Electrolyte for lithium metal battery, lithium metal battery, and recycling method therefor

Abstract

The present application discloses an electrolyte for a lithium metal battery, a lithium metal battery, and a recycling method therefor. The lithium metal battery comprises a positive electrode and a negative electrode. The electrolyte is disposed between the positive electrode and the negative electrode. The negative electrode comprises a lithium metal material or a lithium alloy material. The electrolyte comprises a lithium salt and an additive. The additive comprises chloroethylene carbonate.

Description

Electrolyte for lithium metal battery, lithium metal battery and recycling method thereof

[0001] This application claims priority to the Chinese patent publication with the publication number 202411301933.4, the title of "Electrolyte for lithium metal battery, lithium metal battery and recycling method thereof", which was filed on September 18, 2024, in the China Patent Office, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of electrolyte, in particular to an electrolyte for lithium metal battery, lithium metal battery and recycling method thereof. BACKGROUND

[0003] With the continuous development of portable electronic devices, electric vehicles and large-scale energy storage markets, the demand for lithium metal batteries also continues to grow. Currently, the lithium metal negative electrode of the lithium metal battery is prone to react with the electrolyte, resulting in poor stability of the electrolyte of the lithium metal battery. TECHNICAL PROBLEM

[0004] The present application provides an electrolyte for lithium metal battery, lithium metal battery and recycling method thereof to improve the stability of the electrolyte in the lithium metal battery cycle. TECHNICAL SOLUTION

[0005] In a first aspect, the present application provides an electrolyte for lithium metal battery. The lithium metal battery includes a positive electrode and a negative electrode. The electrolyte is disposed between the positive electrode and the negative electrode. The negative electrode includes a lithium metal material or a lithium alloy material. The electrolyte includes a lithium salt and an additive. The additive includes chloroethylene carbonate.

[0006] In a second aspect, the present application further provides a lithium metal battery, which includes a positive electrode, a negative electrode and the above-mentioned electrolyte, and the electrolyte is disposed between the positive electrode and the negative electrode. The negative electrode includes a lithium metal material or a lithium alloy material.

[0007] In a third aspect, the present application further provides a recycling method of lithium metal battery. The lithium metal battery includes a positive electrode, a negative electrode and an electrolyte disposed between the positive electrode and the negative electrode. The positive electrode includes a positive electrode active material. The negative electrode includes a lithium metal material or a lithium alloy material. The method includes:

[0008] Separating the positive electrode active material of the lithium metal battery;

[0009] Mixing the positive electrode active material with an additive containing chloroethylene carbonate to obtain a mixture; and

[0010] Heating the mixture until the positive electrode active material is decomposed to obtain a target decomposition product. Advantages

[0011] In the electrolyte and the lithium metal battery of some embodiments of the present application, the chloro-ethylene carbonate is added in the electrolyte, the lithium metal of the negative electrode preferentially reacts with the chloro-ethylene carbonate, the problem that the intrinsic electrolyte in the electrolyte reacts with the metal lithium to cause the consumption of the intrinsic electrolyte is improved, and the stability of the electrolyte and the cycle performance of the lithium metal battery are further improved.

[0012] In the recycling method of the lithium metal battery of some embodiments of the present application, the chloro-ethylene carbonate is used as an additive when the positive electrode active material is decomposed, the temperature required for the positive electrode active material to obtain the target decomposition product is reduced, and the power consumption required for recycling the positive electrode active material is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0013] FIG. 1 is an XRD test result of a product obtained after heating a mixture of an electrolyte containing chloro-ethylene carbonate and a nickel-cobalt-manganese lithium acid material at different temperatures. Embodiments of the present application

[0014] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person skilled in the art without creative labor fall within the scope of protection of the present application.

[0015] With the continuous development of portable electronic devices, electric power vehicles, and large-scale energy storage markets, the demand for lithium metal batteries also continues to grow. At present, the lithium metal negative electrode of the lithium metal battery is prone to react with the electrolyte, resulting in poor stability of the electrolyte of the lithium metal battery.

[0016] In view of this, the present application provides an electrolyte for a lithium metal battery to improve the stability of the electrolyte in the lithium metal battery.

[0017] In the first aspect, the present application provides an electrolyte for a lithium metal battery. The lithium metal battery includes a positive electrode and a negative electrode. The electrolyte is arranged between the positive electrode and the negative electrode. The negative electrode includes a lithium metal material or a lithium alloy material. The electrolyte includes a lithium salt and an additive. The additive includes chloro-ethylene carbonate. In this way, when the electrolyte is used in the lithium metal battery, the lithium metal of the negative electrode preferentially reacts with the chloro-ethylene carbonate to form LiCl, the problem that the intrinsic electrolyte (including an organic solvent and a lithium salt) in the electrolyte reacts with the metal lithium of the negative electrode to cause the consumption of the intrinsic electrolyte is improved, and the stability of the electrolyte is further improved.

[0018] The lithium salt is used to provide lithium ions. In some embodiments, the lithium salt is selected from at least one of lithium bis(trifluoromethylsulfonyl)amide, lithium bisfluorosulfonate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethylsulfonate, lithium bis(trifluoromethylsulfonyl)amide, and lithium hexafluorophosphate. Optionally, the lithium salt is lithium bis(trifluoromethylsulfonyl)amide, which has better conductivity and higher stability when dissolved in the organic solvent, and has stronger anti-hydrolysis ability and other properties, which can further improve the stability of the electrolyte.

[0019] In some embodiments, the electrolyte further includes an organic solvent, which is used to dissolve the lithium salt and the additive. The lithium salt has a high solubility in the organic solvent, which in turn improves the ionic conductivity of the intrinsic electrolyte including the organic solvent and the lithium salt.

[0020] In some embodiments, the molar ratio of the lithium salt to the organic solvent is (0.8-1.2):(1.2-1.6). In this way, the lithium salt is ensured to be sufficiently dissolved in the ether solvent, the concentration of the lithium salt in the electrolyte is improved, and the ionic conductivity of the electrolyte is in turn improved.

[0021] Illustratively, the molar ratio of the lithium salt to the organic solvent is 0.8:(1.2-1.6), 0.9:(1.2-1.6), 1.0:(1.2-1.6), 1.1:(1.2-1.6), or 1.2:(1.2-1.6).

