A delocalized lithium electrolyte and its preparation method and application

Abstract

The present invention discloses a delocalized lithium electrolyte that breaks through the limitations of traditional dominant solvent structures, as well as its preparation method and application. The delocalized electrolyte delocalizes its microscopic solvent structure by combining lithium salts and solvents with differentiated physicochemical properties, thereby forming a diversified solvent structure. The delocalized solvent structure not only enriches the microstructure of the electrolyte, but also significantly improves the overall electrolyte performance through performance complementarity, thereby effectively improving the charge and discharge efficiency and cycle life of the lithium battery. The use of this electrolyte can achieve lithium secondary batteries with a capacity of more than 600Wh / kg, which has significant engineering application value.

Description

Technical Field

[0001] The present invention belongs to the field of lithium batteries and energy storage technology, and relates to a lithium-based electrolyte, and specifically to a delocalized lithium-based electrolyte suitable for lithium batteries that breaks through the limitations of traditional dominant solvent structures, as well as a preparation method and application thereof. Background Art

[0002] As a key component of current energy storage technology, lithium batteries have been widely used in 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 technology. However, with the increasing demand for higher energy density and longer service life, traditional electrolyte design schemes have shown obvious limitations. Existing electrolyte systems generally 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 often determines the overall performance of the electrolyte. Common design approaches often focus on optimizing the selection of a single solvent or lithium salt, constructing a solvent architecture based on a single dominant solvent or lithium salt. However, this design approach often suffers from strong dependencies and is limited by the interaction between the solvent and the lithium salt, leading to performance bottlenecks at high voltages and high energy densities. As the energy density of lithium batteries continues to increase, the performance bottlenecks of traditional electrolyte systems at high voltages and high energy densities have become increasingly prominent. In particular, under extreme operating conditions, further optimization of electrolyte stability and lithium-ion conductivity is difficult. This also leads to rapid capacity decay and cycling degradation at high rates or high voltages, a major challenge facing current high-energy lithium batteries. For example, recent studies have shown that at high voltages (e.g., above 4.5V), conventional electrolytes are prone to decomposition or instability, leading to rapid capacity decay and even severe lithium plating in lithium metal batteries, thus compromising battery performance and safety (Advanced Energy Materials, vol. 10, no. 12, 2020). Furthermore, conventional electrolytes often lack stability under extreme temperature conditions, significantly shortening battery life. For example, studies have shown that in high-energy-density batteries, insufficient interaction between the electrolyte solvent and the lithium salt can lead to significant capacity degradation over extended periods of use, particularly at high temperatures or high voltages (Journal of Power Sources, vol. 439, 2019).

[0004] To address these challenges, recent research has attempted to improve electrolyte stability and ionic conductivity by optimizing the combination of solvents and lithium salts. However, traditional electrolyte design methods mostly focus on optimizing a single solvent or lithium salt, ignoring the potential synergistic effects between different components. For example, commonly used lithium salts such as LiPF6 and LiBF4 easily decompose under high voltage conditions, resulting in a sharp decline in electrolyte performance. While recent research on "high-stability" electrolytes has made some progress, most efforts are still limited to optimizing a single component, solvent or salt (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 overcome these bottlenecks, the present invention proposes an innovative "delocalized design" electrolyte. By introducing multiple lithium salts and solvents with complementary physicochemical properties, a complex and dynamic delocalized solvent structure is formed. This structure not only optimizes the electrolyte's microscopic solvent environment but also significantly improves its overall performance, enabling it to exhibit greater stability and longer cycle life in high-energy-density applications. This addresses the performance degradation problem of existing electrolyte systems under high voltage and extreme temperature conditions. Summary of the Invention

[0006] The present invention provides a delocalized lithium-based electrolyte, its preparation method, and applications. By incorporating multiple lithium salts and solvents with complementary physicochemical properties, this electrolyte overcomes the solvent-dominated limitations of traditional electrolyte design, forming a complex and dynamic delocalized solvent structure. This structure not only optimizes the electrolyte's microscopic solvent environment but also significantly enhances its overall performance, resulting in greater stability and longer cycle life in high-energy-density applications.

[0007] The purpose of the present invention is achieved through the following technical solutions:

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

[0009] Step 1: Collect at least three key physicochemical parameters related to lithium salts and solvents, and standardize these data to eliminate dimensional differences.

[0010] Step 2: Perform cluster analysis on these standardized data through an algorithm to classify lithium salts and solvents with similar physicochemical properties into different categories, where there are more than two categories.

[0011] Step 3: Define the required parameters and, through iterative adjustments, ultimately select the lithium salt and solvent combination that maximizes the complementary physicochemical properties.

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

[0013] The electrolyte of the present invention utilizes a variety of lithium salts and solvents with complementary physicochemical properties to enrich its microscopic solvent structure to a delocalized state. This delocalized lithium-based electrolyte contains at least 10 different solvation structures, with volumes ranging from 0.1 to 50 nm³. The diameters of electrolyte microclusters range from 0.5 to 100 nm.

[0014] As one embodiment of the present invention, cluster analysis is used to optimize the selection of lithium salts and solvents. Clustering indicators include, but are not limited to, physicochemical 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 the lithium salt and solvent.

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

[0016] As an embodiment of the present invention, the required parameters include two or more of the following: lithium ion binding energy, electrolyte operating temperature range, lithium salt species type, solvent species type, and lithium salt solubility type. In some implementation examples, the lithium ion binding energy range is limited to -12~-5 eV, the operating temperature range is -80~120℃, the lithium salt species are 5 types, the solvent species are 5 types, and the lithium salt solubility is greater than 0.5 mol / L. In other implementation examples, the lithium ion binding energy is limited to less than 6 eV, the operating temperature range is -60~150℃, the lithium salt species are 5 types, the solvent species are 5 types, and the lithium salt solubility is greater than 0.5 mol / L.

