An in-situ polymerized solid electrolyte, its preparation method and application, and lithium metal batteries

Abstract

This invention relates to the field of electrochemical energy storage materials and lithium metal battery technology, specifically to an in-situ polymerized solid electrolyte, its preparation method and application, and lithium metal batteries. This in-situ polymerized solid electrolyte is prepared by heating a ring-opening polymerization reaction using 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane as reactants, sodium thiosulfate as an initiator, and lithium salt and plasticizer fluoroethylene carbonate as a precursor solution. This electrolyte possesses numerous amorphous regions, which is beneficial for ion transport, enabling the formation of a self-supporting dense structure. It also ensures close contact with the electrode, resulting in a pure interface that effectively reduces interfacial impedance and avoids side reactions at the electrode interface. Furthermore, it enhances oxidation resistance, broadens the electrochemical window, and inhibits dendrite growth. While achieving good mechanical properties, it also improves the cycle stability and safety performance of the battery. It has excellent application prospects in lithium metal batteries, lithium-ion batteries, solid-state energy storage systems, or flexible electronic devices.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage materials and lithium metal battery technology, specifically to an in-situ polymerized solid electrolyte, its preparation method and application, and lithium metal batteries. Background Technology

[0002] With the rapid development of electric vehicles and large-scale energy storage markets, the demand for high-energy-density and high-safety rechargeable batteries is becoming increasingly urgent. Lithium metal batteries, due to their extremely high theoretical specific capacity (3860 mAh / g) and lowest electrochemical potential (-3.04 V vs. SHE) of lithium anodes, are considered ideal candidates for next-generation energy storage technologies. However, traditional liquid electrolytes pose safety hazards such as leakage, combustion, and even explosion, and lithium dendrite growth can easily penetrate the separator and cause short circuits, severely restricting their commercial application. Solid-state electrolytes, due to their inherent safety, lack of leakage risk, and mechanical strength that can suppress lithium dendrite growth, have become a key research direction for replacing liquid electrolytes. Among them, polymer solid-state electrolytes combine good flexibility, ease of processing and molding, and good interfacial compatibility with electrodes, making them particularly suitable for in-situ polymerization integrated battery assembly processes.

[0003] In the prior art, poly-1,3-dioxolane (PDOL) based polymer electrolytes have high room temperature ionic conductivity (10). -4 -10 -3 PDOL (Polydioxanone) has attracted widespread attention in recent years due to its excellent lithium metal interface stability (S / cm). PDOL is usually prepared by cationic ring-opening polymerization, and commonly used initiators include Lewis acids (such as Al(OTf)3) or lithium salts (such as LiPF6). However, these initiators have the following problems: (1) residual Lewis acids can catalyze the degradation of PDOL, leading to a decrease in long-term cycling stability; (2) initiator residues may participate in side reactions, deteriorating the electrode interface. In addition, the oxidation stability window of pure PDOL is relatively narrow (approximately 4.0 V vs. Li). + / Li) is difficult to match with high-voltage cathodes (such as NCM811). Therefore, there is an urgent need to find a suitable initiator for the ring-opening polymerization of cyclic monomers to solve the problems of initiator residue catalyzing polymer degradation and participating in side reactions.

[0004] Furthermore, existing polymer electrolytes require further improvements in their antioxidant capacity, electrochemical window, and interfacial stability. Additionally, existing lithium metal batteries require further improvements in their cycle stability. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the first objective of this invention is to provide a method for preparing an in-situ polymerized solid electrolyte. This method is simple, has low production cost, mild and controllable preparation conditions, is easy to scale up, and the resulting in-situ polymerized solid electrolyte improves antioxidant capacity and broadens the electrochemical window. It also avoids the problems of catalytic polymer degradation and participation in side reactions caused by traditional initiator residues, and can significantly improve interface stability and inhibit lithium dendrite growth.

[0006] To overcome the shortcomings of the prior art, the second objective of this invention is to provide an in-situ polymerized solid electrolyte that enhances antioxidant capacity and broadens the electrochemical window, avoids the problems of residual initiator catalyzing polymer degradation and participating in side reactions, and significantly improves interface stability and inhibits lithium dendrite growth.

[0007] The third objective of this invention is to provide an application of an in-situ polymerized solid electrolyte.

[0008] A fourth objective of this invention is to provide a lithium metal battery that exhibits excellent cycle stability.

[0009] The fifth objective of this invention is to provide a process for preparing lithium metal batteries. This process is an in-situ polymerization integrated molding process that does not require the addition of additional solvents, simplifies the process flow, reduces the preparation cost, facilitates large-scale production, and effectively reduces interfacial impedance.

[0010] To achieve the first objective of the invention, the technical solution adopted by the present invention is as follows:

[0011] This invention provides a method for preparing an in-situ polymerized solid electrolyte, comprising the following steps:

[0012] S1. Using 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane as reactants, sodium thiosulfate as an initiator, and lithium salt and plasticizer fluoroethylene carbonate as added, a precursor solution is prepared by mixing; wherein, the prepared precursor solution is a clear and transparent solution.

[0013] S2. The precursor solution is subjected to a ring-opening polymerization reaction by heating to obtain the in-situ polymerized solid electrolyte.

[0014] This invention discloses a method for preparing an in-situ polymerized solid electrolyte, using sodium thiosulfate as an initiator for the ring-opening polymerization of two cyclic monomers: 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane. Under heating conditions, the SS bonds in sodium thiosulfate break to generate anionic (sulfite and sulfide) active centers, initiating the ring-opening polymerization of the two cyclic monomers to form a polyether backbone. This heated ring-opening polymerization process is mild and controllable, resulting in a pure interface. This ensures a tight and continuous interface between the in-situ polymerized solid electrolyte and the electrode, free from microscopic voids, impurity phases, solvent residues, plasticizer precipitation, phase separation, and side reaction decomposition layers. The interface structure is uniform and stable, effectively solving the problems of polymer degradation and participation in side reactions caused by traditional initiator residues, significantly improving interface stability, and inhibiting lithium dendrite growth.

