Lithium electrolyte adopting delocalization design as well as preparation method and application of lithium electrolyte

Abstract

The invention discloses a delocalized lithium electrolyte which breaks through the limitation of a traditional dominant solvent structure, and a preparation method and application of the delocalized lithium electrolyte. According to the delocalized electrolyte, the lithium salt and the solvent with different physicochemical properties are combined, so that the microcosmic solvent structure of the delocalized electrolyte is delocalized, and a diversified solvent structure is further formed. The solvent structure in the delocalized state not only enriches the microstructure of the electrolyte, but also significantly improves the overall electrolyte performance through performance complementation, thereby effectively improving the charge-discharge efficiency and cycle life of the lithium battery. By adopting the electrolyte, a lithium secondary battery of over 600Wh / kg can be realized, and the electrolyte has a remarkable engineering application value.

Description

Technical Field

[0001] The present invention belongs to the technical fields of lithium batteries and energy storage, and relates to a lithium-based electrolyte, specifically to a lithium-based electrolyte with a delocalized design applicable to lithium batteries that breaks through the limitations of the traditional dominant solvent structure, and its preparation method and application. Background Art

[0002] As a key component in current energy storage technologies, lithium batteries have been widely used in fields such as electric vehicles, renewable energy storage, and portable electronic devices. With their high energy density and excellent cycle stability, lithium batteries occupy a core position in modern energy technologies. However, with the increasing demand for higher energy density and longer service life, the limitations of traditional electrolyte design schemes have become apparent. Existing electrolyte systems usually rely on specific solvation structures. This confined electrolyte design often faces problems such as unstable performance, solvent degradation, and decreased battery efficiency in application environments with high energy density and long cycle life.

[0003] In traditional electrolyte design, the interaction between the solvent and the lithium salt usually determines the overall performance of the electrolyte. Common design methods mainly focus on optimizing the selection of a single solvent or lithium salt, and constructing a solvent structure based on a single dominant solvent or lithium salt. However, this design method often has strong dependencies and is restricted by the interaction between the solvent and the lithium salt, resulting in bottlenecks in its performance in high-voltage and high-energy density environments. As the energy density of lithium batteries continues to increase, the performance bottlenecks of traditional electrolyte systems in high voltage and high energy density become more prominent. Especially under extreme working conditions, it is difficult to further optimize the stability and lithium ion conductivity of the electrolyte. This also leads to rapid capacity decay and cycle degradation of the battery at high rates or high voltages, which is a major challenge faced by current high-energy lithium batteries. For example, in recent years, studies have pointed out that at high voltages (such as above 4.5 V), conventional electrolytes are prone to decomposition or instability, resulting in rapid capacity decay of lithium metal batteries and even serious lithium plating problems, thus affecting the performance and safety of the battery (Advanced Energy Materials, vol. 10, no. 12, 2020). In addition, the stability of traditional electrolytes under extreme temperature conditions is often insufficient, leading to a significant shortening of the battery life. As studies have pointed out, in high-energy density batteries, due to the insufficient interaction strength between the solvent and the lithium salt of the electrolyte, obvious capacity decay will occur after long-term use of the battery, especially the rapid decay phenomenon at high temperature or high voltage (Journal of Power Sources, vol. 439, 2019).

[0004] To address these challenges, recent research has attempted to improve the stability and ionic conductivity of electrolytes by optimizing the combination of solvents and lithium salts. However, most traditional electrolyte design methods have focused on the optimization of single solvents or lithium salts, neglecting the possible synergistic effects between different components. For example, commonly used lithium salts such as LiPF6 and LiBF4 are prone to decomposition in high-voltage environments, leading to a sharp decline in electrolyte performance. Although there has been some progress in the research on "high-stability" electrolytes in recent years, most of them are still limited to optimizing single-component solvents and salts (Journal of Power Sources, vol. 439, 2019). The limitations of these traditional design methods have prompted the exploration of new electrolyte design concepts.

[0005] To break through these bottlenecks, the present invention proposes an innovative "delocalized design" electrolyte, which forms a complex and dynamic delocalized solvent structure by introducing multiple lithium salts and solvents with complementary physical and chemical properties. This structure not only optimizes the microscopic solvent environment of the electrolyte but also significantly improves the overall performance of the electrolyte, enabling it to exhibit higher stability and longer cycle life in high-energy-density applications and solving the problem of performance degradation of existing electrolyte systems under high-voltage and extreme temperature conditions. Summary of the Invention

[0006] The present invention provides a delocalized design lithium-based electrolyte, its preparation method, and applications. By introducing multiple lithium salts and solvents with complementary physical and chemical properties, this electrolyte breaks through the limitations of solvent dominance in traditional electrolyte design and forms a complex and dynamic delocalized solvent structure. This structure not only optimizes the microscopic solvent environment of the electrolyte but also significantly improves the overall performance of the electrolyte, enabling it to exhibit higher stability and longer cycle life in high-energy-density applications.

[0007] The object of the present invention is achieved by the following technical solutions:

[0008] The present invention provides a delocalized design lithium-based electrolyte, which is obtained by an artificial intelligence clustering analysis algorithm, and the clustering method includes one or more of K-means clustering, hierarchical clustering, density-based spatial clustering of applications with noise (DBSCAN), and Gaussian mixture model (GMM). The method comprises the following steps:

[0009] Step 1: Collect at least three key physical and chemical parameters related to lithium salts and solvents, and standardize these data to eliminate the dimension difference.

[0010] Step 2: Perform cluster analysis on these standardized data through an algorithm to divide lithium salts and solvents with similar physical and chemical properties into different categories, with more than 2 categories.

[0011] Step 3: Define the required parameters and finally select a combination of lithium salt and solvent that can maximize the complementarity of physical and chemical properties through iterative adjustment.

[0012] Step 4: Prepare the corresponding electrolyte according to the formula.

[0013] The electrolyte of the present invention selects a variety of lithium salts and solvents with different and complementary physical and chemical properties, enriching its microscopic solvent structure to a delocalized state. In this delocalized-designed lithium-based electrolyte, the number of solvation structures reaches at least 10 or more, and the volume range of solvation structures is from 0.1 to 50 nm 3 not equal, and the diameter of the electrolyte microcluster is distributed between 0.5 and 100 nm.

[0014] As an embodiment of the present invention, lithium salts and solvents are optimized and screened through cluster analysis, and the clustering indicators include but are not limited to physical and chemical property indicators such as redox potential, lithium ion binding energy, melting point, and boiling point. In some embodiments, the clustering indicators include the HOMO energy level, LUMO energy level, and lithium ion binding energy data of lithium salts and solvents.

[0015] As an embodiment of the present invention, lithium salts and solvents are optimized and screened through cluster analysis to ensure that the redox potential of the selected lithium salts and solvents is ≥ 4V, the lithium ion binding energy selection range is from -4 to -10 eV, the melting point selection range is from -90 to 100 °C, and the boiling point selection range is from 100 to 500 °C.

[0016] As an embodiment of the present invention, the defined required parameters include more than 2 of lithium ion binding energy, electrolyte operating temperature range, lithium salt species type, solvent species type, and lithium salt solubility type. In some embodiments, the lithium ion binding energy range is -12 to -5 eV, the operating temperature range is -80 to 120 °C, the lithium salt species is 5 types, the solvent species is 5 types, and the lithium salt solubility > 0.5 mol / L. In some other embodiments, the lithium ion binding energy < 6 eV, the operating temperature range is -60 to 150 °C, the lithium salt species is 5 types, the solvent species is 5 types, and the lithium salt solubility > 0.5 mol / L.