[0022] Illustratively, the molar ratio of the lithium salt to the organic solvent is 0.8:1.2, 0.9:1.2, 1.0:1.2, 1.2:1.2, 0.8:1.4, 0.9:1.4, 1.0:1.4, 1.2:1.4, 0.8:1.6, 0.9:1.6, 1.0:1.6, or 1.2:1.6.

[0023] In some embodiments, the molar ratio of the chloroethylene carbonate to the organic solvent is less than or equal to 0.22. In this way, the risk of shuttle effect caused by too high concentration of the chloroethylene carbonate is reduced while ensuring that the chloroethylene carbonate preferentially reacts with the lithium metal of the negative electrode.

[0024] In some embodiments, the molar ratio of the chloroethylene carbonate to the organic solvent is greater than or equal to 0.007. In this way, the concentration of the chloroethylene carbonate is ensured to be large enough, and in turn the chloroethylene carbonate is ensured to preferentially react with the lithium metal of the negative electrode of the lithium metal battery.

[0025] Optionally, the molar ratio of the chloroethylene carbonate to the organic solvent can be 0.03-0.15. In this way, the risk of shuttle effect caused by too high concentration of the chloroethylene carbonate is reduced while ensuring that the chloroethylene carbonate preferentially reacts with the lithium metal of the negative electrode.

[0026] Optionally, the molar ratio of chloroethylene carbonate to organic solvent can be 0.05-0.08, 0.01-0.2, 0.03-0.18, 0.06-0.15, or 0.065-0.12.

[0027] Illustratively, the molar ratio of chloroethylene carbonate to organic solvent can be selected from any one of the following values: 0.008, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, or 0.22.

[0028] In some embodiments, the molar ratio of organic solvent to chloroethylene carbonate can be (1.2-1.6):(0.01-0.3). In this way, the concentration of chloroethylene carbonate is ensured to be large enough, thereby ensuring that chloroethylene carbonate preferentially reacts with the negative lithium metal of the lithium metal battery and improving the problem of shuttle effect caused by too high concentration of chloroethylene carbonate.

[0029] In some embodiments, the molar ratio of organic solvent to chloroethylene carbonate can be (1.2-1.6):(0.06-0.14). In this way, the concentration of chloroethylene carbonate is ensured to be appropriate, to ensure that chloroethylene carbonate preferentially reacts with the negative lithium metal of the lithium metal battery while reducing the risk of shuttle effect caused by too high concentration of chloroethylene carbonate.

[0030] Optionally, the molar ratio of organic solvent to chloroethylene carbonate is (1.2-1.6):(0.02-0.28), (1.2-1.6):(0.05-0.25), (1.2-1.6):(0.07-0.2), (1.2-1.6):(0.075-0.16), (1.25-1.55):(0.08-0.12), or (1.35-1.55):(0.095-0.115).

[0031] Exemplarily, the molar ratio of the organic solvent to the chloroethylene carbonate is 1.2:(0.01-0.3), 1.4:(0.01-0.3), 1.6:(0.01-0.3), 1.2:(0.03-0.25), 1.4:(0.03-0.25), 1.6:(0.03-0.25), 1.2:(0.05-0.2), 1.4:(0.05-0.2), 1.6:(0.05-0.2), 1.2:(0.07-0.18), 1.4:(0.07-0.18), 1.6:(0.07-0.18), 1.2:(0.08-0.15), 1.4:(0.08-0.15), 1.6:(0.08-0.15), 1.2:(0.09-0.12), 1.4:(0.09-0.12), or 1.6:(0.09-0.12).

[0032] Exemplarily, the molar ratio of the organic solvent to the chloroethylene carbonate is 1.2:0.03, 1.2:0.06, 1.2:0.08, 1.2:0.1, 1.2:0.12, 1.2:0.14, 1.2:0.16, 1.2:0.18, 1.2:0.2, 1.2:0.22, 1.2:0.24, 1.2:0.26, 1.2:0.28, 1.2:0.30, 1.4:0.03, 1.4:0.06, 1.4:0.08, 1.4:0.1, 1.4:0.12, 1.4:0.14, 1.4:0.16, 1.4:0.18, 1.4:0.2, 1.4:0.22, 1.4:0.24, 1.4:0.26, 1.4:0.28, 1.4:0.30, 1.6:0.03, 1.6:0.06, 1.6:0.08, 1.6:0.1, 1.6:0.12, 1.6:0.14, 1.6:0.16, 1.6:0.18, 1.6:0.2, 1.6:0.22, 1.6:0.24, 1.6:0.26, 1.6:0.28, or 1.6:0.30.

[0033] In some embodiments, the organic solvent comprises an ether solvent. Ether solvents have better stability in lithium metal batteries than other solvents, improving the cyclability of lithium metal batteries.

[0034] In some embodiments, the ether solvent is selected from at least one of ethylene glycol dimethyl ether (DME), ethylene glycol monoethyl methyl ether (EME), diethylene glycol dimethyl ether (G2), triethylene glycol dimethyl ether (G3), tetraethylene glycol dimethyl ether (G4), ethylene glycol diethyl ether (DEE), diethylene glycol monoethyl methyl ether (DGEME), 1,3-dioxolane (DOL), 1,3-dioxane (1,3-DX), 1,4-dioxane (1,4-DX), 2-methyl-1,4-dioxane (2-Me-1,4-DX), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-Me-THF), tetrahydropyran (THP). Optionally, the organic solvent is selected from ethylene glycol dimethyl ether to improve the solubility of the lithium salt in the solvent, thereby improving the ionic conductivity of the intrinsic electrolyte, while also better improving the stability of the organic solvent in the lithium metal battery, thereby improving the cycle performance of the lithium metal battery.

[0035] In some embodiments, the electrolyte further comprises a fluoroether diluent, which functions as a diluent. The concentration of the lithium salt in the ether solvent is high, and by introducing a fluoroether diluent that does not dissolve the lithium salt and is difficult to dissolve in the ether solvent, a local high-concentration system of the lithium salt can be formed in the electrolyte. Compared to a high-concentration electrolyte without a diluent, the local high-concentration system has lower viscosity, higher ionic conductivity, and lower internal resistance of the battery, thereby making it more stable during the cycle of the lithium metal battery.

