Lithium metal battery and manufacturing method thereof, energy storage system and electric device

Abstract

The application provides a lithium metal battery and a manufacturing method thereof, an energy storage system and an electric device, at least beneficial to improving the performance of the lithium metal battery. The manufacturing method comprises the following steps: providing a positive electrode sheet, a negative electrode current collector and a separator; performing a winding treatment or a stacking treatment on the positive electrode sheet, the negative electrode current collector and the separator, and then placing the positive electrode sheet, the negative electrode current collector and the separator into a shell to form an initial battery cell; injecting a first electrolyte into the initial battery cell at a first temperature, wherein the first electrolyte comprises a lithium salt, lithium nitrate and an ether solvent; performing a first formation process on the initial battery cell; after the temperature of the initial battery cell is increased from the first temperature to a second temperature, injecting a second electrolyte into the initial battery cell, wherein the second electrolyte comprises a lithium salt, a silicon bridging compound, a fluorine-containing film-forming additive and a nitrile solvent, and the structural formula of the silicon bridging compound is as follows: performing a second formation process on the initial battery cell.

Description

Technical Field

[0001] This application relates to the field of lithium metal batteries, and in particular to a lithium metal battery and its manufacturing method, energy storage system and electrical equipment. Background Technology

[0002] With the rapid development of the global energy transition and the energy storage industry, higher demands are being placed on high-performance rechargeable batteries. Lithium metal anodes, due to their extremely high theoretical specific capacity (3860 mAh / g) and extremely low electrochemical potential (-3.04 V vs. standard hydrogen electrode), are considered ideal anode materials for breaking through the energy density bottleneck of existing rechargeable batteries and realizing next-generation high-energy-density batteries (>500 Wh / kg). To fully leverage the advantages of lithium metal anodes, they need to be combined with high-voltage cathode materials (operating voltage >4.5 V vs. Li / Li). + Matching them to maximize the battery's energy density.

[0003] However, the practical application of high-voltage lithium metal batteries faces a severe challenge stemming from the instability at the electrode / electrolyte interface. Summary of the Invention

[0004] This application provides a lithium metal battery, its manufacturing method, energy storage system, and electrical equipment, which at least helps to improve the performance of lithium metal batteries.

[0005] According to some embodiments of this application, one aspect of this application provides a method for manufacturing a lithium metal battery, comprising: providing a positive electrode sheet, a negative electrode current collector, and a separator; winding or stacking the positive electrode sheet, negative electrode current collector, and separator, and then placing them into a casing to form an initial battery cell, wherein the separator is located between the positive electrode sheet and the negative electrode current collector; injecting a first electrolyte into the initial battery cell at a first temperature, the first electrolyte comprising a lithium salt, lithium nitrate, and an ether solvent; performing a first formation process on the initial battery cell; and after raising the temperature of the initial battery cell from the first temperature to a second temperature, injecting a second electrolyte into the initial battery cell, the second electrolyte comprising a lithium salt, a silicon bridging compound, a fluorinated film-forming additive, and a nitrile solvent, wherein the structural formula of the silicon bridging compound is as follows:

[0006] R is one or more of -CH2CF3, -CH2CF2CF3, -CH2CF2CF2CF3, and -CH2CHF2; a second formation process is performed on the initial cell to form a lithium metal battery.

[0007] In some embodiments, the first temperature is 20°C to 30°C; the second temperature is 40°C to 50°C.

[0008] In some embodiments, the silicon bridging compound accounts for 5 wt% to 20 wt% of the mass of the second electrolyte, and the fluorinated film-forming additive accounts for 10 wt% to 30 wt% of the mass of the fluorinated film-forming additive.

[0009] In some embodiments, after injecting the second electrolyte into the initial cell, the cell is kept at a second temperature for 1 to 2 hours, and then cooled to room temperature at a rate of 0.5°C / min to 2°C / min.

[0010] In some embodiments, a second electrolyte is injected into the initial cell within 24 hours after the completion of the first formation process.

[0011] In some embodiments, the difference between the lithium salt concentration in the first electrolyte and the lithium salt concentration in the mixture of the first and second electrolytes does not exceed ±0.5 mol / L.

[0012] In some embodiments, the lithium salt concentration in the first electrolyte is 0.8 mol / L to 2.0 mol / L.

[0013] In some embodiments, the ether solvent in the first electrolyte includes short-chain ether solvents, long-chain ether solvents, and fluorinated ether solvents. The short-chain ether solvents have 6 or fewer carbon atoms, and the long-chain ether solvents have 6 or more carbon atoms but less than or equal to 10.

[0014] In some embodiments, short-chain ether solvents account for 40% to 80% of the total mass of ether solvents, long-chain ether solvents account for 10% to 40% of the total mass of ether solvents, and fluorinated ether solvents account for 0.01% to 30% of the total mass of ether solvents.

[0015] In some embodiments, short-chain ether solvents are selected from one or more of 1,2-dimethoxyethane, 1,3-dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; long-chain ether solvents are selected from one or more of triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and polyethylene glycol dimethyl ether; and fluorinated ether solvents are selected from one or more of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, bis(2,2,2-trifluoroethyl) ether, and 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether.

[0016] In some embodiments, the second electrolyte further includes a fluorinated carbonate solvent, wherein the mass ratio of the nitrile solvent to the fluorinated carbonate solvent is 70:30 to 90:10.

[0017] In some embodiments, the nitrile solvent is selected from one or more of succinic acid, adiponitrile, glutaronitrile, heptaonitrile, octanoic acid, benzonitrile, and phthalonitrile; the fluorinated carbonate solvent is selected from one or more of fluoroethylene carbonate, difluoroethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate.

[0018] According to some embodiments of this application, another aspect of this application provides a lithium metal battery, which is prepared using the manufacturing method of the lithium metal battery in the above embodiments.

[0019] According to some embodiments of this application, another aspect of this application also provides an energy storage system, including the lithium metal battery in the above embodiments.

[0020] According to some embodiments of this application, in another aspect of this application, an electrical device is provided, the electrical device including a load and the lithium metal battery in the above embodiments; or, the electrical device including a load and the energy storage system in the above embodiments.

[0021] The technical solution provided in this application has at least the following advantages:

[0022] The lithium metal battery manufacturing method provided in this application lies in the synergistic application of a silicon-bridged fluoroether nitrile compound and a temperature-controlled staged electrolyte injection technology. This combines the temperature response characteristics of molecular design with the timing optimization of process control, achieving dynamic adaptive adjustment of electrolyte performance. Compared to the "one-size-fits-all" strategy of existing technologies, this application adopts a progressive interface construction scheme of "basic film formation → temperature-controlled activation → synergistic enhancement." In the first stage, a first electrolyte containing lithium salt, lithium nitrate, and ether solvent is injected, and a first formation process is performed to construct a stable Li3N basic SEI layer. In the second stage, a second electrolyte containing lithium salt, silicon bridging compound, fluorinated film-forming additive, and nitrile solvent is introduced at high temperature, and a second formation process is performed. Through the synergistic reaction of the silicon bridging compound and the fluorinated film-forming additive, a high-ionic-conductivity Li2SiF6 or a similar Li-Si-F composite interface phase is generated. This design avoids the mutual interference of functional components in traditional one-step electrolyte injection methods, achieving precise control of interface performance. The second stage, by introducing silicon bridging units, not only improves the thermal stability of the molecules (Si-O bond energy 452 kJ / mol), but more importantly, endows the silicon-bridged compounds with unique temperature response characteristics. At room temperature, the silicon-bridged molecules maintain a stable conformation; at high temperatures, the Si-O bond rotational energy barrier decreases, promoting the release of functional CF3 groups and their synergistic reaction with fluorinated film-forming additives. This temperature-triggered mechanism perfectly matches the staged liquid injection process, enabling key functional components to function at the most appropriate time. Through this dual innovation of molecules and processes, a systematic solution is provided for the stable operation of high-voltage lithium metal batteries over a wide temperature range.

[0023] The lithium metal batteries provided in this application can be widely used in lithium metal battery fields requiring high energy density and long cycle life, including high-end electric vehicle battery systems, portable electronic devices, and large-scale energy storage power stations. Lithium metal batteries are expected to overcome existing bottlenecks, achieving comprehensive improvements in energy density, cycle life, and safety performance, enabling high-capacity lithium metal batteries suitable for long-term energy storage applications, such as energy storage systems that can operate continuously for 4 to 8 hours at rated power. This provides key technological support for the development of next-generation high-performance electrochemical energy storage systems. Attached Figure Description

[0024] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A flowchart corresponding to the manufacturing method of the lithium metal battery provided in the embodiments of this application. Detailed Implementation

[0026] As the background technology shows, the practical application of high-voltage lithium metal batteries faces a severe challenge stemming from the instability of the electrode / electrolyte interface.