[0017] As an embodiment of the present invention, the lithium-based electrolyte is composed of a lithium salt and a solvent, and the final concentration of the lithium salt is 0.5 to 5 mol / L; the number of lithium salt types is not less than 4, and the mass of each lithium salt accounts for more than 5% of the total mass of the lithium salt; the number of solvent types is not less than 4, and the volume of each solvent accounts for more than 5% of the total volume of the solvent.

[0018] The lithium-based electrolyte can enable the lithium metal battery to have no sudden drop in capacity during the full cycle, until the slope decays to less than 10% of the capacity.

[0019] The addition amount of the lithium-based electrolyte does not exceed 5 g / Ah according to the ratio of the electrolyte mass to the designed capacity.

[0020] The lithium-based electrolyte makes the charging expansion volume of the lithium metal battery less than 10% per week.

[0021] The room temperature ionic conductivity of the lithium-based electrolyte of the present invention is > 3 mS / cm.

[0022] As an embodiment of the present invention, the electrolyte is prepared according to the formula by using a stepwise dissolution and precise temperature control process; during the dissolution process, the temperature is gradually adjusted, and a non-coordinating interaction is formed between the solvent and the lithium salt within 1 minute through a temperature-controlled solvation process to achieve a delocalized solvation structure.

[0023] As an embodiment of the present invention, the lithium salt is added step by step; the temperature change is adjusted according to the melting point of the added lithium salt: when the melting point of the lithium salt is relatively high, the temperature is raised to a temperature below the melting point (about 50 - 200 °C); when the melting point of the lithium salt is relatively low, the temperature is lowered to a set low temperature range (about 0 - 40 °C); for each new lithium salt added, the temperature after mixing is changed within 1 minute through temperature-controlled solvation.

[0024] As an embodiment of the present invention, magnetic stirring and / or ultrasonic oscillation is used during the dissolution process, and within the temperature range of 0 - 100 °C, it is ensured that the lithium salt is uniformly dissolved in the solvent. The stirring time during the dissolution process is based on the condition that no cascade reaction occurs between the selected lithium salt and the solvent type, and at the same time, no precipitation phenomenon caused by excessive dissolution heat occurs. The total stirring time is controlled within 2 - 4 hours to ensure sufficient reaction between the lithium salt and the solvent.

[0025] In some implementation examples, the preparation method of the delocalized-designed lithium-based electrolyte includes the following steps:

[0026] Step 1: Select at least 4 lithium salts according to the algorithm described in claim 1, and the molar mass of each lithium salt accounts for more than 5% of the total molar mass of the lithium salts;

[0027] Step 2: Select at least 4 solvents according to the algorithm described in claim 1, and the volume of each solvent accounts for more than 5% of the total volume of the solvents;

[0028] Step 3: Using the K-means algorithm, based on physicochemical properties such as redox potential, lithium ion binding energy, melting point, and boiling point, screen and optimize the selected lithium salts and solvents to ensure that the redox potential of the selected lithium salts and solvents is ≥ 4V, the lithium ion binding energy ranges from -4 to -10 eV, the melting point ranges from -90 to 100 °C, and the boiling point ranges from 100 to 500 °C;

[0029] Step 4: Mix the optimized and screened lithium salts and solvents. For each newly added lithium salt, change the temperature of the mixture within 1 minute through temperature-controlled solvation. When adding each new lithium salt, change the temperature of the mixture within 1 minute through temperature-controlled solvation. The temperature change is adjusted according to the melting point of the lithium salt: when the melting point of the lithium salt is relatively high, heat up to a temperature close to but below the melting point to promote the solvation process; when the melting point of the lithium salt is relatively low, cool down to the set low temperature range to ensure that the solvation reaction proceeds under suitable temperature conditions. Through this temperature control method, the interaction between the solvent and the lithium salt can be effectively promoted, the solvation structure can be optimized, and the performance and stability of the electrolyte can be further improved.

[0030] As an embodiment of the present invention, the lithium salt according to Step 1 is lithium hexafluoroantimonate (LiSbF6), lithium hexafluorostannate(IV) (Li2SnF6), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluorosilicate (F6Li2Si), lithium bis(fluorosulfonyl)imide (LiFSI), lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imide (CF4LiNO4S2), lithium 1,1,2,2,3,3-hexafluoropropene-1,3-disulfonimide (C3F6LiNO4S2), lithium bis(pentafluoroethylsulfonyl)imide (C4F10LiNO4S2), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), lithium nonafluoro-1-butene sulfonate (C4F9LiO3S), lithium tetrachloroaluminate (LiAlCl4), lithium perchlorate (LiClO4), lithium difluorophosphate (LiPO2F2), lithium trifluoromethanesulfonate (LiOTf), lithium trifluoroacetate (CF3CO2Li), lithium metaphosphate (LiO3P), lithium tetrachloroplatinate(II) (Li2PdCl4), lithium difluoro(oxalato)borate (LiDFOB), lithium 5-methyl-1,3,4-thiadiazole-2-carboxylate (C4H3LiN2O2S), lithium nitrite (LiNO2), lithium carbonate (Li2CO3), lithium chloride (LiCl), lithium iodoacetate (C2H2ILiO2), lithium dodecyl sulfate (C12H25LiO4S), lithium bromide (LiBr), lithium dihydrogen phosphate (LiH2PO4), lithium O-phosphono-L-homoserinate (C4H10NO6P), lithium sulfite (Li2SO3), lithium acrylate (C3H3LiO2), lithium DL-lactate (C3H5O3Li), lithium L-lactate (C3H5LiO3), lithium 5-cyclopropyl-1,3,4-thiadiazole-2-carboxylate (C6H5LiN2O3), lithium D-allonate (C6H11LiO7), lithium isobutyrate (C4H7LiO2), lithium acetate (C2H3LiO2), lithium 2-ethylhexanoate (C8H15LiO2), lithium 4-cyclohexylbutyrate (C10H17LiO2), lithium octanoate (C8H15LiO2), lithium DL-2-hydroxybutyrate (C4H7LiO3), lithium D-(-)-citrate (C6H5Li3O7), lithium (R)-mevalonate (C6H11LiO4), lithium benzoate (C7H5LiO2), lithium tartrate (C4H4Li2O6), lithium oxalate (C2O4Li2), lithium mono-4-methoxypyridine-3-borate (C6H13BLiNO6), lithium propofol-β-D-glucuronide (C18H25LiO7), lithium clavulanate (C8H8LiNO5), lithium p-toluenesulfonimide (CH3C6H4SO2Li), lithium salicylate (C7H5LiO3), lithium bis(nonafluorobutene sulfonyl)imide (C8F18LiNO4S2),Lithium tetraphenylborate tris(1,2-dimethoxyethylene) complex (C36H50BLiO6), lithium 3-morpholinopropionate (C7H12LiNO3), lithium acetylacetonate (C5H7LiO2), lithium 2,2,6,6-tetramethyl-3,5-heptanedionate (C11H19LiO2), lithium cyclopentadienide (C5H5Li), lithium ethylenediaminetetraacetate (C10H14Li2N2O8), lithium oxide (Li2O), lithium peroxide (Li2O2), lithium nitride (Li3N), lithium hexafluoroarsenate(V) (LiAsF6), lithium bis(oxalato)borate (LiBOB), lithium bis(oxalato)borate (LiBOB), lithium difluorophosphate (LiPO2F2), 4,5-dicyano-2-(trifluoromethyl)imidazole-1-sulfide (C6F3LiN4), lithium tetraphenylborate ether complex (C24BF20Li), lithium metaborate (LiBO2), lithium disulfopyruvate (C3H4Li2O6S), lithium 2-oxo-2-(tetrafluorophosphato)acetate (LiF4C2O4P), lithium [1,2,4]triazolo[4,3-a]pyrazine-3-carboxylate (C6H3LiN4O2), lithium 5-sulfoisophthalate (C8H5LiO7S), lithium acetate dihydrate (CH3COOLi), phenyl lithium solution (C6H5Li), lithium iodate (LiIO3), lithium 5-bromopyridine-2-carboxylate (C6H3BrLiNO), lithium dihydroxyacetone phosphate (C3H5Li2O6P), lithium 3-fluoropyridine-2-carboxylate (C6H3FLiNO2), lithium DL-4-hydroxy-2-ketoglutarate (C5H4Li2O6), lithium acetoacetate (C4H5LiO3), lithium adenosine 5′-O-thiomonophosphate (C10H12N5O6PSLi2), lithium phenyl(2,4,6-trimethylphenyl)phosphate (C16H16LiO3P), lithium 6-hydroxy chlorothioxanthene β-D-glucuronide (C13H11ClLiO9), lithium trimethylsilanolate (C3H9LiOSi), lithium phosphate (Li3PO4), lithium 5-methylpyridine-2-boronate (C6H7BLiNO2), lithium profoxidine (C24H31ClLiNO4S), lithium bis(trimethylsilyl)amide (C6H18LiNSi2), lithium (8-quinolinolato) (C9H6LiNO), lithium 2-(2',2”-bipyridin-6'-yl)phenolate (C16H11LiN2O), methyl lithium solution (CH3Li), isobutyl lithium (C4H9Li), hexyl lithium (C6H13Li), sec-butyl lithium solution (C4H9Li), ethyl lithium solution (CH3CH2Li), lithium sulfide (Li2S), tert-butyl lithium (C4H9Li), lithium diisopropylamide (C6H14LiN), lithium dicyclohexylamide ((C6H11)2NLi), lithium diethylamide (C4H12LiN),Select at least 4 from lithium dimethylamide (C2H6LiN).

