Ionic coordination polymer solid electrolyte, battery and preparation method and application thereof

Abstract

This invention relates to the field of solid-state battery technology, specifically to an ion-coordination polymer solid electrolyte, a battery, and its preparation method and applications. The process includes: mixing an alkali metal salt, a polymer monomer containing specific strong coordination functional groups, a plasticizer, and a crosslinking agent to form an electrolyte precursor; then adding an initiator and heating to polymerize the mixture to obtain the electrolyte. This invention utilizes molecular design, selecting polymer monomers containing specific strong coordination functional groups to introduce polar groups with specific electronic properties into the polymer network. After polymerization, these functional groups can form an ordered interaction field in situ at the electrode-electrolyte interface, readjusting the interfacial dynamic behavior of alkali metal ions and effectively coordinating the kinetic matching between bulk transport and interfacial consumption. Through active interface management, metal deposition is transformed from disordered dendritic growth to an ordered, uniform deposition mode, thereby significantly improving the interfacial stability and long-cycle performance of the solid-state battery.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery technology, specifically to an ion-coordination polymer solid electrolyte, a battery, and its preparation method and application. Background Technology

[0002] Secondary batteries using lithium metal or sodium as the negative electrode have high energy density and represent an important development direction for next-generation high-energy-density batteries. However, the negative electrode is prone to dendrite growth during cycling, which not only leads to battery capacity decay and shortened lifespan but may also cause safety hazards such as short circuits, seriously hindering their practical application.

[0003] Replacing traditional liquid electrolytes with solid electrolytes to construct solid-state batteries is one of the effective ways to improve battery safety. Polymer solid electrolytes have been widely studied due to their good processing flexibility and adhesion to electrodes. However, common polymer solid electrolyte systems still have shortcomings: on the one hand, their room temperature ionic conductivity is often low; on the other hand, and more importantly, they lack effective guidance and control over the deposition behavior of metal ions at the electrode interface, making it difficult to suppress dendrite formation. In existing technologies, although some methods have been used to improve related performance by introducing plasticizers and inorganic fillers, they still fail to fundamentally coordinate the transport of ions in the bulk phase and the reaction kinetics at the interface, resulting in poor long-term cycle stability of the battery.

[0004] On the other hand, in commercially available lithium-ion batteries, although the use of intercalated anodes such as graphite has alleviated the dendrite problem to some extent, lithium ions still tend to deposit unevenly on the anode surface after fast charging, low-temperature environments, or long-term cycling, forming lithium dendrites or lithium precipitation. This can also lead to safety hazards such as capacity decay, increased internal resistance, and even short-circuit thermal runaway. Furthermore, with the increasing demands for battery energy density, the application of high-voltage cathode materials is becoming more widespread, posing even more stringent challenges to the electrochemical oxidation stability of electrolytes. Developing a universal high-performance electrolyte that can both suppress dendrites with highly active metal anodes, improve oxidation stability with high-voltage cathodes, and enhance the interfacial stability of carbon-based anodes has become a key technological bottleneck driving the development of next-generation high-safety, high-energy-density batteries.

[0005] Therefore, there is an urgent need to develop a novel polymer solid electrolyte that not only ensures high ionic conductivity but also introduces specific functional groups into the polymer network through active design of the polymer molecular structure, enabling the formation of a strong interfacial dipole field. The role of these functional groups goes beyond general ion coordination; their core function lies in constructing a strong and persistent molecular dipole field in situ at the electrode-electrolyte interface. This actively regulates and addresses the problem of excessively rapid interfacial reactions, coordinating the rate matching between bulk ion transport and interfacial deposition processes. Such a design aims to suppress dendrite initiation and growth at the source, guiding the metal anode to achieve uniform and dense deposition, thereby significantly improving the cycle life and safety performance of solid-state metal batteries. Summary of the Invention

[0006] In view of this, the present invention proposes an ion-coordination polymer solid electrolyte, a battery, and its preparation method and application, aiming to overcome the technical defects of existing polymer solid electrolytes, such as insufficient suppression of dendrite growth in the metal anode and poor interface stability. The technical solution of the present invention is achieved as follows: In a first aspect, the present invention provides a method for preparing an ion-coordination polymer solid electrolyte, comprising the following steps: S1. An alkali metal salt, a polymer monomer containing nitrogen or oxygen coordinating functional groups, a plasticizer, and a crosslinking agent are mixed to obtain a homogeneous electrolyte precursor. S2. An initiator is added to the electrolyte precursor, and a polymerization reaction is initiated by heating to obtain the ion coordination polymer solid electrolyte.

[0007] Preferably, the coordinating functional groups contained in the polymer monomer in step S1 include at least one of isocyanate group (-N=C=O), cyano group (-C≡N), amide group (-CONH- or -CONR-), ester group (-COO-) or hydroxyl group (-OH); the plasticizer includes at least one of cyclic or chain carboxylic esters, cyclic or chain carbonates, amides, ethers, sulfones and their fluorinated or chlorinated derivatives; the crosslinking agent includes at least one of polyethylene glycol derivatives and acrylate compounds.

[0008] More preferably, the polymer monomer includes at least one selected from ethyl isocyanate methacrylate, ethyl cyanoacrylate, ethyl cyanomethacrylate, acrylamide, N-(2-hydroxyethyl)acrylamide, N-isopropylacrylamide, hydroxyethyl methacrylate, hydroxyethyl acrylate, methyl methacrylate, ethyl acrylate, and butyl acrylate.

[0009] Preferably, in the electrolyte precursor of step S1, the mass ratio of polymer monomer to plasticizer is 1:(0.1-10); the concentration of the alkali metal salt is 0.1 mol / L to 5 mol / L; and the amount of crosslinking agent added is 0.5% to 100% of the volume of polymer monomer.

[0010] Preferably, the initiator in step S2 is a free radical initiator, and the mass of the initiator is no more than 5% of the total mass of the electrolyte precursor; the heating conditions for the polymerization reaction are: heating at 30~100 °C for 0.05~48 h.

