Solid electrolyte, lithium-based energy storage device and preparation method

Abstract

The invention discloses a solid electrolyte, a lithium-based energy storage device and a preparation method, the solid electrolyte is obtained by curing an electrolyte through an ultraviolet lamp, the electrolyte comprises polyethylene glycol dimethacrylate, an initiator and a monomer, and the monomer contains a fluorosulfonyl group and an ester group; a monomer side chain contains fluorosulfonyl, so that the crystallinity of the polymer can be reduced, a passivation layer is effectively formed on the surface of a lithium negative electrode, and an electrochemical window of the battery is expanded, so that the cycle life of the battery is prolonged, and a formed flexible polymer skeleton can increase the compatibility between an electrolyte and an electrode, so that the interface resistance is reduced; the passivation layer can homogenize an interface electric field and regulate and control diffusion of lithium ions, so that dendritic crystal growth is effectively inhibited, and compact and uniform deposition is realized; according to the lithium-based energy storage device applying the electrolyte containing the monomer, the cycle life of a lithium half battery can be greatly prolonged, the utilization rate of a lithium metal negative electrode is remarkably improved, the polarization voltage of the battery is effectively reduced, and the coulombic efficiency of the battery is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of electrolyte technology, and more specifically, to a solid electrolyte, a lithium-based energy storage device and a preparation method thereof. Background Art

[0002] With the challenges brought by traditional energy shortages and environmental pollution, the rapid development of renewable energy has been promoted, and the development of stable, reliable and safe energy storage technology is imminent. Although traditional lithium-ion batteries occupy most of the energy storage market with their excellent energy density and cycle stability. However, affected by cost and safety issues, the application of traditional lithium-ion batteries in the field of large-scale energy storage is limited to a certain extent; solid-state batteries, because they can largely avoid traditional battery safety issues and reduce manufacturing costs, have attracted widespread attention. Among them, solid-state lithium-ion batteries have become one of the most promising secondary batteries to replace traditional liquid lithium-ion batteries and achieve large-scale industrialization due to their advantages such as high theoretical capacity of lithium negative electrodes, high safety of solid-state electrolytes and low assembly costs.

[0003] Due to the problems of dendrite growth of metallic lithium negative electrode, solid-liquid incompatibility between solid electrolyte and positive electrode interface, especially under high-rate charge and discharge conditions, it often leads to low coulombic efficiency, rapid capacity decay and limited cycle life. In addition, the irreversible deposition / stripping of the negative electrode makes the utilization rate of lithium negative electrode low, which also seriously limits the energy density of lithium-ion batteries.

[0004] In response to the above problems, researchers have proposed a large number of solutions, mainly including: designing three-dimensional current collectors, constructing artificial interface layers, developing suitable electrolyte additives, constructing compatible electrode and electrolyte interfaces, etc. Among them, the technology of preparing electrolytes by ultraviolet curing is well known and widely cited in the manufacturing process of lithium batteries because it is simple, economical, fast and reliable. Introducing suitable functional groups in the polymer side chains can not only preferentially adsorb on the interface, effectively balance the ion concentration and electric field distribution at the lithium negative electrode interface, and achieve uniform deposition of lithium; it can also regulate the solvation structure of lithium ions in the electrolyte and significantly improve the electrochemical window voltage of the electrolyte. At present, researchers have reported many effective functional groups, mainly including cationic fluorine sulfonyl, carboxylic acid, amide, etc. However, the electrolytes currently developed still have the following challenges. First, although fluorine sulfonyl and carboxylic acid groups can regulate the solvation structure of lithium ions, they cannot effectively regulate the oxidation potential of lithium ions. For amide groups, rich nucleophilic sites can effectively regulate the solvation structure of lithium ions and effectively improve the electrochemical window, but this type of electrolyte often has poor compatibility with electrodes and cannot fully play the role of protecting electrodes. In addition, during the charge and discharge process, the interface state continues to change dynamically. Especially during the rate process, there is great uncertainty in the protective effect on the positive and negative electrode interfaces, which makes it impossible to improve the utilization rate of the lithium negative electrode, thus severely limiting the energy density of lithium-ion batteries.

[0005] Therefore, it is urgent to develop new functional electrolytes to inhibit dendrite growth and solve the instability of the solid-liquid interface and improve the battery cycle life.

[0006] Chinese patent technology application 1 (application number: 202010381309.5, application date: 2020.05.08) discloses a method for preparing a polymer electrolyte and its application in an all-solid-state battery, wherein the polymer electrolyte comprises a polymer matrix and a lithium salt composited in the polymer matrix; the polymer electrolyte is formed by in-situ polymerization of a material comprising a small molecule additive, a cross-linking agent and the lithium salt in a battery by thermal initiation, the lithium ions of the electrolyte are prone to dendrite growth, the solid-liquid interface is unstable, and the battery cycle life is limited.

[0007] Chinese patent technology application 2 (application number: 202280023759.4, application date: 2022.01.25) discloses a flame resistant electrolyte composition, a quasi-solid electrolyte and a solid electrolyte and a lithium battery, wherein the electrolyte comprises a polymer and a lithium salt, the polymer comprises a chain of a polyester of phosphoric acid, and the lithium salt is dissolved or dispersed in the polyester of phosphoric acid. The electrolyte may also contain from 0.1% to 50% by weight of a non-aqueous liquid solvent dispersed in the polyester of phosphoric acid, and the battery cannot significantly improve the cycle life.

