In-situ polymerized single-ion solid-state electrolyte, and preparation method and application thereof

Abstract

The application relates to an electrolyte, a preparation method thereof and application, in particular to an in-situ polymerized single-ion solid-state electrolyte, a preparation method and application thereof. The solid electrolyte is obtained by in-situ polymerization of a metal salt in the presence of a solvent to obtain a single-ion solid-state electrolyte; wherein the metal salt contains an aluminum central anion small molecule metal salt shown in formula I; the solvent includes a fluorinated carbonate; the mass ratio of the fluorinated carbonate and the aluminum central anion small molecule metal salt shown in formula I is 1-10:1-10; the application provides a method for obtaining a single-ion solid-state electrolyte by in-situ polymerization of an aluminum central anion small molecule lithium / sodium / potassium salt, without the need of introducing an initiator. The in-situ prepared solid-state electrolyte has high room temperature conductivity (1*10 ‑4 S / cm-5*10 ‑3 S / cm), a wide potential window (4.5-5.5 V), and simultaneously reduces the solid / solid interface impedance between the solid-state electrolyte and the electrode active material. When the electrolyte is used for a high-load LiCoO2 / Li metal battery, a high capacity retention rate of 98% after 100 cycles can be realized.

Description

Technical Field

[0001] This invention relates to an electrolyte, its preparation method, and its application, particularly to an in-situ polymerized single-ion solid electrolyte, its preparation method, and its application. Background Technology

[0002] Compared with other energy storage methods, lithium-ion secondary batteries have advantages such as high voltage, high energy density, low self-discharge rate, high cycle life, and long storage time, and are widely used in consumer electronics, new energy vehicles, power systems and other fields.

[0003] Traditional lithium-ion batteries, using a mixed solvent system of flammable carbonate (ether) compounds, pose safety hazards such as leakage, fire, and even explosion under conditions of abuse like overcharging, short circuits, and heating, severely hindering the development and application of high-energy lithium-ion batteries. Based on the high-boiling-point and non-flammable solid-state electrolyte, lithium-ion batteries offer high energy density and high safety, leading to widespread research attention on solid-state lithium batteries. Furthermore, solid-state electrolytes possess high chemical inertness and mechanical strength, which can suppress internal side reactions and lithium dendrite formation, thereby improving battery safety and providing a solution for using lithium metal as the battery anode. However, the preparation of solid polymer electrolytes involves pre-fabricating polymer films and then winding or stacking them with the positive and negative electrode sheets to assemble the battery. This results in a very high solid / solid interface impedance between the battery electrodes and the solid electrolyte, leading to poor rate capability and long-cycle performance. Additionally, solid polymers typically contain polyether groups, resulting in low ionic conductivity and a narrow electrochemical window. Moreover, solid electrolytes contain oxygen-containing functional groups that are highly sensitive to moisture, making the solid-state battery fabrication process extremely demanding in terms of dry environments. Therefore, to address the aforementioned problems with polymer solid-state electrolytes, it is urgent to improve the room-temperature conductivity of solid-state electrolytes, broaden the electrochemical window, and simultaneously achieve soft contact between the solid-state electrolyte and the electrode active materials. Furthermore, the fabrication process for solid-state batteries is complex, and the stringent environmental requirements for its fabrication also urgently need improvement.