[0017] As one 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 0.5~5 mol / L; the types of the lithium salt are no less than 4, and the mass of each lithium salt accounts for more than 5% of the total mass of the lithium salt; the types of the solvent are no 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 allow the lithium metal battery to cycle through the entire cycle without a sudden capacity drop until the ramp decays to below 10% capacity.

[0019] The amount of the lithium electrolyte added is not more than 5 g / Ah based on the ratio of electrolyte mass to design capacity.

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

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

[0022] As one embodiment of the present invention, the electrolyte is prepared according to a formula using a gradual 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 through a temperature-controlled solvation process within 1 minute, thereby achieving a delocalized solvation structure.

[0023] As one embodiment of the present invention, the lithium salt is added gradually; 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 (about 50-200 degrees Celsius); when the melting point of the lithium salt is low, the temperature is lowered to a set low temperature range (about 0-40 degrees Celsius); each time a new lithium salt is added, the temperature of the mixed mixture is changed within 1 minute through temperature-controlled solvation.

[0024] In one embodiment of the present invention, the dissolution process utilizes magnetic stirring and / or ultrasonic oscillation within a temperature range of 0-100°C to ensure uniform dissolution of the lithium salt in the solvent. The stirring time during the dissolution process is determined to prevent a cascade reaction between the selected lithium salt and the solvent, while also preventing precipitation due to excessive heat of dissolution. The total stirring time is controlled to 2-4 hours to ensure sufficient reaction between the lithium salt and the solvent.

[0025] In some implementation examples, the method for preparing the delocalized lithium-based electrolyte includes the following steps:

[0026] Step 1: selecting at least four lithium salts according to the algorithm of the present invention, wherein the molar mass of each lithium salt accounts for more than 5% of the total molar mass of the lithium salts;

[0027] Step 2: selecting at least four solvents according to the algorithm of the present invention, wherein the volume of each solvent accounts for more than 5% of the total volume of the solvent;

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

[0029] Step 4: Mix the optimized and screened lithium salt and solvent. Each time a new lithium salt is added, the temperature of the mixture is changed within 1 minute through temperature-controlled solvation. Mix the optimized and screened lithium salt and solvent. Each time a new lithium salt is added, the temperature of the mixture is changed 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 high, the temperature is raised to a temperature close to below the melting point to promote the solvation process; when the melting point of the lithium salt is low, the temperature is lowered to a set low temperature range to ensure that the solvation reaction is carried out under appropriate temperature conditions. This temperature control method can effectively promote the interaction between the solvent and the lithium salt, optimize the solvation structure, and further improve the performance and stability of the electrolyte.

[0030] As an embodiment of the present invention, the lithium salt according to step 1 is in 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), 1,1,2,2,3,3-hexafluoropropylene-1,3-disulfonyl imide lithium (C3F6LiNO4S2), lithium bis(pentafluoroethylenesulfonyl) imide (C4F10LiNO4S2), lithium bis(trifluoromethylsulfonyl) imide (LiTFSI), lithium nonafluoro-1-butenesulfonate (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 hydrogen monophosphate (LiH2PO4), lithium O-phospho-L-homoserine (C4H10NO6P), lithium sulfite (Li2SO3), Lithium acrylate (C3H3LiO2), lithium DL-lactic acid (C3H5O3Li), lithium L-lactic acid (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), (R)-Mevalonate lithium salt (C6H11LiO4), benzoate lithium salt (C7H5LiO2), tartrate lithium salt (C4H4Li2O6), oxalate lithium salt (C2O4Li2), monolithium 4-methoxypyridine-3-borate (C6H13BLiNO6), propofol-β-D-glucuronide lithium salt (C18H25LiO7),Clavulanate lithium salt (C8H8LiNO5), p-toluenesulfonyl imide lithium salt (CH3C6H4SO2Li), salicylate lithium salt (C7H5LiO3), bis(nonafluorobutenesulfonyl)imide lithium salt (C8F18LiNO4S2), lithium tetraphenylborate tris(1,2-dimethoxyethylene) complex (C36H50BLiO6), lithium 3-morpholinepropionate (C7H12LiNO3), lithium acetylacetonate (C5H7LiO2), lithium 2,2,6,6-tetramethyl-3,5-heptenedionate (C11H19LiO2), cyclopentadienyl lithium (C5H5Li), ethylenediaminetetraacetic acid dilithium salt (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)imidazolium-1-sulfide (C6F3LiN4), lithium tetraphenylborate ethyl etherate (C24BF20Li), lithium metaborate (LiBO2), dilithium sulfopyruvate (C3H4Li2O6S), lithium 2-oxo-2-(tetrafluorophosphate) acetate (LiF4C2O4P), [1,2,4]triazolo[4,3-a]pyrazine-3-carboxylate lithium salt (C6H3LiN4O2), 5-sulfoisophthalic acid monolithium salt (C8H5LiO7S), Lithium acetate dihydrate (CH3COOLi), phenyllithium solution (C6H5Li), lithium iodate (LiIO3), 5-bromopyridine-2-carboxylic acid lithium salt (C6H3BrLiNO), dihydroxyacetone phosphate dilithium salt (C3H5Li2O6P), 3-fluoropyridine-2-carboxylic acid lithium salt (C6H3FLiNO2), DL-4-hydroxy-2-ketoglutarate dilithium salt (C5H4Li2O6), lithium acetoacetate (C4H5LiO3), adenosine 5′-O-thiomonophosphate dilithium salt (C10H12N5O6PSLi2), phenyl (2,4,6-trimethylphenyl) phosphate dilithium salt (C16H16LiO3P), 6-hydroxychlorothiol β-D-glucuronic acid lithium salt (C13H11ClLiO9), lithium trimethylsilanol (C3H9LiOSi), Lithium phosphate (Li3PO4), 5-methylpyridine-2-boronic acid monolithium salt (C6H7BLiNO2), Profluoxetine lithium salt (C24H31ClLiNO4S), bis(trimethylsilyl)amine lithium salt (C6H18LiNSi2), (8-quinolinolate) lithium salt (C9H6LiNO), 2-(2',At least four of the following are selected: 2''-bipyridyl-6'-yl)phenol lithium salt (C16H11LiN2O), methyllithium solution (CH3Li), isobutyllithium (C4H9Li), hexamethyllithium (C6H13Li), sec-butyllithium solution (C4H9Li), ethyllithium solution (CH3CH2Li), lithium sulfide (Li2S), tert-butyllithium (C4H9Li), lithium diisopropylamide (C6H14LiN), lithium dicyclohexylamide ((C6H11)2NLi), lithium diethylamide (C4H12LiN), and lithium dimethylamide (C2H6LiN).

