Electrolyte additive for lithium metal battery, electrolyte and preparation method of electrolyte additive

Abstract

The invention provides an electrolyte additive for a lithium metal battery, and a design and preparation method of an electrolyte. The invention provides an application of mesoporous polydopamine and lithium phosphotungstate as additives in a lithium metal battery electrolyte. The electrolyte comprises mesoporous polydopamine, lithium phosphotungstate, a lithium salt and an ether-based solvent. And preparing the Li3PW12O40 nano particles by adopting an ion exchange method. Through chemical adhesion and physical adsorption effects, Li3PW12O40 nanoparticles are supported by mesoporous polydopamine microspheres, and the mesoporous polydopamine microspheres are used as a composite additive of a lithium metal battery. The additive can be adsorbed on the interface of the battery, regulate and control the deposition of metal lithium, improve the components of an SEI film, reduce the transmission energy barrier of lithium ions and meet the quick charge requirement of the lithium metal battery. The electrolyte containing the additive can significantly improve the cycle performance and coulombic efficiency of the lithium metal total battery, and provides a feasible thought for performance improvement and product iteration of the lithium metal battery.

Description

Technical Field

[0001] The present invention belongs to the field of lithium metal batteries, and in particular relates to a lithium metal battery electrolyte additive, an electrolyte preparation method, and metal lithium battery preparation. Background Art

[0003] Lithium metal anode is considered to be the ultimate anode material that can replace graphite anode in high specific energy secondary batteries. It has an ultra-high theoretical specific capacity and the lowest redox potential (-3.04V vs standard hydrogen electrode). At present, lithium metal anode has been used in Li-S, Li-LTMO, Li-O 2 It has excellent performance in systems such as lithium metal anode and has achieved high energy density. However, although it can be matched with various types of positive electrodes, lithium metal anode still has many problems, such as: (1) The interface contact between lithium metal and liquid electrolyte is unstable. Its strong reducibility allows it to react spontaneously with almost all electrolytes to form a SEI film on the surface of lithium metal. As the charge and discharge proceed, the volume change of the lithium metal anode will cause the SEI to continue to break and form, continuously consume the electrolyte and expose the active lithium on the surface, causing the battery cycle performance and service life to decay. (2) During the battery cycle, due to the uneven current density on the electrode surface, the lithium in the electrolyte will form moss-like lithium dendrites on the surface of the lithium metal anode during the deposition process. The growing dendrites can pierce the diaphragm, thereby causing an internal short circuit in the battery and generating the risk of thermal runaway, fire and explosion. (3) The mechanical properties of lithium dendrites are poor. As the charge and discharge proceed, they will break and form "dead lithium", causing the impedance to increase and triggering electrochemical polarization. The above-mentioned safety issues have seriously hindered the commercialization of lithium metal negative electrodes and have caused people to pay attention to the safety of lithium metal batteries.

[0004] In order to regulate the interfacial lithium deposition of lithium metal batteries, two effective methods, interface engineering and electrolyte engineering, are usually used. Among them, interface engineering refers to the introduction of specific additives on the surface of the lithium negative electrode, and the regulation of the composition of the SEI layer by artificial means such as dripping, scraping, and magnetron sputtering. Electrolyte engineering can further regulate the composition and properties of SEI by adjusting the types and proportions of lithium salts and solvents, and adding appropriate amounts of additives, so as to enhance the uniformity of film formation. Trace additives in the electrolyte can often have a "four-two-pound" effect. Some additives have the function of guiding the uniform deposition of lithium on the metal surface, thereby helping to regulate the distribution of lithium ions on the electrode surface.

[0005] Polydopamine (PDA) is a biomolecule that contains abundant N and O groups (-NH 2, -OH and other polar functional groups), which are lithium-philic, can enhance the wettability of the electrolyte, provide a solid SEI interface, and make the alkali metal ions distributed and nucleated uniformly. In addition to the properties of polydopamine, mesoporous polydopamine (PDA) also contains mesoporous channels with a diameter of tens of nanometers. Its mesoporous structure is conducive to the construction of ion transmission channels and promotes Li + Conductivity. Polyoxometalates (POMs) are a class of polyanionic clusters with oxygen-linked MOx polyhedra, which have electronic functionality, rich redox properties and thermal stability. Due to their huge size and structural diversity, they are widely used in advanced technologies (catalysis, nanotechnology and electrochemistry, etc.). Lithium phosphotungstate (Li 3 PW 12 O 40 ) is a polyoxometalate with high stability to water and lithium metal. From the structural point of view, the pseudo-octahedral MO 6 The POM ion core composed of (M=V, Nb, Mo, W) units is conducive to Li + The "jump" transport of Li + diffusion energy barrier.

