Lithium metal electrolyte, lithium metal secondary battery and electric device
By using ester-based organic solvents with specific functional groups and lithium salts in lithium metal batteries, a stable SEI film is formed, which solves the problem of matching lithium metal batteries with high-Ni cathodes, improves battery capacity and cycle performance, and achieves efficient electrochemical window and low-temperature performance.
Patent Information
- Application Number
- CN202511210399.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-27
- Publication Date
- 2025-11-28
AI Technical Summary
Existing organic electrolytes for lithium metal batteries are not resistant to high voltage and are difficult to use with high-Ni cathodes with high specific capacity. Furthermore, ether-based electrolytes are difficult to form a stable SEI layer, resulting in low coulombic efficiency and battery performance degradation.
By using ester-based organic solvents containing specific functional groups and lithium salts, a stable SEI film is formed, optimizing the lithium-ion coordination environment and improving battery reaction kinetics. By introducing a second ester-based organic solvent into the carboxylic acid ester-based electrolyte system and combining it with ternary cathode materials, a stable interface is formed, thereby improving battery capacity and cycle performance.
It achieves high battery capacity, long cycle life, and higher battery stability, improves the battery's electrochemical window and ion conductivity, reduces low-temperature internal resistance, and improves the battery's low-temperature performance.
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Abstract
Description
Technical Field
[0001] This application relates to the field of battery technology, and in particular to a lithium metal electrolyte, a secondary battery, and an electrical device. Background Technology
[0002] Lithium metal batteries (LIBs), with their advantages of high energy density, high efficiency, and stable cycle performance, are widely used in new electronic products such as mobile phones and watches, electric bicycles and hybrid vehicles, as well as various renewable energy storage devices. With the increasing demand for various energy storage devices, new requirements are being placed on the energy density and long-term stability of lithium metal batteries. Lithium metal batteries, using Li metal, have a higher specific capacity (3860 mAh / g) and an extremely low electrochemical potential, making them a promising next-generation energy storage battery. However, Li metal is a highly reactive metal and readily reacts with some organic solvents. Ether-based organic electrolytes exhibit excellent stability with Li metal, but they are often not resistant to high voltages (≥4.3V) and are generally difficult to use with high-capacity, high-Ni cathodes. Therefore, finding an organic electrolyte that is stable with Li metal is a highly challenging task. Summary of the Invention
[0003] This application provides a lithium metal electrolyte, a secondary battery, and an electrical device that replaces traditional carbonates as the polar solvent in the electrolyte. This effectively improves the physical properties of the electrolyte, such as conductivity, and broadens the electrochemical window of the electrolyte. It also forms a stable SEI film, thereby increasing the coulombic efficiency of the battery.
[0004] In a first aspect, this application provides a lithium metal electrolyte, comprising a lithium salt and an ester-based organic solvent, wherein the ester-based organic solvent comprises a first ester-based organic solvent and a second ester-based organic solvent, wherein: The first ester organic solvent includes at least one of the carboxylic acid ester organic solvents; The second ester organic solvent includes at least one of amino-containing ester organic solvents, sulfonate-containing ester organic solvents, and chlorine-containing ester organic solvents.
[0005] This application introduces a second ester-based organic solvent into a carboxylate-based electrolyte system to form a lithium metal electrolyte. The use of the carboxylate-based organic electrolyte ensures a wide electrochemical window, allowing for use with ternary cathode materials and improving battery capacity performance. The additionally introduced second ester-based organic solvent contains specific functional groups (amino-NH2, sulfonyl-SO3, and Cl atoms), which can form a stable SEI interface with the Li metal surface, enhancing the electrolyte's stability against Li metal. Furthermore, the mixed ester-based organic solvent can optimize Li... +The ion coordination environment improves battery reaction kinetics and increases battery capacity. Lithium metal electrolytes using various ester-based organic solvents have lower polarization sites and better Li metal stability than electrolytes using only esters, resulting in batteries with excellent long cycle life and higher capacity.