[0015] In this invention, 1,1,1-trifluoro-2,3-epoxypropane is used as one of the cyclic reactive monomers. Fluorine-containing side chains (-CF3) are covalently introduced into the polyether backbone. Fluorine possesses strong electronegativity and high oxidation stability, significantly improving the antioxidant capacity of the polymer backbone. Simultaneously, it synergistically works with fluoroethylene carbonate plasticizers to readily reduce on lithium metal surfaces, generating a stable LiF-rich interface layer that effectively inhibits dendrite growth. Introducing fluorine atoms into the polymer backbone via covalent bonds enhances the antioxidant capacity intrinsically at the material level and achieves a uniform and stable distribution of the fluorine source.

[0016] Furthermore, in step S1, the molar ratio of 1,3-dioxolane to 1,1,1-trifluoro-2,3-epoxypropane is (85~95):(8~12); under this molar ratio condition, 1,3-dioxolane can provide sufficient oxygen atom anchoring sites to ensure Li + Smooth transport, suppression of concentration polarization, and provision of sufficient fluorine atoms to 1,1,1-trifluoro-2,3-epoxypropane to ensure enhanced antioxidant capacity; and / or

[0017] The molar amount of sodium thiosulfate is 0.4 mol% to 1.0 mol% of the total molar amount of the reactants. This molar amount of sodium thiosulfate ensures catalytic efficiency.

[0018] Furthermore, in step S1, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide; and / or

[0019] The amount of the fluoroethylene carbonate used is 15 wt% to 25 wt% of the total mass of the precursor solution; wherein, the amount of fluoroethylene carbonate used is sufficient to introduce a sufficient amount of plasticizer into the electrolyte system, which can significantly disrupt the regularity of polymer chain segments, inhibit crystallization, increase the content of amorphous phase, and thus construct a continuous and efficient transport channel for lithium ions, improving ion conduction performance. and / or

[0020] The molar concentration of the lithium salt in the precursor solution is 0.5 M to 1.5 M.

[0021] Furthermore, in step S2, the temperature of the heating ring-opening polymerization reaction is 65 ℃~75 ℃, and the reaction time is 12 h~14 h. Specifically, this invention obtains a polymer with a suitable molecular weight by ring-opening polymerization at 65 ℃~75 ℃ for 12 h~14 h, resulting in a number-average molecular weight of 15 × 10⁻⁶. 3 g / mol ~ 25 × 10 3 g / mol, molecular weight distribution index less than 2.2, uniform molecular weight distribution, and high structural regularity.

[0022] To achieve the second objective of the invention, the technical solution adopted by the present invention is as follows:

[0023] This invention provides an in-situ polymerized solid electrolyte, which is prepared by the method described above for preparing an in-situ polymerized solid electrolyte.

[0024] Furthermore, the thickness of the in-situ polymerized solid electrolyte is 10 µm to 20 µm.

[0025] To achieve the third objective of the invention, the technical solution adopted by the present invention is as follows:

[0026] This invention provides an application of an in-situ polymerized solid electrolyte, specifically the in-situ polymerized solid electrolyte prepared by the aforementioned method, in lithium metal batteries, lithium-ion batteries, solid-state energy storage systems, or flexible electronic devices.

[0027] To achieve the fourth objective of the invention, the technical solution adopted by the present invention is as follows:

[0028] This invention provides a lithium metal battery, comprising an in-situ polymerized solid electrolyte as described above or an in-situ polymerized solid electrolyte prepared by the method described above.

[0029] Furthermore, the lithium metal battery further includes a positive electrode and a negative electrode; and / or

[0030] The positive electrode is lithium iron phosphate or lithium nickel cobalt manganese oxide, and the negative electrode is lithium metal; and / or

[0031] The lithium metal battery is a button cell lithium metal battery or a pouch cell lithium metal battery.

[0032] To achieve the fifth objective of the invention, the technical solution adopted by the present invention is as follows:

[0033] This invention provides a process for preparing a lithium metal battery, wherein the precursor solution is injected into the battery casing, and then a ring-opening polymerization reaction is carried out under heating to obtain the lithium metal battery.

[0034] The present invention discloses a process for preparing a lithium metal battery, in which a precursor solution is directly injected into the battery casing for a heated ring-opening polymerization reaction without the need for additional solvents. The precursor solution can uniformly wet the positive and negative electrodes of the battery. After the heated ring-opening polymerization reaction, a tight solid-solid interface contact is formed, which effectively reduces the interface impedance, simplifies the battery assembly process, and facilitates large-scale production.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] (1) A method for preparing an in-situ polymerized solid electrolyte according to the present invention uses sodium thiosulfate (Na2S2O3) as an initiator for the ring-opening polymerization of two cyclic monomers, 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane. This method has the advantages of being inexpensive and low-toxicity. Specifically, the SS bond in sodium thiosulfate breaks under heating conditions to generate sulfite anions (SO32-). 2- ) and hydrosulfide anion (HS) - Two types of nucleophilic anionic active centers initiate the ring-opening polymerization of two cyclic monomers in this invention, forming a polyether backbone. This heated ring-opening polymerization process is mild and controllable, resulting in a pure interface. This allows for a tight and continuous interface between the in-situ polymerized solid electrolyte and the electrode, free from microscopic voids, impurity phases, solvent residues, plasticizer precipitation, phase separation, and side reaction decomposition layers. The interface structure is uniform and stable, effectively solving the problem of polymer degradation and participation in side reactions caused by traditional initiator residues. This significantly improves interface stability, inhibits lithium dendrite growth, and enhances the long-term cycle stability of batteries when applied to them.

[0037] (2) A method for preparing an in-situ polymerized solid electrolyte of the present invention involves ring-opening copolymerization of 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane, in which fluorine-containing side chains (-CF3) are introduced into the polyether backbone in the form of covalent bonds. The strong electronegativity of fluorine significantly enhances the antioxidant capacity of the polymer skeleton and broadens the electrochemical window. At the same time, a stable interface layer rich in LiF is constructed in situ on the lithium metal surface in conjunction with fluoroethylene carbonate plasticizer, which greatly improves the interface stability and inhibits the growth of lithium dendrites.

[0038] (3) The method for preparing an in-situ polymerized solid electrolyte of the present invention uses sodium thiosulfate as an initiator, which has the advantage of low cost. Furthermore, the ring-opening reaction of the two cyclic monomers of the present invention initiated by sodium thiosulfate is mild and controllable. Therefore, the preparation method is simple, has low production cost, mild and controllable preparation conditions, and is easy to scale up.