[0031] As an embodiment of the present invention, the solvent is carbonic acid cyanamide (C2H2N2O), 3-oxyacrylonitrile (C3H3NO), 1-fluoro-2-(methylsulfonyl)benzene (FS) (C7H7FO2S), methylbenzenesulfonate (C7H8O3S), prop-1-ene-1,3-cyclic thiolactone (C3H4O3S), vinyl sulfinate (EVS) (C4H8O2S), N-cyanoformamide (C2H2N2O), 3-oxobutenenitrile (C4H5NO), 2-oxo-1,3-dioxene-4-cyano (C4H3NO3), methyl-2,2,2-trifluoroethyl carbonate (TFEMC) (C4H5F3O3), vinyl sulfinate (ES) (C2H4O3S), 2,2,2-trifluoroethyl methyl carbonate (FEMC) (C4H5F3O3), Propylene sulfinate (PS) (C3H6O3S), Ethyl difluoroacetate (EDFA) (C4H6F2O2), Fluoroacetonitrile (C2H2FN), Trifluoroacetamide (C2H2F3NO), Glycine nitrile (C2H3NO), Cyanoacetic acid (C3H3NO), 3-Cyanopropene-1-sulfonyl fluoride (CPSF) (C4H6FNO2S), Acrylonitrile (MAN) (C3H2N2), Chloromethylsulfonylmethane (C2H5ClO2S), Methanesulfonyl fluoride (FMS) (CH3FO2S), Pentanonitrile (GLN) (C5H6N2), 1,1,1-Trifluoro-2-methylsulfonylurea (FEMS) (C3H5F3O2S), Difluoroethylene carbonate (DFEC) (C3H2F2O3), methyl 2-cyano-2-methylpropionate (C6H9NO2), methyl 3,3,3-trifluoropropionate (TFPM) (C4H5F3O2), methyl (fluoromethyl)sulfinyl (C2H5FO2S), 3,3,3-trifluoroacrylonitrile (C3H2F3N), fluoroethylene carbonate (FEC) (C3H3FO3), difluoromalonate (ADN) (C6H8N2), trifluoromethylsulfonylethane (FMES) (C3H5F3O2S), phenoxyethanol (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-propene cyclic lactone (MESL) (C5H10O3S), propene sulfamate (SEN) (C10H16N2), 1-(fluoromethyl)-1,3-Fluoroisothiazolinone (FPC) (C4H5FO3), Bis(2,2,2-trifluoroethyl) carbonate (HFDEC) (C5H4F6O3), Bis(2,2,2-trifluoroethyl) ether (BTFE) (C4H4F6O), Sulfuronitrile (SUN) (C8H12N2), Acrylonitrile (ACN) (C2H3N), Dimethiconol (DMC) (C4H7N), Perfluorooctyl cyanide (PFPMC) (C5H5F5O3), Trimethylacrylonitrile (C5H9N), Pentenonitrile (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), 3,3,3-trifluoropropyl methyl carbonate (TrFPMC) (C5H7F3O3), 1,1,2,2-tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)propane (FEPE / TTE) (C5H4F8O), 4,4-difluoro-1,3-dioxolane (C4H6F2O2), Difluoro(dimethoxy)methane (C3H6F2O2), 2-oxo-1,3-dioxole-4-carboxylic acid (C4H4O5), Trifluoro(methoxymethoxy)methane (C3H5F3O2), 4-Trifluoromethyl-1,3-dioxolane-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-methylsulfonylethyl-2,2-difluoroacetate (MSPTFA) (C5H8F2O2S), methyl (methylsulfonyl) acetate (MMSA) (C4H8O4S), N,N-dimethylbenzamide (C9H11NO), ethyl methylsulfonyl acetate (EMSA) (C5H10O4S), Chloroethyl ketone (C3H5ClO), Methoxyethyl ketone (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), Diaminovalerolactone (DVL) (C5H8O2), Diethylsulfinate (DES) (C4H10O2S), Ethyl isobutylsulfinate (EiBS) (C6H14O2S), Dipropylsulfinate (DPS) (C6H14O2S), 3-Methoxysulfenane (MESL) (C5H10O3S), 4,5-Dimethyl-1,3-dioxolan-2-one (C5H6O3), 1-(Ethenylsulphinyl)-2-methoxyethane (EMES) (C5H12O3S), Urea (CH4N2O), Methyl-3,3-difluoropropionate (C4H6F2O2), 3-methylsulfinane (3MESL) (C5H10O2S), 1-methoxy-2(2-methoxyethanesulfonyl)ethane (DMES) (C6H14O4S), formic hydrazide (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-(propylene-2-sulfinyl)propane (IPiBS) (C7H16O2S), 2-(Propylene-2-sulfinyl)butane (IPSBS) (C7H16O2S), Isopropylmethylsulfinyl (MiPS) (C4H10O2S), Methylpropylsulfinyl (MPS) (C4H10O2S), Tetraethylenethione (TMS / Sulfolane) (C4H8O2S), 3-Isopropoxytetrahydrosulfane 1,1-dioxide (ISEL) (C7H14O3S), 3-Ethoxysulfinyl (EESL) (C6H12O3S), 3-(2-Methoxyethoxy)sulfane 1,1-dioxide (GLSL) (C7H14O4S), Methylglycinate (C3H7NO2), 3-Fluoropropionamide (C3H6FNO), Isobutyramide (C4H9NO), Propanamide (C3H7NO), Acetamide (C2H5NO), dimethyl methylphosphonate (DMMP) (C3H9PO3), butanamide (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), methylmethoxyacetate (MMOA) (C4H8O3), dimethylsulfenyl oxide (DMSO) (C2H6OS), dimethylformamide (DMF) (C3H7NO), 1-methylimidazole (C4H6N2), N,N-dimethylbutanamide (C9H11NO), diethylsulfenyl oxide (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-dioxan-2-amine (C4H9NO2), dimethoxymethane (DMM) (C3H8O2), Diisopropyl ether (C6H14O), Fluoromethoxy(methoxy)methane (C3H7FO2), Ethylenesulfamide (C2H5NS), 