[0036] In some embodiments, the molar ratio of the ether solvent to the fluoroether diluent is (1.2-1.6):(1.5-5). In this way, a local high-concentration system with suitable viscosity is formed, ensuring that the electrolyte has higher ionic conductivity and lower internal resistance of the battery, while also ensuring that the concentration of the chloroethylene carbonate in the electrolyte is sufficient for the chloroethylene carbonate to react with lithium metal. Too much fluoroether diluent and the concentration of chloroethylene carbonate is too low, which is not conducive to the reaction of chloroethylene carbonate with lithium metal at the negative electrode. Too little fluoroether diluent is not conducive to the formation of a local high-concentration system, and the concentration of chloroethylene carbonate is too high, which is not conducive to reducing the risk of shuttle effect.

[0037] In some embodiments, the molar ratio of the ether solvent to the fluoroether diluent is (1.2-1.6):(2.8-4.0). In this way, a local high-concentration system with suitable viscosity is formed, ensuring that the electrolyte has higher ionic conductivity and lower internal resistance of the battery, while also ensuring that the concentration of the chloroethylene carbonate in the electrolyte is suitable, so that the speed of the reaction of the chloroethylene carbonate with lithium metal is moderate, protecting the intrinsic electrolyte while also inhibiting the shuttle effect.

[0038] Optionally, the molar ratio of the ether solvent to the fluoroether diluent is (1.2-1.6):(1.8-4.8), (1.2-1.6):(2.0-4.5), (1.2-1.6):(2.2-4.2), (1.2-1.6):(2.5-4.0), (1.2-1.6):(2.8-4.0), (1.2-1.6):(3.2-3.8), (1.2-1.6):(3.3-3.6), or (1.2-1.6):(3.45-3.55).

[0039] Illustratively, the molar ratio of the ether solvent to the fluoroether diluent is 1.2:(1.5-5), 1.2:(1.8-4.8), 1.2:(2.0-4.6), 1.2:(2.2-4.4), 1.2:(2.4-4.2), 1.2:(2.6-4.0), 1.2:(2.8-3.8), 1.2:(3.0-3.6), 1.4:(1.5-5), 1.4:(1.8-4.8), 1.4:(2.0-4.6), 1.4:(2.2-4.4), 1.4:(2.4-4.2), 1.4:(2.6-4.0), 1.4:(2.8-3.8), 1.4:(3.0-3.6), 1.6:(1.5-5), 1.6:(1.8-4.8), 1.6:(2.0-4.6), 1.6:(2.2-4.4), 1.6:(2.4-4.2), 1.6:(2.6-4.0), 1.6:(2.8-3.8), or 1.6:(3.0-3.6).

[0040] Exemplarily, the molar ratio of the ether solvent to the lithium salt is 1.2:1.5, 1.2:1.6, 1.2:1.8, 1.2:2.0, 1.2:2.2, 1.2:2.4, 1.2:2.6, 1.2:2.8, 1.2:3.0, 1.2:3.2, 1.2:3.4, 1.2:3.6, 1.2:3.8, 1.2:4.0, 1.2:4.2, 1.2:4.4, 1.2:4.6, 1.2:4.8, 1.2:5.0, 1.4:1.5, 1.4:1.6, 1.4:1.8, 1.4:2.0, 1.4:2.2, 1.4:2.4, 1.4:2.6, 1.4:2.8, 1.4:3.0, 1.4:3.2, 1.4:3.4, 1.4:3.6, 1.4:3.8, 1.4:4.0, 1.4:4.2, 1.4:4.4, 1.4:4.6, 1.4:4.8, 1.4:5.0, 1.6:1.5, 1.6:1.6, 1.6:1.8, 1.6:2.0, 1.6:2.2, 1.6:2.4, 1.6:2.6, 1.6:2.8, 1.6:3.0, 1.6:3.2, 1.6:3.4, 1.6:3.6, 1.6:3.8, 1.6:4.0, 1.6:4.2, 1.6:4.4, 1.6:4.6, 1.6:4.8, 1.6:5.0.

[0041] In some embodiments, the fluoroether diluent is selected from at least one of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 2,2,2-trifluoroethyl-1,1,2,2-tetrafluoroethyl ether, bis(2,2,2-trifluoroethyl) ether, 1,1,2,2-tetrafluoroethyl ethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, 1,1,2,3,3,3-hexafluoropropyl-2,2,2-trifluoroethyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, and bis(2,2,3,3-tetrafluoropropyl) ether. Optionally, the fluoroether diluent is selected from 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether.

[0042] In some embodiments, the electrolyte further comprises a polymer, the polymer being obtained by polymerization of polymerization monomers under the action of a polymerization initiator, the polymerization monomers comprising at least one of an acrylamide monomer and an acrylic ester monomer. In this way, the lithium salt, the organic solvent, and the additives are dispersed in the polymer to form a gel polymer electrolyte, improving the safety of the electrolyte. Moreover, the polymer obtained by polymerization of the polymerization monomers has good flexibility, so that the electrolyte forms good contact with the electrode of the lithium metal battery.

[0043] In some embodiments, the polymerizable monomer comprises an acrylamide-based monomer. In this way, an amide group is also included in the polymer to increase the ionic conductivity of the electrolyte and improve the cycle performance of the lithium metal battery.

[0044] In some embodiments, the acrylamide-based monomer can comprise at least two acrylamide groups. In this way, the ionic conductivity of the electrolyte is more obviously increased, and the cycle performance of the lithium metal battery is improved.

[0045] In some embodiments, the acrylamide-based monomer comprises at least one of acrylamide, methacrylamide, isopropyl acrylamide, N,N-diethyl acrylamide, isobutoxymethyl acrylamide, diacetone acrylamide, and N,N-methylene bisacrylamide. Optionally, the polymerizable monomer comprises N,N-methylene bisacrylamide to more obviously increase the ionic conductivity of the electrolyte and improve the cycle performance of the lithium metal battery.

[0046] In some embodiments, the acrylate-based monomer comprises at least one of methyl acrylate, ethyl acrylate, butyl acrylate, and methacrylate.

[0047] In the electrolyte, the mass percentage of the polymer is 2.5% to 5%. In this way, the consistency of the polymerizable monomer during in-situ curing is improved, and the mechanical properties of the polymer are ensured. At the same time, the interfacial impedance between the polymer and the electrode is reduced, and the electrical performance of the lithium metal battery is improved.

[0048] Optionally, in the electrolyte, the mass percentage of the polymer is 2.8% to 4.8%, 3.0% to 4.5%, 3.2% to 4.3%, or 3.3% to 3.8%.