[0011] More preferably, the alkali metal salt includes at least one of sodium hexafluorophosphate, sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethanesulfonyl)imide, sodium perchlorate, sodium difluorooxalate borate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium hexafluorophosphate.

[0012] More preferably, the carboxylic acid ester compound includes at least one of ethyl acetate, ethyl propionate, γ-butyrolactone, and their fluorinated or chlorinated derivatives.

[0013] More preferably, the carbonate compound includes at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and their fluorinated or chlorinated derivatives.

[0014] More preferably, the amide compound includes at least one of N,N-dimethylformamide, N-methylpyrrolidone, and their fluorinated derivatives.

[0015] More preferably, the ether compound includes at least one of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether.

[0016] More preferably, the sulfone compound includes at least one of sulfolane and methylsulfolane.

[0017] More preferably, the polyethylene glycol derivative includes at least one of polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diglycidyl ether, polyethylene glycol diacrylamide, and tri(ethylene glycol) diacrylate.

[0018] More preferably, the acrylate compound includes at least one of ethoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate.

[0019] More preferably, the initiator includes at least one of azobisisobutyronitrile, azobisisobutyltetraazole, azobisisoheptanenitrile, and benzoyl peroxide.

[0020] In a second aspect, the present invention provides an ion-coordination polymer solid electrolyte obtained by the preparation method described in the first aspect.

[0021] Thirdly, the present invention provides a solid-state battery comprising an ion-coordination polymer solid electrolyte as described in the second aspect.

[0022] Preferably, the solid-state battery includes a positive electrode active material and a negative electrode active material; the positive electrode active material includes at least one of layered oxides, polyanionic compounds, or Prussian blue compounds; the negative electrode active material includes at least one of lithium metal, sodium metal, lithium alloys, sodium alloys, graphite, hard carbon, soft carbon, silicon-based materials, tin-based materials, and lithium titanate.

[0023] More preferably, the layered oxide includes at least one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and sodium nickel iron manganese oxide.

[0024] More preferably, the polyanionic compound includes at least one of lithium iron phosphate, sodium vanadium phosphate, and lithium manganese iron phosphate.

[0025] More preferably, the Prussian blue compound includes at least one of Prussian white and Prussian blue analogues.

[0026] Fourthly, the present invention provides a method for preparing a solid-state battery, comprising the following steps: P1. A battery assembly is provided, which includes at least a positive electrode and a negative electrode; P2. The mixture of electrolyte precursor and initiator in the preparation method described in the first aspect is introduced between the positive electrode and the negative electrode by injection or coating. P3. The battery assembly is heated to cause the electrolyte precursor to undergo an in-situ polymerization reaction, forming the ion coordination polymer solid electrolyte described in the second aspect, thereby obtaining the solid-state battery.

[0027] Fifthly, the present invention provides an application of the ion coordination polymer solid electrolyte as described in the second aspect in a solid-state battery.

[0028] Compared with the prior art, the advantages of the present invention are as follows: (1) This invention proposes a method for preparing ion-coordination polymer solid electrolytes. By screening polymer monomers, plasticizers, crosslinking agents and precursors and optimizing the precursor ratio, ion-coordination polymer solid electrolytes are successfully prepared by in-situ polymerization.

[0029] (2) This invention integrates and synergistically designs functions in a three-dimensional network formed by polymer monomers containing specific strong polar functional groups. These functional groups play different roles in the system and solve specific problems according to their electronic properties and spatial configurations. Some highly polar, strong electron-withdrawing groups act on the electrode interface, forming a strong directional dipole field to solve the problems of disordered ion consumption and excessively fast local reactions at the interface, thereby guiding metal deposition from disordered dendrite growth to ordered planar spreading from the kinetic source. Other strongly coordinating functional groups act on the electrolyte phase and near-interface region, optimizing the solvation structure and transport path of ions to solve the problems of ion migration imbalance and instability of the interface film (such as SEI), thereby enhancing the chemical and mechanical stability of the interface.

[0030] (3) This composite design of the present invention not only suppresses dendrite growth of alkali metal anodes from the root of kinetics, achieving uniform deposition, but also simultaneously enhances the SEI of the anode, reduces active metal loss, and improves battery performance. Furthermore, this electrolyte system has a wide electrochemical window, enabling it to match high-voltage cathodes. Solid-state batteries assembled based on this system exhibit excellent interfacial compatibility, long-cycle stability, and high safety, with a simple process and broad application prospects. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, 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.

[0032] Figure 1 This is a schematic diagram of the preparation method and battery assembly process of the ion coordination polymer solid electrolyte provided in the embodiments of the present invention; Figure 2 The transport number of the ion-coordination polymer solid electrolyte prepared in Example 1 of this invention was tested. Figure 3 The linear sweep voltammetric curve of the polymer electrolyte prepared in Example 1 of this invention is shown to demonstrate its electrochemical stability window. Figure 4 This is a graph showing the long-cycle performance of the Na||Na symmetric battery using the polymer electrolyte in Example 1 of the present invention under constant current. Figure 5 The images show a comparison of scanning electron microscope images of the deposition morphology of the metal anode cross-section after cycling in the Na||Na symmetric battery using the polymer electrolyte in Example 1 of this invention. Figure 6The image shows the battery performance of a solid-state battery assembled with the polymer solid electrolyte, NVP positive electrode, and sodium metal negative electrode prepared in Example 1 of this invention. Figure 7 The Na||Na symmetric cell with conventional polymer electrolyte in Comparative Example 1 of this invention operates at 0.1 mA cm⁻¹. -2 The following is a graph showing the cyclic performance. Figure 8 To demonstrate the Na||Na symmetric cell of the electrolyte system in Comparative Example 2 of this invention at 0.3 mA cm⁻¹ -2 The following is a graph showing the cyclic performance. Figure 9 To demonstrate the Na||Na symmetric cell of the polymer electrolyte in Comparative Example 3 of this invention at 0.1 mA cm⁻¹ -2 The following is a graph showing the cyclic performance. Detailed Implementation

[0033] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0034] The present invention utilizes polymer monomers containing specific highly polar functional groups as follows: one part, such as isocyanate groups and cyano groups (-NCO, -CN), are highly polar and strongly electron-withdrawing groups that mainly act on the electrode interface. By forming a strong directional dipole field, they address the problems of disordered ion consumption and excessively rapid local reactions at the interface, thereby guiding metal deposition from disordered dendrite growth to ordered planar spreading from the kinetic source. The other part, such as strongly coordinating functional groups (-CONH-, -COO-), mainly act on the electrolyte phase and near-interface region. By optimizing the solvation structure and transport path of ions, they address the problems of ion migration imbalance and instability of the interfacial film (such as SEI), thereby enhancing the chemical and mechanical stability of the interface.