[0006] In some embodiments, the carboxylic acid ester organic solvent includes at least one selected from propyl propionate, butyl acetate, and ethyl butyrate. These carboxyl-based organic solvents possess high polar solubility, capable of dissolving various lithium salts while maintaining high concentrations; simultaneously, they have low freezing temperatures, enabling the electrolyte to exhibit good liquid behavior at low temperatures and providing high ionic conductivity; and / or, The amino-containing ester organic solvent includes at least one selected from methyl N-methylcarbamate, ethyl N-ethylcarbamate, dimethylaminoethyl methacrylate, and ethyl glycine. These amino-containing ester organic solvents can form intermolecular hydrogen bonds with carboxylic acid ester organic solvents, enhancing the molecular forces between solvents, thereby regulating the solvation structure of lithium ions; and / or, The sulfonated ester organic solvent includes at least one of methanesulfonamide, ethyl methanesulfonate, methyl methanesulfonate, chloromethyl chlorosulfonate, and methyl chlorosulfonate. These sulfonated ester organic solvents can preferentially decompose at the lithium metal interface to generate more stable lithium sulfide, thereby improving interface stability; and / or, The chlorine-containing ester organic solvent includes at least one of ethyl chloroacetate, ethyl chloroformate, and ethyl trichloroacetate. These chlorine-containing ester organic solvents can compete with carboxylic acid ester organic solvents for coordination with lithium ions, thereby regulating the solvation structure of lithium ions; and / or, The lithium salt includes at least one of lithium hexafluorophosphate, lithium bis(fluorosulfonylimide), lithium perchlorate, lithium tetrafluoroborate, lithium bis(trifluorosulfonylimide) nitrate, and lithium difluorooxalate borate. These lithium salts can provide high ionic conductivity and preferentially decompose at the lithium metal interface to form a stable interface.
[0007] In some embodiments, the mass ratio of the first ester organic solvent to the second ester organic solvent is 1:(0.1~3), with the first ester organic solvent serving as the main solvent and the second ester organic solvent serving as the co-solvent. Maintaining this mass ratio effectively balances the low-temperature solution behavior of the electrolyte while simultaneously regulating the solvation structure of lithium ions and improving ionic conductivity.
[0008] In some embodiments, the lithium metal electrolyte further includes film-forming additives. These additives can rapidly decompose to form a stable solid electrolyte interface (SEI) during the initial stages of battery activation, improving interface stability while effectively inhibiting the continued decomposition of the electrosolvent.
[0009] In some embodiments, the film-forming additive includes at least one of ethylene carbonate, fluoroethylene carbonate, ethylene ethylene carbonate, and vinyl acetate. The above-mentioned film-forming additive can construct a stable SEI film with high ionic conductivity and exhibits certain low-temperature adaptability, thus improving the low-temperature performance of the battery.
[0010] In some embodiments, the mass ratio of the ester organic solvent to the film-forming additive is (4~9):1. This mass ratio promotes the rapid formation of a thin and dense SEI film by the film additive, reducing side reactions between the negative electrode and the electrolyte.
[0011] In some embodiments, the molar concentration of the lithium salt in the lithium metal electrolyte is 0.8~3.0 mol / L. Within this range, the molar concentration of the lithium salt in the lithium metal electrolyte maintains a low-viscosity solution liquid behavior and improves ionic conductivity.
[0012] In some embodiments, the lithium metal electrolyte operates at a temperature of -80 to 60°C. Within this operating temperature range, the lithium metal electrolyte maintains a low-viscosity liquid state while still retaining good ionic conductivity, reducing internal resistance in low-temperature batteries and improving their low-temperature performance.
[0013] Secondly, this application provides a lithium metal secondary battery, including a positive electrode, a negative electrode, a separator, and the lithium metal electrolyte described in the first aspect.