[0027] Under high temperature and high voltage conditions, traditional electrolyte systems exhibit multiple problems: the electrolyte undergoes severe oxidative decomposition at the high-potential positive electrode surface, generating a large amount of gas and damaging the positive electrode structure; the high reactivity of the lithium metal negative electrode leads to uncontrollable dendrite growth and continuous interfacial side reactions; and temperature-induced fluctuations in interfacial performance severely affect battery reliability. Especially in the wide temperature range of practical applications (-20℃ to 60℃), the electrolyte needs to simultaneously meet multiple requirements, including low-temperature ion transport, stable cycling at room temperature, and safe operation at high temperatures.

[0028] While commonly used fluoroether nitrile additives improve the high-voltage stability of electrolytes to some extent, their molecular structures often employ direct CO linkages, which are prone to bond breakage at high temperatures, leading to functional failure. Furthermore, traditional single-filling processes introduce all electrolyte components simultaneously, making it difficult to optimize functionality at different temperature stages and lacking dynamic response capabilities to changes in battery operating states. Therefore, developing novel electrolyte systems with temperature-responsive characteristics, stable operation over a wide temperature range, and performance optimization through process control has become crucial for advancing high-voltage lithium metal battery technology.

[0029] High-voltage lithium metal battery electrolyte technology typically employs a variety of strategies to improve performance.

[0030] Regarding solvent systems, ether solvents are widely used due to their good compatibility with lithium metal. For example, a mixture of 1,3-dioxolane (DOL) and 1,2-dimethoxyethane (DME) can form a relatively stable SEI film (solid electrolyte interface film) on the lithium metal surface. However, the oxidation potential of ether solvents is typically below 4.0 V, limiting their application in high-voltage systems. To address this, researchers have developed nitrile solvents (such as butadionitrile and adiponitrile) and fluorinated solvent systems. These solvents have a wider electrochemical window, but their reduction stability and film formation quality on the lithium metal anode still need improvement.

[0031] In terms of additive technology, fluoroethylene carbonate (FEC), as a classic film-forming additive, can preferentially reduce and form a LiF-rich protective layer on the electrode surface. The typical structure of fluoroether nitrile compounds is a benzene ring directly linked to a fluoroalkoxy group and a nitrile group, such as 4,5-dicyano-1,2-bis(2,2,2-trifluoroethoxy)benzene. These compounds function through a triple mechanism: the phthalonitrile core provides strong electron-withdrawing properties to ensure high voltage stability; the fluoroalkoxy group generates LiF during reduction, improving interfacial stability; and the ether oxygen atom promotes lithium salt dissociation through coordination.

[0032] In terms of process technology, traditional battery manufacturing employs a single-stage electrolyte injection method, injecting all electrolyte components into the battery simultaneously. In recent years, some studies have explored multiple-stage injection or step-by-step formation processes, but these mainly focus on improving electrolyte wetting or optimizing initial SEI film formation, with less attention paid to temperature-responsive functional timing modulation. Some studies have reported high-concentration electrolyte (lithium-ion concentration > 3 mol / L) strategies, which improve the oxidative stability of ether solvents by altering the solvation structure; however, this approach leads to problems such as increased viscosity, higher costs, and deterioration in low-temperature performance.

[0033] Fluoroether nitrile electrolyte technology has several limitations in practical applications. First, the traditional direct substitution structure of the benzene ring has a fundamental defect in terms of thermal stability. The CO bond energy is only 358 kJ / mol, which is prone to breakage under high temperature conditions (>50℃), leading to the loss of the fluoroalkoxy side chain. This not only reduces the functionality of the compound but may also produce harmful byproducts such as hydrofluoric acid, seriously affecting the safety and cycle life of the battery. Second, these compounds lack temperature response characteristics. Their molecular conformation is basically fixed at different temperatures, and they cannot adaptively adjust according to changes in the battery's operating state. They are insufficiently active at low temperatures and may overreact at high temperatures.

[0034] More importantly, the relevant technologies lack effective dynamic control mechanisms. Traditional single-filling processes introduce all electrolyte components simultaneously, causing various functional additives to compete for reaction under the same conditions, making it difficult to achieve optimal performance at the most suitable time. For example, additives designed to form a high-voltage stable interface may react with lithium metal and be consumed in the early stages, while components that need to function later cannot be replenished in time. In addition, the interfacial film formed by commonly used additives has a relatively simple composition, mainly relying on LiF deposition. Although LiF has good chemical stability, its ionic conductivity is extremely low (~10). -8 S / cm has become a bottleneck limiting the rate performance of batteries.

[0035] At the process application level, related technologies lack systematic solutions for optimizing interface performance at different temperature stages. Batteries experience temperature variations during actual use, but traditional electrolyte formulations are static systems designed for specific temperatures and cannot adapt to dynamically changing operating environments. While high-concentration electrolytes can broaden the electrochemical window to some extent, their high viscosity severely affects ion transport and electrode wetting, especially leading to a sharp deterioration in performance at low temperatures. These combined issues make it difficult for high-voltage lithium metal batteries to maintain stable performance over the wide temperature range required for practical applications.

[0036] This application provides a lithium metal battery and its manufacturing method, energy storage system, and electrical equipment, which at least helps to improve the performance of lithium metal batteries.

[0037] In the description of the embodiments of this application, the technical terms "first", "second", etc. are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0038] In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0039] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0040] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0041] Figure 1 A flowchart corresponding to the manufacturing method of the lithium metal battery provided in the embodiments of this application.

[0042] refer to Figure 1 According to some embodiments of this application, one aspect of this application provides a method for manufacturing a lithium metal battery, including:

[0043] S101 provides positive electrode plates, negative electrode current collectors, and separators;

[0044] S102. After the positive electrode sheet, negative electrode current collector and separator are wound or stacked, they are placed into the housing to form the initial cell. The separator is located between the positive electrode sheet and the negative electrode current collector.

[0045] S103. Inject a first electrolyte into the initial cell at a first temperature. The first electrolyte includes lithium salt, lithium nitrate and ether solvent.

[0046] S104. Perform the first formation process on the initial battery cell;

[0047] S105. After raising the temperature of the initial battery cell from the first temperature to the second temperature, a second electrolyte is injected into the initial battery cell. The second electrolyte includes lithium salt, silicon bridging compound, fluorinated film-forming additive, and nitrile solvent. The structural formula of the silicon bridging compound is as follows:

[0048] Wherein, R is one or more of —CH2CF3, —CH2CF2CF3, —CH2CF2CF2CF3, and —CH2CHF2;

[0049] S106. Perform a second formation process on the initial cell to form a lithium metal battery.

[0050] The lithium metal battery manufacturing method provided in this application lies in the synergistic application of a silicon-bridged fluoroether nitrile compound and a temperature-controlled staged electrolyte injection technology. This combines the temperature response characteristics of molecular design with the timing optimization of process control, achieving dynamic adaptive adjustment of electrolyte performance. Compared to the "one-size-fits-all" strategy of existing technologies, this application adopts a progressive interface construction scheme of "basic film formation → temperature-controlled activation → synergistic enhancement." In the first stage, a first electrolyte containing lithium salt, lithium nitrate, and ether solvent is injected, and a first formation process is performed to construct a stable Li3N basic SEI layer. In the second stage, a second electrolyte containing lithium salt, silicon bridging compound, fluorinated film-forming additive, and nitrile solvent is introduced at high temperature, and a second formation process is performed. Through the synergistic reaction of the silicon bridging compound and the fluorinated film-forming additive, a high-ionic-conductivity Li2SiF6 or a similar Li-Si-F composite interface phase is generated. This design avoids the mutual interference of functional components in traditional one-step electrolyte injection methods, achieving precise control of interface performance. The second stage, by introducing silicon bridging units, not only improves the thermal stability of the molecules (Si-O bond energy 452 kJ / mol), but more importantly, endows the silicon-bridged compounds with unique temperature response characteristics. At room temperature, the silicon-bridged molecules maintain a stable conformation; at high temperatures, the Si-O bond rotational energy barrier decreases, promoting the release of functional CF3 groups and their synergistic reaction with fluorinated film-forming additives. This temperature-triggered mechanism perfectly matches the staged liquid injection process, enabling key functional components to function at the most appropriate time. Through this dual innovation of molecules and processes, a systematic solution is provided for the stable operation of high-voltage lithium metal batteries over a wide temperature range.

[0051] In S101, the positive electrode sheet may include a positive current collector and a positive electrode material layer covering the surface of the positive current collector. The positive electrode material layer includes a positive electrode active material, a binder, and a conductive agent.

[0052] The positive current collector can be selected from conductive substrates suitable for high-voltage systems, such as aluminum foil or carbon-coated aluminum foil.

[0053] The formulation of the positive electrode material layer may include 85wt% to 98wt% of positive electrode active material, 2wt% to 10wt% of binder and 2wt% to 8wt% of conductive agent.

[0054] The positive electrode active material can be a high-voltage system with a working voltage greater than or equal to 4.3V, such as high-nickel ternary materials, high-voltage spinel materials, lithium manganese phosphate, or lithium-rich manganese-based materials.