[0035] Among them, the isocyanate group (-N=C=O) is the optimal choice. Its -N=C=O unit possesses a very large intrinsic dipole moment, and both nitrogen and oxygen atoms have high electronegativity, generating an extremely strong and highly directional local molecular electric field. This strong field can most effectively bind and order cations near the interface, significantly increasing their desolvation energy barrier and minimizing the interfacial exchange current density, thus strongly pushing the deposition process towards the reaction control region. The cyano group (-C≡N) is the core preferred choice, as its carbon-nitrogen triple bond also has a large dipole moment, and the nitrogen atom is a strong Lewis base site. It can form a strong dipole field second only to -NCO, effectively participating in cation coordination and kinetic regulation. The amide group (-CONH- / -CONR-) is an effective component, possessing both C=O and NH / NR polar bonds, resulting in a strong dipole moment. However, the presence of hydrogen bonds may complicate intermolecular interactions, partially weakening its efficiency in constructing a uniform interfacial field. The ester group (-COO-) is the basic component. Hydroxyl groups are common polar groups with a certain dipole moment and coordination ability, but their field strength and regulation ability are significantly weaker than the aforementioned groups, mainly providing basic polarity and partial transport improvement. Although the OH bond in hydroxyl groups (-OH) is highly polar, the proton (H) on the hydroxyl group has high reactivity and mobility. In an electrochemical environment, its strong hydrogen bonding tendency may lead to molecular self-aggregation, partially offsetting the positive effects of its polarity and limiting its efficiency in constructing a uniform and stable interfacial dipole field.

[0036] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0037] In this document, the terms “containing,” “comprising,” or “including” are open-ended expressions, meaning they include the contents specified in this invention but do not exclude other aspects.

[0038] In this document, the terms “optional,” “optionally,” or “optional” generally refer to an event or condition that may, but may not, occur, and the description includes both cases in which the event or condition occurs and cases in which the event or condition does not occur.

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0040] This invention provides an ion-coordination polymer solid electrolyte, a solid-state battery, and a preparation method thereof. All embodiments aim to jointly verify the core mechanism proposed in this invention: by introducing specific strongly polar functional groups, a stable and high-intensity molecular dipole field is constructed at the electrode interface, thereby actively regulating and resolving the problem of excessively rapid interfacial reactions and coordinating the rate matching between bulk ion transport and interfacial deposition processes. By varying the coordinating functional groups, plasticizer systems, and salt concentrations and types, each embodiment demonstrates the universality and effectiveness of this design in suppressing dendrites, improving interfacial stability, and extending battery cycle life.

[0041] First, the preparation method of ion-coordination polymer solid electrolytes will be explained. Figure 1 This is a flowchart illustrating the preparation method of the ion-coordination polymer solid electrolyte provided in this embodiment of the invention. Figure 1 As shown, the preparation method of ion-coordination polymer solid electrolytes mainly includes the following steps: Step 110: Mix the alkali metal salt, polymer monomer, plasticizer, and crosslinking agent in a specific ratio to obtain the electrolyte precursor.

[0042] The alkali metal salt can be a lithium salt or a sodium salt; the alkali metal salt includes one or more of sodium hexafluorophosphate, sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethanesulfonyl)imide, sodium perchlorate, sodium difluorooxalate borate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium hexafluorophosphate.

[0043] The polymer monomer includes polymer monomers containing nitrogen or oxygen coordination functional groups; the polymer monomer includes one or more of ethyl isocyanate methacrylate, ethyl cyanoacrylate, ethyl cyanomethacrylate, acrylamide, N-(2-hydroxyethyl)acrylamide, N-isopropylacrylamide, hydroxyethyl methacrylate, hydroxyethyl acrylate, methyl methacrylate, ethyl acrylate, and butyl acrylate.

[0044] Plasticizers include one or more of cyclic / chain carboxylic acid esters, cyclic / chain carbonates, amides, ethers, sulfones, or their fluorinated or chlorinated derivatives. Specifically, the carboxylic acid esters include one or more of ethyl acetate, ethyl propionate, γ-butyrolactone, and their fluorinated or chlorinated derivatives (such as methyl trifluoroacetate and ethyl 2,2-difluoroacetate); the carbonates include one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and their fluorinated or chlorinated derivatives (such as fluoroethylene carbonate and 4-fluoro-1,3-dioxolane-2-one); the amides include one or more of N,N-dimethylformamide, N-methylpyrrolidone, and their fluorinated derivatives (such as N,N-dimethyltrifluoroacetamide); the ethers include one or more of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether; and the sulfones include one or more of sulfolane and methyl sulfolane.

[0045] The crosslinking agent includes one or more of polyethylene glycol derivatives and acrylate compounds. The polyethylene glycol derivative preferably includes one or more of polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diglycidyl ether, polyethylene glycol diacrylamide, and tri(ethylene glycol) diacrylate; the acrylate compound includes one or more of ethoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate.

[0046] In the electrolyte precursor, the mass ratio of polymer monomer to plasticizer is 1:(0.1-10), more preferably 1:(1-5); the concentration of alkali metal salt in the electrolyte precursor is 0.1 mol / L to 5 mol / L, more preferably 0.5 mol / L to 2 mol / L; and the volume of crosslinking agent is 0.5% to 100% of the volume of polymer monomer.