[0049] Illustratively, in the electrolyte, the mass percentage of the polymer is 2.5%, 2.7%, 2.9%, 3.1%, 3.3%, 3.5%, 3.7%, 3.9%, 4.1%, 4.3%, 4.5%, 4.7%, 4.9%, or 5.0%.

[0050] In some embodiments, the polymerization initiator is selected from at least one of ammonium persulfate, benzoyl peroxide, tetramethyl ethylenediamine, benzoyl peroxide, azobisisobutyronitrile, and azobisisoheptane. In this way, the polymerization initiator can initiate the polymerization of the polymerizable monomer at low temperature. Optionally, the polymerization initiator is azobisisobutyronitrile.

[0051] In other embodiments, the electrolyte can be a liquid electrolyte.

[0052] In some embodiments, the lithium salt is lithium bis(trifluoromethylsulfonyl)amide, the organic solvent is ethylene glycol dimethyl ether, the fluoroether diluent is 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, the polymerizable monomer is N,N-methylenebisacrylamide, and the polymerization initiator is azobisisobutyronitrile. In this way, the polymer of the electrolyte has good mechanical properties, can form good contact with the electrode of the lithium metal battery, and has small interface impedance between the polymer and the electrode. Moreover, the electrolyte also has high ionic conductivity and lower internal resistance of the battery, which is beneficial to improve the cycle performance of the lithium battery.

[0053] In some embodiments, the molar ratio of lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether is 1:(1.35-1.55):(0.095-0.115):(3.2-3.8). In this way, the mechanical properties and ionic conductivity of the electrolyte are further improved, the internal resistance of the battery is reduced, and the concentration of chloroethylene carbonate in the electrolyte is also ensured to be appropriate, so that the reaction rate of chloroethylene carbonate with lithium metal is moderate, the intrinsic electrolyte is protected, and the shuttle effect is also inhibited.

[0054] In a second aspect, the present application also provides a preparation method of an electrolyte for a lithium metal battery, which comprises the following steps:

[0055] Step S101: providing a plurality of components of a composition, the plurality of components of the composition comprising a lithium salt and an additive, the additive comprising chloroethylene carbonate; and

[0056] Step S102: uniformly mixing the plurality of components of the composition to obtain a mixture of the composition.

[0057] In the preparation method of the electrolyte in some embodiments of the present application, chloroethylene carbonate is added to the electrolyte, so that the lithium metal of the negative electrode of the lithium metal battery preferentially reacts with the chloroethylene carbonate to form LiCl, thereby improving the problem that the reaction of the intrinsic electrolyte in the electrolyte with the negative electrode metal lithium leads to consumption of the intrinsic electrolyte, and further improving the stability of the electrolyte.

[0058] In some embodiments, in step S101, the plurality of components of the composition can further comprise an organic solvent. The organic solvent is used to dissolve the lithium salt and the additive.

[0059] In some embodiments, in step S101, the plurality of components of the composition can further comprise a fluoroether diluent. The fluoroether diluent is insoluble in the organic solvent, and the lithium salt and the additive are insoluble in the fluoroether diluent.

[0060] In some embodiments, in step S101, the plurality of components of the composition can further include a polymerizable monomer and a polymerization initiator. In this way, the polymerizable monomer is polymerized under the action of the polymerization initiator to form a polymer, and the lithium salt and the additive are dispersed in the polymer to form a gel electrolyte, thereby improving the safety of the electrolyte.

[0061] In some embodiments, in the composition, the mass percentage of the polymerizable monomer is 2.5% to 5%. In this way, the consistency of the polymerizable monomer in the in-situ curing process is improved, thereby ensuring the mechanical properties of the polymer. At the same time, the interfacial impedance between the polymer and the electrode is reduced, and the electrical performance of the lithium metal battery is improved.

[0062] Alternatively, in the composition, the mass percentage of the polymerizable monomer is 2.8% to 4.8%, 3.0% to 4.5%, 3.2% to 4.3%, or 3.3% to 3.8%.

[0063] For example, in the composition, the mass percentage of the polymerizable monomer is 2.5%, 2.7%, 2.9%, 3.1%, 3.3%, 3.5%, 3.7%, 3.9%, 4.1%, 4.3%, 4.5%, 4.7%, 4.9%, or 5.0%.

[0064] In some embodiments, in the composition, the mass percentage of the polymerization initiator is 0.002% to 0.004%. In this way, it is ensured that the polymerization initiator can initiate the polymerization of the polymerizable monomer.

[0065] The process of preparing the electrolyte from the above-mentioned composition mainly involves the polymerization reaction of the polymerizable monomer under the action of the polymerization initiator, and the lithium salt, the organic solvent, the additive, and the fluoroether diluent hardly participate in the chemical reaction. Therefore, the proportions of the lithium salt, the organic solvent, the additive, and the fluoroether diluent in the composition are basically the same as those in the electrolyte. For details, refer to the related content in the electrolyte, which will not be described here.

[0066] In other embodiments, the mixture of the composition obtained in step S102 can be directly used as a liquid electrolyte.

[0067] In some embodiments, the plurality of components of the composition are mixed uniformly, including:

[0068] Step S1021: dissolving the lithium salt and the additive in the organic solvent to obtain a first mixed solution;

[0069] Step S1022: adding the fluoroether diluent to the first mixed solution and stirring uniformly to obtain a second mixed solution;

[0070] Step S1023: adding the polymerizable monomer to the second mixed solution and stirring uniformly to obtain a third mixed solution; and

[0071] Step S1024: adding a polymerization initiator to the third mixed solution, stirring uniformly to obtain a mixture of the composition.

[0072] In some embodiments, in step S1021, the molar ratio of the lithium salt, the additive, and the organic solvent can be (0.08-1.2):(0.06-0.14):(1.2-1.6). The first mixed solution is a transparent solution.

[0073] In some embodiments, in step S1022, the fluoroether diluent reduces the viscosity of the first mixed solution to form a local high-concentration system of the lithium salt. In some embodiments, in step S1022, the molar ratio of the organic solvent to the fluoroether diluent is (1.2-1.6):(1.5-5).

[0074] In some embodiments, in step S1023, after obtaining the third mixed solution, the third mixed solution is stored at low temperature. In this way, the risk of polymerization of the polymerization monomer is reduced.

[0075] In some embodiments, the preparation method of the electrolyte further comprises: step S103: heating the mixture of the composition to make the polymerization initiator initiate polymerization of the polymerization monomer to obtain the electrolyte.