[0014] Thirdly, this application provides an electrical device including the lithium metal secondary battery described in the second aspect. Attached Figure Description
[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0016] Figure 1 This is a graph showing the cycling performance of the lithium metal electrolyte in Example 1 of this application.
[0017] Figure 2 This is a graph showing the cycling performance of the lithium metal electrolyte in Example 2 of this application.
[0018] Figure 3 This is a graph showing the cycling performance of the lithium metal electrolyte in Example 3 of this application.
[0019] Figure 4 This is a graph showing the cycling performance of the lithium metal electrolyte in Comparative Example 1 of this application.
[0020] Figure 5 This is a graph showing the cycling performance of the lithium metal electrolyte in Comparative Example 2 of this application. Detailed Implementation
[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.
[0022] Lithium metal batteries (LIBs), with their advantages of high energy density, high efficiency, and stable cycle performance, are widely used in new electronic products such as mobile phones and watches, electric bicycles and hybrid vehicles, as well as various renewable energy storage devices. With the increasing demand for various energy storage devices in different operating scenarios, new requirements are being placed on the energy density and long-term stability of lithium metal batteries. Lithium metal batteries, using Li metal, have a higher specific capacity (3860 mAh g⁻¹). -1 With its extremely low electrochemical potential, lithium (Li) is a promising next-generation energy storage battery. However, Li is a highly reactive metal that readily reacts with some organic solvents. Ether-based organic electrolytes exhibit excellent stability with Li, but they are often not resistant to high voltages (≥4.3V), making them generally difficult to use with high-capacity, high-Ni cathodes. Therefore, finding an organic electrolyte that is stable with Li is a highly challenging task.
[0023] Short-chain carboxylic esters such as butyl acetate and ethyl acetate can replace traditional carbonates as polar solvents in electrolytes, effectively improving physical properties such as electrolyte properties and conductivity, while also broadening the electrochemical window of the electrolyte. However, short-chain carboxylic esters have strong reactivity, making it difficult to form a stable protective SEI layer at the electrode interface. They also exhibit severe side reactions with the lithium metal anode, resulting in low coulombic efficiency.
[0024] In view of this, this application provides a lithium metal electrolyte, a secondary battery, and an electrical device to replace the traditional carbonate as a polar solvent for the electrolyte. This effectively improves the physical properties of the electrolyte, such as conductivity, and broadens the electrochemical window of the electrolyte. It also forms a stable SEI film, thereby improving the coulombic efficiency of the battery.
[0025] In a first aspect, this application provides a lithium metal electrolyte, comprising a lithium salt and an ester-based organic solvent, wherein the ester-based organic solvent comprises a first ester-based organic solvent and a second ester-based organic solvent, wherein: The first ester organic solvent includes at least one of the carboxylic acid ester organic solvents; The second ester organic solvent includes at least one of amino-containing ester organic solvents, sulfonate-containing ester organic solvents, and chlorine-containing ester organic solvents.
[0026] This application introduces a second ester-based organic solvent into a carboxylate-based electrolyte system to form a lithium metal electrolyte. The use of the carboxylate-based organic electrolyte ensures a wide electrochemical window, allowing for use with ternary cathode materials and improving battery capacity performance. The additionally introduced second ester-based organic solvent contains specific functional groups (amino-NH2, sulfonyl-SO3, and Cl atoms), which can form a stable SEI interface with the Li metal surface, enhancing the electrolyte's stability against Li metal. Furthermore, the mixed ester-based organic solvent can optimize Li... + The ion coordination environment improves battery reaction kinetics and increases battery capacity. Lithium metal electrolytes using various ester-based organic solvents have lower polarization sites and better Li metal stability than electrolytes using only esters, resulting in batteries with excellent long cycle life and higher capacity.
[0027] In conjunction with the first aspect, in some embodiments provided in this application, the carboxylic acid ester organic solvent includes at least one of propyl propionate, butyl acetate, and ethyl butyrate. The above-mentioned carboxyl organic solvent has high polarity solubility, can dissolve a variety of lithium salts and maintain a high concentration; at the same time, it has a low solidification temperature, which enables the electrolyte to have good liquid behavior at low temperatures and provides high ionic conductivity.