[0047] Step 120: Add the initiator to the electrolyte precursor and heat to polymerize, to obtain a polymer solid electrolyte with specific coordination functional groups, which is the ion coordination type polymer solid electrolyte.

[0048] The mass of the initiator is less than or equal to 5% of the mass of the electrolyte precursor, preferably less than or equal to 1%; the heating conditions for the polymerization are: heating at 30~100 ℃ for 0.05~48 h, preferably heating at 45~80 ℃ for 0.5~12 h.

[0049] The initiator includes one or more of azobisisobutyronitrile, azobisisobutyltetraazole, azobisisoheptanenitrile, or benzoyl peroxide.

[0050] This invention prepares an ion-coordination polymer solid electrolyte with excellent interfacial stability by screening polymer monomers containing specific coordination functional groups and suitable plasticizers, optimizing the precursor ratio, and utilizing an in-situ polymerization process.

[0051] By using polymer monomers containing strong coordinating functional groups (such as isocyanate groups, cyano groups, etc.), strong interactions are achieved between these monomers and alkali metal ions within the three-dimensional network formed by polymerization. This interaction not only effectively regulates the transport pathways of ions in the electrolyte bulk phase but also anchors some plasticizer molecules or solvents within the confined environment formed by the polymer chains, reducing leakage and decomposition during cycling. This significantly improves the chemical and electrochemical stability of the electrolyte, especially the electrode-electrolyte interface. The plasticizers used in this invention, such as fluorinated esters or ether compounds, possess good ion dissociation capabilities and certain oxidation resistance. Synergistically with the coordination polymer network, they contribute to achieving a wider electrochemical stability window to match cathode materials with different voltages.

[0052] The strong coordination functional groups retained by the polymer monomers after polymerization form strong coordination bonds or ion-dipole interactions with alkali metal ions. These interactions optimize carrier concentration and mobility in the bulk phase, and effectively regulate the desolvation process and reductive deposition kinetics of metal ions at the interface. The core of this molecular-level design lies in its ability to homogenize the ion flow at the interface, guiding metal ions to deposit in a more uniform and controllable manner, rather than concentrating them in a few active sites for rapid growth, thereby fundamentally suppressing dendrite formation.

[0053] The ion-coordination polymer solid electrolyte prepared by this invention exhibits excellent interfacial compatibility and cycle stability, which can significantly extend the life of solid metal batteries and can be extended from sodium batteries to lithium batteries, showing good application prospects.

[0054] When applied to sodium-based or lithium-based solid-state batteries, solid-state batteries can be fabricated as follows: Step 210: After mixing the polymer monomer and plasticizer in a certain proportion, add the alkali metal salt and crosslinking agent, and after complete dissolution, obtain the electrolyte precursor; add the initiator to the electrolyte precursor to obtain the liquid precursor to be polymerized; The materials used are the same as those used in the preparation of the polymer solid electrolyte mentioned above.

[0055] Step 220: Inject the liquid precursor to be polymerized into the space between the positive and negative electrodes inside the battery, so that the liquid precursor to be polymerized fully wets the positive and negative electrodes and the separator, and then complete the battery encapsulation; or, drop the liquid precursor to be polymerized onto the positive electrode, the separator and the negative electrode, and then complete the battery assembly. Step 230: Initiate polymerization of the battery under heating conditions to obtain a solid-state battery.

[0056] Those skilled in the art can refer to the following materials as needed to select the positive and negative electrode materials for solid-state batteries.

[0057] The positive electrode active material of the solid-state battery includes one or more of layered oxides, polyanionic compounds, or Prussian blue compounds; wherein the layered oxide includes one or more of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and sodium nickel iron manganese oxide; the polyanionic compound includes one or more of lithium iron phosphate, sodium vanadium phosphate, and lithium manganese iron phosphate; the Prussian blue compounds include one or more of Prussian white and Prussian blue analogues; and the negative electrode active material includes one or more of metallic sodium, sodium alloy, metallic lithium, lithium alloy, graphite, hard carbon, soft carbon, silicon-carbon composite, and lithium titanate.

[0058] The specific embodiments and beneficial effects of the present invention are further described in detail below through multiple examples and comparative examples. All materials used in the present invention are commercially available.

[0059] Example 1 This embodiment provides a sodium-ion solid-state battery containing an ion-coordination polymer solid electrolyte and its preparation method, including the following steps: (1) Ethoxylated trimethylolpropane triacrylate (ETPTA) and isocyanate methacrylate (IEMA) were stored separately in containers filled with 4Å molecular sieves and dried for at least 48 hours to completely remove moisture. (2) In an argon-filled glove box (H2O < 0.1 ppm, O2 < 0.1 ppm), weigh 167.95 g of sodium hexafluorophosphate (NaPF6) powder and add it to 1 L of diethylene glycol dimethyl ether (Diglyme) solvent; stir continuously at room temperature (30 ± 2 °C) for 12 h using a magnetic stirrer until a concentration of 1.0 mol L is formed. -1 A homogeneous, transparent solution; (3) In the NaPF6 / Diglyme solution obtained in the previous step, ETPTA crosslinking agent and IEMA monomer dried in step (1) are added in sequence by metering; the amount of ETPTA and IEMA added is 10% (v / v) of the total volume of the mixed solution; then, the initiator azobisisobutyronitrile (AIBN) is added, the mass of which is 5% of the mass of the electrolyte precursor; the resulting mixed solution is stirred in a glove box for 2 hours to ensure that all components are mixed evenly, and finally a clear and transparent electrolyte precursor solution is obtained; (4) The solid electrolyte precursor solution obtained above is heated at 60 °C for 2 h to fully polymerize the solid electrolyte precursor solution, thereby obtaining the polymer solid electrolyte.