[0076] In some embodiments, heating the mixture of the composition comprises: heating the mixture of the composition at 55-65°C for 1.5-2.5h.

[0077] In a third aspect, the present application also provides a lithium metal battery, which comprises the electrolyte described above. In this way, the negative lithium metal of the lithium metal battery preferentially reacts with the chloroethylene carbonate to form LiCl, thereby improving the problem that the intrinsic electrolyte in the electrolyte reacts with the metal lithium to cause consumption of the intrinsic electrolyte, and further improving the stability of the electrolyte in the lithium metal battery and the cycle performance of the lithium metal battery.

[0078] The related content of the electrolyte in the lithium metal battery is selected by reference to the related content of the electrolyte described above, which will not be described here.

[0079] The lithium metal battery further comprises a positive electrode and a negative electrode, and the electrolyte is located between the positive electrode and the negative electrode. The positive electrode comprises a positive electrode current collector and a positive electrode active material located on the positive electrode current collector. The positive electrode active material can comprise a nickel-cobalt-manganese lithium acid material. The positive electrode current collector can comprise a metal foil such as an aluminum foil. The negative electrode comprises a negative electrode current collector and a negative electrode active material located on the negative electrode current collector. The negative electrode active material comprises a lithium metal material or a lithium alloy material. The negative electrode current collector can comprise a metal foil such as a copper foil.

[0080] In some embodiments, the lithium metal battery can further include a separator between the positive electrode and the negative electrode. The separator includes an organic film such as polyethylene. In the case that the electrolyte is a gel electrolyte, the electrolyte is located on both surfaces of the separator facing the positive electrode and the negative electrode. In the case that the electrolyte is a liquid electrolyte or a solid electrolyte, the electrolyte is located between the surfaces of the negative electrode, the positive electrode, and the separator and the interspaces of the negative electrode, the positive electrode, and the separator.

[0081] In a fourth aspect, the present application further provides a recycling method of a lithium metal battery. The lithium metal battery can be a lithium metal battery that has been used for a long time and has become invalid, or can be another lithium metal battery that has become invalid and needs to recycle the positive electrode active material. The lithium metal battery includes a positive electrode, a negative electrode, and an electrolyte between the positive electrode and the negative electrode, and the positive electrode includes a positive electrode active material. The negative electrode includes a lithium metal material or a lithium alloy material. The recycling method includes:

[0082] Step S201: separating the positive electrode active material of the lithium metal battery;

[0083] Step S202: mixing the positive electrode active material with an additive containing chloroethylene carbonate to obtain a mixture; and

[0084] Step S203: heating the mixture until the positive electrode active material is decomposed to obtain a target decomposition product.

[0085] In the related art, when there is no chloroethylene carbonate in the electrolyte, the temperature at which the nickel-cobalt-manganese lithium acid material is decomposed under the action of C is greater than or equal to 800°C, and a large amount of energy needs to be consumed. In some embodiments of the present application, the chloroethylene carbonate is used to reduce the temperature required for the decomposition of the positive electrode active material of the lithium metal battery to obtain a target decomposition product, thereby reducing the power consumption required for recycling the positive electrode active material.

[0086] In some embodiments, the step S201 of separating the positive electrode active material of the lithium metal battery includes:

[0087] The lithium metal battery is disassembled to separate the positive electrode;

[0088] The positive electrode is treated with an eluent to obtain a positive electrode current collector and an eluate; and

[0089] The eluate is filtered to obtain a positive electrode material powder, and the positive electrode material powder includes the positive electrode active material.

[0090] In some embodiments, the eluate includes a solvent such as N-methyl pyrrolidone (NMP).

[0091] In some embodiments, the positive electrode active material includes a nickel-cobalt-manganese lithium acid material, but is not limited thereto. In this way, the raw materials of the nickel-cobalt-manganese lithium acid material are recycled and utilized.

[0092] In some embodiments, the recycling method further comprises: separating the electrolyte of the lithium metal battery, the electrolyte comprising an additive comprising chloroethylene carbonate; and / or; providing additional additive independently of the lithium metal battery. In this way, the decomposition temperature of the positive active material is reduced by at least one of the additive in the electrolyte and the additional introduced additive. And, by using the additive in the electrolyte, the waste electrolyte can be fully utilized to achieve waste treatment with waste.

[0093] In some embodiments, in the step S202, mixing the positive active material of the lithium metal battery with the chloroethylene carbonate comprises: mixing the chloroethylene carbonate with the positive active material at a mass ratio of 1:(5-8). In this way, the chloroethylene carbonate and the positive active material are mixed at a suitable ratio to reduce the decomposition temperature of the nickel-cobalt-manganese lithium material. And, in the case that the additive comes from the electrolyte, the content of chloroethylene carbonate in the lithium metal battery is also moderate to ensure the performance of the lithium metal battery during operation.

[0094] For example, the mass ratio of chloroethylene carbonate to positive active material can be 1:5, 1:6, 1:7 or 1:8.

[0095] In some embodiments, in the step S203, heating the mixture until the positive active material decomposes to obtain the target decomposition product comprises: heating the mixture to greater than or equal to 500°C and less than 800°C. In this way, heating reduces the decomposition temperature of the positive active material while it is decomposed.

[0096] Optionally, the mixture is heated to 500-650°C. In this way, the decomposition temperature of the positive active material is reduced while it is decomposed.

[0097] Optionally, the mixture is heated to 600-650°C, so that the target decomposition product becomes a plurality of independent components, making it easier to process the target decomposition product subsequently.

[0098] For example, the mixture can be heated to any one of the following temperatures: 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, 690°C, 700°C, 710°C, 720°C, 730°C, 740°C, 750°C, 760°C, 770°C, 780°C or 790°C.

[0099] In some embodiments, the mixture is heated to greater than or equal to 500°C and less than 800°C, including: heating the mixture to greater than or equal to 500°C and less than 800°C at a temperature increasing rate of 8°C / min to 12°C / min in an inert gas for 1.5 h to 2.5 h.

[0100] In some embodiments, the inert gas includes, but is not limited to, nitrogen.

[0101] In some embodiments, in the step S203, the target decomposition product is selected from at least one of a nickel-cobalt alloy, MnO, and lithium carbonate. Exemplarily, the target decomposition product includes the nickel-cobalt alloy, the MnO, and the lithium carbonate.