[0008] Chinese Patent Technology Application 3 (Application No.: 202280034485.9, Application Date: 2022.03.10) discloses a bipolar electrode, a bipolar lithium battery and a manufacturing method comprising a flame-resistant quasi-solid electrolyte or a solid electrolyte, which comprises a conductive material foil having two opposing main surfaces, wherein one or both of the main surfaces are optionally coated with a layer of graphene or expanded graphite material having a thickness of from 5nm to 50μm; and (b) a negative electrode layer and a positive electrode layer, which are respectively arranged on the two main surfaces, wherein the positive electrode layer comprises a mixture of particles of a cathode active material and a quasi-solid electrolyte or a solid electrolyte, and the electrolyte comprises a polymer, which is a polymerization product or a cross-linked product of a reactive additive, wherein the reactive additive comprises (i) a polymerizable first liquid solvent, (ii) an initiator or a curing agent, and (iii) a lithium salt. Also provided is a bipolar battery comprising more than one bipolar electrode connected in series, wherein the graphite negative electrode of the battery does not have a passivation layer and is prone to wear, and the battery life is short. Summary of the invention

[0009] In view of this, on the one hand, the present invention provides a solid electrolyte obtained by curing an electrolyte with an ultraviolet lamp, wherein the electrolyte comprises: a lithium salt, polyethylene glycol dimethacrylate, an initiator and a monomer, wherein the monomer comprises a fluorosulfonyl group and an ester group, and the structural formula of the monomer is:

[0010]

[0011] Optionally, the lithium salt includes at least one of lithium hexafluorophosphate, lithium bis(trifluoromethylsulfonyl)imide and lithium bis(fluorosulfonyl)imide;

[0012] And / or, the initiator includes one of lithium bis(oxalatoborate), lithium bis(trifluoromethylsulfonyl)imide, ethylene carbonate, propylene carbonate and fluoroethylene carbonate.

[0013] Optionally, the mass fraction of lithium salt in the electrolyte is 10%-30%;

[0014] The mass fraction of polyethylene glycol dimethacrylate in the electrolyte is 40-80%;

[0015] The mass fraction of the initiator in the electrolyte is 1%-3%;

[0016] And / or, the mass fraction of the monomer in the electrolyte is 10% to 30%.

[0017] Optionally, the average molecular weight of polyethylene glycol dimethacrylate is 550 to 750.

[0018] On the other hand, the present invention provides a lithium-based energy storage device using any of the aforementioned solid electrolytes, including lithium-ion batteries, lithium metal batteries and lithium-air batteries.

[0019] In another aspect, the present invention provides a method for preparing a lithium-based energy storage device, comprising the steps of:

[0020] Synthetic monomers, the synthetic monomers comprising the steps of:

[0021] mixing chlorosulfonyl isocyanate and antimony trifluoride to obtain a first mixed solution;

[0022] Distilling the first mixed liquid in a nitrogen environment; heating the first mixed liquid to a first temperature and stirring for a first time to obtain a fluorosulfonyl isocyanate liquid;

[0023] Dissolving fluorosulfonyl isocyanate liquid in anhydrous dichloromethane, and adding the mixture to hydroxyethyl methacrylate to obtain a second mixed liquid;

[0024] The second mixed liquid is placed in ice water and stirred for a second time, and then placed in a second temperature environment for a third time to obtain a third mixed liquid;

[0025] The third mixed solution is subjected to at least two rotary evaporations to obtain a fourth mixed solution;

[0026] The fourth mixed liquid is washed with anhydrous dichloromethane, filtered, and dried to obtain a monomer;

[0027] The lithium salt, polyethylene glycol dimethacrylate, an initiator and a monomer are mixed and dissolved in an organic solvent to obtain an electrolyte;

[0028] Injecting electrolyte into the battery cell;

[0029] The electrolyte and the battery cell are cured using ultraviolet light and then packaged to obtain a lithium-based energy storage device.

[0030] Optionally, the molar ratio of chlorosulfonyl isocyanate to antimony trifluoride is 3:1 to 4:1.

[0031] Optionally, the first temperature is 70°C-90°C, and the first time is 24h-50h.

[0032] Optionally, the molar ratio of fluorosulfonyl isocyanate to hydroxyethyl methacrylate is 1:1.1 to 1:1.5.

[0033] Optionally, the second time is 0.5h-2h, the second temperature is 18°C ​​to 25°C, and the third time is 24h-50h.

[0034] Compared with the prior art, the solid electrolyte, lithium-based energy storage device and preparation method provided by the present invention achieve at least the following beneficial effects:

[0035] The present invention provides a solid electrolyte, a lithium-based energy storage device and a preparation method. The solid electrolyte is obtained by curing an electrolyte with an ultraviolet lamp. The electrolyte includes polyethylene glycol dimethacrylate, an initiator and a monomer, and the monomer contains a fluorosulfonyl group and an ester group. The fluorosulfonyl group in the side chain of the monomer can reduce the crystallinity of the polymer, and effectively form a passivation layer on the surface of the lithium negative electrode, which expands the electrochemical window of the battery, thereby improving the cycle life of the battery. The formed flexible polymer skeleton can increase the compatibility between the electrolyte and the electrode, thereby reducing the interface resistance. The passivation layer can make the interface electric field uniform and regulate the diffusion of lithium ions, thereby effectively inhibiting the growth of dendrites and achieving dense and uniform deposition. Compared with an electrolyte without a monomer, a lithium-based energy storage device using the monomer-containing electrolyte of the present invention can greatly improve the cycle life of a lithium half-cell, significantly improve the utilization rate of a lithium metal negative electrode, effectively reduce the polarization voltage of the battery, and significantly improve the coulombic efficiency of the battery.

[0036] Of course, any product implementing the present invention does not necessarily need to achieve all of the technical effects described above at the same time.

[0037] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0039] Figure 1 It is a linear scanning curve comparison diagram of a solid electrolyte lithium||stainless steel gasket battery provided by the present invention and a battery in the prior art;

[0040] Figure 2 This is a comparison chart of the rate cycling performance of a lithium iron phosphate||lithium metal half-cell of another solid electrolyte provided by the present invention and a battery of the prior art;

[0041] Figure 3 This is a comparison chart of the rate cycle performance of another solid electrolyte lithium iron phosphate||graphite full battery provided by the present invention and the battery of the prior art;

[0042] Figure 4 This is a comparison of the surface morphology of another solid electrolyte graphite negative electrode battery provided by the present invention and the battery of the prior art after long cycles;

[0043] Figure 5 It is a flow chart of a method for preparing a lithium-based energy storage device provided by the present invention;

[0044] Figure 6 This is a flow chart of a method for preparing another lithium-based energy storage device provided by the present invention. DETAILED DESCRIPTION

[0045] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0046] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0047] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0048] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0049] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0050] The invention provides a solid electrolyte, which is obtained by curing an electrolyte with an ultraviolet lamp. The electrolyte comprises lithium salt, polyethylene glycol dimethacrylate, an initiator and a monomer, and the monomer comprises a fluorosulfonyl group and an ester group.