[0031] As an embodiment of the present invention, the solvent is selected from the group consisting of cyanamide (C2H2N2O), 3-oxopropanenitrile (C3H3NO), 1-fluoro-2-(methylsulfonyl)benzene (FS) (C7H7FO2S), methyl benzenesulfonate (C7H8O3S), prop-1-ene-1,3-epithiolactone (C3H4O3S), ethenesulfinic acid ester (EVS) (C4H8O2S), N-cyanomethylformamide (C2H2N2O), 3-oxobutenenitrile (C4H5NO), 2-oxo-1,3-dioxene-4-carbonitrile (C4H3NO3), methyl-2,2,2-trifluoroethyl carbonate (TFEMC) (C4H5F3O3), ethenesulfinic acid ester (ES) (C2H4O3S), methyl-2,2,2-trifluoroethyl carbonate (FEMC) (C4H5F3O3), propenesulfinic acid ester (PS) (C3H6O3S), ethyl difluoroacetate (EDFA) (C4H6F2O2), fluoroacetonitrile (C2H2FN), trifluoroacetamide (C2H2F3NO), glycine nitrile (C2H3NO), cyanoacetic acid (C3H3NO), 3-cyano-1-propanesulfonyl fluoride (CPSF) (C4H6FNO2S), acrylonitrile (MAN) (C3H2N2), chloromethylsulfonylmethane (C2H5ClO2S), methylsulfonyl fluoride (FMS) (CH3FO2S), valeronitrile (GLN) (C5H6N2), 1,1,1-trifluoro-2-(methylsulfonyl)ethane (FEMS) (C3H5F3O2S), difluoroethylene carbonate (DFEC) (C3H2F2O3), methyl-2-cyano-2-methylpropionate (C6H9NO2), methyl-3,3,3-trifluoropropionate (TFPM) (C4H5F3O2), methyl(fluoromethyl)sulfoxide (C2H5FO2S), 3,3,3-trifluoroacrylonitrile (C3H2F3N), fluoroethylene carbonate (FEC) (C3H3FO3), adiponitrile (ADN) (C6H8N2), trifluoromethylsulfonylalkyl ethane (FMES) (C3H5F3O2S), pemine (PMN) (C7H10N2), ethyl-3,3,3-trifluoropropionate (TFPE) (C5H7F3O2), 1,1,1-trifluoro-3-(methylsulfonyl)propane (FPMS) (C4H7F3O2S), difluoro(methylsulfonyl)methane (DFSM) (C2H4F2O2S), 3-fluoro-1,3-propylene episulfide (MESL) (C5H10O3S), propeneaminosulfonate (SEN) (C10H16N2), 1-(fluoromethyl)-1,3-dioxane (FPC) (C4H5FO3), bis(2,2,2-trifluoroethyl) carbonate (HFDEC) (C5H4F6O3), bis(2,2,2-trifluoroethyl) ether (BTFE) (C4H4F6O), sunamine (SUN) (C8H12N2),Acrylonitrile (ACN) (C2H3N), mecrotonitrile (DMC) (C4H7N), perfluoromethoxyisopropyl methyl carbonate (PFPMC) (C5H5F5O3), trimethylacrylonitrile (C5H9N), pentenenitrile (C5H9N), 2,2-dimethylbutenenitrile (C6H11N), 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (HFE) (C4H2F8O), ethyl 1,1,2,2-tetrafluoroethyl ether (ETFE) (C4H6F4O), 2,2-difluoroethyl ethyl carbonate (EDFEC) (C5H8F2O3), methyl 3,3,3-trifluoropropyl carbonate (TrFPMC) (C5H7F3O3), 1,1,2,2-tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)propane (FEPE / TTE) (C5H4F8O), 4,4-difluoro-1,3-dioxane (C4H6F2O2), difluoro(dimethoxy)methane (C3H6F2O2), 2-oxo-1,3-dioxene-4-carboxylic acid (C4H4O5), trifluoro(methoxymethoxy)methane (C3H5F3O2), 4-trifluoromethyl-1,3-dioxan-2-one (TFPC) (C4H3F3O3), 1-fluoroethyl methyl carbonate (1FEMC) (C4H7FO3), 2,2-difluoroethyl methyl carbonate (DFEMC) (C4H6F2O3), 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (TFTFE) (C4H3F7O), 2-(methylsulfonyl)ethyl 2,2,2-trifluoropropionate (MSTFA) (C5H7F3O4S), 2-mecrosulfonylethyl 2,2-difluoroacetate (MSPTFA) (C5H8F2O2S), methyl(methylsulfonyl)acetate (MMSA) (C4H8O4S), N,N-dimethylbenzamide (C9H11NO), ethyl methylsulfonylacetate (EMSA) (C5H10O4S), chloroacetone (C3H5ClO), methoxyacetone (C4H8O2), ethyl 2-cyano-2-methylpropionate (C7H11NO2), ethyl 2-fluorosulfonylethyl carbonate (EFSEC) (C5H9FO5S), butyl ethyl ketone (C7H14O), 2-fluoroacetamide (C2H4FNO), N-fluoromethyl-N-methylformamide (C3H6FNO), methylsulfonyl(methoxy)methane (MMMS) (C3H8O3S), 2-fluoro-N-methylacetamide (C3H6FNO), 2-(methylsulfonyl)ethyl acetate (MSEA) (C5H10O4S), delta-valerolactone (DVL) (C5H8O2), diethylsulfinate (DES) (C4H10O2S), ethyl isobutylsulfinate (EiBS) (C6H14O2S), dipropylsulfinate (DPS) (C6H14O2S), 3-methoxysultane (MESL) (C5H10O3S), 4,5 - Dimethyl - 1,3 - dioxolan - 2 - one (C5H6O3), 1 - (Ethylenesulfinyl) - 2 - methoxyethane (EMES) (C5H12O3S), Urea (CH4N2O), Methyl - 3,3 - difluoropropionate (C4H6F2O2), 3 - Methylsulfoxolane (3MESL) (C5H10O2S), 1 - Methoxy - 2(2 - methoxyethanesulfonyl)ethane (DMES) (C6H14O4S), Formylhydrazine (CH4N2O), Methyl - 3 - fluoropropionate (C4H7FO2), Ethyl isopropylsulfinate (EiPS) (C5H12O2S), 2 - Methoxyacetamide (C3H7NO2), 2 - (Ethylsulfonyl)butane (EsBS) (C6H14O2S), 2 - Fluoro - N,N - dimethylacetamide (C4H8FNO), 2 - Methyl - 1 - (prop - 2 - sulfinyl)propane (IPiBS) (C7H16O2S), 2 - (Prop - 2 - sulfinyl)butane (IPSBS) (C7H16O2S), Isopropyl methyl sulfoxide (MiPS) (C4H10O2S), Methyl propyl sulfoxide (MPS) (C4H10O2S), Tetraethylene thione (TMS / Sulfolane) (C4H8O2S), 3 - Isopropoxytetrahydrothiophene 1,1 - dioxide (ISEL) (C7H14O3S), 3 - Ethoxysulfoxolane (EESL) (C6H12O3S), 3 - (2 - Methoxyethoxy)thiophene 1,1 - dioxide (GLSL) (C7H14O4S), Methyl glycinate (C3H7NO2), 3 - Fluoropropanamide (C3H6FNO), Isobutyramide (C4H9NO), Propanamide (C3H7NO), Acetamide (C2H5NO), Dimethyl methylphosphonate (DMMP) (C3H9PO3), Butyramide (C4H9NO), N - Methylacetamide (NMA) (C3H7NO), 2 - Fluoroethyl acetate (2FEA) (C4H7FO2), N - Ethylformamide (C3H7NO), N - Methyl - 2 - oxazolidinone (C4H7NO2), N,N - Diethylacetamide (C6H13NO), N,N - Dimethylacrylamide (C5H11NO), Dimethylacetamide (DMA) (C4H9NO), 2 - Pyrrolidone (C4H7NO), Methoxymethoxyacetate (MMOA) (C4H8O3), Dimethyl sulfoxide (DMSO) (C2H6OS), Dimethylformamide (DMF) (C3H7NO), 1 - Methylimidazole (C4H6N2), N,N - Dimethylbutyramide (C9H11NO), Diethyl sulfoxide (DESO) (C4H10SO), N - Methylformamide (C2H5NO), Trimethyl phosphate (TMP) (C3H9PO4), Triethyl phosphate (TEP) (C6H15PO4),Methyl methoxyacetate (MMOA) (C4H8O3), dipropyl sulfoxide (DPSO) (C6H14SO), 1-methyl-2-pyrrolidone (NMP) (C5H9NO), N-methylpyrrolidone (C5H9NO), dibutyl sulfoxide (DBSO) (C8H18OS), methoxy(methoxymethoxy)methane (C4H10O3), 1-ethoxy-2-(2,2,2-trifluoroethoxy)ethane (ETFEE) (C6H11F3O2), N,N'-dimethylimidazolidinone (C5H10N2O), ethyl