[0028] In conjunction with the first aspect, in some embodiments provided in this application, the amino-containing ester organic solvent includes at least one of N-methylcarbamate, N-ethylcarbamate, dimethylaminoethyl methacrylate, and glycine ethyl ester. The above-mentioned amino-containing ester organic solvent can form intermolecular hydrogen bonds with carboxylic acid ester organic solvents, enhance the molecular forces between solvents, and thereby regulate the solvation structure of lithium ions.
[0029] In conjunction with the first aspect, in some embodiments provided in this application, the sulfonated ester organic solvent includes at least one of methanesulfonamide, ethyl methanesulfonate, methyl methanesulfonate, chloromethyl chlorosulfonate, and methyl chlorosulfonate. The above-mentioned sulfonated ester organic solvent can preferentially decompose at the lithium metal interface to generate more stable lithium sulfide and improve interface stability.
[0030] In conjunction with the first aspect, in some embodiments provided in this application, the chlorine-containing ester organic solvent includes at least one of ethyl chloroacetate, ethyl chloroformate, and ethyl trichloroacetate. The aforementioned chlorine-containing ester organic solvent can compete with carboxylic acid ester organic solvents for coordination with lithium ions, thereby regulating the solvation structure of lithium ions.
[0031] In conjunction with the first aspect, in some embodiments provided in this application, the lithium salt includes at least one selected from lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium perchlorate, lithium tetrafluoroborate, lithium nitrate, lithium bis(trifluorosulfonyl)imide, and lithium difluorooxalate borate. The aforementioned lithium salts can provide high ionic conductivity and preferentially decompose at the lithium metal interface to form a stable interface.
[0032] In conjunction with the first aspect, in some embodiments provided in this application, the mass ratio of the first ester organic solvent to the second ester organic solvent is 1:(0.1~3). Within this range, the mass ratio of the first ester organic solvent to the second ester organic solvent can effectively balance the low-temperature solution behavior of the electrolyte while simultaneously regulating the solvation structure of lithium ions and improving ionic conductivity.
[0033] In conjunction with the first aspect, in some embodiments provided in this application, the lithium metal electrolyte further includes film-forming additives. These film-forming additives can rapidly decompose in the early stages of battery activation to form a stable solid electrolyte interface (SEI), improving interface stability while effectively inhibiting the continued decomposition of the electrosolvent.
[0034] In conjunction with the first aspect, in some embodiments provided in this application, the film-forming additive includes at least one of ethylene carbonate, fluoroethylene carbonate, ethylene ethylene carbonate, and vinyl acetate. The above-mentioned film-forming additive can construct a stable SEI film with high ionic conductivity and has certain low-temperature adaptability, thus improving the low-temperature performance of the battery.
[0035] In conjunction with the first aspect, in some embodiments provided in this application, the mass ratio of the ester organic solvent to the film-forming additive is (4~9):1. Within this range, the mass ratio of the ester organic solvent to the film-forming additive can promote the rapid formation of a thin and dense SEI film by the film additive, reducing side reactions between the negative electrode and the electrolyte.
[0036] In conjunction with the first aspect, in some embodiments provided in this application, the molar concentration of the lithium salt in the lithium metal electrolyte is 0.8~3.0 mol / L. Within this range, the molar concentration of the lithium salt in the lithium metal electrolyte maintains a low-viscosity solution liquid behavior and improves ionic conductivity.
[0037] In conjunction with the first aspect, in some embodiments provided in this application, the operating temperature of the lithium metal electrolyte is -80 to 60°C. Within this operating temperature range, the lithium metal electrolyte can maintain a low-viscosity liquid state while still retaining good ionic conductivity, reducing the internal resistance of the low-temperature battery, and improving the battery's low-temperature performance.