[0102] In summary, in the lithium metal battery of some embodiments of the present application, the introduction of chloroethylene carbonate in the electrolyte not only improves the stability of the electrolyte and the cycle performance of the lithium metal battery. Moreover, in the recycling process of the positive active material of the lithium metal battery, the chloroethylene carbonate in the waste electrolyte can reduce the temperature required for the decomposition of the positive active material to obtain the target decomposition product, thereby reducing the difficulty of recycling the nickel-cobalt-manganese-lithium material and achieving waste treatment with waste.

[0103] The technical solutions of the present application are described in detail below in combination with examples and comparative examples. The raw materials used in the following examples are all commercially available products unless otherwise specified.

[0104] Example 1

[0105] The present embodiment provides a composition for preparing an electrolyte and a preparation method of a lithium metal battery.

[0106] (1) The electrolyte of the present embodiment is prepared from a composition including N,N-methylenebisacrylamide (polymerization monomer), azobisisobutyronitrile (polymerization initiator), lithium bis(trifluoromethylsulfonyl)amide (lithium salt), ethylene glycol dimethyl ether (solvent), 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (fluoroether diluent), and chloroethylene carbonate (additive).

[0107] The molar ratio of lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is 1:1.4:0.1:3.5. The mass sum of the above-mentioned proportioned lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is m, the mass of N,N-methylenebisacrylamide is 3.5% of m, and the mass of azobisisobutyronitrile is 0.0035% of m.

[0108] (2) The preparation method of the lithium metal battery of the present embodiment includes:

[0109] The lithium bis(trifluoromethylsulfonyl)amide, the ethylene glycol dimethyl ether, and the chloroethylene carbonate are mixed in the above proportions to obtain a first mixed solution;

[0110] The 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is added to the first mixed solution in the above proportions, and stirred until completely uniform to obtain a second mixed solution;

[0111] The 3.5% m N,N-methylenebisacrylamide is added to the second mixed solution, and stirred until uniform to obtain a third mixed solution, which is then stored at low temperature;

[0112] The 0.0035% m azobisisobutyronitrile is added to the third mixed solution, and stirred until uniform to obtain a mixture of the composition;

[0113] The mixture of the composition is coated on both surfaces of a separator, and the separator is disposed between a positive electrode and a negative electrode; wherein the positive electrode includes an aluminum foil and a positive electrode active material on the aluminum foil, the negative electrode includes a copper foil and a negative electrode material on the copper foil, the positive electrode active material includes NCM811 (nickel cobalt manganese lithium material), the negative electrode material includes lithium metal, the separator is a polyethylene film coated with an Al2O3 layer on both sides, and the thickness of the Al2O3 layer on each side is 2 μm; and

[0114] The mixture of the composition is heated at 60°C for 2 hours to obtain a lithium metal battery including a gel polymer electrolyte.

[0115] Example 2

[0116] The present example provides a composition for preparing an electrolyte and a method for preparing a lithium metal battery.

[0117] The composition in the present example is substantially similar to the composition in Example 1, except that the molar ratio of the lithium bis(trifluoromethylsulfonyl)amide, the ethylene glycol dimethyl ether, the chloroethylene carbonate, and the 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is 1:1.4:0.05:3.5. Also, in the present example, the mass sum of the lithium bis(trifluoromethylsulfonyl)amide, the ethylene glycol dimethyl ether, the chloroethylene carbonate, and the 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether in the above proportions is m, the mass of the N,N-methylenebisacrylamide is 3.5% m, and the mass of the azobisisobutyronitrile is 0.0035% m.

[0118] The method for preparing a lithium battery in the present example is the same as in Example 1, except that the composition is the composition of the present example.

[0119] Example 3

[0120] The present embodiment provides a composition for preparing an electrolyte and a method of preparing a lithium metal battery.

[0121] The composition of the present embodiment is substantially similar to the composition of Example 1, except that the molar ratio of lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is 1:1.4:0.06:3.5. Also, in the present embodiment, the mass sum of the above-mentioned composition of lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is m, the mass of N,N-methylenebisacrylamide is 3.5% of m, and the mass of azobisisobutyronitrile is 0.0035% of m.

[0122] The method of preparing a lithium battery of the present embodiment is the same as that of Example 1, except that the composition is the composition of the present embodiment.

[0123] Example 4

[0124] The present embodiment provides a composition for preparing an electrolyte and a method of preparing a lithium metal battery.

[0125] The composition of the present embodiment is substantially similar to the composition of Example 1, except that the molar ratio of lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is 1:1.4:0.14:3.5. Also, in the present embodiment, the mass sum of the above-mentioned composition of lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is m, the mass of N,N-methylenebisacrylamide is 3.5% of m, and the mass of azobisisobutyronitrile is 0.0035% of m.

[0126] The method of preparing a lithium battery of the present embodiment is the same as that of Example 1, except that the composition is the composition of the present embodiment.

[0127] Example 5

[0128] The present embodiment provides a composition for preparing an electrolyte and a method of preparing a lithium metal battery.

[0129] The composition of the present example is substantially similar to that of Example 1, except that the molar ratio of lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is 1:1.4:0.08:3.5. Also, in the present example, the mass sum of the above-mentioned lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether in the above-mentioned ratio is m, the mass of N,N-methylenebisacrylamide is 3.5% of m, and the mass of azobisisobutyronitrile is 0.0035% of m.

[0130] The method of preparing the lithium battery of the present example is the same as that of Example 1, except that the composition is the composition of the present example.

[0131] Example 6

[0132] The present example provides a composition for preparing an electrolyte and a method of preparing a lithium metal battery.

[0133] The composition of the present example is substantially similar to that of Example 1, except that the molar ratio of lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is 1:1.4:0.12:3.5. Also, in the present example, the mass sum of the above-mentioned lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether in the above-mentioned ratio is m, the mass of N,N-methylenebisacrylamide is 3.5% of m, and the mass of azobisisobutyronitrile is 0.0035% of m.

[0134] The method of preparing the lithium battery of the present example is the same as that of Example 1, except that the composition is the composition of the present example.

[0135] Example 7

[0136] The present example provides a composition for preparing an electrolyte and a method of preparing a lithium metal battery.