[0060] To characterize the ion migration performance of the aforementioned polymer solid electrolyte under standard conditions, it was assembled into a specific test cell to determine the sodium ion transference number. The specific procedure was as follows: The electrolyte precursor was injected into a symmetrical cell (Na|electrolyte|Na) with two sodium metal plates as electrodes, and in-situ polymerized and cured at 60°C for 2 h to form a uniformly thick electrolyte layer. Using an electrochemical workstation, under constant temperature conditions of 30°C, electrochemical impedance spectroscopy (EIS) was first performed on the cell (frequency range 0.1 Hz-1 MHz, amplitude 10 mV), and the initial impedance value R0 was recorded. Subsequently, a small DC polarization voltage ΔV (10 mV) was applied to the cell, and the change in current over time was monitored until a steady-state current I was reached. ss The EIS test was performed again to obtain the polarized impedance value R. ss The test results are as follows: Figure 2 As shown, the solid electrolyte obtained in this embodiment exhibits a sodium ion transport number of 0.57 at 30°C, indicating good cation-selective transport characteristics. Simultaneously, the electrochemical stability window of the electrolyte was evaluated using linear sweep voltammetry, and a Na|SS half-cell was assembled, with the sodium sheet serving as both the counter and reference electrode, and the stainless steel sheet as the working electrode. An electrochemical workstation was used at 1.0 mV s-1. -1 The scan rate is from open circuit potential to 6.0 V (vs. Na). + / Na), the negative electrode stability of the electrolyte was tested, and the results are as follows. Figure 3 As shown, this electrolyte exhibits good reduction stability near the sodium metal potential, and its negative electrode stability potential is higher than 4.5 V, indicating that it is suitable for high-voltage cathode systems.

[0061] Solid-state battery assembly: In an argon-filled glove box, two 12 mm diameter, 0.5 mm thick sodium metal sheets were used as the working and counter electrodes. Approximately 30 μL of precursor solution was added dropwise to the surface of the first sodium sheet, covered with a 19 mm diameter glass fiber membrane (Whatman GF / A), and then another 30 μL of precursor solution was added to ensure complete wetting of the membrane. The second sodium sheet was then stacked on top, followed by a gasket and spring sheet, and sealed using a CR2032 battery casing at a sealing pressure of 800 psi. The sealed battery was transferred to a 60°C oven and allowed to stand for 2 hours to complete in-situ polymerization. The assembled Na||Na battery exhibited performance at 0.3 mA cm⁻¹. -2 Long-cycle testing was performed at current density, and the results are as follows: Figure 4As shown. The battery exhibited a stable polarization voltage and could cycle for over 10,000 hours without short circuits or failure. The morphology of the sodium negative electrode cross-section was characterized after cycling, and scanning electron microscopy images are shown below. Figure 5 As shown. The sodium anode using this electrolyte has a flat and dense cross-section with no obvious dendrites or pores, indicating that the metal deposition is uniform and reversible. Further, using Na3V2(PO4)3 as the positive electrode and metallic sodium as the negative electrode, an NVP||Na full cell was prepared via in-situ polymerization. The assembly steps were similar to those of a symmetric cell: 30 μL of precursor solution was dropped onto the surface of the NVP positive electrode, covered with a glass fiber separator, and then another 30 μL of solution was dropped. The sodium metal anode was then stacked, and the battery was encapsulated. Finally, in-situ polymerization was performed at 60°C for 2 hours to solidify the battery. Its charge-discharge cycle performance is as follows: Figure 6 As shown. This battery operates at 5 C (1 C = 117 mAh g). -1 After 9000 cycles at a given rate, the capacity retention rate reaches 80.0%, and the coulombic efficiency remains stable at over 99.9%, demonstrating excellent interface compatibility and cycle durability.

[0062] Example 2 This embodiment provides a sodium-ion solid-state battery containing an ion-coordination polymer solid electrolyte and its in-situ preparation method, including the following steps: (1) Mix isocyanate-containing methacrylate monomer (IEMA) with plasticizer tetraethylene glycol dimethyl ether (TEGDME) at a mass ratio of 1:5, and then add fluoroethylene carbonate (FEC) additive at a total solution mass of 8 wt%. Stir magnetically at 35 ℃ for about 3 hours until the mixture is uniform. (2) Add sodium bis(fluorosulfonyl)imide (NaFSI) salt to make its concentration in the mixed system 5 mol / L; then add 8% by volume of polyethylene glycol diacrylate (PEGDA) as a crosslinking agent, and continue stirring at 35 °C for about 4 h until completely dissolved to obtain a homogeneous and transparent electrolyte precursor solution. (3) Add 0.8% by mass of azobisisobutyronitrile (AIBN) to the electrolyte precursor obtained above and stir until homogeneous to form a polymerizable precursor solution; (4) Take 20 μL of the precursor solution and uniformly drop it onto the sodium vanadium phosphate (Na3V2(PO4)3, NVP) positive electrode. Then cover it with a Celgard 2500 polypropylene separator and drop another 20 μL of the precursor solution to ensure that the separator is fully wetted. Then stack the sodium metal negative electrode, stainless steel gasket and spring in sequence and encapsulate it with a CR2032 battery case. Transfer the encapsulated battery to a forced-air drying oven and heat it at 100 °C for 0.05 h to allow the IEMA monomer to fully undergo cross-linking polymerization reaction, forming a stable structure integrating the positive electrode, polymer solid electrolyte layer and negative electrode in situ inside the battery, and finally obtaining a solid sodium metal battery.