fluoroethyl carbonate (EFEC) (C5H9FO3), 2-fluoropropyl methyl carbonate (2FPMC) (C5H9FO3), 1,3-dioxolan-2-amine (C4H9NO2), dimethoxymethane (DMM) (C3H8O2), diisopropyl ether (C6H14O), fluoromethoxy(methoxy)methane (C3H7FO2), ethenethioamide (C2H5NS), 2-pyrrolidinethione (C4H7NS), dimethyl ketone (C3H6O), 3,4-difluorofuran (C4H2F2O), 2-butanone (methyl ethyl ketone) (C4H8O), 2,3-difluorofuran (C4H2F2O), methoxybenzene (C7H8O), 3-fluorofuran (C4H3FO), phenylethoxymethane (C8H10O), butyl phenyl ether (C10H14O), propoxybenzene (C9H12O), 2,4-difluorofuran (C4H2F2O), aminomethyl ene (C3H9NO2), 2-fluorofuran (C4H3FO), 2,5-difluorofuran (C4H2F2O), furan (C4H4O), 3-methoxyfuran (C5H6O2), 2-ethylfuran (C6H8O), 1-(2,2,2-trifluoroethoxy)-2-methoxyethane (TFEME) (C5H9F3O3), 2-methoxyfuran (C5H6O2), methyl tert-butyl ether (C5H12O), 3-methyltetrahydrofuran (C5H10O), 5-methoxy-1,3-dioxane (C5H10O3), cyclopentyl methyl ether (C6H12O), 1-(2,2-difluoroethoxy)-2-ethoxyethane (EDFEE) (C6H12F2O2), 2,3-dimethylfuran (C6H8O), 2-methyltetrahydrofuran (2-Me-THF) (C5H10O), 2-methyltetrahydrofuran (C5H10O), 4-methyl-1,3-dioxane (4ME13DOL) (C4H8O2), tetrahydrofuran (THF) (C4H8O), tetrahydropyran (C5H10O), tetrahydropyran (C5H10O), 1-(2-fluoroethoxy)-2-ethoxyethane (EFEE) (C6H13FO2), 1-(2-fluoroethoxy)-2-methoxyethane (FEME) (C5H11FO2), 2,5-dimethylfuran (C6H8O), dioxane (1,3-dioxane (C3H6O2), 2-methyl-1,3-dioxolane (2ME13DOL) (C4H8O2), 1-ethoxy-2-methoxyethane (EME) (C5H12O2), ethoxymethoxymethane (C4H10O2), triether (C8H18O4), diether (C6H14O3), diethyl ether (C4H10O), 1,2-diethoxyethane (DEE) (C6H14O2), 1-ethoxy-2-methoxyethane (EME) (C5H12O2), 2-methyl-1,4-dioxane (C5H10O2), 1,2-dimethoxyethane (DME) (C4H10O2), dioxane (C4H8O2), aminoacetophenone (C3H7NO), 1,3-benzodioxol-2-one (C7H4O3), fluoroacetophenone (C3H5FO), pyridine (C5H5N), methyl fluorosulfonylacetate (C3H5FO4S), methyl fluorosulfonylacetate (MFSA) (C3H5FO4S), succinimide (C4H5NO2), benzyl cyanide (benzonitrile) (C8H7N), 2-fluorobutyrolactone (FGBL) (C4H5FO2), N,N-dimethyltrifluoroacetamide (C4H6F3NO), vinyl acetate (C4H6O2), methyl cyanoacetate (MCA) (C4H5NO2), (methylsulfonyl)propyl acetate (MSPA) (C6H12O4S), aminoacetonitrile (C2H4N2), 1,1-dioxothiolan-3-yl acetate (ACSL) (C6H10O4S), ethyl cyanoacetate (ECA) (C5H7NO2), 1,1,1-trifluoro-2-methylsulfonylpropane (FIMS) (C4H7F3O2S), 1,1-dioxothiolan-3-yl acetate (ECSL) (C7H12O5S), 4-(methylsulfonyl)butanenitrile (MCPS) (C5H9NO2S), ethylene carbonate (VC) (C3H2O3), 2-methylglutaronitrile (C6H8N2), fluoromethyl propionate (C4H7FO2), isobutylene carbonate (C5H8O3), 4-hydroxy-1,3-dioxolan-2-one (C3H4O4), methylpropyl carbonate (MPC) (C5H10O3), methoxyacetonitrile (C3H5NO), 2-fluoroethyl methyl carbonate (MFEMC) (C4H7FO3), N-methoxymethanamide (C2H5NO2), methyl formate (C2H4O2), ethyl 2-fluoropropionate (E2FP) (C5H9FO), dimethyl sulfoxide (DMS) (C2H6O2S), {[(2-mesyl ethoxy)carbonyl]oxy}methane (MSEMC) (C5H10SO5), ethyl (3-(methylsulfonyl)propyl) carbonate (MSPEC) (C6H14SO5), thiophene, 3-fluorotetrahydrothiophene, 1,1-dioxide (3-FTMS) (C4H7FO2S), thiophene, 2-fluorotetrahydrothiophene,1,1-dioxide (2-FTMS) (C4H7FO2S), ethyl [2-(methylsulfonyl)ethyl] carbonate (ethyl 2-mesylsulfonylethyl carbonate) (MSDEC) (C6H12O5S), 2-{[(3-mesylsulfonylallyl) carbonate]oxy}propane (MSPiPC) (C7H16SO5), ethyl methyl sulfoxide (EMS) (C3H8O2S), 2-{[(2-mesylsulfonylethoxy) carbonate]oxy}propane (MSEiPC) (C7H14O5S), 1,4-butanesultone (C4H8O3S), 1,3-propanesultone (C3H6O3S), ethyl formate (C3H6O2), isobutyl formate (C5H10O2), ethyl fluoroacetate (EFA) (C4H7FO2), n-propyl formate (C4H8O2), thietane 1,1-dioxide (TriPS) (C3H6O2S), n-butyl formate (C5H10O2), 2-methylthietane 1,1-dioxide (MTS) (C4H8O2S), Gamma-valerolactone (C5H8O2), isopropyl formate (C4H8O2), methyl (2-methoxyethyl) sulfoxide (MEMS) (C4H10O3S), propylene carbonate (PC) (C4H6O3), methoxyacetonitrile (C4H7NO), 2,3-butene carbonate (C5H8O3), ethylene carbonate (EC) (C3H4O3), 1,2-butene carbonate (BC) (C5H8O3), carbamic acid amide (CH3NO2), 2-fluoroethyl propionate (2FEP) (C5H9FO2), fluoromethyl methyl carbonate (MFDMC) (C3H5FO3), gamma-butyrolactone (GBL) (C4H6O2), dimethylcarbamic fluoride (C3H6FNO), formamide (CH3NO), methyl-2,2,3,3-tetrafluoropropyl carbonate (TeFPMC) (C5H6F4O3), 3-methoxyacetonitrile (C4H7NO), 5-fluoro-1,3-dioxane (C4H7FO2), methyl carbamate (C2H5NO2), methyl isobutyrate (C5H10O2), 2-hydroxyethyl methyl carbonate (C4H8O4), butanesultone (C8H18O3S), 2-methoxyethyl acetate (C5H10O3), 5,5-difluoro-1,3-dioxane (C4H6F2O2), isoamyl acetate (C7H14O2), methyl acetate (MA) (C3H6O2), isopropyl acetate (C5H10O2), isobutyl acetate (C6H12O2), 1-methoxy-2-propyl acetate (MPA) (C6H12O3), methyl propionate (C4H8O2), ethyl acetate (EA) (C4H8O2),Methyl butyrate (MB) (C5H10O2), 3-fluoropropyl methyl carbonate (FPMC) (C5H9FO3), 1-(2,2,2-trifluoroethoxy)-2-methoxyethane (C5H9F3O2), n-butyl acetate (C6H12O2), n-propyl acetate (C5H10O2), difluoro(methoxymethoxy)methane (C3H6F2O2), ethyl propionate (C5H10O2), ethyl butyrate (EB) (C6H12O2), fluoro(dimethoxy)methane (C3H7FO2), ethyl isopropyl carbonate (EiPC) (C6H12O3), diethyl carbonate (DEC) (C5H10O3), methyl isopropyl carbonate (MiPC) (C5H10O3), ethyl methyl carbonate (EMC) (C4H8O3), dimethyl carbonate (DMC) (C3H6O3), 2-methoxy-1,3-dioxane (C5H10O3), ethyl propyl carbonate (EPC) (C6H12O3), 1,1-difluoro-2-(2-methoxyethoxy)ethane (DFEME) (C5H10F2O2), bis(fluoromethyl) carbonate (DFDMC) (C3H4F2O3). Select at least 4 of them (such as in Examples 1 and 2, perform cluster analysis on the above-listed lithium salts and solvents, and divide the lithium salts and solvents with similar physical and chemical properties into different categories).