[0039] (4) An in-situ polymerized solid electrolyte of the present invention has a large number of amorphous regions, a glass transition temperature below -50 °C, and exhibits excellent low-temperature flexibility and chain segment mobility; its number-average molecular weight is 15 × 10⁻⁶. 3 g / mol ~ 25 × 10 3 With a molecular weight distribution index of less than 2.2, uniform molecular weight distribution, and high structural regularity, this in-situ polymerized solid electrolyte can form a self-supporting film with good mechanical strength and structural stability. It can form a tight and pure interface with the electrode, free of impurities, voids, phase separation, and by-reaction product layers, effectively reducing interfacial impedance and promoting ion transport. Simultaneously, this in-situ polymerized solid electrolyte significantly improves antioxidant stability, increases the oxidation decomposition potential, and broadens the electrochemical window, suppressing interfacial side reactions at high potentials and enhancing the cycle stability and safety of the battery over a wide voltage range.

[0040] (5) An in-situ polymerized solid electrolyte of the present invention has a room temperature ionic conductivity of 7.5 × 10⁻⁶. -4 The mechanical properties meet the requirements for self-supporting film formation, with an S / cm ratio, lithium-ion transference number greater than 0.6, an electrochemical window exceeding 5 V, tensile strength of 8 MPa~9 MPa, elongation at break of 150%.

[0041] (6) An in-situ polymerized solid electrolyte of the present invention, wherein the in-situ polymerized solid electrolyte is assembled into a lithium symmetric battery, which can achieve a speed of 0.1 mA cm⁻¹ -2 Stable cycling for over 600 hours at current density with stable polarization voltage and no short circuit indicates excellent interfacial compatibility with lithium metal anodes, effectively suppressing lithium dendrite formation and growth. When assembled into a LiFePO4|SPE|Li full cell, it retains more than 60% of its capacity after 500 cycles at 0.5 C rate, demonstrating excellent cycle stability and good practical potential, making it suitable for constructing high-safety, long-cycle-life lithium metal battery systems.

[0042] (7) An application of an in-situ polymerized solid electrolyte of the present invention, which has great application prospects in lithium metal batteries, lithium-ion batteries, solid energy storage systems or flexible electronic devices.

[0043] (8) A lithium metal battery of the present invention uses the in-situ polymerized solid electrolyte of the present invention. The polymer solid electrolyte is in the form of a self-supporting film and has good mechanical strength and structural stability. At the same time, the electrolyte has a large number of amorphous regions, which can greatly eliminate the obstruction of ion transport by crystalline regions, provide a continuous and efficient transport channel for lithium ions, and significantly improve ion conduction efficiency. In addition, its glass transition temperature is lower than -50 ℃, and the polymer chain segments have strong mobility at room temperature and low temperature, which endows the electrolyte with excellent flexibility, interfacial compatibility and structural adaptability. It can form a tight, stable and uniform contact interface with the lithium metal electrode, significantly suppress the generation and growth of lithium dendrites, improve the cycle stability and safety performance of the battery, and is very suitable for high-performance lithium metal battery systems.

[0044] (9) The lithium metal battery preparation process of the present invention involves directly injecting the precursor solution into the battery casing for a heated ring-opening polymerization reaction without the need for additional solvents, achieving in-situ polymerization and integrated molding. This results in close contact between the electrolyte and the electrode, excellent interfacial compatibility, and effectively solves the problems of poor interfacial contact and insufficient oxidation stability of traditional solid electrolytes. It also simplifies the battery assembly process and facilitates large-scale production. Furthermore, it enables the achievement of ultra-thin electrolytes, improving energy density. The thickness of the in-situ polymerized solid electrolyte in this lithium metal battery is 10 µm to 20 µm. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a SEM image of the in-situ polymerized solid electrolyte of Example 1 of the present invention.

[0047] Figure 2 This is a DSC diagram of the in-situ polymerized solid electrolyte of Example 1 of the present invention.

[0048] Figure 3 This is an XPS image of the SEI film at the lithium anode interface after cycling of the in-situ polymerized solid electrolyte assembled battery of Embodiment 1 of the present invention.

[0049] Figure 4 This is an electrochemical window test curve of the in-situ polymerized solid electrolyte of Example 1 of the present invention.

[0050] Figure 5 This is a graph showing the electrochemical impedance spectroscopy results of the in-situ polymer solid electrolyte of Example 1 of the present invention at room temperature.

[0051] Figure 6 This is a graph showing the electrochemical impedance spectroscopy results of the in-situ polymer solid electrolyte of Comparative Example 1 of the present invention at room temperature.

[0052] Figure 7 This is a graph showing the electrochemical impedance spectroscopy results of the in-situ polymer solid electrolyte of Comparative Example 2 of the present invention at room temperature.

[0053] Figure 8 This is a graph showing the cycle performance of a lithium symmetric battery assembled with an in-situ polymerized solid electrolyte according to Example 1 of the present invention.

[0054] Figure 9 This is a cycle performance curve of the LiFePO4 full cell assembled by in-situ polymerized solid electrolyte in Example 1 of the present invention. Detailed Implementation

[0055] To make the technical problem to be solved, the technical solution, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0056] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. In this invention, the singular forms “a,” “described,” and “the” as used in the embodiments and appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0057] In this embodiment of the invention, a method for preparing an in-situ polymerized solid electrolyte includes the following steps:

[0058] S1. Using 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane as reactants, sodium thiosulfate as an initiator, and lithium salt and plasticizer fluoroethylene carbonate as added, a precursor solution is prepared by mixing.

[0059] S2. The precursor solution is subjected to a ring-opening polymerization reaction by heating to obtain the in-situ polymerized solid electrolyte.

[0060] In some embodiments, in step S1, the molar ratio of 1,3-dioxolane to 1,1,1-trifluoro-2,3-epoxypropane is (85~95):(8~12); and / or

[0061] The molar amount of sodium thiosulfate is 0.4 mol% to 1.0 mol% of the total molar amount of the reactants.