[0055] Among them, high-nickel ternary materials such as LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), LiNi 0.6 Co0.2 Mn 0.2 O2 (NCM622), LiNi 0.8 Co 0.15 Al 0.05 O2 (NCA) and other compounds possess operating voltages of 4.3V~4.6V and high specific capacity, making them ideal cathode choices for high-voltage lithium metal batteries. High-voltage spinel LiNi... 0.5 Mn 1.5 O4 has an operating voltage of up to 4.7V, perfectly matching its high voltage stability. Lithium manganese iron phosphate, as an emerging high-voltage phosphate material, combines safety and high-voltage characteristics.

[0056] The adhesive may be selected from one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), or polyacrylic acid (PAA). The conductive agent may be selected from one or more of conductive carbon black, graphene, carbon nanotubes, or graphite.

[0057] The conductive agent can be selected from one or more of conductive carbon black, graphene, carbon nanotubes or graphite.

[0058] Negative electrode current collectors can take the form of pure lithium metal foil, surface-modified lithium metal, and composite lithium metal. Pure lithium metal negative electrodes typically use lithium foil with a thickness of 20μm to 200μm or ultra-thin lithium foil (5μm to 50μm), which helps to improve energy density and reduce dead lithium formation. Surface-modified lithium metal significantly improves interfacial stability by constructing artificial SEI films (such as inorganic protective layers of LiF, Li3N, and Al2O3 or organic protective layers of conductive polymers). Composite lithium metal, including lithium-carbon composite materials and three-dimensional porous lithium, can effectively reduce local current density and promote uniform deposition. Anode-free technology uses specially treated copper foil current collectors as lithium deposition substrates, and surface-modified copper foil (such as carbon-coated copper foil, lithiophilic coated copper foil), or other special materials can also be used.

[0059] Membranes can be made from a variety of materials, including polypropylene (PP), polyethylene (PE), PP / PE / PP three-layer composite membranes, ceramic-coated membranes, high-strength polymer membranes, and functionalized composite membranes. PP and PE porous membranes typically have a thickness of 12-25 micrometers and a porosity of 30%-50%, exhibiting good mechanical strength and chemical stability. Ceramic-coated membranes, with a coating of ceramic materials such as Al2O3, SiO2, and TiO2 (coating thickness 2-5 micrometers) onto a polyolefin-based membrane, improve high-temperature resistance (thermal shut-off temperature >160℃) and puncture resistance. High-strength polymer membranes (such as polyimide (PI), polyethylene terephthalate (PET), and aramid nanofiber membranes) possess excellent mechanical properties and high-temperature resistance. Functionalized composite membranes (such as membranes with solid electrolyte coatings or lithiophilic coatings) can further enhance lithium deposition stability.

[0060] In step S102, after the initial cell assembly is completed, a drying process and a helium insulation test may be included. The drying process involves vacuum baking the initial cells at 80°C to 120°C for 12 to 24 hours to remove residual moisture, ensuring the internal moisture content of the initial cells is below 20 ppm. A helium insulation test is then performed to confirm that the initial cells are well-sealed and have no leakage risk. The weight of the initial cells before electrolyte injection is recorded as a baseline for subsequent electrolyte injection volume control.

[0061] In S103, the first electrolyte comprises lithium salt, lithium nitrate, and ether solvents, aiming to construct a robust Li3N base layer and lay a stable interfacial foundation for subsequent high-voltage operation. The first electrolyte is mainly composed of ether solvents, with LiNO3 as a key film-forming additive. Utilizing the good wettability of ether solvents to lithium metal and the preferential reduction properties of LiNO3, nitrogen-containing inorganic components such as Li3N and Li2N2O2 are reduced on the lithium metal surface to construct a robust SEI base layer.

[0062] In the first electrolyte, the lithium salt includes, but is not limited to, one or more of lithium hexafluorophosphate (LiPF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium difluorooxalate borate (LiDFOB), lithium tetrafluoroborate (LiBF4), and lithium perchlorate (LiClO4). Optionally, a mixed lithium salt system of LiPF6 and LiFSI, or a mixed lithium salt system of LiPF6 and LiTFSI, or a mixed system of LiFSI and LiTFSI is used.

[0063] In the first electrolyte, the lithium salt concentration is 0.8 mol / L to 2.0 mol / L, for example, 0.8 mol / L to 1 mol / L, 1 mol / L to 1.2 mol / L, 1.2 mol / L to 1.3 mol / L, 1.3 mol / L to 1.5 mol / L, or 1.5 mol / L to 2 mol / L, avoiding the high viscosity, low conductivity, and cost problems of high-concentration electrolytes (>3 mol / L).

[0064] The content of lithium nitrate in the first electrolyte can be 0.5wt% to 5wt%, for example 0.5wt% to 1wt%, 1wt% to 1.5wt%, 1.5wt% to 2.5wt%, 2.5wt% to 3wt%, or 3wt% to 5wt%.

[0065] In some embodiments, the ether solvent in the first electrolyte includes short-chain ether solvents, long-chain ether solvents, and fluoroether solvents. The short-chain ether solvents have 6 or fewer carbon atoms, and the long-chain ether solvents have 6 or more carbon atoms but less than or equal to 10.

[0066] In some embodiments, short-chain ether solvents account for 40% to 80% of the total mass of ether solvents, long-chain ether solvents account for 10% to 40% of the total mass of ether solvents, and fluorinated ether solvents account for 0.01% to 30% of the total mass of ether solvents.

[0067] Among them, the short-chain ether solvent is selected from one or more of 1,2-dimethoxyethane (DME), 1,3-dioxolane (DOL), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether (DEGDME), and may be DME and / or DOL; the long-chain ether solvent is selected from one or more of triethylene glycol dimethyl ether (TEGDME), tetraethylene glycol dimethyl ether (TETRAGLYME), and polyethylene glycol dimethyl ether (average molecular weight 200~1000), and may be TEGDME; the fluorinated ether solvent is selected from one or more of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), bis(2,2,2-trifluoroethyl) ether (BTFE), and 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether.

[0068] The first electrolyte may also include other functional additives, including but not limited to one or more of the following: vinylene carbonate (VC), 1,3-propanesulfonyl lactone (PS), vinyl sulfate (ES), tris(trimethylsilane) phosphite (TMSPi), lithium difluorophosphate (LiPO2F2), tris(trimethylsilane) phosphate (TMSP), and methylene disulfonate (MMDS).

[0069] The content of functional additives in the first electrolyte is 0.5wt% to 3wt%, for example, it can be 0.5wt%, 1wt%, 1.2wt%, 1.5wt%, 1.8wt%, 2wt%, 2.3wt%, 2.6wt% or 3wt%.

[0070] The first electrolyte comprises 70wt% to 90wt% of the total electrolyte volume, for example, 70wt%, 75wt%, 80wt%, 85wt%, or 90wt%. The total electrolyte volume refers to the total mass of electrolyte required to be injected into the initial cell. Insufficient initial electrolyte volume may result in inadequate wetting of the initial cell, potentially leading to lithium plating after formation. Conversely, excessive initial electrolyte volume can lead to an overly high additive concentration in the second electrolyte injection, resulting in uneven additive concentration distribution within the initial cell.

[0071] During the injection of the first electrolyte, the first temperature is 20℃~30℃, for example, it can be 20℃, 22℃, 25℃, 28℃ or 30℃, to avoid the solvent evaporation caused by excessively high temperature or the fluidity being affected by excessively low temperature.

[0072] The injection rate of the first electrolyte is controlled at 0.1 mL / min to 0.5 mL / min, specifically 0.1 mL / min, 0.2 mL / min, 0.3 mL / min, 0.4 mL / min or 0.5 mL / min, to ensure sufficient wetting of the electrode.

[0073] In some embodiments, after the first electrolyte is injected, the initial battery cell is left to stand and soak at a first temperature for 6 to 24 hours, optionally 12 to 18 hours, so that the first electrolyte can fully penetrate into the electrode pores.

[0074] In S104, the current range of the first formation process is 0.01C to 0.2C, optionally 0.02C to 0.1C. A lower current rate avoids an excessively fast reaction rate that could lead to a porous SEI structure. The voltage window of the first formation process ranges from open-circuit voltage to 4.5V, optionally 2.8V to 4.5V. The first formation process may include multiple charge-discharge cycles, ranging from 1 to 10 cycles, optionally 3 to 4 cycles. The charging rate and voltage range during different charge-discharge cycles can be the same or different.

[0075] For example, the first formation process may include: (1) standing for 30 minutes to stabilize the voltage; (2) charging at a constant current of 0.02C to 3.0V to form an initial SEI film; (3) standing for 10 minutes to allow the voltage to relax; (4) charging at a constant current of 0.05C to 3.8V to continue growing the SEI film; (5) discharging at a constant current of 0.05C to 2.5V to stabilize the SEI film; (6) repeating steps (4) and (5) twice to optimize the SEI film.

[0076] The first formation process controls the initial state of charge (SOC) of the battery cell in steps. In the first step, the SOC of the initial battery cell needs to reach more than 50% to ensure that LiNO3 is fully decomposed. Overall, the SOC of the initial battery cell needs to be controlled to reach more than 85% to form a complete basic SEI layer.

[0077] In some embodiments, after the first formation process is completed, the initial cell is aged and left to stand at 25±5°C for 12 to 24 hours to further stabilize the initially formed Li3N base layer structure.