[0032] The present invention also provides an application of a delocalized-designed lithium-based electrolyte in the preparation of a lithium battery. Among them, the addition amount of the lithium-based electrolyte does not exceed 5 g / Ah according to the ratio of the electrolyte mass to the battery design capacity. The lithium battery includes a lithium-ion battery, a lithium metal battery, and a lithium-sulfur battery.

[0033] The principle of the present invention is realized in the following way:

[0034] First, select lithium salts and solvents suitable for the design of delocalized electrolytes. To this end, systematic computational and experimental methods are adopted to conduct detailed classification and clustering analysis on candidate solvents and lithium salts. Clustering methods include K-means clustering, Hierarchical Clustering, density-based clustering (such as DBSCAN), Gaussian Mixture Model (GMM), etc. Through these clustering methods, candidate substances can be divided into several groups according to the physical and chemical properties of solvents and lithium salts, such as polarity, solubility, ionization ability, stability, etc., ensuring that the combination of lithium salts and solvents forms an ideal delocalized solvation structure in the electrolyte, thereby optimizing the migration path of lithium ions and enhancing the overall performance of the battery. This process aims to ensure that the final electrolyte not only has high ionic conductivity, low battery internal resistance, but also has a wide electrochemical window to meet the requirements of high-performance batteries. In the selection of lithium salts, first consider their ionization ability and solubility. Lithium salts with a strong ionization tendency are preferred, such as lithium trifluoromethanesulfonate (LiTFSI), lithium hexafluorophosphate (LiPF6), and lithium difluorooxalate borate (LiDFOB). These salts have low conductivity limitations and good solubility and high chemical stability in solvents. However, there are many studies that only use these lithium salts, and common knowledge still cannot solve the problems commonly existing in lithium metal batteries, such as poor cycle life and narrow operating temperature range (room temperature 20 - 30 °C), because this involves the compatibility problem between the designed lithium salt domain and the solvent. Therefore, the compatibility between lithium salts and solvents is an important criterion for screening. An ideal lithium salt should be able to form a stable solution with the selected solvent within a certain concentration range without side reactions or precipitation, thus ensuring the long-term stability of the electrolyte during battery use. In the screening of solvents, mainly based on the polarity of the solvent, chemical stability, and its influence on the solubility of lithium salts. Specifically, the selected solvent should have a high polarity to better dissolve lithium salts and support ion conduction. At the same time, the stability of the solvent is crucial for the long-term use of the electrolyte, especially under high-voltage operation. For this reason, fluorinated solvents such as fluoroethylene carbonate (FEC) and difluoroethylene carbonate (DFEC) are considered as the main candidate solvents. However, these two well-known solvents have good stability but low dissociation degree of lithium salts. To achieve a delocalized structure, it is necessary to re-screen and match them with the help of artificial intelligence, and re-screen and combine them with the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and the lithium ion binding energy (Bindingenergy) as the three key indicators.