[0004] Compared to the process of using solid polymer films in lithium batteries, the in-situ polymerization method for preparing solid electrolytes can effectively solve problems such as high interfacial impedance, complex preparation process, and low conductivity. Patent application CN109994783A describes injecting a mixture of lithium salt, small molecule monomer additives, and crosslinking agents into the porous electrodes and separator of an assembled battery cell, followed by in-situ polymerization via electron irradiation. Patent application CN106785028A describes in-situ polymerization of chitosan, aldehyde crosslinking agents, and lithium salts coated onto the positive electrode surface to obtain a solid electrolyte. Patent application CN107645015A describes dissolving lithium salt and polyethylene oxide in anhydrous acetonitrile, then adding plasticizers, polyethylene glycol diacrylate, crosslinking agents, and photoinitiators, mixing thoroughly, and initiating with ultraviolet light. After the solvent acetonitrile completely evaporates, a solid electrolyte with a thickness of 80-200 micrometers is obtained. The invention patent with application number CN 108550907 A describes mixing lithium salt, additives, and a small-molecule monomer initiator containing unsaturated bonds to obtain a mixture; then, it is in-situ polymerized and bonded in the positive electrode layer, solid electrolyte layer, and negative electrode layer, as well as between the layers, to obtain a composite solid electrolyte. Although there are various reports on the preparation of solid electrolytes by in-situ polymerization, these methods either require the addition of an initiator to initiate the in-situ polymerization of the electrolyte, which introduces more side reactions and byproducts detrimental to battery performance; or they require the introduction of a small-molecule solvent to dissolve the reactants and then remove the small-molecule solvent, making the in-situ preparation process more complex, and the introduced small-molecule solvent is difficult to remove completely, leading to more side reactions. Summary of the Invention

[0005] The purpose of this invention is to provide an in-situ polymerized single-ion solid electrolyte, its preparation method, and its application in batteries. To achieve the above objectives, the present invention adopts the following technical solution: A monoionic solid electrolyte obtained by in-situ polymerization of a metal salt in the presence of a solvent; wherein the metal salt contains a small molecule metal salt with an aluminum central anion as shown in Formula 1; the solvent includes a fluorocarbonate; and the mass ratio of the fluorocarbonate to the small molecule metal salt with an aluminum central anion as shown in Formula 1 is 1-10:1-10. The aluminum-central anion small molecule metal salt is shown in Formula 1. Formula 1 T is selected from lithium, sodium, or potassium; Y1 is selected from halogen, O, S, or NR. 1 When Y1 is a halogen, there is no R group; Y2 and Y3 can be the same or different and are selected from O, S or NR. 1 ; R, R 1 Can be the same or different from C1-C 20Alkyl, C1-C 20 Halogenated alkyl, C3-C 10 cycloalkyl, C3-C 10 A halogenated cycloalkyl group, unsubstituted or substituted benzene with at least one of the same or different substituents listed below, wherein the substituents are halogenated, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C3-C 10 cycloalkyl, C3-C 10 Halogenated cycloalkyl groups; R 1 It can also be hydrogen; p1 is an integer from 0 to 10, p2 is an integer from 1 to 10, and the value of p1 + p2 makes the anion have a negative monovalent.

[0006] Preferably, in Equation 1, R, R 1 The same or different benzenes may be selected from C2-C8 alkyl groups, C2-C8 haloalkyl groups, C3-C6 cycloalkyl groups, C3-C6 halocycloalkyl groups, unsubstituted or substituted by at least one of the same or different substituents, wherein the substituents are halogens, C2-C8 alkyl groups, C2-C8 haloalkyl groups, C3-C6 cycloalkyl groups, and C3-C6 halocycloalkyl groups; The aforementioned fluorocarbonate solvent is a fluorolinear carbonate solvent or a fluorocyclic carbonate solvent. Preferably, the fluorocarbonate solvent is selected from fluorocyclic carbonate solvents.

[0007] The in-situ polymerized single-ion solid electrolyte is produced according to the following reaction at 30-80°C for 1-20 hours.

[0008] The metal salt is an aluminum-centered anionic small molecule metal salt of Formula 1, or a mixture of aluminum-centered anionic small molecule metal salt of Formula 1 and other anionic metal salts; wherein, when the metal salt is a mixture of aluminum-centered anionic small molecule metal salt of Formula 1 and other anionic (central atom M) metal salts, it is polymerized in situ in the presence of a solvent; wherein, the central atom M in the other anionic metal salts is B, P, N, Cl, or As.