[0078] In S105, after the initial cell temperature is raised from a first temperature to a second temperature, a second electrolyte is injected into the initial cell. Precise temperature control activates the functional release of the silicon bridging compound. At the second temperature, the electrochemical reduction of the fluorinated film-forming additive (using FEC as an example) occurs: FEC + 2e⁻. - +2Li + →LiF + LiOCH2CHF + CO2; Under temperature-controlled conditions, the Si-O bond of the silicon-bridged compound is activated, releasing fluorine-containing groups and generating SiF. x Species. Synergistic reactions generate high ionic conductivity phases: SiF4 + 2LiF → Li2SiF6 or other Li-Si-F composite phases. The resulting Li2SiF6 or similar composite phases exhibit higher ionic conductivity than conventional LiF, potentially improving interfacial ion transport performance. Simultaneously, the polymer generated by the reduction of fluorine-containing film-forming additives provides flexible support, accommodating volume changes in lithium metal.

[0079] In some embodiments, a second electrolyte is injected into the initial cell within 24 hours after the completion of the first formation process. At this time, the Li3N base layer is sufficiently stable but still has active sites on its surface, which is beneficial for the anchoring of subsequent functional layers.

[0080] The second temperature is 40℃~50℃, or 43℃~47℃. At this temperature, the Si-O bond rotation energy barrier of the silicon-bridged compound is significantly reduced, which is beneficial to the release of CF3 groups and the synergistic reaction with fluorine-containing film-forming additives.

[0081] The heating rate for raising the initial cell temperature from the first temperature to the second temperature can be 1℃ / min to 3℃ / min, specifically 1℃ / min, 1.5℃ / min, 2℃ / min, 2.5℃ / min or 3℃ / min.

[0082] Silicon bridging compounds include one or more of the following compounds:

[0083] , , , .

[0084] In silicon-bridged compounds, silicon atoms are connected to the benzene ring via Si-C bonds, forming a stable bridging structure. The R group is connected to the silicon atom via Si-O bonds, with the Si-O bond energy reaching 452 kJ / mol, significantly higher than the 358 kJ / mol of a traditional CO bond. The two nitrile groups on the benzene ring provide a strong electron-withdrawing effect, enhancing the oxidative stability of the molecule. The methyl group on the silicon atom provides steric protection, preventing excessive reactions. This structural design allows silicon-bridged compounds to remain stable at room temperature while undergoing controlled conformational changes and functional release at high temperatures.

[0085] The purity of the silicon-bridged compound is ≥99%, and the moisture content is <50ppm.

[0086] In the second electrolyte, the mass percentage of the silicon bridging compound is 5wt% to 20wt%, for example, it can be 5wt%, 8wt%, 10wt%, 11wt%, 12wt%, 13wt%, 15wt%, 18wt%, or 20wt%.

[0087] Fluorinated film-forming additives may be selected from one or more of fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), trifluoroethylene carbonate (TFEC), fluoroethylene sulfate (FESE), tris(2,2,2-trifluoroethyl) phosphate (TTFP), and di(2,2,2-trifluoroethyl) carbonate (DTFEC), with FEC and / or DFEC being optional.

[0088] In the second electrolyte, the mass percentage of the fluorinated film-forming additive is 10wt% to 30wt%, for example, it can be 10wt%, 13wt%, 15wt%, 18wt%, 20wt%, 22wt%, 25wt%, 28wt%, or 30wt%.

[0089] The lithium salt in the second electrolyte can be selected from one or more of LiPF6, LiFSI, LiTFSI, LiDFOB, LiBF4, and LiClO4.

[0090] In some embodiments, the lithium salt system in the second electrolyte is the same as the lithium salt system in the first electrolyte to facilitate system compatibility and continuity of lithium-ion transport.

[0091] In some embodiments, the difference between the lithium salt concentration in the first electrolyte and the total lithium salt concentration in the mixture of the first and second electrolytes does not exceed ±0.5 mol / L, in order to ensure the compatibility of the system and the continuity of lithium-ion transport.

[0092] In the second electrolyte, the nitrile solvent, as a high-voltage solvent system, can be mixed with one or more selected from butadionitrile (SN), adiponitrile (ADN), glutaronitrile, heptacyanide, octanoic acid, benzonitrile, and phthalonitrile, with butadionitrile and / or adiponitrile being the most suitable.

[0093] In some embodiments, the second electrolyte may further include a fluorinated carbonate solvent, wherein the mass ratio of the nitrile solvent to the fluorinated carbonate solvent is 70:30 to 90:10, for example, it may be 70:30, 75:25, 80:20, 85:15 or 90:10.

[0094] Fluorinated carbonate solvents may be selected from one or more of fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC).

[0095] The second electrolyte may also include fluorinated ether diluents, such as 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) and bis(2,2,2-trifluoroethyl) ether (BTFE). The content of the fluorinated ether diluent in the second electrolyte is 5wt% to 15wt%, and can be selected as 8wt% to 12wt%.

[0096] The second electrolyte may also include functional additives, such as film-forming modifiers, flame retardants, and high-voltage stabilizers.

[0097] The film-forming modifiers include vinylene carbonate (VC), vinyl sulfate (ES), 1,3-propane sulpholactone (PS), and 1,4-butane sulpholactone (BS). The content of the film-forming modifiers in the second electrolyte is 0.01 wt% to 3 wt%.

[0098] Flame retardants include trimethyl phosphate (TMP), triphenyl phosphate (TPP), hexamethylphosphoric acid triamine (HMPA), and phosphazene compounds. The content of flame retardants in the second electrolyte is 0.01wt%~5wt%.

[0099] High-voltage stabilizers include tris(pentafluorophenyl)borane (TPFPB), lithium difluorodioxolane borate (LiDFBOP), and nitrile additives. The content of high-voltage stabilizers in the second electrolyte is 0.01wt%~2wt%.

[0100] In some embodiments, after injecting the second electrolyte into the initial cell, the cell is held at a second temperature for 1 to 2 hours, and then cooled to room temperature at a rate of 0.5°C / min to 2°C / min. During the holding process, the Si-O bonds of the silicon bridging compound are activated, releasing fluorine-containing groups. The fluorine-containing film-forming additive is electrochemically reduced to generate LiF, and a synergistic reaction is performed to generate Li2SiF6 or a similar Li-Si-F composite phase. After holding, the temperature is slowly lowered to avoid interfacial stress caused by rapid cooling.

[0101] In S106, the rate current of the second formation process is 0.2C~0.5C, and the upper limit voltage is 4.5V. The second formation process charges the cell to more than 85% SOC. The second formation process can include multiple charge-discharge cycles, with the number of charge-discharge cycles ranging from 1 to 5, and optionally from 2 to 3. The charging rate and voltage range in different charge-discharge cycles can be the same or different.

[0102] For example, the second formation process may include: (1) charging to 4.5V with a constant current of 0.2C; (2) discharging to 2.8V with a constant current of 0.2C; (3) repeating steps (1) and (1) twice to construct a complete Li2SiF6 or similar Li-Si-F composite interface phase, thereby completing all formation processes of the lithium metal battery.

[0103] In this embodiment, the example is that the temperature of the initial battery cell is raised from a first temperature to a second temperature before the second electrolyte is injected. In other embodiments, the second electrolyte can be injected into the initial battery cell first, and then the temperature of the initial battery cell can be gradually raised from the first temperature to the second temperature.

[0104] The lithium metal battery manufacturing method provided in this application embodiment is based on a temperature-controlled staged liquid injection process using fluoroether nitrile compounds with silicon bridging structures. It cleverly utilizes the temperature response characteristics of silicon bridging compounds and achieves the controllable construction of a layered composite SEI film of "Li3N base layer + Li2SiF6 functional enhancement layer" on the surface of the negative electrode current collector through staged functional additive injection and precise temperature control. This fundamentally solves the key problems of competitive reactions among components and premature consumption of high-voltage functional components in traditional one-time liquid injection processes.

[0105] The first stage involves injecting a first electrolyte containing lithium salt, lithium nitrate, and ether solvents, followed by a first formation process. This aims to construct a robust Li3N base layer, laying a stable interfacial foundation for subsequent high-voltage operation. The first electrolyte is primarily composed of an ether solvent system, with LiNO3 used as a key film-forming additive. Utilizing the excellent wettability of ether solvents to lithium metal and the preferential reduction properties of LiNO3, a Li3N-rich inorganic basic protective layer is formed on the lithium metal surface.

[0106] The second stage involves introducing a second electrolyte containing lithium salt, silicon bridging compound, fluorinated film-forming additive, and nitrile solvent at high temperature, followed by a second formation process. Through the synergistic reaction of the silicon bridging compound and the fluorinated film-forming additive, a high-ionic-conductivity Li₂SiF₆ or a similar Li-Si-F composite interface phase is generated. Compared to conventional techniques using direct CO bond connections (bond energy 358 kJ / mol), which are prone to breakage and failure at high temperatures, this application utilizes Si-O bond connections (bond energy 452 kJ / mol), which not only improves thermal stability but, more importantly, endows the molecules with temperature-responsive characteristics by utilizing the d orbitals of silicon atoms. At high temperatures, the rotational energy barrier of the Si-O bond decreases, enabling the controlled release of functional groups—a smart responsive function that traditional carbon-based structures cannot achieve. The synergistic mechanism of the silicon bridging compound and fluorinated film-forming additives such as FEC generates Li₂SiF₆ or a similar Li-Si-F composite phase, whose ionic conductivity is approximately two orders of magnitude higher than that of conventional LiF. This gradient interface structure of "Li3N mechanical support layer + Li2SiF6 ion conduction layer" solves the conflicting requirements of mechanical strength and ion transport.