[0035] Secondly, a delocalized electrolyte is prepared. Specifically, at least four lithium salts are selected, and the mass of each lithium salt accounts for more than 5% of the total mass of the lithium salts. At least four solvents are also selected, and the volume of each solvent accounts for more than 5% of the total volume of the solvents. The selection of lithium salts and solvents is carried out by means of cluster analysis to ensure the complementarity of their respective physical and chemical properties, thereby optimizing the performance of the electrolyte. The types of lithium salts selected include, but are not limited to, LiTFSI, LiPF6, LiDFOB, etc. These lithium salts have high ionization ability and good compatibility with solvents. The mass of each lithium salt accounts for more than 5% of the total mass to ensure sufficient ionic conductivity. The types of solvents selected include fluorinated solvents (such as FEC, DFEC), carbonate solvents (such as EC, DMC), etc. These solvents have different polarities, solubilities and dissolution abilities for lithium salts, and play a synergistic role in the electrolyte to form a stable solvation structure. The preparation process adopts a stepwise dissolution and precise temperature control process to ensure the formation of an ideal delocalized solvation structure between the lithium salt and the solvent. And the stirring time cannot be too long, because the delocalized structure may collapse due to cascade reactions of the selected lithium salts and solvents. For example, LiDFOB will preferentially dissociate DFEC to generate BF3, destroying the delocalized structure. Therefore, it is necessary to avoid stirring similar species at high temperature for too long. First, the lithium salt and the solvent are mixed according to the required ratio, and magnetic stirring and ultrasonic oscillation techniques are used to ensure that the lithium salt is uniformly dissolved in the solvent within the temperature range of 0 to 100 °C, because some lithium salts are insoluble at low temperatures. The stirring time is controlled within 2 to 4 hours to ensure sufficient reaction between the lithium salt and the solvent and also avoid destroying the overall delocalized structure. The temperature and stirring time during the dissolution process are precisely controlled, and it is also necessary to prevent precipitation caused by excessive dissolution heat to ensure the uniformity and stability of the solution.

[0036] Finally, to achieve the formation of delocalized solvation characteristics, the present invention adopts a "temperature-controlled solvation" process. In this process, by gradually cooling or heating the solution, its concentration and solvation process are adjusted to ensure the gradual establishment of non-coordinating interactions between the solvent and lithium salt molecules. As the temperature changes, the interaction strength between the solvent and the lithium salt is effectively adjusted, thereby promoting the formation of a structure with delocalized solvation characteristics. This structure has a high degree of freedom, effectively avoiding the limitations of lithium ion migration in the traditional solvation structure, enabling lithium ions to migrate more freely in the electrolyte, and thus improving the conductivity of the electrolyte and the performance of the battery.

[0037] Finally, the prepared delocalized electrolyte is applied to a high-energy lithium battery system, and its performance in an actual battery environment is evaluated. Especially during long-term charge and discharge processes, it can effectively inhibit the formation of lithium dendrites, maintain a low battery internal resistance and good cycle stability.

[0038] The delocalized electrolyte design of the present invention and its application in lithium batteries have the following remarkable beneficial effects:

[0039] 1) Improve lithium-ion conductivity: By introducing various lithium salts and solvents with complementary properties, the solvation structure of the electrolyte is optimized, enhancing the free migration ability of lithium ions in the electrolyte, thus effectively improving the ionic conductivity of the electrolyte, which can be > 3 mS / cm.

[0040] 2) Prolong the battery cycle life. Using a delocalized electrolyte enables the battery to inhibit the formation of lithium dendrites during long-term charge and discharge processes, reducing the instability of lithium metal deposition, thereby improving the cycle stability and service life of the battery, such that the charging volume expansion per week of the battery is less than 10%.

[0041] 3) Broaden the electrochemical window: Through a reasonable combination of solvents and lithium salts, the delocalized electrolyte of the present invention has a wide electrochemical window and can stably operate in a high voltage range (such as 4.0 V to 6.5 V), significantly enhancing the energy density of the battery and being suitable for the development of high energy density batteries.

[0042] 4) Enhance battery safety: Due to the unique solvation structure and low reactivity of the delocalized electrolyte, it can effectively inhibit the occurrence of solvent degradation and side reactions, improving the safety of the battery under extreme conditions such as high voltage and long-term cycling, achieving no sudden drop in capacity during the full cycle of the lithium metal battery, but gradually decreasing to less than 10% of the initial capacity.

[0043] 5) Multifunctional electrolyte system: The electrolyte system designed in the present invention can flexibly adjust the ratio of solvents and lithium salts according to different requirements to adapt to different types of lithium batteries, having good applicability and scalability, and being able to meet the diverse needs of high-performance lithium batteries.

[0044] 6) This electrolyte is applicable to high-energy lithium batteries, can effectively improve the charge and discharge efficiency, cycle stability and safety of lithium batteries, especially showing excellent performance in the design of soft-pack batteries in high voltage and high energy density environments. Compared with traditional electrolytes, the electrolyte of the present invention has a wider range of applicability and provides a breakthrough application value in battery technology. Description of the Drawings

[0045] Other features, objects and advantages of the present invention will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0046] Figure 1 K-means clustering analysis result of the solvent for Example 1;

[0047] Figure 2 Comparison of solvation structures of electrolytes with different degrees of delocalization;

[0048] Figure 3For the comparison of the cycling performance of coin cells with electrolytes of different delocalization degrees in the 1C charge-discharge cycle test of 4.3V Ni90 / 4.6V LCO batteries;

[0049] Figure 4 For the comparison of the cycling performance of 500Wh / kg pouch cells with electrolytes of different delocalization degrees;

[0050] Figure 5 For the comparison of the cycling performance of 600Wh / kg pouch cells with electrolytes of different delocalization degrees. Specific implementation manners

[0051] The present invention will be described in detail below in conjunction with embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those of ordinary skill in the art can make several adjustments and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0052] Embodiment 1

[0053] The K-means clustering analysis method is adopted and screening is carried out according to the following steps.

[0054] Step 1: Collect key physical and chemical parameters related to lithium salts and solvents, directly query them with the help of material databases (such as MaterialsProject, NIST Chemistry WebBook, etc.), or use theoretical calculation software (such as VASP, Gaussian, etc.) to perform density functional theory (DFT) calculations to obtain these data. For example, use the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and the lithium ion binding energy (Binding energy) as 3 key indicators, and standardize these data to eliminate the dimension difference.

[0055] Step 2: Perform clustering analysis on the standardized data using the K-means clustering analysis algorithm. First, collect the HOMO energy level, LUMO energy level, and lithium ion binding energy data of lithium salts and solvents, and perform normalization to eliminate the dimensional difference. Subsequently, map the normalized data points to a three-dimensional Euclidean space, where the three-dimensional coordinates of each data point correspond to the normalized values of its HOMO energy level, LUMO energy level, and lithium ion binding energy. Through K-means clustering analysis, first randomly initialize four cluster centers, calculate the Euclidean distances from all data points to these centers, and classify each data point to the nearest cluster center. Subsequently, calculate the mean value of the data points within each category and iteratively update the cluster centers until convergence. Finally, the K-means algorithm divides lithium salts and solvents into four categories according to the distribution pattern of the data points in the three-dimensional space, so that the materials within the same category have similar characteristics in terms of HOMO, LUMO, and lithium ion binding energy, and different colored spheres are used to represent each category, such as Figure 1 shown.

[0056] Step 3: Limit the lithium ion binding energy range to -12 to -5 eV, the working temperature range to -80 to 120 °C, the lithium salt species to 5 types, the solvent species to 5 types, and the lithium salt solubility > 0.5 mol / L. Through iterative adjustment, finally select the lithium salt and solvent combination that can maximize the complementarity of physical and chemical properties as shown in Table 1.

[0057] Table 1 Electrolyte formulation of Example 1

[0058] Lithium salt Molar ratio Solvent Volume ratio C6F3LiN4 0.2M FEC 0.2V LiBO2 0.2M FEMC 0.2V LiDFOB 0.2M DFEC 0.2V <![CDATA[LiPF6]]> 0.2M 1FEMC 0.2V LiPO2F2 0.2M DFEMC 0.2V

[0059] For the electrolysis formulation described in Table 1, its redox potential ≥ 6.0 V, the lithium ion binding energy is -7.38 eV, the melting point is -83 °C, and the boiling point is 136 °C.

