comprises a magnesium salt, an organic solvent, and an electrolyte additive. The magnesium salt is magnesium bis(trifluoromethanesulfonyl)imide with a concentration of 0.5 mol / L. The solvent is diethylene glycol dimethyl ether. The electrolyte additive is ammonia borane with a weight percentage of up to 20% wt.
[0072] The preparation method is as follows:
[0073] (1) Diethylene glycol dimethyl ether was treated with activated 4A molecular sieve for 48 h, bis(trifluoromethanesulfonyl)imide magnesium salt was dried under vacuum at 120 °C for 24 h, and ammonia borane was dried under vacuum at 50 °C for 12 h.
[0074] (2) Under anhydrous and oxygen-free conditions, dissolve the magnesium salt treated in step (1) in the solvent according to the specified molar concentration, and stir for 10 hours until the solution is clear and uniform.
[0075] (3) Add the dried ammonia borane to the clear and uniform solution in step (2) under stirring according to the above ratio, and continue stirring at 500 rpm for 5 hours until the additive is dissolved uniformly to obtain a magnesium battery electrolyte containing amine additives.
[0076] Comparative Example 3
[0077] This comparative magnesium electrolyte is prepared without removing water and includes magnesium salt, organic solvent and electrolyte additive. The magnesium salt is magnesium bis(trifluoromethanesulfonyl)imide with a concentration of 0.5 mol / L; the solvent is diethylene glycol dimethyl ether; and the electrolyte additive is ammonia borane with a weight percentage of 5% wt.
[0078] The preparation method is as follows:
[0079] (1) Dissolve the purchased bis(trifluoromethanesulfonyl)imide magnesium salt directly in the purchased diethylene glycol dimethyl ether solvent according to the specified molar concentration, and stir for 10 hours until the solution is clear and uniform.
[0080] (2) Add the purchased ammonia borane additive directly to the above solution under stirring until the electrolyte is stirred evenly to obtain a magnesium battery electrolyte containing amine additives.
[0081] The electrolytes in Examples 1-5 and Comparative Examples 1-3 were subjected to constant current charge-discharge tests in magnesium-copper half-cells, with a discharge current density of 0.5 mA / cm². 2 The discharge time is 0.5 hours, and the charging current density is 0.5 mA / cm². 2 The charging cutoff voltage is 1V. Test results are as follows: Figure 1-8 As shown in Table 1, the cycling stability of the magnesium-copper half-cell and the coulombic efficiency of deposited and dissolved magnesium during the cycling process are shown in Table 1.
[0082] Sample number Stable cycle number First-cycle Coulomb efficiency Coulomb efficiency in 30th lap overpotential Example 1 120 52％ 95％ 0.26V Example 2 200 87％ 96％ 0.15V Example 3 100 66％ 93.7％ 0.12V Example 4 150 70％ 98％ 0.08V Example 5 200 90％ 97％ 0.2V Comparative Example 1 15 0.3％ - 2V Comparative Example 2 35 48％ 72％ 0.37V Comparative Example 3 50 52％ 34.4％ 0.27V
[0083] As shown in Table 1, the coulombic efficiency and cycle stability obtained in the examples containing additives are superior to those in Comparative Example 1 without additives. Furthermore, the mass ratio of additives in the electrolyte also affects the coulombic efficiency of the magnesium-ion battery. When the concentration of amine additives is too high, the coulombic efficiency and overpotential obtained in Comparative Example 2 are significantly worse than those obtained in the other examples. When the electrolyte and additive components are not dehydrated, the coulombic efficiency and overpotential obtained in Comparative Example 3 are also significantly worse than those of Example 2 after dehydration treatment, fully demonstrating that the lower the water content, the better the reversibility of magnesium deposition / dissolution.
[0084] Example 6
[0085] This embodiment provides a magnesium metal secondary battery, which is assembled in the following order: negative electrode shell, negative electrode sheet, electrolyte, separator, positive electrode sheet, and positive electrode shell. The negative electrode sheet is a magnesium sheet with a thickness of 100 μm, the positive electrode sheet is an aluminum foil coated with titanium disulfide active material, the separator is a glass fiber (Whatman, GF / A) separator, and the electrolyte is the magnesium electrolyte provided in Example 1.
[0086] Comparative Example 4
[0087] The difference from Example 6 is that the electrolyte is the magnesium electrolyte provided in Comparative Example 1, and the rest is the same as in Example 6.
[0088] The charge-discharge performance of the magnesium metal secondary batteries in Example 6 and Comparative Example 4 was tested, such as... Figure 9-10 As shown, the battery performance in Example 6 is superior to that in Comparative Example 4 in terms of discharge specific capacity, discharge voltage plateau, and charge-discharge reversibility. This demonstrates that the introduction of additives plays an important role in improving the long-cycle stability and energy density of magnesium metal secondary batteries, thus achieving the objective of this invention.
[0089] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A magnesium battery electrolyte containing amine additives, wherein the electrolyte is a magnesium salt and an organic solvent, characterized in that, Additives are added to the electrolyte, and the additives are one or more of gaseous amines and solid amines.
2. The magnesium battery electrolyte containing amine additives according to claim 1, characterized in that: The additive accounts for 0.5% to 10% of the mass of the magnesium battery electrolyte, and the water content in the electrolyte is less than 20 ppm.
3. The magnesium battery electrolyte containing amine additives according to claim 1, characterized in that: The additive is one or more of ammonia, ammonia borane, methylamine, dimethylamine, trimethylamine, ethylamine, and tetrabutylammonium bromide.
4. The magnesium battery electrolyte containing amine additives according to claim 1, characterized in that: The magnesium salt is one or more of bis(trifluoromethanesulfonyl)imide magnesium, magnesium trifluoromethanesulfonate, and magnesium tetra(hexafluoroisopropyl)borate; the molar concentration of the magnesium salt in the electrolyte is 0.1–2 mol / L; The organic solvent is one or a mixture of several of the following: tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, acetonitrile, valerate, trimethyl phosphate, triethyl phosphate, dimethyl sulfoxide, sulfolane, dipropyl sulfone, and dibutyl sulfone.
5. A method for preparing a magnesium battery electrolyte containing amine additives as described in claim 1, characterized in that, Includes the following steps: (1) Under anhydrous and oxygen-free conditions, dissolve the magnesium salt in the organic solvent at the specified molar concentration and stir for 2 to 10 hours until the solution is clear and uniform. (2) Add additives to the above solution under stirring until the electrolyte is stirred evenly to obtain magnesium battery electrolyte containing amine additives.
6. The method for preparing the magnesium battery electrolyte containing amine additives according to claim 5, characterized in that: Trace amounts of water in the organic solvents and amine gases are removed using molecular sieves activated at 400°C for 8 hours; trace amounts of water in the magnesium salts and solid amine additives are removed using vacuum heating at 60–125°C for 24–48 hours.
7. The method for preparing the magnesium battery electrolyte containing amine additives according to claim 5 or 6, characterized in that, In step (2), after adding the additive, the water content in the system is controlled to be less than 20 ppm. When the additive is a gas, the solution is blown into the air through the tube inserted in step (1), and the solution is stirred. When the additive is solid, weigh the corresponding amount of additive and add it to the solution obtained in step (1) under stirring, and then mix and stir for 2-10 hours until the solution is uniform.
8. The application of the magnesium battery electrolyte containing amine additives as described in claim 1, characterized in that: The application of the electrolyte in the preparation of magnesium metal secondary batteries.
9. A magnesium metal secondary battery, characterized in that: The electrolyte in the magnesium battery is the magnesium battery electrolyte as described in claim 1.