2-Pyrrolidinothione (C4H7NS), Dimethyl ketone (C3H6O), 3,4-Difluorofuran (C4H2F2O), 2-Butanone (methyl ethyl ketone) (C4H8O), 2,3-Difluorofuran (C4H2F2O), Methoxybenzene (C7H8O), 3-Fluorofuran (C4H3FO), Phenethoxymethane (C8H10O), Butylphenyl ether (C10H14O), Propoxybenzene (C9H12O), 2,4-Difluorofuran (C4H2F2O), Aminomethyl olefin (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-dioxolane (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-dioxolane (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-dioxane (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-dioxolane (C5H10O2), 1,2-dimethoxyethane (DME) (C4H10O2), dioxane (C4H8O2), aminoacetophenone (C3H7NO), 1,3-benzodioxan-2-one (C7H4O3), fluoroacetophenone (C3H5FO), pyridine (C5H5N), methylfluorosulfonylacetate (C3H5FO4S), methylfluorosulfonylacetate (MFSA) (C3H5FO4S), succinimide (C4H5NO2), benzylnitrile (benzonitrile) (C8H7N), 2-Fluorobutyryl lactone (FGBL) (C4H5FO2), N,N-dimethyltrifluoroacetamide (C4H6F3NO), vinyl acetate (C4H6O2), methyl cyanoacetate (MCA) (C4H5NO2), (methylsulfonyl)propyl acetate (MSPA) (C6H12O4S), aminoacetonitrile (C2H4N2), 1,1-Dioxythioxan-3-yl acetate (ACSL) (C6H10O4S), ethyl cyanoacetate (ECA) (C5H7NO2), 1,1,1-trifluoro-2-methylsulfonylpropane (FIMS) (C4H7F3O2S), 1,1-Dioxythioxan-3-yl acetate (ECSL) (C7H12O5S), 4-(methylsulfonyl)butyronitrile (MCPS) (C5H9NO2S), ethylene carbonate (VC) (C3H2O3), 2-methylglutaronitrile (C6H8N2), fluoromethylpropionate (C4H7FO2), isobutylene carbonate (C5H8O3), 4-hydroxy-1,3-dioxan-2-one (C3H4O4), methylpropyl carbonate (MPC) (C5H10O3), Methoxyacetonitrile (C3H5NO), 2-fluoroethyl methyl carbonate (MFEMC) (C4H7FO3), N-methoxyformamide (C2H5NO2), methyl formate (C2H4O2), ethyl-2-fluoropropionate (E2FP) (C5H9FO), dimethylsulfinyl (DMS) (C2H6O2S), {[(2-methylsulfonylethoxy) carbonate]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-methoxysulfonylethyl carbonate) (MSDEC) (C6H12O5S), 2-{[(3-methoxysulfonylpropenyl) carbonate]oxy}propane (MSPiPC) (C7H16SO5), ethyl methylsulfinyl (EMS) (C3H8O2S), 2-{[(2-methoxysulfonylethoxy) carbonate]oxy}propane (MSEiPC) (C7H14O5S), 1,4-butane sultone (C4H8O3S), 1,3-propene sultone (C3H6O3S), ethyl formate (C3H6O2), isobutyl formate (C5H10O2), ethyl fluoroacetate (EFA) (C4H7FO2), n-propyl formate (C4H8O2), Thiothioxane 1,1-dioxide (TriPS) (C3H6O2S), n-butyl formate (C5H10O2), 2-methylthiothioxane 1,1-dioxide (MTS) (C4H8O2S), Gamma-valerolactone (C5H8O2), isopropyl formate (C4H8O2),Methyl (2-methoxyethyl) sulfenyl (MEMS) (C4H10O3S), Propylene carbonate (PC) (C4H6O3), Methoxypropionitrile (C4H7NO), 2,3-Butene carbonate (C5H8O3), Ethylene carbonate (EC) (C3H4O3), 1,2-Butene carbonate (BC) (C5H8O3), Ammonium carbonate (CH3NO2), 2-Fluoroethyl propionate (2FEP) (C5H9FO2), Fluoromethyl methyl carbonate (MFDMC) (C3H5FO3), γ-Butyrolactone (GBL) (C4H6O2), Dimethylcarbamic fluoride (C3H6FNO), Formamide (CH3NO), Methyl-2,2,3,3-tetrafluoropropyl carbonate (TeFPMC) (C5H6F4O3), 3-Methoxypropionitrile (C4H7NO), 5-Fluoro-1,3-dioxolane (C4H7FO2), Methoxyformamide (Methyl carbamate) (C2H5NO2), Methyl isobutyrate (C5H10O2), 2-Hydroxyethyl methyl carbonate (C4H8O4), Butyl sultone (C8H18O3S), 2-Methoxyethyl acetate (C5H10O3), 5,5-Difluoro-1,3-dioxolane (C4H6F2O2), Isoamyl acetate (C7H14O2), Methyl acetate (MA) (C3H6O2), Isopropyl acetate (C5H10O2), Isobutyl acetate (C6H12O2), 1-Methoxy-2-propyl acetate (MPA) (C6H12O3), Methylpropionate (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 propylene-2-ethyl carbonate (EiPC) (C6H12O3), Diethyl carbonate (DEC) (C5H10O3), Methyl isopropyl carbonate (MiPC) (C5H10O3), ethyl methyl carbonate (EMC) (C4H8O3), dimethyl carbonate (DMC) (C3H6O3), 2-methoxy-1,Select at least four of the following: 3-dioxane (C5H10O3), ethylpropyl carbonate (EPC) (C6H12O3), 1,1-difluoro-2-(2-methoxyethoxy)ethane (DFEME) (C5H10F2O2), and bis(fluoromethyl) carbonate (DFDMC) (C3H4F2O3). (As in Examples 1 and 2, cluster analysis is performed on the above-listed lithium salts and solvents, and lithium salts and solvents with similar physicochemical properties are divided into different categories).