[0051] Optionally, the mass fraction of the monomer in the electrolyte is 10% to 30%.

[0052] The mass fraction of the monomer in the electrolyte can be 10%, 11%, 11.3%, 11.6%, 12%, 12.7%, 13%, 13.6%, 14%, 14.3%, 14.6%, 15%, 15.7%, 16%, 17%, 18%, 19%, 20%, 21.7%, 22%, 22.5%, 23.4%, 24.5%, 25%, 25.6%, 26%, 26.7%, 28%, 28. 3%, 29%, 29.4% and 30%. The side chain containing fluorosulfonyl can reduce the crystallinity of the polymer and effectively form a passivation layer on the surface of the lithium negative electrode, which expands the electrochemical window of the battery and thus improves the cycle life of the battery. The flexible polymer skeleton formed by the monomer increases the compatibility between the electrolyte and the electrode, thereby reducing the interface resistance. The passivation layer can even out the interface electric field and regulate the diffusion of lithium ions, thereby effectively inhibiting the growth of dendrites and achieving dense and uniform deposition.

[0053] It should be noted that the solid electrolyte provided by the present invention uses an ultraviolet lamp to cure the electrolyte. The ultraviolet lamp curing technology is a fast and efficient curing method. In the electrolyte curing process, the use of ultraviolet lamps can significantly shorten the curing time, thereby improving production efficiency; no chemical agent needs to be added during the ultraviolet curing process, which reduces solvent volatilization and waste gas emissions, thereby reducing pollution to the environment. At the same time, the energy required for ultraviolet curing is relatively low, which helps to save energy; ultraviolet curing can ensure that the electrolyte is uniformly and fully cured, thereby improving the quality and stability of the product. The cured electrolyte has better mechanical strength and chemical stability, and can meet the needs of various application scenarios; the ultraviolet curing process can be precisely controlled by adjusting parameters such as the power, irradiation time and irradiation distance of the ultraviolet lamp. This makes the curing process more flexible and controllable, which helps to meet the curing requirements of different products; the combination of ultraviolet curing technology and automation equipment can realize the continuous production and automated control of electrolytes, which can effectively reduce labor costs, improve production efficiency, and also help to ensure the stability and consistency of product quality.

[0054] Optionally, the lithium salt includes at least one of lithium hexafluorophosphate, lithium bis(trifluoromethylsulfonyl)imide and lithium bis(fluorosulfonyl)imide.

[0055] It should be noted that the decomposition of lithium salts in electrolytes can produce lithium ions (Li+) and other chemical substances. These lithium ions are transferred between the positive and negative electrodes of the battery to provide continuous current output for the battery. The addition of lithium salts can significantly improve the ion transfer performance of the electrolyte, reduce the internal resistance of the battery, and thus improve the overall efficiency of the battery. The ideal lithium salt should be easily soluble or dissociated in the solvent so that the dissociated lithium ions can move smoothly. The lithium salt can maintain the uninterrupted redox reaction in the battery to ensure the normal operation of the battery. The lithium salt can effectively reduce the evaporation rate of the electrolyte, maintain the stability and durability of the electrolyte, and thus extend the service life of the battery. The right amount of lithium salt can prevent the battery from overcharging and over-discharging to a certain extent. When the battery is charged with too much charge, the lithium salt can play a stabilizing role, avoid battery overflow, and ensure the safe use of the battery. The selection and concentration of lithium salts will also affect the electrochemical properties of the battery, such as voltage, capacity, and cycle stability. For example, lithium hexafluorophosphate (LiPF6) and lithium bis(trifluoromethanesulfonyl imide) (LiTFSI) are the most common lithium salts in liquid electrolytes for lithium batteries. They are widely used due to their comprehensive considerations of price, viscosity and ionic conductivity.

[0056] Optionally, the mass fraction of the lithium salt in the electrolyte is 10%-30%.

[0057] The mass fraction of lithium salt can specifically be 10%, 11%, 11.3%, 11.6%, 12%, 12.7%, 13%, 13.6%, 14%, 14.3%, 14.6%, 15%, 15.7%, 16%, 17%, 18%, 19%, 20%, 21.7%, 22%, 22.5%, 23.4%, 24.5%, 25%, 25.6%, 26%, 26.7%, 28%, 28.3%, 29%, 29.4% and 30%. When the mass fraction of lithium salt is less than 10%, the low lithium salt content in the electrolyte will lead to a decrease in the conductivity of the electrolyte, thereby affecting the capacity of the battery. The capacity is the ability of the battery to store electrical energy and is an important indicator for evaluating battery performance. When the lithium salt content is insufficient, the ion conduction efficiency of the electrolyte decreases. Low, so that the battery can store and release less electricity during the charging and discharging process, resulting in a decrease in battery capacity; low lithium salt content will accelerate the imbalance of the chemical reaction inside the battery, resulting in faster performance degradation of the battery during the cycle; insufficient lithium salt will reduce the stability of the electrolyte, thereby increasing the possibility of thermal runaway; when the mass fraction of lithium salt is greater than 30%, too much lithium salt will cause the internal structure of the battery to become unstable, and even internal short circuit will occur, thus affecting the safety performance of the battery; too much lithium salt will cause the electrolyte system to become complicated, making the electrolytic cell process parameters disordered and difficult to operate, thereby affecting the current efficiency and increasing power consumption; so when the mass fraction of lithium salt in the electrolyte is 10%-30%, the lithium salt content is sufficient, and the right amount of lithium salt can prevent the battery from overcharging and over-discharging to a certain extent. When the battery is charged with too much charge, lithium salt can play a stabilizing role, avoid battery overflow, and ensure the safe use of the battery.

[0058] Optionally, the mass fraction of polyethylene glycol dimethacrylate in the electrolyte is 40-80%.