[0060] Step 4: Mix the optimized and screened lithium salts and solvents to prepare the electrolyte. The preparation process includes the following steps: First, weigh the lithium salts according to the ratio and dissolve them in the solvent to ensure that the concentration of each lithium salt is 0.2 M while ensuring the uniformity of the solvent ratio. Then, use a combination of magnetic stirring and ultrasonic oscillation to stir for 3 hours (including the temperature change time) within the temperature range of 0 - 70 °C to ensure complete dissolution of the lithium salts. During the dissolution process, gradually adjust the temperature to form a non-coordinating interaction between the solvent and the lithium salts within 1 minute through the temperature-controlled solvation process, thereby achieving a delocalized solvation structure. Specifically, first stir FEC, FEMC, DFEC, 1FEMC, and DFEMC at room temperature according to the ratio in Table 2 for 1 hour, then heat up to 100 °C, add LiBO2 according to the formula in Table 2 and stir for 1 minute until it is completely dissolved. Then cool down to 80 °C, add LiPO2F2 according to the formula in Table 2 and stir for 1 minute until it is completely dissolved. Then cool down to 65 °C, add LiDFOB according to the formula in Table 2 and stir for 1 minute until it is completely dissolved. Then cool down to 40 °C, add LiPF6 according to the formula in Table 1 and stir for 1 minute until it is completely dissolved. Finally, cool down to 25 °C, add C6F3LiN4 and stir for 1 minute to obtain a typical delocalized electrolyte.

[0061] Example 2

[0062] The K-means clustering analysis method is used for screening according to the following steps.

[0063] Step 1: Collect the key physical and chemical parameters related to lithium salts and solvents, taking the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and the lithium ion binding energy as 3 key indicators, and standardize these data to eliminate the dimensional difference.

[0064] Step 2: Perform clustering analysis on these standardized data through the K-means clustering analysis algorithm, and divide the lithium salts and solvents with similar physical and chemical properties into 4 categories (basically the same as Step 2 of Example 1).

[0065] Step 3: Limit the lithium ion binding energy < 6 eV, the working temperature range is -60 to 150 °C, the types of lithium salts are 5, the types of solvents are 5, and the solubility of lithium salts > 0.5 mol / L. Through iterative adjustment, select 5 types of lithium salts and 5 types of solvent combinations from the candidate lithium salts and solvents as shown in Table 2.

[0066] Table 2 Electrolyte formula of Example 2

[0067] Lithium salt Molar ratio Solvent Volume ratio <![CDATA[LiPF6]]> 0.2M FEC 0.2V <![CDATA[LiBF4]]> 0.2M FEMC 0.2V LiDFOB 0.2M DFEC 0.2V LiTFSI 0.2M 1FEMC 0.2V LiOTf 0.2M TTE 0.2V

[0068] As described in Table 2, the measured redox potential of the electrolysis formulation is ≥5.5 V, the lithium ion binding energy is -6.77 eV, the melting point is -66 °C, and the boiling point is 216 °C.

[0069] Step 4: Mix the optimized and screened lithium salts and solvents to prepare the electrolyte. The preparation process includes the following steps: First, weigh the lithium salts according to the ratio and dissolve them in an appropriate amount of solvent to ensure that the concentration of each lithium salt is 0.2 M while ensuring the uniformity of the solvent ratio; then, use a combination of magnetic stirring and ultrasonic oscillation to stir for 2 hours (including the temperature change time) in the temperature range of 25 - 100 °C to ensure that the lithium salts are completely dissolved; during the dissolution process, gradually adjust the temperature and form a non-coordinating interaction between the solvent and the lithium salts within 1 minute through a temperature-controlled solvation process to achieve a delocalized solvation structure. Specifically, first stir FEC, FEMC, DFEC, and 1FEMC at room temperature according to the ratio in Table 1 for 1 h, then raise the temperature to 70 °C, add LiOTf according to the formulation in Table 1 and stir for 1 minute to completely dissolve it; then cool down to 60 °C, add LiBF4 according to the formulation in Table 1 and stir for 1 minute to completely dissolve it; then cool down to 0 °C, add the TTE solvent according to the formulation in Table 1 and stir well for 1 h, then maintain this temperature and add LiTFSI and stir for 1 minute to completely dissolve it; then raise the temperature to 50 °C, add LiDFOB according to the formulation in Table 1 and stir for 1 minute to completely dissolve it; finally, cool down to 25 °C and add LiPF6 and stir for 1 minute to obtain a typical delocalized electrolyte. As Figure 2 shown, compared with the other two non-delocalized commercial electrolytes, namely commercial type 1: 1 mol / L LiPF6 EC / EMC (1:1 volume ratio) and commercial type 2: 1 mol / L LiPF6 FEC / FEMC (1:1 volume ratio), the delocalized electrolyte designed in this case shows the widest range of solvation structures in the small-angle scattering spectrum, corresponding to the delocalized solvation structure inside the electrolyte.

[0070] Application Example 1

[0071] The delocalized electrolyte prepared in Example 1 was used for the test of a lithium metal button cell, as Figure 2 shown. A 4.3 V high-nickel cathode Ni90 (LiNi 0.9 Co 0.05 Mn 0.05 O2) || lithium metal anode (Li) and a 4.6 V high-voltage lithium cobalt oxide cathode LCO (LiCoO2) || Li button cell were used for the cyclic performance test. In the 1C charge-discharge cycle test of the 4.3 V Ni90 cell, as Figure 3As shown, the delocalized electrolyte exhibits excellent cycle stability, with a capacity retention rate as high as 93.4% after 100 cycles. In contrast, the capacity retention rate of the non-delocalized electrolyte under the same conditions is only 64.9%. Similarly, in the 1C charge-discharge cycle test of the 4.6V LCO battery, as Figure 3 shown, the delocalized electrolyte demonstrates a relatively high initial discharge capacity and maintains a capacity retention rate of 94.3% after 100 cycles, while the capacity retention rate of the commercial type 2 non-delocalized electrolyte is 70.8%.

[0072] Application Example 2

[0073] The delocalized electrolyte prepared in Example 2 was used for the test of a lithium metal soft-pack battery. The specific design parameters of the lithium metal soft-pack battery are shown in Tables 3 and 4.

[0074] Table 3 Design Parameters of the 500 Wh / kg-level Lithium Metal Soft-Pack Battery in Application Example 2

[0075]

[0076]

[0077] Table 4 Design Parameters of the 600 Wh / kg-level Lithium Metal Soft-Pack Battery in Application Example 2

[0078]

[0079] As Figure 4 shown, for the 500 Wh / kg-level lithium metal soft-pack battery, at room temperature, a constant current charge-discharge test was conducted with a charging rate of 0.2C and a discharging rate of 0.5C. The test electrolytes were the delocalized electrolyte prepared in Example 2 and a commercial type 1 non-delocalized electrolyte, and the voltage range was from 2.8V to 4.3V. The discharge capacity and energy density after each cycle were recorded; the cycling continued until 300 cycles, and the capacity decay was observed. The test results of the lithium metal soft-pack battery showed that the 1.9 Ah lithium metal soft-pack battery with the delocalized electrolyte prepared in Example 2 achieved an energy density as high as 510.1 Wh / kg, maintained an energy density of 404.1 Wh / kg after 150 cycles at a rate of 0.5C, and showed no obvious capacity decay after 300 cycles. This level of durability cannot be achieved by existing lean electrolyte lithium metal soft-pack batteries and meets the goals of the US Battery500 project.

[0080] As Figure 5As shown, for a lithium metal pouch cell at the 600 Wh / kg level, at room temperature, a constant current charge-discharge test was carried out with a charging rate of 0.2C and a discharging rate of 0.25C for the cycle performance test. The test electrolytes were the delocalized electrolyte prepared in Example 2 and a commercial type 1 non-delocalized electrolyte. The voltage range was from 2.8V to 4.3V. The discharge capacity and energy density after each cycle were recorded. The 5.5Ah lithium metal pouch cell using the delocalized electrolyte prepared in Example 2 also showed excellent performance. Its energy density reached 604.2 Wh / kg, and still maintained an energy density of 517.7 Wh / kg after 100 cycles, and no obvious polarization phenomenon was observed during the long cycle process, breaking through the milestone of Battery600.