[0032] The present invention also provides the use of a delocalized lithium-based electrolyte in the preparation of a lithium battery. The lithium-based electrolyte is added in an amount not exceeding 5 g / Ah, based on the ratio of electrolyte mass to battery design capacity. The lithium batteries include lithium-ion batteries, lithium metal batteries, and lithium-sulfur batteries.

[0033] The principle of the present invention is achieved in the following ways:

[0034] First, lithium salts and solvents suitable for delocalized electrolyte design are selected. To this end, systematic computational and experimental methods are used to conduct detailed classification and cluster analysis of candidate solvents and lithium salts. Clustering methods include K-means clustering, hierarchical clustering, density-based clustering (such as DBSCAN), Gaussian mixture models (GMM), etc. Through these clustering methods, candidate substances can be divided into several groups based on the physicochemical properties of the solvent and lithium salt, such as polarity, solubility, ionization ability, stability, etc., to ensure that the combination of lithium salt and solvent forms an ideal delocalized solvation structure in the electrolyte, thereby optimizing the migration path of lithium ions and improving the overall performance of the battery. This process aims to ensure that the final electrolyte not only has high ionic conductivity and low battery internal resistance, but also has a wide electrochemical window to meet the needs of high-efficiency batteries. In the selection of lithium salts, their ionization ability and solubility are first considered. Lithium salts with strong ionization tendencies, such as lithium trifluoromethanesulfonyl trifluoride (LiTFSI), lithium hexafluorophosphate (LiPF6), and lithium difluorooxalatoborate (LiDFOB), are preferred. These salts have low conductivity limits, good solubility in solvents, and high chemical stability. However, while numerous studies have focused solely on these lithium salts, conventional wisdom suggests that none of them address the common issues of lithium metal batteries, such as poor cycle life and a narrow operating temperature range (20-30°C at room temperature). This is due to compatibility issues between the lithium salt and the solvent. Therefore, compatibility between the lithium salt and the solvent is a key selection criterion. An ideal lithium salt should form a stable solution with the selected solvent within a certain concentration range without side reactions or precipitation, thereby ensuring long-term electrolyte stability during battery operation. Solvent selection is primarily based on the solvent's polarity, chemical stability, and its effect on the lithium salt's solubility. Specifically, the solvent should have high polarity to better dissolve the lithium salt and support ion conduction. Furthermore, solvent stability is crucial for the long-term performance of the electrolyte, especially under high-voltage operation. To this end, fluorinated solvents such as fluoroethylene carbonate (FEC) and bisfluoroethylene carbonate (DFEC) are considered as the main candidate solvents. However, these two well-known solvents have good stability and low dissociation degree of lithium salts. In order to achieve a delocalized structure, it is necessary to use artificial intelligence to re-screen and match them, and re-screen the combination based on the three key indicators of the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and the lithium ion binding energy (Binding energy).

[0035] Secondly, a delocalized electrolyte is prepared by selecting at least four lithium salts, the mass of each lithium salt accounting for more than 5% of the total mass of the lithium salts, and selecting at least four solvents, the volume of each solvent accounting for more than 5% of the total volume of the solvents. The selection of lithium salts and solvents is carried out through cluster analysis to ensure that their respective physicochemical properties complement each other, 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 solubility for lithium salts, which play a synergistic role in the electrolyte to form a stable solvation structure. The preparation process utilizes a gradual dissolution process with precise temperature control to ensure the formation of an ideal delocalized solvation structure between the lithium salt and the solvent. Stirring should be avoided for extended periods of time, as this delocalized structure may collapse due to a cascade reaction between the selected lithium salt and solvent. For example, LiDFOB preferentially dissociates DFEC to form BF3, destroying the delocalized structure. Therefore, stirring similar species at high temperatures for extended periods of time is best avoided. First, the lithium salt and solvent are mixed in the desired ratio. Magnetic stirring and ultrasonic oscillation techniques are used to ensure uniform dissolution of the lithium salt in the solvent within a temperature range of 0-100°C, as some lithium salts are insoluble at low temperatures. The stirring time is controlled between 2-4 hours to ensure sufficient reaction between the lithium salt and the solvent and to avoid disrupting the overall delocalized structure. The temperature and stirring time of the dissolution process are precisely controlled, and precipitation caused by excessive heat of dissolution must be prevented to ensure the uniformity and stability of the solution.