[0137] The composition of the present example is substantially similar to that of Example 1, except that the molar ratio of lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is 1:1.4:0.1:2.5. Also, in the present example, the mass sum of the above-mentioned lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether in the above-mentioned ratio is m, the mass of N,N-methylenebisacrylamide is 3.5% of m, and the mass of azobisisobutyronitrile is 0.0035% of m.

[0138] The method of preparing the lithium battery of the present example is the same as that of Example 1, except that the composition is the composition of the present example.

[0139] Example 8

[0140] The present example provides a composition for preparing an electrolyte and a method of preparing a lithium metal battery.

[0141] The composition of the present example is substantially similar to that of Example 1, except that the molar ratio of lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is 1:1.4:0.1:2.8. Also, in the present example, the mass sum of the above-mentioned lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether in the above-mentioned ratio is m, the mass of N,N-methylenebisacrylamide is 3.5% of m, and the mass of azobisisobutyronitrile is 0.0035% of m.

[0142] The method of preparing the lithium battery of the present example is the same as that of Example 1, except that the composition is the composition of the present example.

[0143] Example 9

[0144] The present example provides a composition for preparing an electrolyte and a method of preparing a lithium metal battery.

[0145] The composition of the present example is substantially similar to that of Example 1, except that the molar ratio of lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is 1:1.4:0.1:4.0. Also, in the present example, the mass sum of the above-mentioned lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether in the above-mentioned ratio is m, the mass of N,N-methylenebisacrylamide is 3.5% of m, and the mass of azobisisobutyronitrile is 0.0035% of m.

[0146] The method of manufacturing the lithium battery of the present example is the same as that of Example 1, except that the composition is the composition of the present example.

[0147] Example 10

[0148] The present example provides a composition for manufacturing an electrolyte and a method of manufacturing a lithium metal battery.

[0149] The composition of the present example is substantially similar to that of Example 1, except that the molar ratio of lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether is 1:1.4:0.1:4.5. Also, in the present example, the mass sum of the above-mentioned lithium bis(trifluoromethylsulfonyl)amide, ethylene glycol dimethyl ether, chloroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether in the above-mentioned ratio is m, the mass of N,N-methylenebisacrylamide is 3.5% of m, and the mass of azobisisobutyronitrile is 0.0035% of m.

[0150] The method of manufacturing the lithium battery of the present example is the same as that of Example 1, except that the composition is the composition of the present example.

[0151] Example 11

[0152] The present example provides a composition for manufacturing an electrolyte and a method of manufacturing a lithium metal battery.

[0153] The composition of the present example is substantially similar to that of Example 1, except that the polymerization monomer N,N-methylenebisacrylamide is replaced with “butyl acrylate”.

[0154] The method of manufacturing the lithium battery of the present example is the same as that of Example 1, except that the composition is the composition of the present example.

[0155] Example 12

[0156] The present example provides a composition for manufacturing an electrolyte and a method of manufacturing a lithium metal battery.

[0157] The composition of the present example is substantially similar to the composition of Example 1, except that the mass of N,N-methylenebisacrylamide is 4.5% m.

[0158] The method of preparing the lithium battery of the present example is the same as that of Example 1, except that the composition is the composition of the present example.

[0159] Example 13

[0160] The present example provides a composition for preparing an electrolyte and a method of preparing a lithium battery.

[0161] The composition of the present example is substantially similar to the composition of Example 1, except that the mass of N,N-methylenebisacrylamide is 2.5% m.

[0162] The method of preparing the lithium battery of the present example is the same as that of Example 1, except that the composition is the composition of the present example.

[0163] Comparative Example 1

[0164] The present example provides a composition for preparing an electrolyte and a method of preparing a lithium battery.

[0165] The composition of the present example is substantially similar to the composition of Example 1, except that the composition does not contain chloroethylene carbonate.

[0166] The method of preparing the lithium battery of the present example is the same as that of Example 1, except that the composition is the composition of the present example.

[0167] The lithium metal batteries of Example 1 to Example 13 and Comparative Example 1 were respectively subjected to the following performance tests.

[0168] Cycle test: the lithium battery was charged at a constant current of 0.33C rate to a voltage of 4.2V at 25℃, and then discharged at a constant current of 0.5C rate until the voltage reached 3V, and the above charging and discharging cycles were repeated 300 times, the time interval between adjacent two cycles was 10min, and the capacity retention rate at 25℃ for 150 cycles was obtained.

[0169] Table 1

[0170] As can be seen from Table 1, compared with Comparative Example 1, the lithium metal battery of some embodiments of the present application has a greater capacity retention rate at 25℃ for 150 cycles. Therefore, the introduction of chloroethylene carbonate in the electrolyte of the lithium metal battery can better improve the stability of the electrolyte in the lithium metal battery and improve the cycle performance of the lithium metal battery.

[0171] And, compared with Example 11, the capacity retention rate of the lithium metal battery of Examples 1 to 10 and Examples 12 to 13 is greater after 150 cycles at 25℃, indicating that using N,N-methylene bisacrylamide as a polymerization monomer can improve the cycle performance of the lithium metal battery.

[0172] Decomposition temperature test of lithium metal battery nickel cobalt manganese lithium acid material

[0173] The test method comprises: mixing chloroethylene carbonate and nickel cobalt manganese lithium acid material at a mass ratio of 1:7 to obtain a mixture; heating the mixture to a temperature of 400℃-650℃ at a heating rate of 10℃ / min, and heating for 2h to obtain products at different temperatures. The products at different temperatures are analyzed by X-ray diffraction spectrum test.

[0174] It can be known in combination with FIG. 1 that when the temperature is 500℃ and above, the nickel cobalt manganese lithium acid material is decomposed into nickel cobalt alloy (Ni x Co 1-x ), MnO and lithium carbonate (Li2CO3) under the action of chloroethylene carbonate. It can be known that chloroethylene carbonate can reduce the decomposition temperature of the nickel cobalt manganese lithium acid material.

[0175] The above examples are only used to help understand the technical solutions of the present application and the core ideas thereof; those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the examples of the present application.

Claims

1. An electrolyte for a lithium metal battery, wherein, The lithium metal battery includes a positive electrode and a negative electrode, an electrolyte is disposed between the positive electrode and the negative electrode, the negative electrode includes a lithium metal material or a lithium alloy material, the electrolyte includes: a lithium salt; and an additive including chloro-ethylene carbonate.

2. The electrolyte of claim 1, wherein, The electrolyte further includes an organic solvent, and a molar ratio of chloro-ethylene carbonate to the organic solvent is less than or equal to 0.