[0081] Comparative Example 1

[0082] The electrolyte of Example 1 in the authorized invention CN113782810B was used (where the main solvent was 71% (DMC, MMA), the fluorinated solvent was 26% (FEC, TFEB), the self-sacrificing inducer was 3% (AIBN, TTE), and the lithium salt (LATP, LiPF6) was 1.5 mol / L), and a 7Ah-level pouch cell was designed (calculated based on the theoretical value of 4.45V for the positive electrode). Using commercial LCO as the positive electrode, metallic lithium as the negative electrode, and commercial celgard 2325 as the separator to form the battery core, the electrolyte addition amount was such that the E / C ratio was equal to 1.2 g / Ah. The formed pouch cell was aged at 45°C for 24h and then vacuum-sealed to obtain a prototype battery; the prototype battery was charged to 4.45V at 0.1C, and the self-sacrificing charging voltage fluctuation curve appeared at 4.2V. The 0.1C discharge cut-off voltage was 3V, and it was cycled 5 times. The actual discharge capacity of the pouch cell was 7.53Ah, and the average specific energy was 433 Wh / kg; then, the prototype battery was charged to 4.6V at 0.3C, and the 0.3C discharge cut-off voltage was 3V. The actual discharge capacity of the pouch cell was 9.35Ah, the initial discharge specific energy was 539 Wh / kg, and the 100th cycle discharge specific energy was 460.8 Wh / kg.

[0083] In the application of high energy density with the delocalized electrolyte, the battery can operate stably and maintain a long service life. It is particularly noteworthy that for the low electrolyte injection volume of the delocalized electrolyte, in this test, the electrolyte injection volume of the battery was controlled at 1.5 g / Ah. This design of low electrolyte injection volume not only effectively reduced the usage amount of the electrolyte, but also further optimized the overall energy density of the battery. The low electrolyte injection volume can reduce the electrolyte volume inside the battery, thereby effectively improving the energy density of the lithium metal battery, while maintaining excellent cycle stability and low internal resistance. Compared with the initial uncycled state of the battery, with the help of a thickness measuring instrument, its volume expansion was only 9.3%.

[0084] In summary, the present invention provides an innovative delocalized electrolyte design aimed at breaking through the performance bottlenecks of traditional electrolytes in lithium batteries, especially the challenges in high energy density and long cycle stability. The delocalized electrolyte of the present invention forms a diversified solvent structure by combining lithium salts and solvents with different physical and chemical properties, enabling the delocalization of its microscopic solvent structure. The delocalized solvent structure not only enriches the microscopic structure of the electrolyte but also significantly improves the overall electrolyte performance through complementary properties, thereby effectively improving the charge-discharge efficiency and cycle life of lithium batteries. More precisely, the present invention combines an artificial intelligence clustering analysis algorithm to accurately select various lithium salts and solvents, adopts a ratio of lithium salts and solvents with complementary physical and chemical properties, optimizes the solvation structure, and significantly improves the conductivity of lithium ions and the stability of the battery, especially showing excellent performance in high-voltage and high-energy density applications.

[0085] The application of the delocalized electrolyte of the present invention in batteries has significant innovation and practicality. First, by precisely regulating the combination of the solvent and lithium salt in the electrolyte, the limitation of the traditional solvation structure is broken through, forming a more free and dynamic solvation structure. This not only improves the ionic conductivity of the battery but also effectively inhibits the formation of lithium dendrites, thereby enhancing the safety and cycle stability of the battery. Second, the low electrolyte injection volume design of the delocalized electrolyte effectively reduces the amount of electrolyte used, greatly improving the energy density of the battery and providing a new solution for the development of the next generation of high-energy density lithium batteries.

[0086] In addition, the delocalized electrolyte has wide applicability in various types of lithium batteries. Especially in lithium metal soft-pack batteries, by improving the electrochemical window of the electrolyte, enhancing the lithium ion migration efficiency, and suppressing side reactions, the electrolyte of the present invention significantly improves the energy density and service life of the battery, promoting the further development of high-performance battery technology.

[0087] Therefore, the delocalized electrolyte of the present invention not only has innovation in theory but also shows extremely high practicality in actual applications. It can provide a reliable solution for high-performance, long-life, and low-injection-volume lithium batteries, having broad market prospects and application values.

[0088] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A delocalized design lithium-based electrolyte, characterized in that, The electrolyte is obtained by an artificial intelligence clustering analysis algorithm, and the clustering methods include one or more of K-means clustering, hierarchical clustering, density-based clustering, and Gaussian mixture model; the method comprises the following steps: S1. Collect at least three key physical and chemical parameters related to lithium salts and solvents, and perform standardization processing on these data to eliminate the dimension difference; S2. Perform clustering analysis on these standardized data through an algorithm, and divide lithium salts and solvents with similar physical and chemical properties into different categories, with more than two categories; S3. Define the required parameters, and through iterative adjustment, select a combination of lithium salts and solvents that can maximize the complementarity of physical and chemical properties; S4. Prepare the corresponding electrolyte according to the formula.

2. The delocalized lithium-based electrolyte according to claim 1, characterized in that, Lithium salts and solvents are optimized and screened through clustering analysis, and the clustering indicators include but are not limited to redox potential, lithium ion binding energy, melting point, and boiling point.

3. The delocalized lithium-based electrolyte according to claim 2, wherein Ensure that the redox potential of the selected lithium salts and solvents is ≥4V, the selection range of lithium ion binding energy is -4 to -10 eV, the selection range of melting point is -90 to 100 °C, and the selection range of boiling point is 100 to 500 °C.

4. The delocalized lithium-based electrolyte according to claim 1, wherein The defined required parameters include more than two of lithium ion binding energy, electrolyte operating temperature range, lithium salt species type, solvent species type, and lithium salt solubility type.

5. The delocalized lithium-based electrolyte according to claim 1, characterized in that, The lithium-based electrolyte is composed of lithium salts and solvents, and the final concentration of the lithium salts is 0.5 to 5 mol / L; there are no less than four types of lithium salts, and the mass of each lithium salt accounts for more than 5% of the total mass of the lithium salts; there are no less than four types of solvents, and the volume of each solvent accounts for more than 5% of the total volume of the solvents.

6. The delocalized lithium-based electrolyte according to claim 1, characterized in that The electrolyte is prepared according to the formula by a stepwise dissolution and precise temperature control process; during the dissolution process, the temperature is gradually adjusted, and a non-coordinating interaction is formed between the solvent and the lithium salt within 1 minute through a temperature-controlled solvation process to achieve a delocalized solvation structure.

7. The delocalized lithium-based electrolyte according to claim 6, wherein The lithium salts are added step by step; the temperature change is adjusted according to the melting point of the added lithium salt: when the melting point of the lithium salt is high, the temperature is raised to a temperature below the melting point; when the melting point of the lithium salt is low, the temperature is lowered to the set low temperature range; every time a new lithium salt is added, the temperature after mixing is changed within 1 minute through temperature-controlled solvation.

8. The delocalized lithium-based electrolyte according to claim 6, wherein, Magnetic stirring and / or ultrasonic oscillation is used during the dissolution process to ensure that the lithium salts are uniformly dissolved in the solvent within the temperature range of 0 to 100 °C.

9. Use of a delocalized lithium-based electrolyte as described in any one of claims 1-8 in the preparation of a lithium battery, characterized in that, The addition amount of the lithium-based electrolyte does not exceed 5 g / Ah according to the ratio of the electrolyte mass to the battery design capacity.

10. The application according to claim 9, wherein The lithium battery includes a lithium-ion battery, a lithium metal battery, and a lithium-sulfur battery.

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