[0063] Example 3 This embodiment provides a polymer solid electrolyte using a cyano-containing coordination monomer and its application in a high-voltage lithium metal solid-state battery, including the following steps: (1) Mix cyano-containing acrylate monomer (ethyl cyanoacrylate, CEA) with plasticizer fluoroethylene carbonate (FEC) at a mass ratio of 1:0.1 and stir magnetically at 30°C for 2 hours in an argon atmosphere glove box. (2) Add sodium bis(fluorosulfonyl)imide (NaFSI) salt to make its concentration in the mixed system 1.5 mol / L; then add 8% by volume of polyethylene glycol diacrylate (PEGDA) as a crosslinking agent, and continue stirring at 35 °C for about 4 h until completely dissolved to obtain a uniform and transparent electrolyte precursor solution. (3) Add 1.2% of the total mass of azobisisobutyronitrile (AIBN) initiator to the solution and stir until homogeneous to obtain a polymerizable liquid precursor; (4) Assemble coin cells using in-situ polymerization; using high-voltage positive electrode material LiNi 0.8 Mn 0.1 Co 0.1 O2 (NCM811) is the positive electrode (active material loading is approximately 8.5 mg / cm³). -2 The lithium metal sheet is used as the negative electrode. In a glove box, 25 μL of the above precursor solution is evenly dropped onto the surface of the NCM811 positive electrode sheet. After covering it with a porous polypropylene separator (Celgard 2400), another 25 μL of solution is dropped to ensure complete wetting. Then, the lithium metal negative electrode sheet, stainless steel gasket and spring sheet are stacked, and the battery is packaged using a CR2032 battery case with a packaging pressure of 800 psi. The packaged battery is transferred to a 30 ℃ constant temperature oven for heating and curing for 48 h to complete the in-situ thermal polymerization of the monomer and form a stable polymer electrolyte layer inside the battery.

[0064] Example 4 This embodiment provides a polymer solid electrolyte using an amide-containing coordination monomer and its application in sodium metal symmetric batteries and full battery systems, including the following steps: (1) The monomer containing amide group (N-hydroxyethyl acrylamide, HEAA) and the plasticizer N,N-dimethyltrifluoroacetamide (DMTFA) were mixed at a mass ratio of 1:10 and magnetically stirred at 30°C for 2.5 h in an argon atmosphere glove box; (2) Add sodium perchlorate (NaClO4) salt to prepare a solution with a concentration of 0.1 mol / L, and add 0.5% by volume of triethylene glycol diacrylate as a crosslinking agent. Continue stirring for 5 hours until completely dissolved and a homogeneous system is formed. (3) Add 0.6% of benzoyl peroxide (BPO) by its total mass to the solution as an initiator, and stir evenly to obtain a clear polymerizable precursor solution; (4) Symmetrical battery assembly: Two sodium metal sheets of the same diameter (12 mm) were used as electrodes. In a glove box, 30 μL of the above precursor solution was dropped onto the surface of the first sodium sheet, covered with a glass fiber membrane (Whatman GF / D), and then another 30 μL of solution was dropped to fully wet the membrane. The second sodium sheet was then stacked, and a gasket and a spring sheet were placed in sequence. The battery was then encapsulated using a CR2032 battery case. After encapsulation, the battery was placed in a 55 ℃ forced-air drying oven and heated for 2 hours to complete in-situ polymerization. (5) Full cell assembly: Prussian white (Na2Fe[Fe(CN)6]) was used as the positive electrode (active material loading of approximately 4.0 mg / cm³). -2 The precursor solution is coated onto aluminum foil, and the sodium sheet is used as the negative electrode. The assembly process is similar to that of a symmetrical battery. The precursor solution is dropped onto the positive electrode and the separator, the sodium negative electrode is stacked, and then it is encapsulated and in-situ polymerized and cured under the same conditions (55 °C, 2 h).

[0065] Example 5 This embodiment provides a polymer solid electrolyte using a monomer with bifunctional coordination groups of ester and hydroxyl groups, and applies it to a high-voltage lithium metal full battery system, including the following steps: (1) The bifunctional monomer containing ester and hydroxyl groups (hydroxyethyl methacrylate, HEMA) and the plasticizer methyl trifluoroethyl carbonate (FEMC) were mixed in a mass ratio of 1:2 and magnetically stirred for 3h at 30 °C in an argon atmosphere glove box. (2) Add a mixed lithium salt of lithium hexafluorophosphate (LiPF6) and lithium difluorooxalate borate (LiDFOB) (molar ratio 4:1) to prepare a solution with a total lithium ion concentration of 1.5 mol / L, and add ethoxylated trimethylolpropane triacrylate (ETPTA) accounting for 4% of the monomer volume as a crosslinking agent and continue stirring for 8 hours until a homogeneous and transparent system is formed. (3) Add 0.5% of the total mass of azobisisobutyltetraazole (ABCN) as an initiator, and stir until homogeneous to obtain a polymerizable precursor solution; (4) Using lithium cobalt oxide (LiCoO2) as the high-voltage cathode material (active material loading of approximately 10.2 mg / cm³) -2 The precursor solution (coated onto aluminum foil) was used as the negative electrode. In a glove box, 30 μL of the above precursor solution was uniformly dropped onto the surface of the LiCoO2 positive electrode, and a layer of anodic alumina ceramic composite separator with a pore size of about 50 nm was covered. Then, another 30 μL of solution was dropped to ensure complete wetting. Subsequently, lithium metal negative electrode sheets, stainless steel gaskets, and spring sheets were stacked, and the battery was encapsulated using a CR2032 battery case at a pressure of 850 psi. The encapsulated battery was transferred to a 70 ℃ constant temperature vacuum drying oven for 2 hours to heat and cure, completing the in-situ polymerization of the monomers and forming a solid electrolyte layer with a stable interface structure inside the battery.