[0062] In some embodiments, in step S1, the lithium salt is lithium bis(trifluoromethanesulfonylimide); and / or

[0063] The fluoroethylene carbonate is 15 wt% to 25 wt% of the total mass of the precursor solution; and / or

[0064] The molar concentration of the lithium salt in the precursor solution is 0.5 M to 1.5 M.

[0065] In some embodiments, in step S2, the temperature of the heating ring-opening polymerization reaction is 65 ℃~75 ℃, and the time of the heating ring-opening polymerization reaction is 12 h~14 h.

[0066] In this embodiment of the invention, an in-situ polymerized solid electrolyte is prepared by the method described above for preparing an in-situ polymerized solid electrolyte.

[0067] The thickness of the in-situ polymerized solid electrolyte is 10 µm to 20 µm.

[0068] In this embodiment of the invention, an in-situ polymerized solid electrolyte is applied in lithium metal batteries, lithium-ion batteries, solid-state energy storage systems, or flexible electronic devices.

[0069] In this embodiment of the invention, a lithium metal battery includes an in-situ polymerized solid electrolyte as described above or an in-situ polymerized solid electrolyte prepared by the method described above.

[0070] The lithium metal battery further includes a positive electrode and a negative electrode; and / or

[0071] The positive electrode is lithium iron phosphate or lithium nickel cobalt manganese oxide, and the negative electrode is lithium metal; and / or

[0072] The lithium metal battery is a button cell lithium metal battery or a pouch cell lithium metal battery.

[0073] In this embodiment of the invention, a process for preparing a lithium metal battery involves injecting the precursor solution into a battery casing and then performing a heated ring-opening polymerization reaction to obtain the lithium metal battery.

[0074] The following description is based on specific embodiments. Example 1

[0075] A method for preparing an in-situ polymerized solid electrolyte includes the following steps:

[0076] S1. Add the reactants 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane, the initiator sodium thiosulfate, the lithium salt lithium bis(trifluoromethanesulfonyl)imide, and the plasticizer fluoroethylene carbonate to a container and stir magnetically for 30 minutes to prepare a precursor solution. In this embodiment, the molar ratio of 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane is 90:10; the molar amount of sodium thiosulfate is 0.6 mol% of the total molar amount of the reactants; the fluoroethylene carbonate is 20 wt% of the total mass of the precursor solution; and the molar concentration of the lithium salt in the precursor solution is 1.0 M.

[0077] S2. The precursor solution is injected into the battery casing, sealed, and then transferred to an oven at 70 °C for a ring-opening polymerization reaction for 14 h. After natural cooling to room temperature, a semi-transparent, flexible in-situ polymerized solid electrolyte (denoted as CDT90) is obtained. Example 2

[0078] A method for preparing an in-situ polymerized solid electrolyte includes the following steps:

[0079] S1. Add the reactants 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane, the initiator sodium thiosulfate, the lithium salt lithium bis(trifluoromethanesulfonyl)imide, and the plasticizer fluoroethylene carbonate to a container and stir magnetically for 30 minutes to prepare a precursor solution. In this embodiment, the molar ratio of 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane is 85:8; the molar amount of sodium thiosulfate is 0.4 mol% of the total molar amount of the reactants; the fluoroethylene carbonate is 15 wt% of the total mass of the precursor solution; and the molar concentration of the lithium salt in the precursor solution is 0.5 M.

[0080] S2. The precursor solution is injected into the battery casing, sealed, and then transferred to an oven at 65 °C for a ring-opening polymerization reaction for 13 h. After natural cooling to room temperature, a translucent and flexible in-situ polymerized solid electrolyte is obtained. Example 3

[0081] A method for preparing an in-situ polymerized solid electrolyte includes the following steps:

[0082] S1. Add the reactants 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane, the initiator sodium thiosulfate, the lithium salt lithium bis(trifluoromethanesulfonyl)imide, and the plasticizer fluoroethylene carbonate to a container and stir magnetically for 30 minutes to prepare a precursor solution. In this embodiment, the molar ratio of 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane is 95:12; the molar amount of sodium thiosulfate is 1.0 mol% of the total molar amount of the reactants; the fluoroethylene carbonate is 25 wt% of the total mass of the precursor solution; and the molar concentration of the lithium salt in the precursor solution is 1.5 M.

[0083] S2. The precursor solution is injected into the battery casing, sealed, and then transferred to an oven at 75 °C for a ring-opening polymerization reaction for 12 h. After natural cooling to room temperature, a translucent and flexible in-situ polymerized solid electrolyte is obtained. Example 4

[0084] A method for preparing an in-situ polymerized solid electrolyte includes the following steps:

[0085] S1. Add the reactants 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane, the initiator sodium thiosulfate, the lithium salt lithium bis(trifluoromethanesulfonyl)imide, and the plasticizer fluoroethylene carbonate to a container and stir magnetically for 30 minutes to prepare a precursor solution. In this embodiment, the molar ratio of 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane is 88:9; the molar amount of sodium thiosulfate is 0.5 mol% of the total molar amount of the reactants; the fluoroethylene carbonate is 18 wt% of the total mass of the precursor solution; and the molar concentration of the lithium salt in the precursor solution is 0.8 M.

[0086] S2. The precursor solution is injected into the battery casing, sealed, and then transferred to an oven at 68 °C for a ring-opening polymerization reaction for 13.5 h. After natural cooling to room temperature, a translucent and flexible in-situ polymerized solid electrolyte is obtained. Example 5

[0087] A method for preparing an in-situ polymerized solid electrolyte includes the following steps:

[0088] S1. Add the reactants 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane, the initiator sodium thiosulfate, the lithium salt lithium bis(trifluoromethanesulfonylimide), and the plasticizer fluoroethylene carbonate to a container and stir magnetically for 30 minutes to prepare a precursor solution. In this embodiment, the molar ratio of 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane is 92:11; the molar amount of sodium thiosulfate is 0.8 mol% of the total molar amount of the reactants; the fluoroethylene carbonate is 23 wt% of the total mass of the precursor solution; and the molar concentration of the lithium salt in the precursor solution is 1.3 M.