[0038] Secondly, this application provides a lithium metal secondary battery, including a positive electrode, a negative electrode, a separator, and the lithium metal electrolyte described in the first aspect.
[0039] Thirdly, this application provides an electrical device including the lithium metal secondary battery described in the second aspect.
[0040] The technical solutions provided in this application will be described in detail below with reference to the embodiments.
[0041] Example 1 Example 1 of this application provides a lithium metal electrolyte, in which lithium hexafluorophosphate (LiPF6) is dissolved in a mixed solvent of a mixed ester solvent (ethyl butyrate and ethyl methanesulfonate, mass ratio 1:3) and a film-forming additive (fluoroethylene carbonate), the lithium salt concentration is 1.0 mol / L, and the mass ratio of fluoroethylene carbonate to the mixed ester solvent is 1:4. The solution is obtained by magnetic stirring at 25°C for 5 hours.
[0042] Example 2 Example 2 of this application provides a lithium metal electrolyte, in which lithium hexafluorophosphate (LiPF6) and lithium difluorooxalate borate (LiDFOB) are dissolved in a mixed solvent of a mixed ester solvent (ethyl butyrate and ethyl methanesulfonate, mass ratio 1:2) and a film-forming additive (fluoroethylene carbonate). The lithium salt concentration is 0.8 mol / L, and the mass ratio of fluoroethylene carbonate to the mixed ester solvent is 1:5. The electrolyte is obtained by magnetic stirring at 25°C for 5 hours.
[0043] Example 3 Example 3 of this application provides a lithium metal electrolyte, in which lithium hexafluorophosphate (LiPF6) and lithium difluorooxalate borate (LiDFOB) are dissolved in a mixed solvent of a mixed ester solvent (ethyl butyrate and ethyl methanesulfonate, mass ratio 1:1) and a film-forming additive (fluoroethylene carbonate). The lithium salt concentration is 1.0 mol / L, and the mass ratio of fluoroethylene carbonate to the mixed ester solvent is 1:6. The mixture is magnetically stirred at 25°C for 5 h, and then 0.145 mol / L LiNO3 is added to obtain the lithium metal electrolyte.
[0044] Example 4 Example 4 of this application provides a lithium metal electrolyte, in which lithium bis(trifluorosulfonylimide) and lithium bis(trifluorosulfonylimide) are dissolved in a mixed solvent of a mixed ester solvent (propyl propionate and ethyl glycine, mass ratio 1:0.1) and a film-forming additive (ethylene carbonate). The lithium salt concentration is 1.0 mol / L, and the mass ratio of ethylene carbonate to the mixed ester solvent is 1:9. The mixture is magnetically stirred at 25°C for 5 hours, and then 2.0 mol / L lithium difluorooxalate borate is added to obtain the lithium metal electrolyte.
[0045] Example 5 Example 5 of this application provides a lithium metal electrolyte, in which lithium perchlorate (LiClO4) and lithium tetrafluoroborate (LiBF4) are dissolved in a mixed solvent of a mixed ester solvent (butyl acetate and ethyl chloroacetate, mass ratio 1:2) and a film-forming additive (ethylene ethylene carbonate). The lithium salt concentration is 1.0 mol / L, and the mass ratio of ethylene ethylene carbonate to the mixed ester solvent is 1:4. The solution is magnetically stirred at 25°C for 5 hours to obtain the lithium metal electrolyte.
[0046] Comparative Example 1 Comparative Example 1 of this application provides a lithium metal electrolyte in which lithium hexafluorophosphate (LiPF6) and lithium difluorooxalate borate (LiDFOB) are dissolved in a mixed solvent of ethyl butyrate and a film-forming additive (fluoroethylene carbonate). The lithium salt concentration is 1.0 mol / L, and the mass ratio of fluoroethylene carbonate to the mixed ester solvent is 1:4. The electrolyte is obtained by magnetic stirring at 25°C for 5 hours.