[0036] Finally, in order 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, adjusting its concentration and solvation process, it is ensured that the non-coordination interaction between the solvent and the lithium salt molecules is gradually established. 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 traditional solvation structures, allowing lithium ions to migrate more freely in the electrolyte, thereby improving the conductivity of the electrolyte and the performance of the battery.

[0037] Finally, the prepared delocalized electrolyte was applied to a high-energy lithium battery system, and its performance in an actual battery environment was evaluated. Especially during long-cycle charge and discharge, it effectively inhibited the formation of lithium dendrites, maintained 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 significant beneficial effects:

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

[0040] 2) Extend the battery cycle life. The use of delocalized electrolyte can inhibit the formation of lithium dendrites during long-term charge and discharge, reduce the instability of lithium metal deposition, thereby improving the battery's cycle stability and service life, and making the battery's weekly charging volume expansion 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 wider electrochemical window and can operate stably in a high voltage range (such as 4.0 V to 6.5 V), significantly improving the energy density of the battery and being suitable for the development of high energy density batteries.

[0042] 4) Enhanced battery safety: Due to the unique solvation structure and low reactivity of the delocalized electrolyte, it can effectively inhibit solvent degradation and side reactions, improve the safety of the battery under extreme conditions such as high voltage and long-term cycling, and achieve full cycle of lithium metal batteries without a sudden drop in capacity, but gradually reduce 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 solvent and lithium salt according to different needs to adapt to different types of lithium batteries. It has good applicability and scalability and can meet the diverse needs of high-performance lithium batteries.

[0044] 6) This electrolyte is suitable for high-energy lithium batteries, effectively improving their charge-discharge efficiency, cycle stability, and safety. It demonstrates exceptional performance, particularly in pouch cell designs operating at high voltage and high energy density. Compared to conventional electrolytes, this electrolyte possesses broader applicability and offers groundbreaking applications in battery technology. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0046] Figure 1 The K-means cluster analysis results of the solvent in Example 1;

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

[0048] Figure 3The 1C charge-discharge cycle test of a 4.3V Ni90 / 4.6V LCO battery compares the cycling performance of button cells with different delocalized electrolytes.

[0049] Figure 4 Comparison of the cycling performance of 500Wh / kg soft-pack batteries with electrolytes of different delocalization levels;

[0050] Figure 5 Comparison of the cycling performance of 600Wh / kg soft-pack batteries with electrolytes of different delocalization degrees. DETAILED DESCRIPTION

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

[0052] Example 1

[0053] The K-means cluster analysis method was used to screen the samples according to the following steps.

[0054] Step 1: Collect key physicochemical parameters related to lithium salts and solvents, directly query them with the help of material databases (such as Materials Project, 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, such as the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and the lithium ion binding energy (Binding energy) as the three key indicators, and standardize these data to eliminate dimensional differences.

[0055] Step 2: Use the K-means clustering analysis algorithm to perform cluster analysis on the standardized data. First, the HOMO energy level, LUMO energy level and lithium ion binding energy data of lithium salts and solvents are collected and normalized to eliminate dimensional differences. Subsequently, the normalized data points are mapped 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, four cluster centers are first randomly initialized, and the Euclidean distances of all data points to these centers are calculated, and each data point is classified into the nearest cluster center. Subsequently, the mean of the data points in each category is calculated, and the cluster centers are iteratively updated until convergence. Finally, the K-means algorithm divides lithium salts and solvents into four categories based on the distribution pattern of data points in three-dimensional space, so that materials in the same category have similar characteristics in terms of HOMO, LUMO and lithium ion binding energy, and each category is represented by a sphere of a different color, such as Figure 1 shown.

[0056] Step 3: Limit the lithium ion binding energy range to -12~-5 eV, the operating temperature range to -80~120℃, the lithium salt species to 5 types, the solvent species to 5 types, and the lithium salt solubility to >0.5 mol / L. Through iterative adjustment, the lithium salt and solvent combination that can maximize the complementary physicochemical properties is finally selected as shown in Table 1.

[0057] Table 1 Electrolyte formula of Example 1

[0058]

[0059] The electrolytic formula described in Table 1 has a redox potential ≥ 6.0 V, a lithium ion binding energy of -7.38 eV, a melting point of -83 °C, and a boiling point of 136 °C.

[0060] Step 4: Mix the optimized and screened lithium salts with a solvent to prepare the electrolyte. The preparation process includes the following steps: First, the lithium salts are weighed according to the ratio and dissolved in the solvent, ensuring that the concentration of each lithium salt is 0.2 M and the uniformity of the solvent ratio is ensured; then, a method combining magnetic stirring and ultrasonic oscillation is used to stir the mixture at a temperature range of 0-70°C for 3 hours (including temperature change time) to ensure that the lithium salt is completely dissolved; during the dissolution process, the temperature is gradually adjusted, and a non-coordination interaction is formed between the solvent and the lithium salt through a temperature-controlled solvation process within 1 minute, thereby achieving a delocalized solvation structure. Specifically, FEC, FEMC, DFEC, 1FEMC, and DFEMC were first stirred at room temperature according to the proportions in Table 1 for 1 hour, then the temperature was raised to 100°C, and LiBO2 was added according to the formula in Table 1 and stirred for 1 minute to completely dissolve it; then the temperature was lowered to 80°C, and LiPO2F2 was added according to the formula in Table 1 and stirred for 1 minute to completely dissolve it; then the temperature was lowered to 65°C, and LiDFOB was added according to the formula in Table 1 and stirred for 1 minute to completely dissolve it; then the temperature was lowered to 40°C, and LiPF6 was added according to the formula in Table 1 and stirred for 1 minute to completely dissolve it; finally, the temperature was lowered to 25°C, C6F3LiN4 was added, and finally stirred for 1 minute to obtain a typical delocalized electrolyte.

[0061] Example 2

[0062] The K-means cluster analysis method was used to screen the samples according to the following steps.