22.

3. The electrolyte of claim 2, wherein, The molar ratio of chloro-ethylene carbonate to the organic solvent is greater than or equal to 0.

007.

4. The electrolyte of claim 2, wherein, The organic solvent includes an ether solvent, and the electrolyte further includes a fluorinated ether diluent, and a molar ratio of the ether solvent to the fluorinated ether diluent is (1.2-1.6):(2.8-4.0).

5. The electrolyte of claim 4, wherein, The ether solvent is selected from at least one of ethylene glycol dimethyl ether (DME), ethylene glycol monoethyl methyl ether (EME), diethylene glycol dimethyl ether (G2), triethylene glycol dimethyl ether (G3), tetraethylene glycol dimethyl ether (G4), ethylene glycol diethyl ether (DEE), diethylene glycol monoethyl methyl ether (DGEME), 1,3-dioxolane (DOL), 1,3-dioxane (1,3-DX), 1,4-dioxane (1,4-DX), 2-methyl-1,4-dioxane (2-Me-1,4-DX), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-Me-THF), and tetrahydropyran (THP); and / or, The fluorinated ether diluent is selected from at least one of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 2,2,2-trifluoroethyl-1,1,2,2-tetrafluoroethyl ether, bis(2,2,2-trifluoroethyl) ether, 1,1,2,2-tetrafluoroethyl ethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, 1,1,2,3,3,3-hexafluoropropyl-2,2,2-trifluoroethyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, and bis(2,2,3,3-tetrafluoropropyl) ether.

6. The electrolyte of claim 1, wherein The electrolyte further includes a polymer, the polymer is obtained by a polymerization reaction of a polymerization monomer under the action of a polymerization initiator, and the polymerization monomer includes at least one of an acrylamide monomer and an acrylic ester monomer.

7. The electrolyte of claim 6, wherein, In the electrolyte, a mass percentage of the polymer is 2.5%-5%.

8. The electrolyte according to any one of claims 1 to 7, characterized in that The lithium salt is selected from at least one of lithium bis(trifluoromethylsulfonyl)amide, lithium bisfluorosulfonate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethylsulfonate, lithium bis-trifluoromethylsulfonamide, and lithium hexafluorophosphate.

9. A lithium metal battery, wherein, includes: a positive electrode; a negative electrode including a lithium metal material or a lithium alloy material; and an electrolyte disposed between the positive electrode and the negative electrode, the electrolyte including a lithium salt and an additive including chloro-ethylene carbonate.

10. The lithium metal battery of claim 9, wherein, The electrolyte further includes an organic solvent, and a molar ratio of chloro-ethylene carbonate to the organic solvent is less than or equal to 0.

22.

11. The lithium metal battery of claim 10, wherein, The molar ratio of chloro-ethylene carbonate to the organic solvent is greater than or equal to 0.

007.

12. The lithium metal battery of claim 10, wherein, The organic solvent includes an ether solvent, the electrolyte further includes a fluorinated ether diluent, and a molar ratio of the ether solvent to the fluorinated ether diluent is (1.2-1.6):(2.8-4.0).

13. The lithium metal battery of claim 12, wherein, The ether solvent is selected from at least one of ethylene glycol dimethyl ether (DME), ethylene glycol monoethyl methyl ether (EME), diethylene glycol dimethyl ether (G2), triethylene glycol dimethyl ether (G3), tetraethylene glycol dimethyl ether (G4), ethylene glycol diethyl ether (DEE), diethylene glycol monoethyl methyl ether (DGEME), 1,3-dioxolane (DOL), 1,3-dioxane (1,3-DX), 1,4-dioxane (1,4-DX), 2-methyl-1,4-dioxane (2-Me-1,4-DX), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-Me-THF), and tetrahydropyran (THP); and / or, The fluorinated ether diluent is selected from at least one of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 2,2,2-trifluoroethyl-1,1,2,2-tetrafluoroethyl ether, bis(2,2,2-trifluoroethyl) ether, 1,1,2,2-tetrafluoroethyl ethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, 1,1,2,3,3,3-hexafluoropropyl-2,2,2-trifluoroethyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, and bis(2,2,3,3-tetrafluoropropyl) ether.

14. The lithium metal battery of claim 10, wherein, The electrolyte further includes a polymer, the polymer is obtained by a polymerization reaction of a polymerization monomer under the action of a polymerization initiator, and the polymerization monomer includes at least one of an acrylamide monomer and an acrylic ester monomer.

15. The lithium metal battery of claim 14, wherein, In the electrolyte, a mass percentage of the polymer is 2.5%-5%.

16. A recycling method of a lithium metal battery, wherein, The lithium metal battery includes a positive electrode, a negative electrode, and an electrolyte arranged between the positive electrode and the negative electrode, the positive electrode includes a positive electrode active material, the negative electrode includes a lithium metal material or a lithium alloy material, and the method includes: Separating the positive electrode active material of the lithium metal battery; Mixing the positive electrode active material with an additive including chloroethylene carbonate to obtain a mixture; and Heating the mixture until the positive electrode active material is decomposed to obtain a target decomposition product.

17. The recycling method of lithium metal batteries according to claim 16, wherein, The method further includes: Separating the electrolyte of the lithium metal battery, the electrolyte including the additive including chloroethylene carbonate; and / or; Independently providing the additional additive from the lithium metal battery.

18. The recycling method of lithium metal batteries according to claim 16, wherein, The positive electrode active material includes a nickel-cobalt-manganese lithium acid material; and / or, The target decomposition product is selected from at least one of the following compounds: a nickel-cobalt alloy, MnO, and lithium carbonate.

19. The method of recycling lithium metal batteries of claim 16, wherein, The mixing of the positive electrode active material of the lithium metal battery with chloroethylene carbonate includes: Mixing chloroethylene carbonate with the positive electrode active material at a mass ratio of 1:(5-8).

20. The method of recycling lithium metal batteries of claim 16, wherein, The heating of the mixture until the positive electrode active material is decomposed to obtain a target decomposition product includes heating the mixture to greater than or equal to 500°C and less than 800°C, preferably 500°C to 650°C, to obtain the target decomposition product. The heating of the mixture until the positive electrode active material is decomposed to obtain a target decomposition product includes heating the mixture to greater than or equal to 500°C and less than 800°C, preferably 500°C to 650°C, to obtain the target decomposition product.

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