[0089] S2. The precursor solution is injected into the battery casing, sealed, and then transferred to an oven at 73 °C for a ring-opening polymerization reaction for 12.5 h. After natural cooling to room temperature, a translucent and flexible in-situ polymerized solid electrolyte is obtained. Example 6

[0090] Application of an in-situ polymerized solid electrolyte: Application of any one of the in-situ polymerized solid electrolytes in lithium metal batteries, lithium-ion batteries, solid-state energy storage systems, or flexible electronic devices, as described in Examples 1 to 5. Example 7

[0091] A lithium metal battery includes any one of the in-situ polymerized solid electrolytes from Examples 1 to 5, and further includes a positive electrode and a negative electrode, wherein the positive electrode is lithium iron phosphate or lithium nickel cobalt manganese oxide, and the negative electrode is lithium metal.

[0092] Among them, the lithium metal battery is either a button-type lithium metal battery or a pouch-type lithium metal battery.

[0093] The above-mentioned lithium metal battery preparation process, according to any one of the in-situ polymerization solid electrolyte preparation methods in Examples 1 to 5, involves injecting the precursor solution into the casing of a coin-type lithium metal battery or a pouch lithium metal battery, sealing it, and then carrying out a heated ring-opening polymerization reaction under any one of the ring-opening polymerization reaction conditions in Examples 1 to 5 to obtain the lithium metal battery.

[0094] Comparative Example 1

[0095] A method for preparing an in-situ polymerized solid electrolyte. The difference between this comparative example and Example 1 is that the molar amount of sodium thiosulfate in this comparative example is 0.2 mol% of the total molar amount of the reactants. The rest of the preparation method is the same as in Example 1.

[0096] Comparative Example 2

[0097] A method for preparing an in-situ polymerized solid electrolyte. The difference between this comparative example and Example 1 is that the molar amount of sodium thiosulfate in this comparative example is 1.2 mol% of the total molar amount of the reactants. The rest of the preparation method is the same as in Example 1.

[0098] Comparative Example 3

[0099] A method for preparing an in-situ polymerized solid electrolyte. The difference between this comparative example and Example 1 is that the molar ratio of 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane in this comparative example is 95:5. All other preparation methods are the same as in Example 1.

[0100] Comparative Example 4

[0101] A method for preparing an in-situ polymerized solid electrolyte. The difference between this comparative example and Example 1 is that the molar ratio of 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane in this comparative example is 85:15. All other preparation methods are the same as in Example 1.

[0102] Comparative Example 5

[0103] A method for preparing an in-situ polymerized solid electrolyte. The difference between this comparative example and Example 1 is that, in this comparative example, fluoroethylene carbonate accounts for 10 wt% of the total mass of the precursor solution. The rest of the preparation method is the same as in Example 1.

[0104] Comparative Example 6

[0105] A method for preparing an in-situ polymerized solid electrolyte. The difference between this comparative example and Example 1 is that, in this comparative example, fluoroethylene carbonate accounts for 30 wt% of the total mass of the precursor solution. The rest of the preparation method is the same as in Example 1.

[0106] Comparative Example 7

[0107] A method for preparing an in-situ polymerized solid electrolyte is disclosed. The difference between this comparative example and Example 1 is that in this comparative example, only 1,3-dioxolane is used as the reactant monomer, without the addition of 1,1,1-trifluoro-2,3-epoxypropane. All other preparation methods are the same as in Example 1.

[0108] Comparative Example 8

[0109] A method for preparing an in-situ polymerized solid electrolyte. The difference between this comparative example and Example 1 is that the ring-opening polymerization reaction time in this comparative example is 11 h. The rest of the preparation method is the same as in Example 1.

[0110] Comparative Example 9

[0111] A method for preparing an in-situ polymerized solid electrolyte. The difference between this comparative example and Example 1 is that the ring-opening polymerization reaction time in this comparative example is 16 h. The rest of the preparation method is the same as in Example 1.

[0112] Comparative Example 10

[0113] A method for preparing an in-situ polymerized solid electrolyte. The difference between this comparative example and Example 1 is that in this comparative example, the conventional initiator lithium hexafluorophosphate (LiPF6) is used instead of the initiator sodium thiosulfate (Na2S2O3) in Example 1. The rest of the preparation method is the same as in Example 1.

[0114] Structural morphology characterization

[0115] (I) Morphological characterization by scanning electron microscopy

[0116] The surface morphology of the in-situ polymerized solid electrolyte (CDT90) prepared in Example 1 was characterized by scanning electron microscopy (SEM), such as... Figure 1 As shown.

[0117] Depend on Figure 1 As can be seen, the in-situ polymerized solid electrolyte prepared by this invention has a dense structure with no visible pores or micropores inside. The structure is continuous and uniform, which can effectively avoid problems such as ion transport obstruction, aggravated side reactions at the electrode interface and battery short circuit caused by the presence of pores. At the same time, it can improve the interfacial contact tightness between the electrolyte and the electrode, and ensure the electrochemical performance and safety of the battery.

[0118] (ii) Differential Scanning Calorimetry (DSC) Analysis

[0119] The in-situ polymerized solid electrolyte (CDT90) prepared in Example 1 was analyzed by differential scanning calorimetry (DSC). Figure 2 As shown.

[0120] Depend on Figure 2 It can be seen that a typical glass transition step appears at approximately -50.2 °C, exhibiting a clear Tg. g The step-like, distinct shift in the baseline indicates that the glass transition temperature of the in-situ polymerized solid electrolyte prepared in this invention is below -50 °C.

[0121] In addition, since the in-situ polymerized solid electrolyte has a low glass transition temperature, which is significantly lower than room temperature, it indicates that it has significant chain segment mobility at room temperature. The system contains a large number of amorphous regions, which is beneficial for ion transport.

[0122] (III) Characterization by X-ray photoelectron spectroscopy (XPS)

[0123] A lithium-ion symmetric battery assembled from the in-situ polymerized solid electrolyte (CDT90) prepared in Example 1 was tested at 0.1 mA cm⁻¹. -2 0.1 mAh cm -2 The SEI film at the lithium anode interface was characterized by X-ray photoelectron spectroscopy (XPS) after cycling at a current for 10 h. Figure 3 As shown.