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

[0064] Step 2: Perform cluster analysis on these standardized data using the K-means cluster analysis algorithm, and divide lithium salts and solvents with similar physicochemical properties into four categories (basically the same as step 2 in Example 1).

[0065] Step 3: Limit the lithium ion binding energy to less than 6 eV, the operating temperature range to -60~150°C, the lithium salt species to 5 types, the solvent species to 5 types, and the lithium salt solubility to more than 0.5 mol / L. Through iterative adjustment, select 5 lithium salt and 5 solvent combinations from the candidate lithium salts and solvents as shown in Table 2.

[0066] Table 2 Electrolyte formulations for Example 2

[0067]

[0068] The electrolytic formula described in Table 2 was measured to have an oxidation-reduction potential ≥5.5 V, a lithium ion binding energy of -6.77 eV, a melting point of -66 °C, and a boiling point of 216 °C.

[0069] Step 4: Mix the optimized and screened lithium salts with a solvent to prepare the electrolyte. The preparation process includes the following steps: First, the lithium salts are weighed according to the ratio and dissolved in an appropriate amount of solvent to ensure that the concentration of each lithium salt is 0.2 M and the uniformity of the solvent ratio is ensured; then, a method combining magnetic stirring and ultrasonic oscillation is used to stir the mixture at a temperature range of 25-100°C for 2 hours (including temperature change time) to ensure that the lithium salt is completely dissolved; during the dissolution process, the temperature is gradually adjusted to form a non-coordinating interaction between the solvent and the lithium salt within 1 minute through a temperature-controlled solvation process, thereby achieving a delocalized solvation structure. Specifically, first stir FEC, FEMC, DFEC, and 1FEMC at room temperature according to the proportion in Table 2 for 1 hour, then heat to 70°C, add LiOTf according to the formula in Table 2 and stir for 1 minute to completely dissolve it; then cool to 60°C, add LiBF4 according to the formula in Table 2 and stir for 1 minute to completely dissolve it; then cool to 0°C, add TTE solvent according to the formula in Table 2 and stir thoroughly for 1 hour, then maintain the temperature, add LiTFSI and stir for 1 minute to completely dissolve it; then heat to 50°C, add LiDFOB according to the formula in Table 2 and stir for 1 minute to completely dissolve it; finally cool to 25°C, add LiPF6 and stir for 1 minute to obtain a typical delocalized electrolyte. Figure 2 As shown in the figure, compared with the other two non-delocalized commercial electrolytes, namely commercial type 1: 1 mol / L LiPF6EC / EMC (1:1 volume ratio) and commercial type 2: 1 mol / L LiPF6FEC / FEMC (1:1 volume ratio), the delocalized electrolyte designed in this case shows the widest solvation structure range 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 to test lithium metal button cells. Figure 2 As shown. Using 4.3 V high nickel cathode Ni90 (LiNi 0.9 Co 0.05 Mn 0.05 O2) || lithium metal negative electrode (Li) and 4.6 V high voltage lithium cobalt oxide positive electrode LCO (LiCoO2) || Li button battery cycle performance test. In the 1C charge and discharge cycle test of 4.3V Ni90 battery, such as Figure 3As shown in Figure 2, the delocalized electrolyte exhibits excellent cycling stability, with a capacity retention rate of up to 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, Figure 3 As shown, the delocalized electrolyte exhibits a higher initial discharge capacity and maintains a capacity retention of 94.3% after 100 cycles, while the capacity retention 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 to test lithium metal soft pack batteries. The specific design parameters of the lithium metal soft pack batteries are shown in Tables 3 and 4.

[0074] Table 3 Design parameters of 500Wh / kg lithium metal soft pack battery for application example 2

[0075]

[0076] Table 4 Design parameters of 600Wh / kg lithium metal soft pack battery for application example 2

[0077]

[0078] like Figure 4 As shown, for 500Wh / kg-level lithium metal soft-pack batteries, a constant current charge and discharge test was performed at room temperature using a 0.2C rate charge and a 0.5C rate discharge. The test electrolytes were the delocalized electrolyte prepared in Example 2 and the commercial Type 1 non-delocalized electrolyte. The voltage range was 2.8 V to 4.3 V, and the discharge capacity and energy density after each cycle were recorded. The cycle was continued to 300 times to observe the capacity decay. 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 of up to 510.1 Wh / kg, and maintained an energy density of 404.1 Wh / kg after 150 cycles at a 0.5C rate, and no obvious capacity decay occurred after 300 cycles. This level of durability is unattainable by existing lean electrolyte lithium metal soft-pack batteries and meets the goals of the US Battery500 project.

[0079] like Figure 5As shown, for 600Wh / kg-level lithium metal soft-pack batteries, at room temperature, constant current charge and discharge tests were carried out using a 0.2C charge rate and a 0.25C discharge rate. The test electrolytes were the delocalized electrolyte prepared in Example 2 and the commercial Type 1 non-delocalized electrolyte. The voltage range was 2.8 V to 4.3 V, and the discharge capacity and energy density after each cycle were recorded. The 5.5 Ah lithium metal soft-pack battery using the delocalized electrolyte prepared in Example 2 also showed excellent performance, with an energy density of 604.2 Wh / kg. After 100 cycles, it still maintained an energy density of 517.7 Wh / kg, and no obvious polarization phenomenon was observed during the long cycle process, breaking the Battery600 milestone.