[0006] In the present invention, mesoporous polydopamine microspheres are used to support Li 3 PW 12 O 40 Nanoparticles are used as composite additives for lithium metal batteries. The additives can regulate the interfacial deposition of lithium metal anodes, reduce the diffusion energy barrier, and accelerate the lithium ion transfer rate at the interface. Summary of the invention

[0007] The purpose of the present invention is to provide a lithium metal battery electrolyte additive, an electrolyte design and preparation method, and a lithium metal battery prepared using the additive, which can reduce the transmission energy barrier of lithium ions while regulating the deposition of metallic lithium, thereby meeting the fast charging requirements of lithium metal batteries.

[0008] In order to achieve the above object, the present invention adopts the following solution:

[0009] In a first aspect, the present invention provides the use of lithium phosphotungstate and mesoporous polydopamine microspheres in electrolyte additives.

[0010] In a second aspect, the present invention provides a method for preparing lithium phosphotungstate, the steps of which are as follows:

[0011] Lithium phosphotungstate was prepared by ion exchange method. 3 PW 12 O 40 ·28H 2 O and anhydrous LiCl were mixed and dissolved in deionized water according to the stoichiometric ratio and stirred evenly with a magnetic bar; ammonia (NH3 ·H 2 O) to make its pH neutral, dry it, wash it with anhydrous ethanol, and dry it to obtain a white powder Li 3 PW 12 O 40 solid.

[0012] In the preparation method, H 3 PW 12 O 40 ·28H 2 The stoichiometric ratio of O and anhydrous LiCl is 1:3.

[0013] In the preparation method, preferably, the mixture is stirred in deionized water for 5 to 10 minutes, the stirring time after the ammonia water is added is 2 hours, and the drying condition is 3 hours at 80°C.

[0014] In a third aspect, the present invention provides a method for preparing a composite additive for a lithium metal battery electrolyte, comprising a mesoporous polydopamine solution, a phosphotungstic acid hydrate, and anhydrous lithium chloride (LiCl), and the steps are as follows:

[0015] Lithium phosphotungstate is prepared by ion exchange method, and the preparation method is as described in the second aspect.

[0016] Preparation of composite additives. The prepared lithium phosphotungstate is added to the mesoporous polydopamine solution, dissolved and stirred. After being dried in an oven, the composite additive is obtained on the bottle wall.

[0017] Furthermore, the mass ratio of lithium phosphotungstate and mesoporous PDA is (1-10):1; preferably, the mass ratio of lithium phosphotungstate and mesoporous PDA is 7:2.

[0018] Furthermore, the mixed solution is stirred for more than 3 hours, and is placed in a 60° C. oven for more than 12 hours until the water is completely dried.

[0019] Scrape the additive powder off the bottle wall with a medicine spoon, grind it into fine powder in a small mortar to obtain a composite additive powder.

[0020] In a fourth aspect, the present invention provides a method for preparing a lithium metal battery electrolyte containing the additive.

[0021] The additive powder prepared according to the method is added to the electrolyte in a mass fraction ratio, and stirred continuously until the additive is evenly distributed, and the battery is assembled for testing.

[0022] Furthermore, the stirring time of the electrolyte mixture needs to be greater than 24 hours.

[0023] Further, optionally, the mass fraction ratio of the additive is 1% to 5%.

[0024] Furthermore, the electrolyte is an ether-based electrolyte containing 1,3-dioxolane (DOL) or ethylene glycol dimethyl ether (DME) components.

[0025] In a fifth aspect, the present invention provides a lithium metal battery, including the lithium metal battery electrolyte and the electrolyte obtained by the preparation method.

[0026] It can be seen from the above technical solution that this method has the following advantages:

[0027] 1. The preparation method of lithium phosphotungstate provided by the present invention comprises taking H 3 PW 12 O 40 ·28H 2 O and anhydrous LiCl were mixed in deionized water according to the stoichiometric ratio and stirred evenly; ammonia water was added dropwise to make its pH neutral, and then dried and washed with anhydrous ethanol to obtain white powder LiCl. 3 PW 12 O 40 The ion exchange method has the characteristics of simple operation, high purity, high efficiency, and environmental friendliness, and can be prepared without complicated reaction conditions.