[0124] Depend on Figure 3 It is evident that the SEI film at the lithium anode interface is rich in LiF components. LiF is a recognized high-quality SEI film component in solid-state battery systems, which can effectively improve interfacial ion transport capabilities and optimize the mechanical stability of the interfacial film.

[0125] Performance testing

[0126] (I) Electrochemical window testing of in-situ polymerized solid electrolytes

[0127] The electrochemical window of the in-situ polymerized solid electrolyte (CDT90) prepared in Example 1 was tested using linear sweep voltammetry (LSV). Electrochemical window test curves were obtained to characterize its electrochemical stable voltage range, such as... Figure 4 As shown.

[0128] Depend on Figure 4 As can be seen, the electrochemical window of this in-situ polymer solid electrolyte (CDT90) reaches 5.2 V, exhibiting excellent antioxidant stability.

[0129] (II) Electrochemical impedance spectroscopy of in-situ polymerized solid electrolytes

[0130] The in-situ polymerized solid electrolytes prepared in Example 1, Comparative Example 1, and Comparative Example 2 were subjected to electrochemical impedance spectroscopy (EIS) tests. The EIS results for Example 1 are as follows: Figure 5 As shown, the electrochemical impedance spectroscopy results for Comparative Example 1 are as follows: Figure 6 As shown, the electrochemical impedance spectroscopy results for Comparative Example 2 are as follows: Figure 7 As shown.

[0131] Depend on Figure 5 As can be seen, the in-situ polymer solid electrolyte of Example 1 has an electrochemical impedance of 2.3 Ω at room temperature, the in-situ polymer solid electrolyte of Comparative Example 1 has an electrochemical impedance of 5.8 Ω at room temperature, and the in-situ polymer solid electrolyte of Comparative Example 2 has an electrochemical impedance of 4.1 Ω at room temperature. This shows that the in-situ polymer solid electrolyte prepared by the present invention achieves the minimum impedance and the highest ionic conductivity under the condition that the molar amount of sodium thiosulfate initiator is 0.6 mol% of the total molar amount of the reactant monomers.

[0132] (III) Cycle performance testing of lithium symmetric batteries

[0133] The in-situ polymerized solid electrolyte (CDT90) prepared in Example 1 was used to assemble a lithium-symmetric battery (Li|SPE|Li) at a current density of 0.1 mA cm⁻¹. -2 The surface capacity is 0.1 mAh cm -2 The cycle performance of the lithium symmetric battery was tested under the specified test conditions, and the test results are as follows: Figure 8 As shown.

[0134] Depend on Figure 8 As can be seen, the in-situ polymerized solid electrolyte (CDT90) of this invention assembles a lithium symmetric battery at a current density of 0.1 mA cm⁻¹. -2 The surface capacity is 0.1 mAh cm -2 Under constant current cycling conditions, the polarization voltage stabilized at approximately 100 mV, and the battery remained short-circuited for 600 hours. This demonstrates that the in-situ polymerized solid electrolyte of this invention exhibits extremely low interfacial impedance and polarization voltage in lithium symmetric batteries, and can cycle stably for a long time without short circuits. This indicates that the in-situ polymerized solid electrolyte has excellent interfacial compatibility with the lithium metal anode, effectively uniformizing lithium-ion flux, suppressing the formation and growth of lithium dendrites, and significantly improving the interfacial stability and safety performance of lithium metal batteries.

[0135] (iv) Cyclic performance test of LiFePO4 full cell

[0136] The in-situ polymerized solid electrolyte (CDT90) prepared in Example 1 was used to assemble a LiFePO4 full cell. The LiFePO4 full cell cycle performance was tested at room temperature and a charge / discharge rate of 0.5C. The results are as follows: Figure 9 As shown.

[0137] Depend on Figure 9 As can be seen, the LiFePO4 full cell assembled with the in-situ polymerized solid electrolyte (CDT90) of this invention exhibits an initial discharge capacity of 142 mAh / g under room temperature and 0.5 C charge / discharge rate conditions, and retains 60% of its capacity after 500 cycles. This demonstrates that the LiFePO4 full cell assembled with the in-situ polymerized solid electrolyte of this invention exhibits excellent discharge specific capacity, cycle stability, and rate performance. The electrolyte has good interfacial compatibility with both the lithium metal anode and the LFP cathode, effectively suppressing the formation and growth of lithium dendrites, reducing interfacial impedance, resulting in slow capacity decay and high coulombic efficiency during long-term cycling. It demonstrates excellent safety performance and cycle stability, making it suitable for high-safety, long-life lithium metal batteries.

[0138] (v) Performance comparison of Example 1, Comparative Example 1 and Comparative Example 2

[0139] The in-situ polymerized solid electrolytes prepared in Example 1, Comparative Example 1, and Comparative Example 2 differ in the molar amount of sodium thiosulfate used, i.e., the concentration of sodium thiosulfate in the system is different.

[0140] The in-situ polymerized solid electrolytes prepared in Examples 1, 1, and 2 were tested for product morphology, monomer conversion rate, room temperature ionic conductivity, and lithium-ion symmetric battery cycle performance. The monomer conversion rate was determined by gravimetric method; the room temperature ionic conductivity was measured by electrochemical impedance spectroscopy (EIS), using SS|SPE|SS blocking batteries (SS being a stainless steel electrode and SPE being the in-situ polymer solid electrolyte); and the lithium-ion symmetric battery cycle performance was measured using lithium-ion symmetric batteries assembled with the in-situ polymer solid electrolyte at a current density of 0.1 mA cm⁻¹. -2 The surface capacity is 0.1 mAh cm -2 The results were obtained under the specified test conditions. The test results are shown in Table 1.

[0141] Table 1. Performance test results of different initiator dosages in Example 1, Comparative Example 1, and Comparative Example 2.

[0142]

[0143] As shown in Table 1, the in-situ polymerized solid electrolyte prepared in Example 1 is a semi-transparent self-supporting membrane with high monomer conversion rate and room temperature ionic conductivity, and exhibits excellent lithium-ion symmetric battery cycle life of up to 600 hours. In Comparative Example 1, when the initiator concentration is below 0.4 mol%, polymerization is incomplete, and the electrolyte remains a viscous liquid, failing to yield a solid electrolyte with good mechanical properties. In Comparative Example 2, an excessively high initiator concentration leads to excessive cross-linking and side reactions in the ring-opening polymerization reaction, resulting in poor electrochemical performance; the lithium-ion symmetric battery short-circuited after only 200 hours of cycling. This demonstrates that the concentration of sodium thiosulfate in the system has a significant impact on the product morphology and performance of the in-situ polymerized solid electrolyte.