[0009] The other anionic (central atom M) metal salts are selected from one or more of LiPF6, LiAsF6, LiClO4, LiTFSI, LiFSI, LiBOB, LiDFOB, LiBF4, sodium hexafluorophosphate, sodium hexafluoroarsenate, sodium perchlorate, sodium bis(trifluoromethanesulfonyl)imide, sodium bis(fluorosulfonyl)imide, sodium bis(oxaloyl)borate, sodium difluorooxaloylborate, sodium tetrafluoroborate, potassium hexafluorophosphate, potassium hexafluoroarsenate, potassium perchlorate, potassium bis(trifluoromethanesulfonyl)imide, potassium bis(fluorosulfonyl)imide, potassium bis(oxaloyl)borate, potassium difluorooxaloylborate, and potassium tetrafluoroborate.

[0010] Preferably, the other anionic metal salts are selected from one or more of LiPF6, LiTFSI, LiBOB, LiDFOB, sodium hexafluorophosphate, sodium bis(trifluoromethanesulfonyl)imide, sodium bis(oxalatoborate), sodium difluorooxalatoborate, potassium hexafluorophosphate, potassium bis(trifluoromethanesulfonyl)imide, potassium bis(oxalatoborate), and potassium difluorooxalatoborate.

[0011] When the metal salt in Formula 1 is a lithium / sodium / potassium salt, and the group attached to the central atom Al of the anion in the lithium / sodium / potassium salt is a -Y group, then Y is selected from halogens. When the group attached to the central atom Al of the anion is an RY- group or a -YRY- group, Y can be the same or different and selected from halogens, O, S, or NR. 1 At least one of the groups attached to Al is -YRY-, so as to connect different Al and / or M central atoms.

[0012] The other anionic metal salts are selected from TPF6, TAsF6, TClO4, TTFSI, TFSI, TBOB, TDFOB, and TBF4, wherein T is lithium, sodium, or potassium. Preferably, the other anionic metal salts are selected from one or more of TPF6, TFSI, TBOB, and TDFOB.

[0013] The solvent is a fluorocarbonate solvent, or a fluorocarbonate solvent and other solvents; wherein, the other solvents are selected from C3-C. 10 Non-fluorinated linear carbonate solvents, C3-C 10 The solvents are selected from one or more of the following: non-fluorinated cyclic carbonate solvents, ether solvents, ester solvents, sulfone solvents, and nitrogen-containing solvents. Other solvents mentioned above are preferably selected from C3-C4 solvents. 10 Non-fluorinated linear carbonates, C3-C 10 One or more of the following: non-fluorinated cyclic carbonates and sulfones.

[0014] The solid electrolyte is a fluorocarbonate, other solvents, aluminum-centered anionic small molecule metal salts as shown in Formula 1, and other anionic metal salts in a mass ratio of 1-60:0-40:1-60:0-50.

[0015] When the metal salt is a mixture of the aluminum-centered anionic small molecule metal salt of Formula 1 and other anionic (central atom M) metal salts, it is polymerized in situ in the presence of a solvent; and the mass ratio of fluorocarbonate, other solvents, aluminum-centered anionic small molecule metal salt of Formula 1 and other anionic metal salts is 30-50:15-40:10-50:10-40.

[0016] A method for preparing an in-situ polymerized single-ion solid electrolyte involves injecting the raw materials of the single-ion solid electrolyte into a battery and polymerizing it in situ at 30-80°C for 1-20 hours to obtain the in-situ polymerized single-ion solid electrolyte.

[0017] Application of an in-situ polymerized single-ion solid electrolyte, wherein the in-situ polymerized single-ion solid electrolyte is used in a battery, which is a primary or secondary battery of Li, Na, and K.

[0018] A battery includes a positive electrode, a negative electrode, and an electrolyte between the positive and negative electrodes, wherein the electrolyte is a single-ion solid electrolyte polymerized in situ; the battery is a primary or secondary battery of Li, Na, or K.