[0059] The mass fraction of polyethylene glycol dimethacrylate can specifically be 40%, 41%, 42.3%, 43.6%, 44%, 45.7%, 46%, 47.6%, 48%, 49.3%, 50.6%, 52%, 53.7%, 54%, 55%, 56%, 57%, 59%, 60.7%, 62%, 64.5%, 65.4%, 67.5%, 70%, 71.6%, 72%, 73.7%, 74%, 75.3%, 77%, 78.4% and 80%. When the mass fraction of polyethylene glycol dimethacrylate is less than 40%, the content of polyethylene glycol dimethacrylate is too little and may not provide sufficient structural support for the electrolyte. This may cause the electrolyte membrane to become fragile, easily damaged or deformed; as a plasticizer, too little polyethylene glycol dimethacrylate may not fully exert its plasticizing effect, which may cause the electrolyte to become too rigid or difficult to process; too little polyethylene glycol dimethacrylate may also affect the overall performance of the electrolyte, such as ion conductivity and electrochemical stability. This may limit the application of electrolytes in certain specific fields; when the mass fraction of polyethylene glycol dimethacrylate is greater than 80%, excessive content of polyethylene glycol dimethacrylate may cause the mechanical properties of the electrolyte to decrease. For example, too much PEGDMA may make the electrolyte membrane too soft or brittle, reducing its tensile and tearing strength; too much polyethylene glycol dimethacrylate may also affect the electrical properties of the electrolyte, such as ionic conductivity and electrochemical stability. This may cause the performance of the electrolyte to deteriorate and fail to meet the requirements of specific applications; polyethylene glycol dimethacrylate is flammable and irritating, so when the mass fraction of polyethylene glycol dimethacrylate is 40-80%, an appropriate amount of PEGDMA can optimize the ion conduction path of the electrolyte and increase the migration rate of ions, thereby improving the electrochemical properties of the electrolyte and giving it higher energy density and power density.

[0060] Optionally, the average molecular weight of polyethylene glycol dimethacrylate is 550 to 750.

[0061] It should be noted that polyethylene glycol dimethacrylate, as a polymer, can play multiple roles in electrolytes. It can form an electrolyte membrane through polymerization, provide structural support for the electrolyte, and affect the mechanical and electrical properties of the electrolyte. In addition, polyethylene glycol dimethacrylate can also be used as a plasticizer in the electrolyte to improve the flexibility and plasticity of the electrolyte, making it easier to process and apply.

[0062] Optionally, the average molecular weight of polyethylene glycol dimethacrylate can be specifically 550, 560, 570, 580, 595, 600, 610, 620, 630, 640, 650, 660, 675, 680, 710, 720, 730, 745, 750. When the average molecular weight of polyethylene glycol dimethacrylate is less than 550, the average molecular weight is too small. PEGDMA with too small molecular weight may not form a stable electrolyte structure, resulting in the electrolyte being easily deformed or ruptured during use. The unstable structure may also affect the mechanical strength and durability of the electrolyte and reduce its service life; PEGDMA with too small molecular weight may form a lower cross-linking density, resulting in the electrolyte membrane becoming too soft and easy to deform; low cross-linking density may also affect the dimensional stability and chemical stability of the electrolyte, making it difficult to withstand changes in the external environment; PEGDMA with too small molecular weight may be excessively dissolved in the solvent, resulting in The loss of electrolyte components and the degradation of performance; PEGDMA with a molecular weight that is too small may limit certain properties of the electrolyte, such as thermal stability, chemical stability, etc.; when the average molecular weight of polyethylene glycol dimethacrylate is greater than 750, the average molecular weight is too large, and PEGDMA with a molecular weight that is too large may cause its solubility in the solvent to decrease, making it difficult to form a uniform and stable electrolyte solution; poor solubility may also cause the electrolyte components to precipitate or precipitate during storage and use, affecting the performance of the electrolyte; PEGDMA with a molecular weight that is too large may form an excessively high cross-linking density, causing the electrolyte membrane to become too hard and brittle; high cross-linking density may also affect the flexibility and plasticity of the electrolyte, making it difficult to adapt to application requirements of different shapes and sizes; PEGDMA with a molecular weight that is too large may have lower reactivity, resulting in a lower reaction rate with other monomers or polymers, which may extend the preparation cycle of the electrolyte, increase production costs, and reduce production efficiency.

[0063] Optionally, the initiator includes one of lithium bis(oxalatoborate), lithium bis(trifluoromethylsulfonyl)imide, ethylene carbonate, propylene carbonate and fluoroethylene carbonate.

[0064] It should be noted that the initiator produces active intermediates (such as free radicals, anions, cations, etc.) in the electrolysis reaction. These active intermediates act on the monomer molecules to initiate the polymerization reaction. By adjusting the amount of initiator, the rate of the polymerization reaction can be controlled, thereby adjusting the molecular weight distribution and properties of the polymer.

[0065] Optionally, the mass fraction of the initiator in the electrolyte is 1%-3%.

[0066] The mass fraction of the initiator in the electrolyte can be specifically 1%, 1.1%, 1.5%, 1.6%, 2%, 2.7%, 2.3% and 3%. When the mass fraction of the initiator in the electrolyte is greater than 3%, the active intermediates generated per unit time increase, resulting in a too fast polymerization reaction speed, which may cause implosion and make the reaction difficult to control; because too much initiator leads to an increase in chain termination reactions, the molecular weight of the polymer finally formed is low; too much initiator may cause uneven polymer structure, affecting the physical and chemical properties of the product; some initiators may decompose under high temperature or light conditions to produce toxic gases or flammable and explosive substances, increasing safety hazards; when the mass fraction of the initiator in the electrolyte is less than 1%, there is too little initiator, the polymerization reaction speed is slow, resulting in low production efficiency; the monomer is not fully converted into a polymer, resulting in a waste of raw materials; due to insufficient initiator, the chain growth reaction continues, which may result in a too high molecular weight of the polymer, affecting the processing performance and use performance of the product; the polymerization reaction may be incomplete, resulting in unreacted monomers or initiators remaining in the product, affecting the quality and safety of the product; so the mass fraction of the initiator in the electrolyte is 1%-3%, and the initiator content is appropriate.