[0066] Example 6 This embodiment provides an ion-coordination polymer solid electrolyte using a mixed plasticizer system, and applies it to a sodium metal solid-state battery, including the following steps: (1) Mix isocyanate-containing methacrylate monomer (IEMA) with plasticizer methyl trifluoroacetate (MTFA) and diethylene glycol dimethyl ether (Diglyme) in a mass ratio of 1:2:2, and then add 5 wt% of the total solution of additive vinyl sulfite (ES). Stir magnetically in an argon atmosphere glove box at 30 °C for 4 h until fully mixed. (2) Add sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) salt to prepare a solution with a concentration of 1.2 mol / L, and add 2% by volume of pentaerythritol triacrylate as a crosslinking agent. Continue stirring for 6 hours until a uniform and transparent precursor system is formed. (3) Add 0.7% of the total mass of azobisisobutyronitrile (AIBN) initiator to the system and stir until homogeneous to obtain a polymerizable precursor solution; (4) Using sodium vanadium phosphate (NVP), a polyanionic cathode material, as the cathode (active material loading approximately 6.5 mg cm⁻¹) -2The precursor solution (coated onto aluminum foil) is used as the negative electrode. In a glove box, a two-stage drop-coating process is employed: first, 25 μL of the precursor solution is uniformly dropped onto the surface of the NVP positive electrode, covered with a glass fiber and polypropylene composite separator, and then another 25 μL of solution is dropped to fully wet the separator. Subsequently, the sodium metal negative electrode, stainless steel gasket, and spring sheet are stacked in sequence, and the battery is encapsulated using a CR2032 battery case at a pressure of 750 psi. The encapsulated battery is then transferred to a 60 ℃ constant temperature oven for heating and polymerization for 2 hours to complete the in-situ crosslinking polymerization reaction, forming a solid electrolyte layer with a three-dimensional network structure inside the battery.

[0067] Example 7 This embodiment provides a polymer-based solid electrolyte using an ester-containing coordination monomer and its application in a high-voltage lithium-ion full battery system, including the following steps: (1) Methyl methacrylate (MMA) containing ester groups is mixed with plasticizer ethyl methyl carbonate (EMC) and fluoroethylene carbonate (FEC) in a mass ratio of 2:6:2 and magnetically stirred at 30 °C for 4 hours in an argon atmosphere glove box until fully mixed. (2) Add a mixed lithium salt of lithium difluorosulfonylimide (LiFSI) and lithium difluorooxalate borate (LiDFOB) (molar ratio 9:1) to prepare a solution with a total lithium ion concentration of 1.2 mol / L. Then add pentaerythritol tetraacrylate, which accounts for 6% of the monomer volume, as a crosslinking agent and stir until completely dissolved to form a homogeneous and transparent precursor system. (3) Add 0.3% of benzoyl peroxide (BPO) as an initiator to the total mass of the system and stir until homogeneous to obtain a polymerizable precursor solution; (4) Using high-voltage positive electrode material NCM811 as the positive electrode and graphite as the negative electrode; in a glove box, 30 μL of the above precursor solution is uniformly dropped onto the surface of the positive electrode sheet, and after covering it with a porous polyolefin separator, another 30 μL of solution is dropped onto the separator, and then graphite negative electrode sheets are stacked to complete the encapsulation of CR2032 coin cell; the battery is placed in a 70 ℃ oven for heating and curing for 3 h to complete in-situ polymerization and form a quasi-solid electrolyte system.

[0068] Comparative Example 1 This comparative example provides a conventional polymer electrolyte system that does not contain such functional groups and its properties, including the following steps: (1) Sodium hexafluorophosphate (NaPF6) was prepared at a concentration of 1 mol / L -1 The concentration was dissolved in a mixed solvent composed of propylene carbonate (PC) and fluoroethylene carbonate (FEC) (PC:FEC volume ratio of 95:5), and stirred until completely dissolved to form a homogeneous and transparent precursor system; (2) Add the monomer trifluoromethyl acrylate and the crosslinking agent polyethylene glycol diacrylate to the solution, both at 10% of the total volume of the solution. Finally, add azobisisobutyronitrile (AIBN) at 1% of the total mass of the monomer as an initiator and mix thoroughly to obtain a homogeneous precursor solution; (3) Assembly and in-situ polymerization of symmetrical cells: In an argon atmosphere glove box, take two sodium metal sheets; add about 30 μL of the above precursor solution to one sodium sheet, cover it with a glass fiber membrane, and then add another 30 μL of solution to ensure wetting. Then stack the second sodium sheet and complete the encapsulation of the CR2032 type battery; place the encapsulated battery in a 60 °C oven and heat for 6 hours to allow the monomers to undergo in-situ polymerization and crosslinking to form a polymer electrolyte layer.

[0069] Electrochemical performance tests showed that the assembled Na||Na symmetric cell performed well at 30 °C and 0.1 mA cm⁻¹. -2 Constant current cycling tests were performed at a current density of 0.1 mAh / cm³ (each cycle had a deposition / stripping time of 1 h, corresponding to an areal capacity of 0.1 mAh / cm³). -2 (See attached) Figure 7 As shown, the battery is unstable during cycling and subsequently fails due to a continuous increase in polarization voltage.

[0070] Comparative Example 2 This comparative example does not introduce any characteristic functional groups with significant dipole moments or coordination capabilities, and includes the following steps: (1) In an argon atmosphere glove box, sodium bis(fluorosulfonyl)imide (NaFSI) was added at 1 mol / L -1 The concentration of is dissolved in propylene carbonate (PC) and fluoroethylene carbonate (FEC), and the mixture is magnetically stirred until clear, wherein the volume ratio of PC to FEC is 9:1; (2) Assembly of symmetrical cells: In an argon atmosphere glove box, take two sodium metal sheets. Add about 30 μL of the above electrolyte onto one sodium sheet, cover it with a glass fiber separator, and then add another 30 μL of electrolyte to ensure wetting. Then stack the second sodium sheet and complete the encapsulation of the CR2032 type cell.

[0071] Electrochemical performance tests and results show that the assembled battery performs well at 30 °C and 0.3 mA cm⁻¹. -2 Constant current cycling tests were performed at a current density of [value missing]. (See attached image.) Figure 8 As shown, the battery can only cycle stably for about 50 hours before short-circuiting.

[0072] This comparative example did not use any characteristic functional groups with significant dipole moments or coordination capabilities. The electrolyte composed of such functional groups could not generate effective dipole-ion interactions with sodium ions and lacked the ability to actively regulate interfacial ion flow or reaction kinetics. Its extremely short cycle life and severe dendrite growth clearly define the lower limit of performance without the introduction of characteristic polar functional groups. This conversely proves that introducing functional groups with sufficient dipole moments into the polymer network is an essential condition for achieving effective dendrite suppression.