[0028] 2. In the additive provided by the present invention, the nitrogen-containing and oxygen-containing polar functional groups on the surface of the mesoporous PDA have a greater affinity for lithium metal, thereby enhancing the wettability of the electrolyte, providing a solid SEI interface, and making the distribution and nucleation of alkali metal ions uniform. The hollow mesoporous structure provides a higher specific surface area, which is conducive to the construction of ion transmission channels and promotes the conduction of lithium ions.

[0029] 3. In the additive provided by the present invention, the polyoxometalate has electronic functionality, rich redox properties and thermal stability, as well as a special structure. 3 PW 12 O 40 The ion core is favorable for Li + The "jump" transport can reduce the diffusion energy barrier of lithium ions.

[0030] 4. In the additive provided by the present invention, the chemical viscosity and physical adsorption of the mesoporous PDA can make Li 3 PW 12 O 40 The two components of mesoporous PDA are effectively combined to play a dual-effect regulating role on the performance of the electrolyte. The hollow structure of mesoporous PDA can be used to load lithium phosphotungstate as a composite component.

[0031] 5. The preparation method of the lithium metal battery additive provided by the present invention comprises preparing lithium phosphotungstate by ion exchange method, adding the prepared lithium phosphotungstate to a mesoporous polydopamine solution, dissolving and drying, scraping off the additive powder, grinding it, and mixing it with lithium salt, solvent, etc. to obtain an electrolyte. The preparation method is simple and convenient, and can significantly improve the circulation and fast charging performance of the electrolyte, and is suitable for production and promotion.

[0032] 6. The metal lithium battery provided by the present invention comprises the metal lithium battery electrolyte, or the metal lithium battery electrolyte obtained by the preparation method. The metal lithium battery has a dense SEI film, which significantly improves the safety of the lithium metal negative electrode, has small battery polarization and impedance, has good electrochemical performance, and effectively improves the cycle performance and coulomb efficiency of the lithium metal full battery, and is a next-generation alkali metal secondary battery with good chemical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to further explain the specific technical solutions in the present invention, the following is a brief introduction to the drawings required for use in the specific implementation methods:

[0034] Figure 1 (a~b) are optical photographs of composite additive powder samples; (c) is a photograph of the experimental sample electrolyte.

[0035] Figure 2 For the synthesis of Li 3 PW 12 O 40 The XRD spectrum of the solid and H 3 PW 12 O 40 comparison.

[0036] Figure 3 SEM images of the lithium deposition morphology of (a) the blank group and (b) the experimental group in the Li||Li symmetric cell; and the deposition on copper foil of (c) the blank group and (d) the experimental group in the Li||Cu half cell.

[0037] Figure 4 Comparison of long cycle curves of Li||Li symmetric batteries.

[0038] Figure 5 Comparison of the Coulombic efficiency of Li||Cu half-cells over long cycles.

[0039] Figure 6 Impedance comparison of Li||Li symmetric cells assembled using (a) blank sample and (b) experimental sample electrolyte.

[0040] Figure 7The curves of specific capacity and coulombic efficiency of Li||LFP batteries containing additives and blank samples changing with time when the voltage is 2.5-4.0V at a rate of 5C. DETAILED DESCRIPTION

[0041] The embodiments of the present invention provide a lithium metal battery electrolyte additive, an electrolyte preparation method and a lithium battery, which are used to solve the interface and cycle life problems of lithium metal batteries.

[0042] In order to make the conditions of the present invention more specific and the features more obvious, the embodiments of the present invention are specifically cited below and described in detail as follows.

[0043] The basic idea of ​​the present invention is to prepare Li 3 PW 12 O 40 Nanoparticles are used as electrolyte additives; Mesoporous polydopamine microspheres are loaded with Li by chemical adhesion and physical adsorption. 3 PW 12 O 40 Nanoparticles are used as composite additives for lithium metal batteries; by providing a lithium metal battery electrolyte additive to regulate the deposition of metallic lithium, improve the composition of the SEI film, and at the same time reduce the transmission energy barrier of lithium ions to meet the fast charging requirements of lithium metal batteries; by using an electrolyte containing the additive to enhance the electrochemical properties of lithium metal batteries, the cycle performance and coulombic efficiency of lithium metal full batteries are improved.