[0107] The lithium metal battery manufacturing method provided in this application has good process and equipment compatibility and can be implemented on the basis of a conventional liquid filling production line by adding a temperature control module and a precision metering system. Although a temperature control step is added, the cycle life of the lithium metal battery can be extended through significant improvement in interface performance, resulting in excellent overall cost-effectiveness.

[0108] In terms of environmental protection and safety, the temperature-controlled activation of the silicon bridging compound avoids violent reactions at high temperatures, improving process safety. All solvents and additives used are low-toxicity materials, and the resulting Li2SiF6 interfacial phase is chemically stable, producing no harmful byproducts. The entire process meets green manufacturing requirements and has promising prospects for industrial application.

[0109] According to some embodiments of this application, another aspect of this application provides a lithium metal battery, which is prepared using the manufacturing method of the lithium metal battery in the above embodiments.

[0110] Lithium metal batteries can be classified into cylindrical batteries, prismatic batteries, and pouch batteries according to their battery type.

[0111] According to some embodiments of this application, another aspect of this application also provides an energy storage system, including the lithium metal battery in the above embodiments.

[0112] The energy storage system includes a battery pack, an energy management system (EMS), a battery management system (BMS), and an energy storage converter (PCS), wherein the battery pack includes multiple lithium metal batteries as described in the above embodiments.

[0113] According to some embodiments of this application, in another aspect of this application, an electrical device is provided, the electrical device including a load and the lithium metal battery in the above embodiments; or, the electrical device including a load and the energy storage system in the above embodiments.

[0114] Electrical equipment includes vehicles, household appliances, electric motors, medical equipment, scientific research instruments, and power grids.

[0115] The following are specific embodiments of this application.

[0116] The examples and comparative examples were prepared using the following methods:

[0117] (1) Provide positive electrode, negative current collector and separator.

[0118] The positive electrode comprises a 15μm aluminum foil current collector and a positive electrode slurry coated on the surface of the aluminum foil current collector. The positive electrode slurry is composed of NCM811 active material, Super P conductive agent, CNT (carbon nanotube) conductive agent, and PVDF binder in a mass ratio of 95:2:1:2, with an areal density of 18±0.5mg / cm³. 2 The compacted density is 3.2 g / cm³. 3 .

[0119] The negative electrode current collector is a high-purity lithium metal foil with a thickness of 50μm.

[0120] The diaphragm adopts a PP / PE / PP three-layer composite structure with a thickness of 20μm.

[0121] (2) The positive electrode, separator and negative current collector are stacked in sequence to form a stacked structure, and then heat-sealed with an aluminum-plastic film of 113μm. The assembled initial cell is dried in a vacuum oven at 80°C for 24 hours to remove moisture.

[0122] (3) Inject the first electrolyte into the initial cell at 25°C. The formulation of the first electrolyte is shown in Tables 1 and 2. The first electrolyte accounts for 85% of the total injected electrolyte. Let it stand at 25°C for 12 hours to ensure sufficient wetting.

[0123] (4) The initial cell is charged to 3.8V at a constant current of 0.05C, then charged to 4.5V at 0.1C, and then charged at a constant voltage until the current drops to 0.02C.

[0124] (5) Raise the temperature of the initial cell from 25°C to 40°C~50°C at a rate of 2°C / min, and inject the second electrolyte into the initial cell. The formula of the second electrolyte is shown in Table 1 and Table 2. The amount of the second electrolyte injected is 15% of the total amount injected. Maintain at 45°C for 2 hours.

[0125] (6) After slowly cooling to room temperature at a rate of 0.5℃ / min, charge and discharge at a constant current of 0.2C for 3 cycles, with a voltage range of 2.8V~4.5V.

[0126] It is important to note that when preparing the first electrolyte containing LiNO3, the solubility limit of LiNO3 in ether solvents must be considered. When the LiNO3 content reaches 2 wt%, the dissolution temperature needs to be appropriately increased (40℃~50℃) and thorough stirring is required to ensure complete dissolution of LiNO3 before cooling to room temperature for use. Simultaneously, the moisture content of the system should be strictly controlled to <20 ppm to avoid performance degradation caused by moisture absorption by LiNO3.

[0127] Table 1

[0128]

[0129] Table 2

[0130]

[0131] In this embodiment, silicon bridging compound 1 is... The preparation method is as follows:

[0132] Starting with 1,2-dibromo-4,5-dicyanobenzene, a lithium-halogen exchange reaction was carried out with n-butyllithium in anhydrous tetrahydrofuran solvent under nitrogen protection at -78°C to generate the intermediate 1,2-dilithium-4,5-dicyanobenzene. Subsequently, chloro(2,2,2-trifluoroethoxy)dimethylsilane was added, and the reaction was slowly heated to room temperature for 12 hours.

[0133] The specific preparation steps are as follows: In a 500 mL three-necked flask equipped with a mechanical stirrer and a nitrogen protection device, add 10.0 g (35.0 mmol) of 1,2-dibromo-4,5-dicyanobenzene and 200 mL of anhydrous tetrahydrofuran, stir to dissolve, and cool to -78 °C. Slowly add 30 mL (75.0 mmol) of a 2.5 M n-butyllithium solution in hexane, and after the addition is complete, stir at -78 °C for 2 hours. Then slowly add 13.5 g (76.5 mmol) of a tetrahydrofuran solution (approximately 50 mL), followed by slow heating to room temperature and continuing the reaction for 12 hours. After the reaction is complete, quench the reaction with saturated ammonium chloride solution, extract with ethyl acetate (3 × 100 mL), combine the organic phases, dry with anhydrous magnesium sulfate, filter, and remove the solvent by vacuum distillation. The crude product was separated by silica gel column chromatography (petroleum ether:ethyl acetate volume ratio = 10:1) to obtain 12.8 g of colorless oily product, with a yield of 79.2% and a purity ≥ 99.0%. Before use, it was dried in a vacuum drying oven at 60°C for 24 hours to remove adsorbed moisture and ensure that the moisture content was below 20 ppm.

[0134] In this embodiment, silicon bridging compound 2 is... The preparation method is as follows:

[0135] In a 500 mL three-necked flask equipped with a mechanical stirrer and nitrogen protection, 10.0 g (35.0 mmol) of 1,2-dibromo-4,5-dicyanobenzene and 200 mL of anhydrous tetrahydrofuran were added, stirred to dissolve, and cooled to -78 °C. 30 mL (75.0 mmol) of a 2.5 M n-butyllithium solution in hexane was slowly added dropwise, and the mixture was stirred at -78 °C for 2 hours after the addition was complete. Then, approximately 50 mL of a tetrahydrofuran solution containing 15.8 g (76.5 mmol) of chloro(2,2,3,3,3-pentafluoropropoxy)dimethylsilane was slowly added dropwise, and the mixture was slowly heated to room temperature and the reaction was continued for 14 hours. After the reaction was complete, a saturated ammonium chloride solution was added to quench the reaction, and the mixture was extracted with ethyl acetate (3 × 100 mL). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by vacuum distillation. The crude product was separated by silica gel column chromatography (petroleum ether:ethyl acetate volume ratio = 12:1) to obtain 14.6 g of a colorless oily product, with a yield of 76.5% and a purity ≥ 99.0%. Before use, it was dried in a vacuum drying oven at 60°C for 24 hours to ensure that the moisture content was below 20 ppm.

[0136] In this embodiment, silicon bridging compound 3 is... The preparation method is as follows:

[0137] In a 500 mL three-necked flask equipped with a mechanical stirrer and nitrogen protection, 10.0 g (35.0 mmol) of 1,2-dibromo-4,5-dicyanobenzene and 200 mL of anhydrous tetrahydrofuran were added, stirred to dissolve, and cooled to -78 °C. 30 mL (75.0 mmol) of a 2.5 M n-butyllithium solution in hexane was slowly added dropwise, and the mixture was stirred at -78 °C for 2 hours after the addition was complete. Then, approximately 50 mL of a tetrahydrofuran solution containing 18.1 g (76.5 mmol) of chloro(2,2,3,3,4,4,4-heptafluorobutoxy)dimethylsilane was slowly added dropwise, and the mixture was slowly heated to room temperature and the reaction was continued for 16 hours. After the reaction was complete, a saturated ammonium chloride solution was added to quench the reaction, and the mixture was extracted with ethyl acetate (3 × 100 mL). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by vacuum distillation. The crude product was separated by silica gel column chromatography (petroleum ether:ethyl acetate volume ratio = 15:1) to obtain 16.2 g of colorless oily product, with a yield of 73.8% and a purity of ≥99.0%. Before use, it was dried in a vacuum drying oven at 60°C for 24 hours to ensure that the moisture content was below 20 ppm.