[0073] Comparative Example 3 This comparative example provides an ion-coordination polymer solid electrolyte containing a hydroxyl functional group monomer and its application, including the following steps: (1) Prepare 1 mol L in an argon atmosphere glove box. -1 A Diglyme solution of NaPF6 was prepared. Hydroxyethyl methacrylate monomer and polyethylene glycol diacrylate crosslinking agent were added to this solution, each at 10% of the total solution volume. Finally, AIBN initiator at 1% of the total monomer mass was added and mixed thoroughly. (2) Assembly and in-situ polymerization of symmetrical cells: The assembly and polymerization processes are exactly the same as those in Comparative Example 1.

[0074] Electrochemical performance tests and results show that at 30 °C and 0.1 mA cm⁻¹, -2 Constant current cycling tests were performed at a current density of 0.1 mAh / cm³ (each cycle had a deposition / stripping time of 1 h, corresponding to an areal capacity of 0.1 mAh / cm³). -2 ), as attached Figure 9 As shown, the Na||Na symmetric cell can cycle stably for about 500 hours, after which the cell fails due to a short circuit.

[0075] This comparative example demonstrates that introducing hydroxyl-containing monomers does indeed improve performance, primarily due to the polarity of the OH bond providing a certain degree of dipole interaction and weak coordination ability. However, its performance is far inferior to Example 1 of this invention (>10000h). The main reasons for the limited efficiency are: first, the active proton (H) on the hydroxyl group has certain reactivity within the electrochemical window and may participate in slight interfacial side reactions, affecting the uniformity and compactness of the solid electrolyte interfacial film (SEI); second, the strong hydrogen bonding interactions between hydroxyl groups may lead to local aggregation of polymer chains, which to some extent disrupts the uniformity and stability of the molecular dipole field at the interface. Therefore, although the hydroxyl group is a polar functional group, its ability to construct an efficient and stable interfacial dipole field is inherently limited, and it is not the optimal solution for solving the problem of interfacial stability in ultra-long cycling.

[0076] This invention optimizes the precursor composition and ratio by screening polymer monomers with specific coordination functional groups and suitable plasticizers, and employs an in-situ polymerization process to prepare an ion-coordination polymer solid electrolyte with excellent interfacial stability. This electrolyte actively regulates the transport and deposition behavior of alkali metal ions through coordination sites in the polymer network, overcoming the limitations of traditional electrolytes that passively withstand interfacial changes. As shown in the embodiments, this strategy can be flexibly adapted to various ion battery systems such as sodium and lithium, and can be matched with various cathodes ranging from polyanions to layered oxides.

[0077] Solid-state batteries prepared using the ion-coordination polymer solid electrolyte of this invention exhibit good interfacial compatibility, cycle stability, and safety, and have broad prospects for industrial application.

[0078] The embodiments described above are some, but not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for producing an ionically coordinated polymer solid electrolyte, characterized by, Includes the following steps: S1. An alkali metal salt, a polymer monomer containing nitrogen or oxygen coordinating functional groups, a plasticizer, and a crosslinking agent are mixed to obtain a homogeneous electrolyte precursor. S2. An initiator is added to the electrolyte precursor, and a polymerization reaction is initiated by heating to obtain the ion-coordination polymer solid electrolyte; The coordination functional groups contained in the polymer monomer in step S1 include at least one of isocyanate group, cyano group, amide group, ester group or hydroxyl group.

2. The preparation method according to claim 1, characterized in that, The plasticizer includes at least one of cyclic or chain carboxylic esters, cyclic or chain carbonates, amides, ethers, sulfones, and their fluorinated or chlorinated derivatives; the crosslinking agent includes at least one of polyethylene glycol derivatives and acrylate compounds.

3. The preparation method according to claim 2, characterized in that, The polymer monomers include at least one of ethyl isocyanate methacrylate, ethyl cyanoacrylate, ethyl cyanoacrylate methacrylate, acrylamide, N-(2-hydroxyethyl)acrylamide, N-isopropylacrylamide, hydroxyethyl methacrylate, hydroxyethyl acrylate, methyl methacrylate, ethyl acrylate, and butyl acrylate.

4. The preparation method according to claim 1, characterized in that, In the electrolyte precursor of step S1, the mass ratio of polymer monomer to plasticizer is 1:(0.1-10); the concentration of alkali metal salt is 0.1 mol / L to 5 mol / L; and the amount of crosslinking agent added is 0.5% to 100% of the volume of polymer monomer.

5. The preparation method according to claim 1, characterized in that, The initiator mentioned in step S2 is a free radical initiator, and the mass of the initiator is no more than 5% of the total mass of the electrolyte precursor; the heating conditions for the polymerization reaction are: heating at 30~100 °C for 0.05~48 h.

6. An ion-coordination polymer solid electrolyte obtained by the preparation method according to any one of claims 1 to 5.

7. A solid-state battery, characterized in that, Includes the ion coordination polymer solid electrolyte as described in claim 6.

8. The solid-state battery according to claim 7, characterized in that, The solid-state battery includes a positive electrode active material and a negative electrode active material; the positive electrode active material includes at least one of layered oxides, polyanionic compounds, or Prussian blue compounds; the negative electrode active material includes at least one of lithium metal, sodium metal, lithium alloy, sodium alloy, graphite, hard carbon, soft carbon, silicon-based materials, tin-based materials, and lithium titanate.

9. A method for preparing a solid-state battery, characterized in that, Includes the following steps: P1. A battery assembly is provided, which includes at least a positive electrode and a negative electrode; P2. The mixture of electrolyte precursor and initiator in the preparation method according to any one of claims 1 to 5 is introduced between the positive electrode and the negative electrode by injection or coating. P3. The battery assembly is heated to cause the electrolyte precursor to undergo an in-situ polymerization reaction, forming the ion coordination polymer solid electrolyte as described in claim 6, thereby obtaining the solid-state battery.

10. The application of the ion coordination polymer solid electrolyte as described in claim 6 in a solid-state battery.

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