[0067] It can be understood that the present invention provides a solid electrolyte, the electrolyte includes lithium salt, polyethylene glycol dimethacrylate, an initiator and a monomer, the monomer contains a fluorosulfonyl group and an ester group; the side chain of the monomer contains a fluorosulfonyl group, which can reduce the crystallinity of the polymer, and effectively form a passivation layer on the surface of the lithium negative electrode, which expands the electrochemical window of the battery, thereby improving the cycle life of the battery, and the formed flexible polymer skeleton can increase the compatibility between the electrolyte and the electrode, thereby reducing the interface resistance; the passivation layer can make the interface electric field uniform, regulate the diffusion of lithium ions, thereby effectively inhibiting the growth of dendrites, and achieving dense and uniform deposition; compared with an electrolyte without a monomer, a lithium-based energy storage device using the monomer-containing electrolyte of the present invention can greatly improve the cycle life of a lithium half-cell, significantly improve the utilization rate of a lithium metal negative electrode, effectively reduce the polarization voltage of the battery, and significantly improve the coulombic efficiency of the battery.

[0068] The present invention also provides a method for preparing a lithium-based energy storage device, comprising the steps of:

[0069] S1: Synthesizing monomers, the synthesis of monomers includes the following steps:

[0070] S11: mixing chlorosulfonyl isocyanate and antimony trifluoride to obtain a first mixed solution;

[0071] S12: distilling the first mixed liquid in a nitrogen environment; S13: heating the first mixed liquid to a first temperature and stirring for a first time to obtain a fluorosulfonyl isocyanate liquid;

[0072] S14: dissolving fluorosulfonyl isocyanate liquid in anhydrous dichloromethane, and adding the solution to hydroxyethyl methacrylate to obtain a second mixed solution;

[0073] S15: placing the second mixed liquid in ice water and stirring for a second time, and then placing it in a second temperature environment for a third time to obtain a third mixed liquid;

[0074] S16: performing rotary evaporation on the third mixed solution at least twice to obtain a fourth mixed solution;

[0075] S17: washing the fourth mixed liquid with anhydrous dichloromethane, filtering it, and drying it to obtain a monomer;

[0076] S2: dissolving lithium salt, polyethylene glycol dimethacrylate, initiator and monomer in an organic solvent to obtain an electrolyte;

[0077] S3: injecting electrolyte into the battery cell;

[0078] S4: Use ultraviolet light to cure the electrolyte and battery cells, and encapsulate them to obtain lithium-based energy storage devices.

[0079] Optionally, the molar ratio of chlorosulfonyl isocyanate to antimony trifluoride is 3:1 to 4:1.

[0080] Optionally, the molar ratio of fluorosulfonyl isocyanate to hydroxyethyl methacrylate is 1:1.1 to 1:1.5.

[0081] It should be noted that the molar ratio of chlorosulfonyl isocyanate to antimony trifluoride is 3:1 to 4:1, and the molar ratio of fluorosulfonyl isocyanate to hydroxyethyl methacrylate is 1:1.1 to 1:1.5, which can ensure that the final yield of 2-(1-fluorosulfonylamino)vinyl-oxy-ethyl methacrylate (monomer) is high, and the reaction can be carried out more completely, thereby improving the yield of the target product; the appropriate molar ratio can reduce the generation of unnecessary by-products; the reasonable molar ratio can ensure that each reactant is fully utilized to avoid unnecessary waste; in a complex reaction system, there may be multiple competitive reaction paths. By adjusting the molar ratio, the reaction conditions can be optimized, the target product becomes the main product, and the selectivity of the reaction is improved; the appropriate molar ratio helps to determine the optimal reaction temperature, pressure, catalyst dosage and other conditions. The optimization of these conditions can further improve the efficiency of the reaction and the quality of the product; by accurately controlling the molar ratio, the reaction process can be optimized and unnecessary energy consumption can be reduced. For example, unnecessary heating or cooling steps can be reduced during the synthesis process, thereby reducing energy consumption; by controlling the molar ratio, the reaction can be ensured to be carried out within a safe range and reduce the risk of accidents.

[0082] Optionally, the first temperature is 70°C-90°C, and the first time is 24h-50h.

[0083] For example, the first temperature can be 70°C, 71°C, 72°C, 73°C, 74°C, 75.4°C, 76.8°C, 79°C, 81.2°C, 83.6°C, 87.8°C and 90°C. When the first temperature is greater than 90°C, the temperature is too high, the reactant flow reacts violently in the high temperature zone, the macromolecules continue to break, and more heat is released, making the temperature higher. Such a vicious cycle may lead to a temperature runaway accident; too high a temperature may easily cause a low yield and increase production costs; when the first temperature is less than 70°C, the temperature is too low, which may make the reaction difficult to start or the reaction rate slow, thereby affecting product quality and output; if the temperature is too low, the reactants cannot react fully, the accumulated energy is difficult to release, and an explosion accident may easily occur; so the first temperature is 70°C-90°C, the temperature is appropriate, the reaction is sufficient while ensuring the yield, and the production cost is reduced.

[0084] The first time can be 24h, 25h, 26h, 27h, 28h, 29h, 30h, 31h, 32h, 33h, 34h, 35h, 36h, 37h, 38h, 39h, 40h, 41h, 42h, 43h, 44h, 45h, 46h, 47h, 48h, 59 and 50h. When the first time is less than 24h, the reaction time is too short, too little target substance is precipitated, the reaction is insufficient, and the yield is low. When the first time is greater than 50h, the reaction time is too long, the target substance may have side reactions due to the long reaction time, and the yield is also easily caused to be too low. Therefore, when the first time is 24h-50h, the reaction time is sufficient, more target substance is precipitated, and the reaction is sufficient.

[0085] Optionally, the second time is 0.5h-2h, the second temperature is 18°C ​​to 25°C, and the third time is 24h-50h.

[0086] For example, the second time can be 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1.0h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h and 2h. When the second time is less than 0.5h, the reaction time is too short, too little target substance is precipitated, the reaction is insufficient, and the yield is low; when the second time is greater than 2h, the reaction time is too long, the target substance may have side reactions due to the long reaction time, and the yield is also easily caused to be too low; so when the first time is 0.5h-2h, the reaction time is sufficient, more target substance is precipitated, and the reaction is sufficient.