[0044] Example 1

[0045] This embodiment is a specific embodiment of preparing lithium phosphotungstate.

[0046] Lithium phosphotungstate is prepared by ion exchange method.

[0047] (1) At room temperature, weigh 2.88 g of H 3 PW 12 O 40 ·28H 2 O and 0.128 g of anhydrous LiCl were mixed and placed in a beaker, deionized water was added to dissolve, a magnet was added and the mixture was stirred on a magnetic stirrer for 5 min to obtain a mixed solution.

[0048] (2) Add ammonia (NH4OH) to the mixed solution after the reaction (1). 3 ·H 2 O), when the pH is 6-7 as measured by a pH meter, stop adding ammonia water.

[0049] (3) The mixed solution in (2) was placed in an oven at 80°C and dried for 3 h. The obtained white solid was washed with anhydrous ethanol and dried again to obtain a white powdery solid, which is Li 3 PW 12 O 40 Component.

[0050] Example 2

[0051] This example is to prepare a Li 3 PW 12 O 40 Specific embodiments of lithium metal battery electrolyte additives of mesoporous PDA.

[0052] (1) Lithium phosphotungstate was prepared by ion exchange method. At room temperature, 2.88 g of H 3 PW 12 O 40 ·28H 2 O and 0.128g of anhydrous LiCl, mix and place in a beaker, add deionized water to dissolve, add a magnet and stir on a magnetic stirrer for 5 minutes to obtain a mixed solution. Add ammonia water to the mixed solution after the reaction, and stop adding ammonia water when the pH is 6-7 measured by a pH meter. The mixed solution is placed in an oven at 80°C and dried for 3 hours. The obtained white solid is washed with anhydrous ethanol and dried again to obtain a white powdery solid, which is Li 3 PW 12 O 40 Component.

[0053] (2) Weigh 70 mg of the prepared lithium phosphotungstate and add it to 2 ml of a mesoporous polydopamine aqueous solution, wherein the concentration of the mesoporous polydopamine microspheres is 8-10 mg / ml; then add 2 ml of deionized water and stir for about 3 h.

[0054] (3) The sample bottle is placed in an oven and allowed to stand for drying, and the composite additive is obtained on the bottle wall.

[0055] (4) Use a medicine spoon to scrape the powder off the bottle wall, and grind it in a mortar. The resulting black powder is the additive.

[0056] Example 3

[0057] This example is to prepare a Li 3 PW 12 O 40 Specific embodiments of lithium metal battery electrolyte additives of mesoporous PDA.

[0058] (1) Lithium phosphotungstate was prepared by ion exchange method. At room temperature, 2.88 g of H3 PW 12 O 40 ·28H 2 O and 0.128g of anhydrous LiCl, mix and place in a beaker, add deionized water to dissolve, add a magnet and stir on a magnetic stirrer for 10 minutes to obtain a mixed solution. Add ammonia water to the mixed solution after the reaction, and stop adding ammonia water when the pH is 6-7 measured by a pH meter. Place the mixed solution in an oven at 80°C and dry for 3 hours. Wash the obtained white solid with anhydrous ethanol and dry again to obtain a white powdery solid, which is Li 3 PW 12 O 40 Component.

[0059] (2) Weigh 100 mg of the prepared lithium phosphotungstate and add it to 2 ml of a mesoporous polydopamine aqueous solution, wherein the concentration of the mesoporous polydopamine microspheres is 8-10 mg / ml; then add 2 ml of deionized water and stir for about 3 h.

[0060] (3) The sample bottle is placed in an oven and allowed to stand for drying, and the composite additive is obtained on the bottle wall.

[0061] (4) Use a medicine spoon to scrape the powder off the bottle wall, and grind it in a mortar. The resulting black powder is the additive.

[0062] Example 4

[0063] This example is to prepare a Li 3 PW 12 O 40 Specific embodiments of lithium metal battery electrolytes containing mesoporous PDA additives.