[0144] (vi) Performance comparison of Example 1, Comparative Example 3 and Comparative Example 4

[0145] The in-situ polymerized solid electrolytes prepared in Examples 1, 3, and 4 differed in the molar ratio of the two cyclic reactive monomers, 1,3-dioxolane (DOL) and 1,1,1-trifluoro-2,3-epoxypropane (TFPO).

[0146] The in-situ polymerized solid electrolytes prepared in Examples 1, 3, and 4 were subjected to DSC analysis, room temperature ionic conductivity, electrochemical window, and lithium-ion transport number (t). Li +The tests included elongation at break, LiFePO4 full-cell cycle performance, and lithium-symmetric battery cycle performance. The methods for DSC analysis, room-temperature ionic conductivity, and lithium-symmetric battery cycle performance testing were consistent with those described above. Furthermore, the electrochemical window was tested using linear sweep voltammetry (LSV), and the test battery was a Li|SPE|SS battery (Li is a lithium metal electrode, SS is a stainless steel electrode, and SPE is an in-situ polymer solid electrolyte). Lithium-ion transport number (t...) Li + The tensile strength was determined using the Bruce-Vincent method. Elongation at break was obtained through tensile testing. The testing methods for elongation at break and tensile strength are as follows: Using an INSTRON 3367 electronic universal testing machine, tensile tests were performed on an in-situ polymer solid electrolyte with dimensions of 60 mm × 40 mm × 3 mm according to the test method of GB / T1040.2; the tensile strength and elongation at break of the material were evaluated through the obtained stress-strain curves. The LiFePO4 full-cell cycle performance test involved assembling a LiFePO4 full cell using the in-situ polymer solid electrolyte. Under room temperature and a charge / discharge rate of 0.5 C, the initial discharge capacity of the full cell was 142 mAh / g, and the capacity retention was measured after 500 cycles. The test results are shown in Table 2.

[0147] Table 2. Performance test results for different monomer ratios in Examples 1, 3, and 4.

[0148]

[0149] As shown in Table 2, for the two cyclic reactive monomers DOL and TFPO of the present invention, when the proportion of TFPO is too low (see Comparative Example 3), the glass transition temperature of the in-situ polymer solid electrolyte is greatly increased. g =-15℃ and there are a large number of crystalline regions. Affected by this crystallization phenomenon, the improvement of its electrochemical window is limited, resulting in a decrease in room temperature ionic conductivity and elongation at break. The presence of crystalline phase will destroy the uniformity of the interface contact between the electrolyte and the lithium metal electrode, which can easily cause local current concentration, accelerate the growth of lithium dendrites, and in severe cases, puncture the electrolyte membrane, leading to battery short circuit and reducing battery safety performance and cycle life.

[0150] Furthermore, when the TFPO ratio is too high (see Comparative Example 4), the glass transition temperature of the in-situ polymer solid electrolyte increases significantly to -20.4℃, and its flexibility decreases, with an elongation at break of only 80%, reducing chain segment mobility and decreasing the cycling performance of the LiFePO4 full cell. Insufficient flexibility leads to poor interfacial contact between the electrolyte and the lithium metal electrode, easily generating interfacial voids, which in turn triggers side reactions to form an interfacial impedance layer. After long-term cycling, this further increases internal resistance, resulting in faster battery capacity decay and decreased cycle stability.

[0151] (vii) Performance comparison of Example 1, Comparative Example 5 and Comparative Example 6

[0152] The in-situ polymerized solid electrolytes prepared in Examples 1, 5, and 6 differed in the amount of fluoroethylene carbonate plasticizer used in the precursor solution.

[0153] The in-situ polymerized solid electrolytes prepared in Examples 1, 5, and 6 were subjected to tests to determine their room temperature ionic conductivity, electrochemical window, and lithium-ion transport number (t). Li + The tensile strength, elongation at break, and cycle performance of the lithium-ion symmetric battery were tested. The test results are shown in Table 3.

[0154] Table 3. Performance test results for different amounts of plasticizer in Examples 1, 5, and 6.

[0155]

[0156] As shown in Table 3, when the amount of fluoroethylene carbonate plasticizer added to the system is too low, the plasticizing effect is insufficient, the improvement in conductivity and interfacial stability is limited, the tensile strength and elongation at break decrease significantly, and the cycle life of lithium symmetric batteries decreases significantly. Furthermore, when the amount of fluoroethylene carbonate plasticizer added to the system is too high, a small amount of liquid seeps out from the surface of the in-situ polymerized solid electrolyte membrane, leading to a significant decrease in tensile strength and elongation at break, a significant decrease in the cycle life of lithium symmetric batteries, and a significant increase in polarization voltage in the later stages of cycling. This indicates that excessive fluoroethylene carbonate plasticizer can damage the integrity of the polymer network and lead to a decrease in the long-term stability of the battery.

[0157] (viii) Performance comparison between Example 1 and Comparative Example 7

[0158] The difference between the in-situ polymerized solid electrolytes prepared in Example 1 and Comparative Example 7 is that Example 1 uses two reactive monomers, DOL and TFPO, while Comparative Example 7 uses only the reactive monomer DOL.

[0159] The in-situ polymerized solid electrolytes prepared in Example 1 and Comparative Example 7 were subjected to DSC analysis, room temperature ionic conductivity, electrochemical window, lithium symmetric battery cycle performance, and post-cycle appearance of the lithium anode, respectively. The test results are shown in Table 4.

[0160] Table 4. Performance test results of Example 1 and Comparative Example 7

[0161]

[0162] As shown in Table 4, the in-situ polymerized solid electrolyte prepared in Comparative Example 7 using only the reactive monomer DOL, without the reactive monomer TFPO, exhibits a significantly higher glass transition temperature and a large number of crystalline regions. This results in reduced chain segment mobility, a narrower electrochemical stability window, and poorer interfacial compatibility and stability with the electrode. Therefore, this invention demonstrates that the in-situ polymerized solid electrolyte prepared by heating and ring-opening polymerization of two cyclic reactive monomers, DOL and TFPO, possesses a large number of amorphous regions, effectively broadening the electrochemical stability window and significantly improving interfacial compatibility and stability with the electrode. The assembled lithium-ion symmetric battery can achieve stable cycling for up to 600 hours.