[0080] Comparative Example 1

[0081] The electrolyte of Example 1 in the authorized invention CN113782810B (including 71% main solvent (DMC, MMA), 26% fluorinated solvent (FEC, TFEB), 3% self-sacrificial inducer (AIBN, TTE) and 1.5 mol / L lithium salt (LATP, LiPF6)) was used to design a 7Ah-class soft-pack battery (calculated based on the theoretical value of 4.45V for the positive electrode). The battery cell was composed of commercial LCO as the positive electrode, metallic lithium as the negative electrode, and commercial celgard 2325 as the separator. The electrolyte was added in an E / C ratio of 1.2g / Ah. The assembled soft-pack battery was aged at 45°C for 24h and then vacuum-packaged to obtain a prototype battery. The prototype battery was charged to 4.45V at 0.1C, and the self-sacrificial charging voltage fluctuation curve appeared at 4.2V. The 0.1C discharge cut-off voltage was 3V. After 5 cycles, the actual discharge capacity of the soft-pack battery was 7.53Ah and the average specific energy was 433Wh / 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 soft-pack battery was 9.35Ah, the initial discharge specific energy was 539Wh / kg, and the discharge specific energy at the 100th cycle was 460.8Wh / kg.

[0082] Delocalized electrolytes enable batteries to operate stably and maintain a long service life under high energy density applications. Particularly noteworthy is the low injection volume of the delocalized electrolyte. In this test, the battery's electrolyte injection volume was controlled at 1.5 g / Ah. This low injection volume design not only effectively reduces the amount of electrolyte used, but also further optimizes the battery's overall energy density. The low injection volume can reduce the volume of the electrolyte 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, the battery's volume expansion was only 9.3% with the help of a thickness measuring instrument.

[0083] In summary, the present invention provides an innovative delocalized electrolyte design, which aims to break through the performance bottleneck of traditional electrolytes in lithium batteries, especially in terms of high energy density and long cycle stability. The delocalized electrolyte of the present invention delocalizes its microscopic solvent structure by combining lithium salts and solvents with differentiated physicochemical properties, thereby forming a diversified solvent structure. The delocalized solvent structure not only enriches the microstructure of the electrolyte, but also significantly improves the overall electrolyte performance through performance complementarity, thereby effectively improving the charge and discharge efficiency and cycle life of the lithium battery. More specifically, the present invention combines an artificial intelligence cluster analysis algorithm to accurately select a variety of lithium salts and solvents, adopts a lithium salt and solvent ratio with complementary physicochemical properties, optimizes the solvation structure, significantly improves the conductivity of lithium ions and the stability of the battery, and especially exhibits excellent performance in high voltage and high energy density applications.

[0084] The application of the delocalized electrolyte of the present invention in batteries has significant innovation and practicality. First, by precisely controlling the combination of the solvent and lithium salt of the electrolyte, the limitations of the traditional solvation structure are broken through, and a more free and dynamic solvation structure is formed, which not only improves the ionic conductivity of the battery, but also effectively inhibits the formation of lithium dendrites, thereby improving the safety and cycle stability of the battery. Secondly, the low 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.

[0085] 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 efficiency of lithium ion migration, and inhibiting the occurrence of side reactions, the electrolyte of the present invention significantly improves the energy density and service life of the battery, and promotes the further development of high-performance battery technology.

[0086] Therefore, the delocalized electrolyte of the present invention is not only innovative 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, and has broad market prospects and application value.

[0087] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A delocalized lithium electrolyte, characterized in that: The lithium-based electrolyte is composed of a lithium salt and a solvent, wherein the final concentration of the lithium salt is 0.5 to 5 mol / L; the types of the lithium salt are at least four, and the mass of each lithium salt accounts for more than 5% of the total mass of the lithium salt; the types of the solvent are at least four, and the volume of each solvent accounts for more than 5% of the total volume of the solvent; the electrolyte is derived by an artificial intelligence clustering analysis algorithm, and the clustering method includes 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 physicochemical parameters related to lithium salts and solvents and standardize these data to eliminate dimensional differences. S2. performing cluster analysis on the standardized data using an algorithm to classify lithium salts and solvents having similar physicochemical properties into different categories, where there are at least two categories; S3. Define required parameters and, through iterative adjustment, select a lithium salt and solvent combination that maximizes the complementary physicochemical properties; the defined required parameters include two or more of the following: lithium ion binding energy, electrolyte operating temperature range, lithium salt species type, solvent species type, and lithium salt solubility type; S4. Prepare the corresponding electrolyte according to the formula.

2. The delocalized lithium electrolyte according to claim 1, wherein Cluster analysis was used to optimize the screening of lithium salts and solvents. Clustering indicators included but were not limited to redox potential, lithium ion binding energy, melting point, and boiling point.

3. The delocalized lithium electrolyte according to claim 2, wherein Ensure that the redox potential of the selected lithium salt and solvent is ≥4 V, the lithium ion binding energy is selected in the range of -4~-10 eV, the melting point is selected in the range of -90~100 ℃, and the boiling point is selected in the range of 100~500 ℃.

4. The delocalized lithium electrolyte according to claim 1, wherein The electrolyte is prepared according to the formula using a gradual dissolution and precise temperature control process; during the dissolution process, the temperature is gradually adjusted, and a non-coordination interaction is formed between the solvent and the lithium salt through a temperature-controlled solvation process within 1 minute, achieving a delocalized solvation structure.

5. The delocalized lithium electrolyte according to claim 4, characterized in that Lithium salts are added gradually; temperature changes are 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 a set low temperature range; each time a new lithium salt is added, the temperature of the mixture is changed within 1 minute through temperature-controlled solvation.

6. The delocalized lithium electrolyte according to claim 4, characterized in that The dissolution process uses magnetic stirring and / or ultrasonic oscillation in the temperature range of 0~100°C to ensure that the lithium salt is uniformly dissolved in the solvent.

7. Use of the delocalized lithium electrolyte according to any one of claims 1 to 6 in the preparation of a lithium battery, characterized in that: The amount of lithium electrolyte added shall not exceed 5 g / Ah based on the ratio of electrolyte mass to battery design capacity.

8. The use according to claim 7, characterized in that The lithium batteries include lithium-ion batteries, lithium metal batteries and lithium-sulfur batteries.

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