[0047] Comparative Example 2 Comparative Example 2 of this application provides a lithium metal electrolyte in which lithium hexafluorophosphate (LiPF6) and lithium difluorooxalate borate (LiDFOB) are dissolved in a mixed solvent of ethyl methanesulfonate and a film-forming additive (fluoroethylene carbonate). The lithium salt concentration is 1.0 mol / L, and the mass ratio of fluoroethylene carbonate to the mixed ester solvent is 1:4. The electrolyte is obtained by magnetic stirring at 25°C for 5 hours.
[0048] Comparative Example 3 Comparative Example 3 of this application provides a lithium metal electrolyte, which is an ether-based organic electrolyte. Lithium hexafluorophosphate (LiPF6) and lithium difluorooxalate borate (LiDFOB) are dissolved in a mixed solvent of ethylene glycol dimethyl ether and a film-forming additive (fluoroethylene carbonate). The lithium salt concentration is 1.0 mol / L, and the mass ratio of fluoroethylene carbonate to the ether solvent (ethylene glycol dimethyl ether) is 1:4. The electrolyte is obtained by magnetic stirring at 25°C for 5 hours.
[0049] Performance testing The lithium metal electrolytes of Examples 1 to 5 and Comparative Examples 1 to 3 were subjected to performance tests. The specific test methods were as follows: Positive electrode sheet: A ternary cathode material (Ni622, Ni83, Ni811, etc.) is used as the positive electrode active material, polyvinylidene fluoride (PVDF) as the binder, and Super P as the conductive agent, with a mass ratio of 85:7:8. The positive electrode slurry is formed by mixing the materials in an organic solvent, N-methylpyrrolidone (NMP) or dimethylformamide (DMF), and then coated onto an Al current collector and vacuum dried for 48 hours. It is then cut into circular sheets of a specific size (10 mm in diameter), with an active material loading of 5 mg / cm³.2 .
[0050] Negative electrode: Li metal foil with a diameter of 16 mm and a thickness of 100~200 μm is used.
[0051] Separator: Commercial PP diaphragm (Celgard 2500, 25μm thick) is used and cut into discs with a diameter of 19 mm.
[0052] Assembly: Button battery model CR-2032.
[0053] Initial coulombic efficiency: The initial coulombic efficiency is calculated based on the first charge-discharge cycle capacity with the battery activated at 0.1C.
[0054] Capacity retention rate: The discharge capacity of the third cycle is used as the initial capacity (after 2 activation cycles). The discharge capacity after a certain number of cycles is compared with the initial capacity to calculate the capacity retention rate.
[0055] Cyclic performance: Using a certain capacity retention rate (80%) as a reference, the number of cycles of each embodiment and comparative example were compared to compare the cycle performance of each group of batteries.
[0056] The results are shown in Table 1: Table 1 Performance results of Examples 1 to 5 and Comparative Examples 1 to 3
[0057] The cycling performance diagram of the lithium metal electrolyte in Example 1 is shown below. Figure 1 As shown in the figure. The cycling performance diagram of the lithium metal electrolyte in Example 2 is shown in the figure. Figure 2 As shown in the figure. The cycling performance diagram of the lithium metal electrolyte in Example 3 is shown in the figure. Figure 3 As shown in the figure. The cycling performance diagram of the lithium metal electrolyte in Comparative Example 1 is shown in the figure. Figure 4 As shown in the figure. The cycling performance of the lithium metal electrolyte in Comparative Example 2 is shown in the figure. Figure 5 As shown.
[0058] As shown in Table 1, in Examples 1 to 5, the batteries exhibited high initial capacity and coulombic efficiency, and all exceeded 100 cycles, demonstrating certain application potential. Example 3, using both lithium salts and mixed ester solvents, achieved the best cycle performance, indicating that the combined use of lithium salts and mixed ester solvents imparts the best battery performance.
[0059] Comparative Example 1 contains only carboxylic acid ester solvents that are unstable to lithium metal, as it does not contain second ester organic solvents. This makes it prone to anodic corrosion, which leads to a continuous decline in battery performance.