[0064] (1) Lithium phosphotungstate was prepared by ion exchange method. At room temperature, 2.88 g of H 3 PW 12 O 40 ·28H 2 O and 0.128g of anhydrous LiCl, mix and place in a beaker, add deionized water to dissolve, add a magnet and stir on a magnetic stirrer for 5 minutes to obtain a mixed solution. Add ammonia water to the mixed solution after the reaction, and stop adding ammonia water when the pH is 6-7 measured by a pH meter. The mixed solution is placed in an oven at 80°C and dried for 3 hours. The obtained white solid is washed with anhydrous ethanol and dried again to obtain a white powdery solid, which is Li 3 PW 12 O 40 Component.

[0065] (2) Weigh 70 mg of the prepared lithium phosphotungstate and add it to 2 ml of a mesoporous polydopamine aqueous solution, wherein the concentration of the mesoporous polydopamine microspheres is 8-10 mg / ml; then add 2 ml of deionized water and stir for about 3 h.

[0066] (3) The sample bottle is placed in an oven and allowed to stand for drying, and the composite additive is obtained on the bottle wall.

[0067] (4) Use a medicine spoon to scrape the powder off the bottle wall, and grind it in a mortar. The resulting black powder is the additive.

[0068] (5) In a glove box filled with argon (the oxygen and water contents in the glove box were both less than 1 ppm), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) and lithium nitrate (LiNO 3 ) is added to an organic solvent and mixed uniformly to obtain a mixed solvent; the organic solvent is composed of 1,3-dioxolane (DOL) and ethylene glycol dimethyl ether (DME) in a volume ratio of 1:1, the concentration of LiTFSI is 1 mol / L, and the concentration of LiNO 3 The mass fraction in the solution is 1%.

[0069] (6) In the glove box filled with argon, add the composite additive powder at a mass fraction of 1% to the electrolyte; the additive powder is the prepared Li 3 PW 12 O 40 The mixture is stirred for more than 24 hours using a magnetic stirrer to achieve uniform mixing, and the obtained mixed solution is the desired electrolyte.

[0070] Example 5

[0071] This example is to prepare a Li 3 PW 12 O 40 Specific embodiments of lithium metal battery electrolytes containing mesoporous PDA additives.

[0072] (1) Lithium phosphotungstate was prepared by ion exchange method. At room temperature, 2.88 g of H 3 PW 12 O 40 ·28H 2O and 0.128g of anhydrous LiCl, mix and place in a beaker, add deionized water to dissolve, add a magnet and stir on a magnetic stirrer for 5 minutes to obtain a mixed solution. Add ammonia water to the mixed solution after the reaction, and stop adding ammonia water when the pH is 6-7 measured by a pH meter. The mixed solution is placed in an oven at 80°C and dried for 3 hours. The obtained white solid is washed with anhydrous ethanol and dried again to obtain a white powdery solid, which is Li 3 PW 12 O 40 Component.

[0073] (2) Weigh 70 mg of the prepared lithium phosphotungstate and add it to 2 ml of a mesoporous polydopamine aqueous solution, wherein the concentration of the mesoporous polydopamine microspheres is 8-10 mg / ml; then add 2 ml of deionized water and stir for about 3 h.

[0074] (3) The sample bottle is placed in an oven and allowed to stand for drying, and the composite additive is obtained on the bottle wall.

[0075] (4) Use a medicine spoon to scrape the powder off the bottle wall, and grind it in a mortar. The resulting black powder is the additive.

[0076] (5) In a glove box filled with argon (the oxygen and water contents in the glove box are both less than 1 ppm), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) is added to an organic solvent and mixed evenly to obtain a mixed solvent; the organic solvent is composed of 1,3-dioxolane (DOL) and ethylene glycol dimethyl ether (DME) in a volume ratio of 7:3, and the concentration of LiTFSI is 1 mol / L.

[0077] (6) In the glove box filled with argon, add the composite additive powder at a mass fraction of 1% to the electrolyte; the additive powder is the prepared Li 3 PW 12 O 40 The mixture is stirred for more than 24 hours using a magnetic stirrer to achieve uniform mixing, and the obtained mixed solution is the desired electrolyte.

[0078] Example 6

[0079] This example is to prepare a Li 3 PW 12 O 40 Specific embodiments of lithium metal battery electrolytes containing mesoporous PDA additives.