[0087] For example, the second temperature can be 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, and 25°C. When the second temperature is greater than 25°C, the reaction temperature exceeds room temperature. The temperature is too high, the reactant flow reacts violently in the high temperature zone, the macromolecules continue to break, and more heat is released, making the temperature higher. Such a vicious cycle may lead to a temperature runaway accident; too high a temperature may easily cause a low yield and increase production costs; when the second temperature is less than 18°C, the temperature is lower than room temperature. Too low a temperature will make it difficult to start the reaction or the reaction rate will slow down, thereby affecting product quality and output; if the temperature is too low, the reactants cannot react fully, the accumulated energy is difficult to release, and an explosion accident may easily occur; so the second temperature is 18°C-25°C, the temperature is appropriate, the reaction is sufficient, and the yield is guaranteed, thereby reducing production costs.

[0088] For example, the third time can be 24h, 25h, 26h, 27h, 28h, 29h, 30h, 31h, 32h, 33h, 34h, 35h, 36h, 37h, 38h, 39h, 40h, 41h, 42h, 43h, 44h, 45h, 46h, 47h, 48h, 59 and 50h. When the third time is less than 24h, the reaction time is too short, too little target substance is precipitated, the reaction is insufficient, and the yield is low; when the third time is greater than 50h, the reaction time is too long, the target substance may have side reactions due to the long reaction time, and the yield is also easily caused to be too low; so when the third time is 24h-50h, the reaction time is sufficient, more target substance is precipitated, and the reaction is sufficient.

[0089] It should be noted that in the above reaction process, after continuous stirring for 24 hours, fluorosulfonyl isocyanate liquid begins to precipitate. If the reaction is continuously stirred for more than 50 hours, the yield will gradually decrease. Too high a temperature can also easily affect the product yield and generate unnecessary by-products.

[0090] Example 1

[0091] Lithium bis(fluorosulfonyl)imide (LiFSI) is used as the lithium salt in the electrolyte, and its mass fraction is set to 10%, the mass fraction of the monomer is 10%, the mass fraction of the initiator is 1.5%, and the mass fraction of polyethylene glycol dimethacrylate is 78.5%. The above reagents are completely dissolved in an organic solvent. In this embodiment, the organic solvent is acetone solvent to obtain an electrolyte solution, and then the electrolyte solution is slowly introduced into a mold. The size of the mold is 8cm×8cm, and the mold includes a lithium iron phosphate positive electrode sheet containing active materials. Then, it is placed in a vacuum oven at 40°C for 15 minutes, and then cured under an ultraviolet lamp for 10 minutes to obtain Example 1.

[0092] Example 2

[0093] Lithium bis(fluorosulfonyl)imide (LiFSI) is used as the lithium salt in the electrolyte, and its mass fraction is set to 20%, the mass fraction of the monomer is 20%, the mass fraction of the initiator is 1.5%, and the mass fraction of polyethylene glycol dimethacrylate is 58.5%. The above reagents are dissolved in an organic solvent. In this embodiment, the organic solvent is acetone solvent to obtain an electrolyte solution, and then the electrolyte solution is slowly introduced into a mold. The size of the mold is 8cm×8cm. The mold includes a lithium iron phosphate positive electrode sheet containing active materials, and then placed in a vacuum oven at 40°C for 15 minutes, and then cured under an ultraviolet lamp for 10 minutes to obtain Example 2.

[0094] Example 3

[0095] Lithium bis(fluorosulfonyl)imide (LiFSI) is used as the lithium salt in the electrolyte, and its mass fraction is set to 30%, the mass fraction of the monomer is 30%, the mass fraction of the initiator is 1.5%, and the mass fraction of polyethylene glycol dimethacrylate is 38.5%. When preparing the electrolyte of this embodiment 3, the above reagents are dissolved in an organic solvent. In this embodiment, the organic solvent is acetone solvent to obtain an electrolyte, and then the electrolyte is slowly introduced into a mold. The size of the mold is 8cm×8cm. The mold includes a lithium iron phosphate positive electrode sheet containing active materials, and then placed in a vacuum oven at 40°C for 15 minutes, and then cured under an ultraviolet lamp for 10 minutes to obtain Example 3.

[0096] A solid electrolyte in the prior art is used as a comparative example, the electrolyte includes a lithium salt, polyethylene glycol dimethacrylate and an initiator, lithium bis(fluorosulfonyl)imide (LiFSI) is used as the lithium salt in the electrolyte, the mass fraction of which is 30%, the mass fraction of the initiator is 1.5%, and the mass fraction of polyethylene glycol dimethacrylate is 68.5%. The above reagents are dissolved in an organic solvent, in which the organic solvent is an acetone solvent, to obtain an electrolyte, and then the electrolyte is slowly introduced into a mold, the size of the mold is 8cm×8cm, and the mold includes a lithium iron phosphate positive electrode sheet containing an active material, and then placed in a vacuum oven at 40°C for 15 minutes, and then cured under an ultraviolet lamp for 10 minutes to obtain a comparative example.

[0097] Experiment on the effect of different mass fractions of monomers on the electrochemical window of lithium-ion batteries:

[0098] A lithium sheet with a thickness of 0.25 mm and a stainless steel gasket (SS) with a thickness of 1 mm were used as electrodes. The electrolytes of Example 1, Example 2, Example 3 and the comparative example were taken respectively, and then the solutions were slowly introduced into the mold, and then placed in a vacuum oven at 40° C. for 15 minutes, and finally cured under an ultraviolet lamp for 10 minutes to obtain an electrolyte membrane. The electrolyte membranes were assembled into button-type lithium / SS symmetrical batteries, and the electrochemical window of the battery was tested under the conditions of 0.1 mv / s and 25° C., and the following was obtained: Figure 1 The linear scanning curve shown in Figure 1 It can be seen that under the conditions of 0.1 mv / s and 25° C., the electrochemical window of Example 3 reaches 5.24 V, which is much higher than 4.52 V of the comparative example.

[0099] Experiment on the effect of different mass fractions of monomers on the cycle performance of lithium-ion batteries:

[0100] Using lithium iron phosphate as the positive electrode, the electrolytes of Example 1, Example 2, Example 3 and the comparative example were taken respectively, and the solutions were slowly introduced into the mold, and then placed in a 40°C vacuum oven for 15 minutes, and finally cured under an ultraviolet lamp for 10 minutes to obtain a positive electrode + electrolyte composite film. A positive electrode sheet with a thickness of 14 mm and a negative electrode with a thickness of 0.25 mm were taken. The cycle life and coulomb efficiency of the battery were tested at 0.2C and 25°C. The test results are as follows Figure 2 As shown by Figure 2 It can be seen that after 500 cycles, the battery capacity decay rate using the comparative example, i.e., the electrolyte without monomers, is significantly higher than that of the electrolyte provided by the present invention, and the average coulombic efficiency of the electrolytes of Examples 1, 2, and 3 is also higher than that of the comparative example.