[0138] In this embodiment, silicon bridging compound 4 is... The preparation method is as follows:

[0139] In a 500 mL three-necked flask equipped with a mechanical stirrer and a nitrogen-protected atmosphere, 10.0 g (35.0 mmol) of 1,2-dibromo-4,5-dicyanobenzene and 200 mL of anhydrous tetrahydrofuran were added, stirred to dissolve, and cooled to -78 °C. 30 mL (75.0 mmol) of a 2.5 M n-butyllithium solution in hexane was slowly added dropwise, and the mixture was stirred at -78 °C for 2 hours after the addition was complete. Then, approximately 50 mL of a tetrahydrofuran solution containing 11.9 g (76.5 mmol) of chloro(2,2-difluoroethoxy)dimethylsilane was slowly added dropwise, and the mixture was slowly heated to room temperature and the reaction continued for 12 hours. After the reaction was complete, a saturated ammonium chloride solution was added to quench the reaction, and the mixture was extracted with ethyl acetate (3 × 100 mL). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by vacuum distillation. The crude product was separated by silica gel column chromatography (petroleum ether:ethyl acetate volume ratio = 10:1) to obtain 11.5 g of colorless oily product, with a yield of 81.3% and a purity ≥ 99.0%. Before use, it was dried in a vacuum drying oven at 60°C for 24 hours to ensure that the moisture content was below 20 ppm.

[0140] The above-mentioned chloro(fluoroalkoxy)dimethylsilane can be derived from the corresponding fluoroalcohol and dimethyldichlorosilane under alkaline conditions using conventional organosilicon derivatization methods.

[0141] LiTFSI is lithium bis(trifluoromethanesulfonyl)imide, with the molecular formula C2F6LiNO4S2. It is a battery-grade reagent with a purity ≥99.0% and a moisture content <20ppm.

[0142] LiNO3 is lithium nitrate, a battery-grade reagent with a purity ≥99.5%. Before use, dry it in a 120℃ drying oven for 12 hours to ensure a moisture content <50ppm.

[0143] DME is 1,2-dimethoxyethane, with the molecular formula C4H. 10 O2, battery-grade reagent, moisture content <20ppm.

[0144] DOL is 1,3-dioxolane, with the molecular formula C3H6O2. It is a battery-grade reagent with a moisture content of <20ppm.

[0145] TEGDME is triethylene glycol dimethyl ether, with the molecular formula C8H. 18 O4, battery-grade reagent, moisture content <30ppm.

[0146] SN is succinate, molecular formula C4H4N2, battery-grade reagent, moisture content <50ppm.

[0147] ADN is adiponitrile, with the molecular formula C6H8N2. It is a battery-grade reagent with a moisture content of <50ppm.

[0148] FEC is fluoroethylene carbonate, with the molecular formula C3H3FO3. It is a battery-grade reagent with a purity of ≥99.0% and a moisture content of <50ppm.

[0149] DFEC is difluoroethylene carbonate, with the molecular formula C3H2F2O3. It is a battery-grade reagent with a purity ≥98.0% and a moisture content <50ppm.

[0150] BTFE is a bis(2,2,2-trifluoroethyl) ether with the molecular formula C4H4F6O. It is a battery-grade reagent with a purity ≥99.0% and a moisture content <30ppm.

[0151] VC is vinylene carbonate, molecular formula C3H2O3, battery-grade reagent, purity ≥99.0%, moisture content <50ppm.

[0152] The fluoroether nitrile compound is 4,5-dicyano-1,2-bis(2,2,2-trifluoroethoxy)benzene, with the molecular formula C5. 12 H6F6N2O2, purity ≥98.0%.

[0153] In Tables 1 and 2, all formulations were calculated using the internal addition method, where the actual solvent mass equals 100 minus the mass percentage of lithium salt and additives, multiplied by the percentage of each solvent in the total solvent. The numerical ratios of DME, DOL, TEGDME, SN, and ADN in the tables represent the mass ratio of each solvent. LiFSI is expressed as molar concentration (mol / L), while LiNO3, VC, FEC, BTFE, silicon bridging compounds, and fluoroether nitrile compounds are expressed as mass percentages (wt%). The content of these additives is calculated based on the total mass of the electrolyte at each stage. Comparative Examples 2 and 3 used a one-stage electrolyte injection method, meaning the first and second electrolytes were mixed and injected into the initial cell in a single step.

[0154] Electrolyte conductivity, electrolyte viscosity, 25°C cycle capacity retention, 45°C cycle capacity retention, and 60°C storage performance were tested on the above embodiments and comparative examples.

[0155] Electrolyte conductivity testing: The conductivity of the electrolyte was tested using a conductivity meter at three temperature conditions: -10℃, 25℃, and 45℃. The test sample was an electrolyte solution obtained by thoroughly mixing the first and second electrolytes under controlled temperature and injection ratios. Conductivity is an important parameter for measuring the ion conduction capacity of an electrolyte, usually expressed in millisiemens per centimeter (mS / cm). Higher conductivity indicates better ion conduction of the electrolyte, thereby improving the power performance and low-temperature performance of lithium metal batteries.

[0156] Electrolyte viscosity test: The dynamic viscosity of the electrolyte was measured using a viscometer at three temperatures: -10℃, 25℃, and 45℃. The test sample was an electrolyte solution obtained by thoroughly mixing the first and second electrolytes under controlled temperature conditions and injection ratios. Viscosity is a measure of the resistance to liquid flow, usually expressed in millipascals per second (mPa·s). The lower the viscosity, the better the fluidity of the electrolyte, which is beneficial for ion transport and battery wetting performance.

[0157] 25℃ Cyclic Capacity Retention Test: The following three cyclic test conditions were performed at 25℃:

[0158] (1) 0.5C / 0.5C@4.5V: Charge at a constant current of 0.5C to the upper limit voltage of 4.5V, then charge at a constant voltage to the current of 0.05C, and then discharge at a constant current of 0.5C to the lower limit voltage of 2.8V;

[0159] (2) 1C / 1C@4.5V: 1C constant current charging to the upper limit voltage of 4.5V, then constant voltage charging to the current of 0.05C, and then 1C constant current discharging to the lower limit voltage of 2.8V;

[0160] (3) 2C / 2C@4.5V: 2C constant current charging to the upper limit voltage of 4.5V, then constant voltage charging to the current of 0.05C, and then 2C constant current discharging to the lower limit voltage of 2.8V.

[0161] Record the discharge capacity at the 100th, 200th, and 500th cycles, with capacity retention rate = (Nth discharge capacity / First discharge capacity) × 100%; record the first-cycle coulombic efficiency = (First discharge capacity / First charge capacity) × 100%; and simultaneously test the battery internal resistance after the 100th, 200th, and 500th cycles, with internal resistance growth rate = (Nth cycle internal resistance value / Initial internal resistance value - 1) × 100%.

[0162] 45℃ Cyclic Capacity Retention Rate Test: At 45℃, the same three cyclic test conditions as the 25℃ Cyclic Capacity Retention Rate Test are performed, with the same test methods and recorded indicators.

[0163] 60℃ Storage Performance Test: At 25℃, charge at a constant current of 1C to the upper limit voltage of 4.5V, then charge at a constant voltage to a current of 0.05C, and then discharge at a constant current of 1C to the lower limit voltage of 2.8V. Record the discharge capacity as the initial capacity C1. Charge again at a constant current of 1C to the upper limit voltage of 4.5V, and then charge at a constant voltage to a current of 0.05C, ensuring the battery is at 100% SOC. Store the fully charged battery at 60℃ for 28 days, and calculate the capacity retention rate (%) = (discharge capacity after storage / initial capacity C1) × 100%. After storage, let it rest at room temperature for at least 2 hours, discharge at a constant current of 1C to the lower limit voltage of 2.8V, then charge at a constant current and constant voltage of 1C to the upper limit voltage of 4.5V at room temperature, cut off at 0.05C, and then discharge again at a constant current of 1C to the lower limit voltage of 2.8V. Record the recovered capacity C2, and calculate the capacity recovery rate (%) = (C2 / C1) × 100%.

[0164] The results of the electrolyte conductivity and viscosity tests are shown in Table 3. The results of the 25℃ cycle capacity retention test are shown in Table 4. The results of the 45℃ cycle capacity retention test are shown in Table 5. The results of the internal resistance growth rate test are shown in Table 6. The results of the 60℃ storage performance test are shown in Table 7.