[0163] (ix) Performance comparison of Example 1, Comparative Example 8 and Comparative Example 9

[0164] The in-situ polymerized solid electrolytes prepared in Example 1, Comparative Example 8, and Comparative Example 9 differ in that the heating time for the ring-opening polymerization reaction is different.

[0165] The in-situ polymerized solid electrolytes prepared in Examples 1, 8, and 9 were tested for monomer conversion rate, room temperature ionic conductivity, lithium-symmetric battery cycle performance, and LiFePO4 full cell cycle performance. The test results are shown in Table 5.

[0166] Table 5. Performance test results for different polymerization times in Example 1, Comparative Example 8, and Comparative Example 9.

[0167]

[0168] As shown in Table 5, insufficient heating time for ring-opening polymerization leads to low monomer conversion and small polymer molecular weight, resulting in poor electrolyte interface stability. Conversely, excessively long polymerization time causes excessively high polymer molecular weight, significantly reducing the ionic conductivity of the system and ultimately affecting the battery's cycle life and interface stability. This demonstrates that the in-situ polymerized solid electrolyte prepared by this invention using an appropriate polymerization reaction time can impart excellent cycle life and stability to the battery.

[0169] (x) Performance comparison between Example 1 and Comparative Example 10

[0170] The difference between the in-situ polymerized solid electrolytes prepared in Example 1 and Comparative Example 10 is that they use different initiators.

[0171] The in-situ polymerized solid electrolytes prepared in Example 1 and Comparative Example 10 were observed or tested for polymerization reaction, room temperature ionic conductivity, and lithium-ion transport number (t). Li + The cycling performance of lithium-symmetric batteries and LiFePO4 full cells were compared. The results are shown in Table 6.

[0172] Table 6. Performance observation results of different initiators in Example 1 and Comparative Example 10

[0173]

[0174] As shown in Table 6, the polymerization reaction of traditional lithium salt initiators is violent and difficult to control, leading to interface degradation and poor cycle stability due to initiator residue. The in-situ polymerized solid electrolyte prepared using sodium thiosulfate as the initiator in this invention exhibits excellent lithium symmetric battery cycle performance and LiFePO4 full-cell cycle performance.

[0175] In summary, the in-situ polymerized solid electrolyte prepared by this invention exhibits synergistic advantages in both structure and performance: it possesses numerous amorphous regions, enabling the formation of a self-supporting, dense structure that achieves stable self-support without additional reinforcement; simultaneously, this in-situ polymeric solid electrolyte maintains close contact with the electrode, with a pure interface free of impurities and voids, and no side reaction products, effectively reducing interfacial impedance. It exhibits smooth ion transport at room temperature and excellent oxidation resistance, effectively preventing side reactions at the electrode interface. Furthermore, this in-situ polymeric solid electrolyte achieves good mechanical properties while further enhancing the cycle stability and safety performance of the battery, effectively addressing the technical pain points of insufficient flexibility and poor interfacial compatibility in traditional solid electrolytes, and demonstrating promising application prospects.

[0176] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing an in-situ polymerized solid electrolyte, characterized in that, Includes the following steps: S1. Using 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane as reactants, sodium thiosulfate as an initiator, and lithium salt and plasticizer fluoroethylene carbonate as added, a precursor solution is prepared by mixing. S2. The precursor solution is subjected to a ring-opening polymerization reaction by heating to obtain the in-situ polymerized solid electrolyte.

2. The method for preparing an in-situ polymerized solid electrolyte as described in claim 1, characterized in that, In step S1, the molar ratio of 1,3-dioxolane and 1,1,1-trifluoro-2,3-epoxypropane is (85~95):(8~12); and / or The molar amount of sodium thiosulfate is 0.4 mol% to 1.0 mol% of the total molar amount of the reactants.

3. The method for preparing an in-situ polymerized solid electrolyte as described in claim 1, characterized in that, In step S1, the lithium salt is lithium bis(trifluoromethanesulfonylimide); and / or The fluoroethylene carbonate is 15 wt% to 25 wt% of the total mass of the precursor solution; and / or The molar concentration of the lithium salt in the precursor solution is 0.5 M to 1.5 M.

4. The method for preparing an in-situ polymerized solid electrolyte as described in claim 1, characterized in that, In step S2, the temperature of the heating ring-opening polymerization reaction is 65 ℃~75 ℃, and the time of the heating ring-opening polymerization reaction is 12 h~14 h.

5. An in-situ polymerized solid electrolyte, characterized in that, It is prepared by the method of in-situ polymerized solid electrolyte as described in any one of claims 1 to 4.

6. The in-situ polymerized solid electrolyte as described in claim 5, characterized in that, The thickness of the in-situ polymerized solid electrolyte is 10 µm to 20 µm.

7. An application of an in-situ polymerized solid electrolyte, characterized in that, The application of an in-situ polymerized solid electrolyte as described in any one of claims 5 to 6 or an in-situ polymerized solid electrolyte prepared by any one of claims 1 to 4 in lithium metal batteries, lithium-ion batteries, solid-state energy storage systems or flexible electronic devices.

8. A lithium metal battery, characterized in that, This includes an in-situ polymerized solid electrolyte as described in any one of claims 5 to 6, or an in-situ polymerized solid electrolyte prepared by any one of claims 1 to 4.

9. A lithium metal battery as described in claim 8, characterized in that, It also includes positive and negative electrodes; The positive electrode is lithium iron phosphate or lithium nickel cobalt manganese oxide, and the negative electrode is lithium metal. The lithium metal battery is a button cell lithium metal battery or a pouch cell lithium metal battery.

10. A process for preparing a lithium metal battery according to any one of claims 8 to 9, characterized in that, The precursor solution is injected into the battery casing, and then subjected to a heated ring-opening polymerization reaction to obtain the lithium metal battery.

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