[0101] Using lithium iron phosphate as the positive electrode, the electrolytes of Example 1, Example 2, Example 3 and the comparative example were taken respectively, and the solutions were slowly introduced into the mold, and then placed in a 40°C vacuum oven for 15 minutes, and finally cured under an ultraviolet lamp for 10 minutes to obtain a positive electrode + electrolyte composite film. A 14 mm positive electrode sheet was taken, and the negative electrode was a graphite electrode sheet. The cycle life and coulomb efficiency of the battery were tested at 0.2C and 25°C. The test results are as follows Figure 3 As shown by Figure 3 It can be seen that after 500 cycles, the full battery capacity decay rate of the same comparative electrolyte, i.e., the electrolyte without monomers, is significantly higher than that of the solid electrolyte provided by the present invention, and the average coulombic efficiency of the electrolytes of Examples 1, 2, and 3 is also higher than that of the comparative electrolyte.

[0102] Comparative analysis of the morphological characteristics of graphite negative electrodes after long cycles:

[0103] The full batteries with lithium iron phosphate as the positive electrode and graphite as the negative electrode in the above-mentioned Example 1, Example 2, Example 3 and the comparative example were disassembled after completing 500 cycles, and the morphology of the corresponding graphite negative electrode was observed under a scanning electron microscope. Figure 4 It can be seen that the graphite surface smoothness of the full cells of Examples 1, 2 and 3 of the present invention is better than that of the full cell of the comparative example, indicating that the added monomer has a certain effect on the protection of the graphite negative electrode.

[0104] Example 4

[0105] The present invention also provides a lithium-based energy storage device, using any of the above-mentioned solid electrolytes, the lithium-based energy storage device includes a lithium-ion battery, a lithium metal battery and a lithium-air battery.

[0106] It can be understood that the present invention provides a solid electrolyte and a lithium-based energy storage device, wherein the electrolyte includes polyethylene glycol dimethacrylate, an initiator and a monomer, and the monomer contains a fluorosulfonyl group and an ester group; the fluorosulfonyl group in the side chain of the monomer can reduce the crystallinity of the polymer, and effectively form a passivation layer on the surface of the lithium negative electrode, thereby expanding the electrochemical window of the battery, thereby improving the cycle life of the battery, and the formed flexible polymer skeleton can increase the compatibility between the electrolyte and the electrode, thereby reducing the interface resistance; the passivation layer can make the interface electric field uniform, regulate the diffusion of lithium ions, thereby effectively inhibiting the growth of dendrites, and achieving dense and uniform deposition; compared with an electrolyte without a monomer, a lithium-based energy storage device using the electrolyte containing a monomer of the present invention can greatly improve the cycle life of the lithium battery, significantly improve the utilization rate of the lithium metal negative electrode, effectively reduce the polarization voltage of the battery, and significantly improve the coulombic efficiency of the battery.

[0107] Example 5

[0108] When synthesizing the monomer, firstly, 169.9 g, 1200 mmol, of chlorosulfonyl isocyanate is slowly added into a two-necked round-bottomed flask containing 53.63 g, 300 mmol of antimony trifluoride, and the mixture is stirred to obtain a first mixed solution. The flask containing the first mixed solution is connected to a distillation reflux device in a nitrogen environment, and then the flask is placed under a reaction condition of 90 degrees, and the reaction is continuously stirred for 24 hours to obtain a transparent, strongly acidic fluorosulfonyl isocyanate liquid product with a yield of more than 70%.

[0109] Freshly obtained fluorosulfonyl isocyanate liquid (500 mmol) was dissolved in an appropriate amount of anhydrous dichloromethane, and then slowly added to a 250 mL two-necked flask containing hydroxyethyl methacrylate (750 mmol) in small amounts through a dropper. After sufficient mixing, a second mixed solution was obtained. The flask containing the second mixed solution was first placed in an ice water environment and stirred for 2 hours, and then reacted at room temperature for 24 hours to finally obtain a transparent third mixed solution. After three rotary evaporations, a fourth mixed solution was obtained, which was washed with anhydrous dichloromethane, filtered, and dried to finally obtain a white crystalline monomer.

[0110] S2: dissolving lithium salt, polyethylene glycol dimethacrylate, initiator and monomer in an organic solvent to obtain an electrolyte;

[0111] S3: injecting electrolyte into the battery cell;

[0112] S4: Use ultraviolet light to cure the electrolyte and battery cells, and encapsulate them to obtain lithium-based energy storage devices.

[0113] Example 6

[0114] When synthesizing the monomer, firstly, 127.4 g, 900 mmol, of chlorosulfonyl isocyanate is slowly added into a two-necked round-bottomed flask containing 53.63 g, 300 mmol of antimony trifluoride, and the mixture is stirred to obtain a first mixed solution. The flask containing the first mixed solution is connected to a distillation reflux device in a nitrogen environment, and then the flask is placed under a reaction condition of 80 degrees, and the reaction is continuously stirred for 48 hours to obtain a transparent, strongly acidic fluorosulfonyl isocyanate liquid product with a yield of more than 90%.

[0115] Take the freshly obtained fluorosulfonyl isocyanate liquid (500mmol), dissolve it in an appropriate amount of anhydrous dichloromethane, and then slowly add it to a 250mL two-necked flask containing hydroxyethyl methacrylate (550mmol) through a dropper in small amounts and multiple times. After fully mixing, a second mixed solution is obtained. The flask containing the second mixed solution is first placed in an ice water environment and stirred for 1 hour, and then reacted at room temperature for 48 hours to finally obtain a transparent third mixed solution. After three rotary evaporations, a fourth mixed solution is obtained, which is washed with anhydrous dichloromethane, filtered, and dried to finally obtain a white crystalline monomer.

[0116] It should be noted that fluorosulfonyl isocyanate liquid needs to be sealed and refrigerated for storage.