[0165] Table 3

[0166]

[0167] Table 4

[0168]

[0169] Table 5

[0170]

[0171] Table 6

[0172]

[0173] Table 7

[0174]

[0175] The comprehensive performance test results show that Examples 1 and Examples 9 to 11, which utilize silicon-bridged fluoroether nitrile compounds, exhibit all-around performance advantages. Example 1 (R=-CH2CF3) retained 85.4% capacity after 500 cycles at 25°C and 2C rate; Example 9 (R=-CH2CF2CF3) retained 85.2% capacity after 500 cycles at 25°C and 2C rate; Example 10 (R=-CH2CF2CF2CF3) retained 84.5% capacity after 500 cycles at 25°C and 2C rate; and Example 11 (R=-CH2CHF2) retained 83.8% capacity after 500 cycles at 25°C and 2C rate. This fully demonstrates that the technical advantage of the Si-O bond (452 ​​kJ / mol) over the CO bond (358 kJ / mol) is not dependent on a specific R group and has universal applicability. Compared to Comparative Example 1, which does not contain the core additive silicon bridging compound, the capacity retention rate was 65.2% after 500 cycles at 25°C and 2C rate. This significant improvement directly verifies the core value of the silicon bridging compound.

[0176] First, the Si-O bond energy (452 ​​kJ / mol) is significantly higher than that of the traditional CO bond (358 kJ / mol). This 94 kJ / mol bond energy difference translates into superior chemical stability under high voltage and high temperature conditions. Second, the participation of silicon atoms' d orbitals gives the molecule unique temperature-responsive characteristics. At activation temperatures of 40℃~50℃, the rotational energy barrier of the Si-O bond decreases, promoting the controlled release of functional groups. Furthermore, the silicon-bridged structure can generate Li₂SiF₆ or similar Li-Si-F composite phases in interfacial reactions, with ionic conductivity approximately two orders of magnitude higher than that of traditional LiF, fundamentally improving the ion transport performance at the interface.

[0177] Comparative Example 2 (using a single-use injection) achieved a capacity retention of 76.8% under the same conditions, which, while better than Comparative Example 1, was still significantly lower than Example 1, demonstrating the importance of a staged process for fully utilizing the functionality of the silicon bridging compound. Comparative Example 5 (lacking temperature-controlled activation) achieved a capacity retention of 72.5%, proving the necessity of temperature-controlled activation in optimizing the interface formation process. More importantly, Comparative Example 6 (lacking FEC) achieved a capacity retention of only 69.9%, strongly demonstrating the strong synergistic effect between the silicon bridging compound and the fluorinated film-forming additive. This triple innovation of "molecular innovation + process optimization + synergistic design" is key to the breakthrough performance improvement achieved in the embodiments of this application.

[0178] The interfacial impedance evolution in Table 5 provides important clues for understanding the formation mechanism of the SEI film. At 25°C, the impedance growth rate of Example 1 after 500 cycles was only 45.5%, while that of Comparative Example 1 increased dramatically to 110.8%, indicating that impedance growth was effectively suppressed and the growth rate decreased by 58.9%. This significant difference clearly reflects the essential difference in stability between the two interfacial structures.

[0179] This excellent impedance stability is closely related to the formation of the Li2SiF6 functional layer. In the first stage, LiNO3 is reduced on the lithium metal surface to form a basic protective layer rich in Li3N, providing mechanical strength and chemical stability. In the second stage, under temperature-controlled conditions of 40℃~50℃, the silicon bridging compound reacts synergistically with FEC to generate a high ionic conductivity phase via the following pathway: FEC electrochemical reduction: FEC + 2e - +2Li + →LiF + LiOCH2CHF + CO2; Under temperature-controlled conditions, the Si-O bond of the silicon-bridged compound is activated, releasing fluorine-containing groups and generating SiF. x Species; concerted reaction to form a high ionic conductivity phase: SiF4 + 2LiF → Li2SiF6. The resulting gradient structure of "Li3N base layer + Li2SiF6 functional layer" possesses both mechanical strength and excellent ion transport performance. The crystal structure of Li2SiF6 contains three-dimensional Li... + The transport channel has an ionic conductivity of (~10) -6 The S / cm ratio is much higher than that of pure LiF (~10). -8 (S / cm), which is the fundamental reason why the interface impedance remains low.

[0180] The impedance growth rate of Comparative Example 5 (lacking temperature-controlled activation) was 80.2%, significantly higher than that of Example 1, confirming the crucial role of temperature-controlled activation in the formation of Li2SiF6. More importantly, the impedance growth rate of Comparative Example 6 (lacking FEC) reached as high as 95.4%, a result that strongly demonstrates that the synergistic effect of FEC and silicon bridging compounds is a necessary condition for the formation of a high-quality Li2SiF6 interface layer.

[0181] Regarding the optimization of silicon bridging compound concentration, the capacity retention rates at 25°C, 2C, and 500 cycles in Examples 4, 5, 1, and 6 were 78.3%, 85.1%, 85.4%, and 82.6%, respectively, exhibiting a typical "volcano-shaped" optimization curve. As the concentration increased, the capacity retention rate improved by 7.1 percentage points; however, further increases resulted in a performance decrease of 2.8 percentage points. This trend indicates that too low a concentration is insufficient to form a complete Li2SiF6 protective layer, while too high a concentration may lead to an excessively thick SEI film or unnecessary side reactions.

[0182] The capacity retention rates of Comparative Example 5 (25℃, no temperature-controlled activation), Example 2 (40℃ activation), Example 1 (45℃ activation), and Example 3 (50℃ activation) were 72.5%, 84.1%, 85.4%, and 84.8%, respectively, clearly showing that 45℃ is the optimal activation temperature. From 25℃ to 45℃, the performance improved by 12.9 percentage points, but from 45℃ to 50℃, the performance slightly decreased. Combining theoretical calculations and experimental observations, 45℃ corresponds precisely to the range where the Si-O bond rotation energy barrier is significantly reduced while the molecular framework remains stable. Below 40℃, the silicon-bridged compound is not sufficiently activated, resulting in limited Li2SiF6 formation; above 50℃, excessive reactions may occur, destroying the already formed ordered interface structure.

[0183] Example 7 used DFEC instead of FEC, while Example 8 used a 1:1 mixture of FEC and DFEC. As shown in Table 3, the capacity retention rates of these two sets of experiments after 25°C, 2C, and 500 cycles reached 85.2% and 85.3%, respectively, which are highly consistent with the performance of Example 1 (85.4%) using pure FEC. This fully demonstrates the excellent universality of the technical solutions of this application, and its synergistic mechanism is not limited to a single fluorinated additive, but can effectively cooperate with a variety of mainstream fluorinated additives (such as FEC, DFEC, and their combinations) to jointly construct a high-performance interfacial protective layer. This broad compatibility greatly expands the application potential of the embodiments of this application in different electrolyte formulation systems.

[0184] Of particular note is the good consistency in the physical properties of the electrolytes in Table 2. The conductivity at 25°C for Examples 1-8 ranges from 8.10 mS / cm to 8.20 mS / cm, and the viscosity ranges from 3.81 mPa·s to 3.88 mPa·s. This indicates that the staged process and the selection of different fluorinated additives in the embodiments of this application do not adversely affect the basic physical properties of the electrolytes, demonstrating good process compatibility.

[0185] Table 6 shows the high-temperature storage test results, which fully demonstrate the thermal stability advantage of the silicon-bridged structure. Under the harsh condition of 28 days of storage at 60°C, Example 1 retained 90.5% of its capacity, while Comparative Example 1 retained only 75.3%, representing a 20.2% improvement in capacity retention. More extreme, Comparative Example 4 (a fluoroether nitrile compound using a traditional CO bond structure) experienced a sharp capacity decline to 65.8% under these conditions, losing almost one-third of its capacity. This significant difference stems directly from two factors: firstly, the high bond energy of the Si-O bond provides intrinsic thermal stability; and secondly, the Li2SiF6 interface layer maintains structural integrity and chemical stability even at high temperatures.

[0186] More importantly, Example 1 exhibited superior stability during high-temperature, high-rate cycling at 45°C and 2C, maintaining 80.2% capacity retention after 500 cycles, compared to only 55.4% for Comparative Example 1 under the same conditions, representing a 44.8% performance improvement. Comparative Example 4, after 500 cycles at 45°C, maintained only 45.5% capacity retention, essentially rendering it useless. This excellent performance under extreme conditions demonstrates that the silicon bridging compound not only provides thermodynamic stability but also ensures kinetic stability by forming a high-quality Li2SiF6 functional layer. Even under the dual stress of high temperature and high rate, the interface effectively suppresses side reactions and maintains rapid ion transport.

[0187] The comprehensive improvement in initial coulombic efficiency further confirms the improvement in interface quality. Example 1 achieved an initial efficiency of 97.2%, a 3.7 percentage point improvement compared to Comparative Example 1's 93.5%. This high initial efficiency not only signifies a reduction in initial irreversible capacity loss but, more importantly, reflects the high efficiency and selectivity of the SEI film formation process. For costly lithium metal anodes, every 1% improvement in initial efficiency translates into significant economic value. Combined with the comprehensive performance in cycle stability, high-temperature performance, and low impedance growth, the embodiments of this application provide a solid technical guarantee for the long-term reliable operation of high-voltage lithium metal batteries in practical application environments.