[0080] (1) Lithium phosphotungstate was prepared by ion exchange method. At room temperature, 2.88 g of H 3 PW 12 O40 ·28H 2 O and 0.128g of anhydrous LiCl, mix and place in a beaker, add deionized water to dissolve, add a magnet and stir on a magnetic stirrer for 5 minutes to obtain a mixed solution. Add ammonia water to the mixed solution after the reaction, and stop adding ammonia water when the pH is 6-7 measured by a pH meter. The mixed solution is placed in an oven at 80°C and dried for 3 hours. The obtained white solid is washed with anhydrous ethanol and dried again to obtain a white powdery solid, which is Li 3 PW 12 O 40 Component.

[0081] (2) Weigh 70 mg of the prepared lithium phosphotungstate and add it to 2 ml of a mesoporous polydopamine aqueous solution, wherein the concentration of the mesoporous polydopamine microspheres is 8-10 mg / ml; then add 2 ml of deionized water and stir for about 3 h.

[0082] (3) The sample bottle is placed in an oven and allowed to stand for drying, and the composite additive is obtained on the bottle wall.

[0083] (4) Use a medicine spoon to scrape the powder off the bottle wall, and grind it in a mortar. The resulting black powder is the additive.

[0084] (5) In a glove box filled with argon (the oxygen and water contents in the glove box are both less than 1 ppm), lithium bis(fluoromethanesulfonyl imide) (LiFSI) is added to an organic solvent and mixed evenly to obtain a mixed solvent; the organic solvent is ethylene glycol dimethyl ether (DME), and the concentration of LiFSI is 1 mol / L.

[0085] (6) In the glove box filled with argon, add the composite additive powder at a mass fraction of 2% to the electrolyte; the additive powder is the prepared Li 3 PW 12 O 40 The mixture is stirred for more than 24 hours using a magnetic stirrer to achieve uniform mixing, and the obtained mixed solution is the desired electrolyte.

[0086] The above embodiments are only examples for the purpose of clear description and are not intended to limit the implementation methods. Therefore, other conditions may be varied on the basis of the above conditions. The specific conditions are not exhaustively listed here.

Claims

1. Application of mesoporous polydopamine microspheres and lithium phosphotungstate as additives in electrolytes.

2. A lithium metal battery electrolyte additive, characterized in that: Mesoporous polydopamine microspheres and lithium phosphotungstate are used as components of the additive.

3. A lithium metal battery electrolyte, comprising a lithium salt, an ether-based solvent, and an electrolyte additive, characterized in that: The invention comprises mesoporous polydopamine microspheres and lithium phosphotungstate as additive components.

4. The lithium metal battery electrolyte according to claim 3, characterized in that: 1.3-dioxolane or ethylene glycol dimethyl ether is used as the ether-based solvent, and mesoporous polydopamine and lithium phosphotungstate are used as components of the electrolyte additive.

5. A method for preparing lithium phosphotungstate, characterized in that: include: Lithium phosphotungstate is prepared by ion exchange method. Get H3PW 12 O 40 ·28H2O and anhydrous LiCl are mixed evenly, and the pH is adjusted to be neutral. After drying, washing and drying, white powder Li3PW is obtained. 12 O 40 solid.

6. The preparation method according to claim 5, characterized in that: H3PW 12 O 40 The stoichiometric ratio of 28H2O and anhydrous LiCl is 1:(2-4).

7. A method for preparing a lithium metal battery electrolyte, characterized in that: include: The lithium phosphotungstate is added into the mesoporous polydopamine microsphere solution to dissolve and mix, and the solution is allowed to stand and dry to obtain a composite additive. The additive powder prepared according to the method is mixed with the electrolyte and stirred evenly to obtain the desired electrolyte.

8. The method for preparing a lithium metal battery electrolyte according to claim 7, characterized in that: Nano-scale lithium phosphotungstate prepared by the method described in claim 4.

9. The method for preparing a lithium metal battery electrolyte according to claim 7, characterized in that: The mass ratio of lithium phosphotungstate and mesoporous PDA is (1-10):

1. The electrolyte is an ether-based electrolyte containing 1,3-dioxolane (DOL) or ethylene glycol dimethyl ether (DME). The mass fraction of the additive accounts for 1% to 5% of the electrolyte.

10. A lithium metal battery, characterized in that: The invention comprises the electrolyte according to claims 7 to 9, or the electrolyte prepared according to any one of claims 6 to 8.

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