[0117] Example 7

[0118] When synthesizing the monomer, firstly, 148.6 g, 1050 mmol, of chlorosulfonyl isocyanate is slowly added into a two-necked round-bottom flask containing 53.63 g, 300 mmol, of antimony trifluoride, and the mixture is stirred to obtain a first mixed solution. The flask containing the first mixed solution is connected to a distillation reflux device in a nitrogen environment, and then the flask is placed under a reaction condition of 70 degrees, and the reaction is continuously stirred for 50 hours to obtain a transparent, strongly acidic fluorosulfonyl isocyanate liquid product.

[0119] Freshly obtained fluorosulfonyl isocyanate liquid (500 mmol) was dissolved in an appropriate amount of anhydrous dichloromethane, and then slowly added to a 250 mL two-necked flask containing hydroxyethyl methacrylate (600 mmol) in small amounts through a dropper. After fully mixing, a second mixed solution was obtained. The flask containing the second mixed solution was first placed in an ice water environment and stirred for 0.5 hours, and then reacted at room temperature for 50 hours to finally obtain a transparent third mixed solution. After three rotary evaporations, a fourth mixed solution was obtained, which was washed with anhydrous dichloromethane, filtered, and dried to finally obtain a white crystalline monomer;

[0120] S2: dissolving lithium salt, polyethylene glycol dimethacrylate, initiator and monomer in an organic solvent to obtain an electrolyte;

[0121] S3: injecting electrolyte into the battery cell;

[0122] S4: Use ultraviolet light to cure the electrolyte and battery cells, and encapsulate them to obtain lithium-based energy storage devices.

[0123] It can be seen from the above embodiments that the solid electrolyte, lithium-based energy storage device and preparation method provided by the present invention achieve at least the following beneficial effects:

[0124] The present invention provides a solid electrolyte, a lithium-based energy storage device and a preparation method. The solid electrolyte is obtained by curing an electrolyte with an ultraviolet lamp. The electrolyte includes polyethylene glycol dimethacrylate, an initiator and a monomer, and the monomer contains a fluorosulfonyl group and an ester group. The fluorosulfonyl group in the side chain of the monomer can reduce the crystallinity of the polymer, and effectively form a passivation layer on the surface of the lithium negative electrode, which expands the electrochemical window of the battery, thereby improving the cycle life of the battery. The formed flexible polymer skeleton can increase the compatibility between the electrolyte and the electrode, thereby reducing the interface resistance. The passivation layer can make the interface electric field uniform and regulate the diffusion of lithium ions, thereby effectively inhibiting the growth of dendrites and achieving dense and uniform deposition. Compared with an electrolyte without a monomer, a lithium-based energy storage device using the monomer-containing electrolyte of the present invention can greatly improve the cycle life of a lithium half-cell, significantly improve the utilization rate of a lithium metal negative electrode, effectively reduce the polarization voltage of the battery, and significantly improve the coulombic efficiency of the battery.

[0125] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A solid electrolyte, characterized in that The electrolyte is cured by ultraviolet light, wherein the electrolyte includes lithium salt, polyethylene glycol dimethacrylate, an initiator and a monomer, wherein the monomer includes a fluorosulfonyl group and an ester group, and the structural formula of the monomer is:

2. The solid electrolyte according to claim 1, characterized in that The lithium salt comprises at least one of lithium hexafluorophosphate, lithium bis(trifluoromethylsulfonyl imide) and lithium bis(fluorosulfonyl imide); And / or, the initiator includes one of lithium bis(oxalatoborate), lithium bis(trifluoromethylsulfonylimide), ethylene carbonate, propylene carbonate and fluoroethylene carbonate.

3. The solid electrolyte according to claim 1, characterized in that The mass fraction of the lithium salt in the electrolyte is 10%-30%; The mass fraction of the polyethylene glycol dimethacrylate in the electrolyte is 40-80%; The mass fraction of the initiator in the electrolyte is 1%-3%; And / or, the mass fraction of the monomer in the electrolyte is 10% to 30%.

4. The solid electrolyte according to claim 1, characterized in that The average molecular weight of the polyethylene glycol dimethacrylate is 550 to 750.

5. A lithium-based energy storage device, using the solid electrolyte according to any one of claims 1 to 4, characterized in that: Including lithium-ion batteries, lithium metal batteries and lithium-air batteries.

6. A method for preparing a lithium-based energy storage device, characterized in that: Includes steps: Synthesizing monomers, the synthesizing monomers comprising the steps of: mixing chlorosulfonyl isocyanate and antimony trifluoride to obtain a first mixed solution; distilling the first mixed liquid in a nitrogen environment; Heating the first mixed liquid to a first temperature and stirring for a first time to obtain a fluorosulfonyl isocyanate liquid; Dissolving the fluorosulfonyl isocyanate liquid in anhydrous dichloromethane, and adding the solution to hydroxyethyl methacrylate to obtain a second mixed solution; The second mixed liquid is placed in ice water and stirred for a second time, and then placed in a second temperature environment for a third time to obtain a third mixed liquid; The third mixed solution is subjected to at least two rotary evaporations to obtain a fourth mixed solution; The fourth mixed liquid is washed with anhydrous dichloromethane, filtered, and dried to obtain the monomer; Mixing and dissolving lithium salt, polyethylene glycol dimethacrylate, an initiator and the monomer in an organic solvent to obtain an electrolyte; injecting the electrolyte into the battery cell; The electrolyte and the battery core are cured by using an ultraviolet lamp, and the lithium-based energy storage device is obtained by encapsulation.

7. The method for preparing a lithium-based energy storage device according to claim 6, characterized in that: The molar ratio of the chlorosulfonyl isocyanate to the antimony trifluoride is 3:1 to 4:

1.

8. The method for preparing a lithium-based energy storage device according to claim 6, characterized in that: The first temperature is 70° C.-90° C., and the first time is 24 h-50 h.

9. The method for preparing a lithium-based energy storage device according to claim 6, characterized in that: The molar ratio of the fluorosulfonyl isocyanate to the hydroxyethyl methacrylate is 1:1.1 to 1:1.

5.

10. The method for preparing a lithium-based energy storage device according to claim 6, characterized in that: The second time is 0.5h-2h, the second temperature is 18°C ​​to 25°C, and the third time is 24h-50h.

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