[0060] Comparative Example 2, lacking both first-stage ester organic solvents and high-voltage stable carboxylic acid ester solvents, stopped charging during the second cycle due to the inability to recharge.
[0061] Comparative Example 3, due to the use of ether-based organic electrolytes and the absence of high-voltage stable ester solvents, experienced a rapid decline in battery performance after 5 cycles.
[0062] In summary, by introducing a second ester-based organic solvent into the carboxylate-based electrolyte system, a lithium metal electrolyte is formed. The use of the carboxylate-based organic electrolyte ensures the electrochemical window of the electrolyte, allowing it to be used with ternary cathode materials to improve battery capacity performance. The additionally introduced second ester-based organic solvent contains specific functional groups (amino-NH2, sulfonyl-SO3, Cl atoms), which can form a stable SEI interface with the Li metal surface, improving the electrolyte's stability against Li metal. Furthermore, the mixed ester-based organic solvent can optimize Li... + The ion coordination environment improves battery reaction kinetics and increases battery capacity. Lithium metal electrolytes using various ester-based organic solvents have lower polarization sites and better Li metal stability than electrolytes using only esters, resulting in batteries with excellent long cycle life and higher capacity.
[0063] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.
[0064] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.
[0065] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.
[0066] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A lithium metal electrolyte, characterized in that, It includes lithium salts and ester organic solvents, wherein the ester organic solvents include a first ester organic solvent and a second ester organic solvent, wherein: The first ester organic solvent includes at least one of the carboxylic acid ester organic solvents; The second ester organic solvent includes at least one of amino-containing ester organic solvents, sulfonate-containing ester organic solvents, and chlorine-containing ester organic solvents.
2. The lithium metal electrolyte as described in claim 1, characterized in that: The carboxylic acid ester organic solvent includes at least one of propyl propionate, butyl acetate, and ethyl butyrate; and / or, The amino-containing ester organic solvents include at least one of methyl N-methylcarbamate, ethyl N-ethylcarbamate, dimethylaminoethyl methacrylate, and ethyl glycine; and / or, The sulfonated ester organic solvents include at least one of methanesulfonamide, ethyl methanesulfonate, methyl methanesulfonate, chloromethyl chlorosulfonate, and methyl chlorosulfonate; and / or, The chlorine-containing ester organic solvents include at least one of ethyl chloroacetate, ethyl chloroformate, and ethyl trichloroacetate; and / or, The lithium salt includes at least one of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium perchlorate, lithium tetrafluoroborate, lithium nitrate, lithium bis(trifluorosulfonyl)imide, and lithium difluorooxalate borate.
3. The lithium metal electrolyte as described in claim 1, characterized in that, The mass ratio of the first ester organic solvent to the second ester organic solvent is 1:(0.1~3).
4. The lithium metal electrolyte as described in claim 1, characterized in that, The lithium metal electrolyte also includes film-forming additives.
5. The lithium metal electrolyte as described in claim 4, characterized in that, The film-forming additive includes at least one of ethylene carbonate, fluoroethylene carbonate, ethylene ethylene carbonate, and vinyl acetate.
6. The lithium metal electrolyte as described in claim 4, characterized in that, The mass ratio of the ester organic solvent to the film-forming additive is (4~9):
1.
7. The lithium metal electrolyte as described in claim 1, characterized in that, The molar concentration of the lithium salt in the lithium metal electrolyte is 0.8~3 mol / L.
8. The lithium metal electrolyte as described in claim 1, characterized in that, The operating temperature of the lithium metal electrolyte is -80 to 60°C.
9. A lithium metal secondary battery, characterized in that, It includes a positive electrode, a negative electrode, a separator, and a lithium metal electrolyte as described in any one of claims 1 to 8.
10. An electrical appliance, characterized in that, Including the lithium metal secondary battery as described in claim 9.