[0019] The positive electrode is a mixture of positive electrode active material, polyvinylidene fluoride, and conductive carbon black in a mass ratio of 80:10:10; the positive electrode active material is the active material corresponding to Li, Na, and K batteries; for example, one of cobalt oxide T, iron phosphate T, manganese iron phosphate T, vanadium phosphate T, Prussian blue, manganese oxide T, nickel manganese oxide T, nickel cobalt manganese oxide T, and nickel cobalt aluminum oxide T, where T is lithium, sodium, or potassium; The negative electrode is composed of negative electrode active material, SBR binder, and conductive carbon black mixed in a mass ratio of 80:10:10. The negative electrode active material is a Li, Na, K battery corresponding active material; for example, one of the following: metal sheet, metal alloy, graphite, hard carbon, molybdenum disulfide, T titanate, graphene, and silicon-carbon negative electrode, where T is lithium, sodium, or potassium, and the metal is lithium, sodium, or potassium.

[0020] Compared with the prior art, the present invention has the following advantages: 1. This invention uses aluminum-centered anionic small molecule metal salts to directly crosslink and polymerize into single-ion solid electrolytes, which increases the metal ion transference number. Furthermore, the aluminum-centered anionic metal salts can form an interfacial protective film in situ at the positive and negative electrode interfaces, inhibiting the occurrence of side reactions and dendrite growth.

[0021] 2. The single-ion solid electrolyte is directly crosslinked and polymerized using aluminum-centered anionic small molecule metal salts, eliminating the need for additional thermal or photoinitiators. This simplifies the electrolyte formulation, avoids side reactions caused by initiators, and improves coulombic efficiency and battery cycle performance. Furthermore, the in-situ curing method enables soft contact at the interface, effectively reducing interfacial impedance.

[0022] 3. No other precursors need to be introduced, thus avoiding the introduction of other small molecules and the removal of byproducts.

[0023] 4. While some reported electrolytes are composed of lithium salts and corresponding fluorocarbonates, these do not solve the problem of low ion transport numbers, and the liquid nature of the electrolyte makes it volatile and flammable. The electrolyte in this invention, however, can significantly increase the metal ion transport number, and its solidification properties make it less volatile and less flammable. Attached Figure Description

[0024] Figure 1 Images showing the solid electrolyte from Example 1 after multiple washings with THF solvent and centrifugation.

[0025] Figure 2 The long-cycle curves and coulombic efficiency of the aluminum-centered lithium salt in-situ polymerized solid electrolyte battery of Example 1 are shown.

[0026] Figure 3 This is an image of the in-situ polymerized single-ion solid electrolyte from Example 2.

[0027] Figure 4 The long-cycle curve and coulombic efficiency of the lithium salt in-situ polymerized solid electrolyte battery in Example 3 are shown.

[0028] Figure 5 The long-cycle curve and coulombic efficiency of the lithium salt in-situ polymerized solid electrolyte battery in Example 6 are shown. Detailed Implementation

[0029] The following examples further illustrate specific embodiments of the present invention. It should be noted that the specific embodiments described herein are merely for illustration and explanation and are not intended to limit the scope of the present invention.

[0030] This invention provides a method for preparing solid electrolytes through in-situ polymerization of metal salts containing aluminum-centered anionic small molecules, without the need for an initiator. The aluminum-centered metal salt can be in-situ polymerized into a single-ion solid electrolyte, increasing the T-ion migration number and inhibiting dendrite growth; furthermore, the Al in the aluminum-centered T-salt... 3+ The large radius of the ions allows for coordination with the solvent, which is beneficial for the desolvation of T ions. Furthermore, the aluminum-centered salt can form a favorable interfacial film on the positive and negative electrode surfaces in situ, suppressing side reactions. This in-situ prepared solid electrolyte exhibits high room temperature conductivity (1×10⁻⁶). -4 S / cm-5×10 -3The solid electrolyte exhibits a wide potential window (4.5–5.5 V) and simultaneously enables soft contact between the solid electrolyte and electrode active materials, as well as between the solid electrolyte and the electrode, effectively solving the problem of high solid-solid interface impedance between the solid electrolyte and electrode active materials. This improves the room temperature charge / discharge capability and rate performance of solid-state batteries. When the obtained solid electrolyte is used in high-load LiCoO2 / Li metal batteries, it can achieve a high capacity retention rate of 98% after 100 cycles.