[0188] Under accelerated aging test conditions of 25°C, 2C, and 4.5V, with an estimated lifespan endpoint of 80% capacity retention, Example 1 achieved approximately 460 cycles, while Comparative Example 1 only achieved approximately 240 cycles. This translates to a 91.7% improvement in cycle life, nearly doubling it. Achieving such a significant improvement under harsh testing conditions suggests that under normal operating conditions in real-world applications (typically 0.5C to 1C charge / discharge), the lifespan extension could be even more substantial.

[0189] The significant improvement in cycle life directly translates into economic benefits. Taking grid-connected energy storage applications as an example, based on 1.5 charge-discharge cycles per day, the battery replacement cycle can be extended from approximately 5.3 months to 10.2 months. For electric vehicle applications, based on a full charge-discharge cycle every 3 days, battery life can be extended from approximately 2.0 years to 3.8 years. This not only reduces users' battery procurement costs but also significantly reduces downtime losses, labor costs, and waste battery disposal costs associated with battery replacement. Overall, it is expected to reduce the levelized cost of electricity (LCOE) of energy storage systems by 30% to 40%, greatly enhancing the market competitiveness of high-voltage lithium metal batteries.

[0190] The lithium metal battery manufactured by the method described in this application exhibits excellent performance under 2C high-rate conditions, providing crucial support for the development of fast-charging technology. Example 1, after 500 cycles at 45°C and 2C, still retains 80.2% of its capacity. This performance level is close to or even surpasses the performance of many traditional technologies under milder conditions (such as 25°C and 0.5C). This demonstrates that the battery using the embodiments of this application has the potential to operate stably at higher power levels, laying a material foundation for achieving fast-charging goals.

[0191] The improved high-rate tolerance not only means shorter charging times, but more importantly, it expands the application boundaries of batteries. In the electric vehicle sector, supporting continuous charging at 2C or higher can significantly alleviate users' range anxiety; in grid energy storage, high-rate performance enables batteries to better participate in grid frequency regulation and cope with sudden load changes; in special applications such as aerospace and military equipment, instantaneous high-power output capability is often a decisive technical indicator. This multi-scenario adaptability significantly enhances the commercial value and market potential of the technology.

[0192] The temperature-controlled, staged electrolyte injection process described in this application has good industrialization feasibility. As can be seen from the electrolyte properties in Table 2, the electrolyte using the technology described in this application has key parameters such as conductivity (8.10 mS / cm~8.20 mS / cm) and viscosity (3.81 mPa·s~3.88 mPa·s) that are essentially the same as traditional electrolytes. This means that existing injection equipment and piping systems can be adapted to the new process without large-scale modifications. The addition of a temperature control module can be achieved by adding a heating device to the existing injection station; the technology is mature and the investment cost is controllable.

[0193] From a material cost perspective, the silicon bridging compound is added at only 1.8 wt% of the total electrolyte system. Even considering its relatively high synthesis cost (estimated to be 3 to 5 times that of traditional additives), its impact on the total electrolyte cost is only within the range of 5% to 8%. In stark contrast, the value brought by the 91.7% improvement in cycle life far outweighs the increase in raw material costs. In summary, although the cost per battery increases slightly after adopting the technology of this application, the cost per unit of energy used over the entire life cycle is expected to decrease by 30% to 40%, significantly improving the return on investment (ROI) and providing a solid economic foundation for large-scale industrial application.

[0194] Through systematic experimental verification and in-depth mechanistic analysis, the silicon-bridged fluoroether nitrile compound combined with temperature-controlled staged liquid injection technology proposed in this application successfully solves the key technical challenges faced by high-voltage lithium metal batteries. Experimental data show that: the capacity retention rate at 25℃ high-rate cycling increased from 65.2% to 85.4% (an improvement of 31.0%); the high-temperature high-rate cycling performance at 45℃ increased from 55.4% to 80.2% (an improvement of 44.8%); the high-temperature storage capacity retention rate increased from 75.3% to 90.5% (an improvement of 20.2%); the interfacial impedance growth rate decreased from 110.8% to 45.5% (a reduction of 58.9%); and the initial coulombic efficiency increased from 93.5% to 97.2% (an improvement of 3.7 percentage points). This series of breakthroughs fully verifies the effectiveness of the three-in-one innovation strategy of "silicon-bridged molecular design + temperature-controlled activation process + synergistic interface engineering".

[0195] The lithium metal battery and its manufacturing method provided in this application not only represent an innovative breakthrough in scientific principles, but more importantly, demonstrate a clear prospect for industrialization. Good process compatibility, controllable cost increases, and significant performance improvements clear key technical obstacles for the commercial application of high-voltage lithium metal batteries. In particular, by forming a Li2SiF6 high-ionic-conductivity interface phase, the bottleneck problem of limited ion transport in traditional LiF interface layers is fundamentally solved. With the rapid development of new energy vehicles and large-scale energy storage industries, this technology is expected to play an important role in high-end power batteries, grid-scale energy storage systems, aerospace power supplies, and other fields, promoting the industrialization of next-generation high-energy-density, long-life battery technologies.

[0196] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A method for manufacturing a lithium metal battery, characterized in that, include: We provide positive electrode plates, negative electrode current collectors, and separators; The positive electrode, the negative current collector, and the separator are wound or stacked and then placed into a housing to form an initial battery cell. The separator is located between the positive electrode and the negative current collector. A first electrolyte is injected into the initial cell at a first temperature. The first electrolyte includes lithium salt, lithium nitrate and ether solvent. The initial battery cell undergoes a first formation process to decompose the lithium nitrate and form a basic SEI layer; After raising the temperature of the initial battery cell from the first temperature to the second temperature, a second electrolyte is injected into the initial battery cell. The second temperature is 40°C to 50°C. The second electrolyte includes lithium salt, silicon bridging compound, fluorine-containing film-forming additive, and nitrile solvent. The structural formula of the silicon bridging compound is as follows: Wherein, R is one or two of —CH2CF3, —CH2CF2CF3, —CH2CF2CF2CF3, and —CH2CHF2; The initial cell is subjected to a second formation process to form the lithium metal battery.

2. The method for manufacturing a lithium metal battery according to claim 1, characterized in that, The first temperature is 20℃~30℃.

3. The method for manufacturing a lithium metal battery according to claim 1, characterized in that, In the second electrolyte, the silicon bridging compound accounts for 5wt% to 20wt% by mass, and the fluorinated film-forming additive accounts for 10wt% to 30wt% by mass.

4. The method for manufacturing a lithium metal battery according to claim 1, characterized in that, After injecting the second electrolyte into the initial cell, it is kept at the second temperature for 1 to 2 hours, and then cooled to room temperature at a rate of 0.5°C / min to 2°C / min.

5. The method for manufacturing a lithium metal battery according to claim 1, characterized in that, The second electrolyte is injected into the initial cell within 24 hours after the completion of the first formation process.

6. The method for manufacturing a lithium metal battery according to claim 1, characterized in that, The difference between the lithium salt concentration in the first electrolyte and the lithium salt concentration in the mixture of the first electrolyte and the second electrolyte does not exceed ±0.5 mol / L.

7. The method for manufacturing a lithium metal battery according to claim 6, characterized in that, The lithium salt concentration in the first electrolyte is 0.8 mol / L to 2.0 mol / L.

8. The method for manufacturing a lithium metal battery according to claim 1, characterized in that, In the first electrolyte, the ether solvent includes short-chain ether solvents, long-chain ether solvents, and fluoroether solvents. The short-chain ether solvent has 6 or fewer carbon atoms, and the long-chain ether solvent has 6 or more carbon atoms but less than or equal to 10.

9. The method for manufacturing a lithium metal battery according to claim 8, characterized in that, The short-chain ether solvent accounts for 40% to 80% of the total ether solvent by mass, the long-chain ether solvent accounts for 10% to 40% of the total ether solvent by mass, and the fluorinated ether solvent accounts for 0.01% to 30% of the total ether solvent by mass.

10. The method for manufacturing a lithium metal battery according to claim 8 or 9, characterized in that, The short-chain ether solvents are selected from one or more of 1,2-dimethoxyethane, 1,3-dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; the long-chain ether solvents are selected from one or more of triethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether; the fluorinated ether solvents are selected from one or more of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, bis(2,2,2-trifluoroethyl) ether, and 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether.

11. The method for manufacturing a lithium metal battery according to claim 1, characterized in that, The second electrolyte also includes a fluorinated carbonate solvent, wherein the mass ratio of the nitrile solvent to the fluorinated carbonate solvent is 70:30 to 90:

10.

12. The method for manufacturing a lithium metal battery according to claim 11, characterized in that, The nitrile solvent is selected from one or more of succinic acid, adiponitrile, glutaronitrile, heptonitrile, octanoic acid, benzonitrile, and phthalonitrile; the fluorinated carbonate solvent is selected from one or more of fluoroethylene carbonate and difluoroethylene carbonate.

13. A lithium metal battery, characterized in that, It is prepared by the manufacturing method of lithium metal battery as described in any one of claims 1 to 12.

14. An energy storage system, characterized in that, Including the lithium metal battery as described in claim 13.

15. An electrical appliance, characterized in that, The electrical device includes a load and a lithium metal battery as described in claim 13; or, the electrical device includes a load and an energy storage system as described in claim 14.

Images