[0031] The aluminum-centered anion small molecule metal salts shown in the following examples can be prepared by reacting LiAlH4 with the corresponding pinacol or by using AlF3 with the corresponding lithium pinacol, and then by ion exchange to obtain the corresponding sodium or potassium salts.

[0032] Example 1: Take 1g of the lithium salt with the aluminum-centered anion shown in the above structural formula, add 1ml of fluoroethylene carbonate to prepare an electrolyte, and inject it into a 2032 coin cell (the negative electrode is lithium metal, the positive electrode is LiCoO2, and the separator is PP2500; reference: Chem. Sci., 2018, 3451). Polymerization can be achieved by heating at 60 °C for 2 hours, forming a solid electrolyte in the cell. The conductivity of this electrolyte is 2.3 × 10⁻⁶. -3 S cm -1 The electrochemical window was 4.9 V. The resulting solid polymer was no longer soluble in various solvents, proving that a cross-linked structure was obtained. Figure 1 As shown, the polymer polymerized in a vial at 60°C remained undissolved after repeated washing with THF solvent. Upon centrifugation, the solid adhered to the bottom of the vial. This demonstrates that a cross-linked structure was obtained. Quantitative calculations also indicate a favorable environment for the formation of cross-linked structures.

[0033] The battery was then subjected to long-cycle testing at room temperature (see [reference]). Figure 2 The charge / discharge rate is 0.2 C, the voltage range is 3-4.3 V, and the capacity retention rate is 98% after 100 long cycles.

[0034] Example 2: Take 0.5 g of the lithium salt with the aluminum-centered anion shown in the above structural formula and 0.5 g of LiDFOB, and dissolve them together in 1 ml of fluoroethylene carbonate (FEC). After dissolution, inject the solution into a 2032 coin cell (the negative electrode is graphite, the positive electrode is LiCoO2, and the separator is PP2500). Polymerization will occur when heated at 60 °C for 1.5 hours, forming a solid electrolyte in the cell (see [link to product]). Figure 3The electrochemical window of this electrolyte is 5.2 V. The resulting solid polymer is no longer soluble in various solvents, proving that a cross-linked structure has been obtained. Quantitative calculations also indicate a favorable environment for the formation of cross-linked structures.

[0035] The battery was then subjected to a long-cycle test at room temperature, with a charge / discharge rate of 0.3 C and a voltage range of 3-4.3 V. After 100 cycles, the capacity retention rate was 96%.

[0036] like Figure 3 The prepared electrolyte solution can be solidified by heating it at 60°C for 1.5 hours in a small bottle. The electrolyte will not flow after solidification when the bottle is inverted.

[0037] Example 3: 0.5 g of the lithium salt with the aluminum-centered anion shown in the above structural formula and 0.5 g of LiPF6 were dissolved together in 1 ml of fluoroethyl methyl tricarbonate (FEMC), and then injected into a 2032 coin cell (the negative electrode is graphite, the positive electrode is LiFePO4, and the separator is glass fiber). Polymerization was achieved by heating at 60 °C for 5 hours, forming a solid electrolyte in the cell. The resulting solid polymer was insoluble in various solvents, proving that a cross-linked structure was obtained. Quantitative calculations also showed a favorable environment for the formation of a cross-linked structure.

[0038] The battery was then subjected to long-cycle testing at room temperature (see [reference]). Figure 4 The charge / discharge rate is 1 C, the voltage range is 2.5-3.7 V, and the capacity retention rate is 98% after 100 long cycles.

[0039] Example 4: 0.5 g of the lithium salt with the aluminum-centered anion shown in the above structural formula and 0.5 g of LiBF4 were dissolved in a mixed solvent of 0.5 ml FEC and 0.5 ml ethylene carbonate (EC) (volume ratio 1:1), and then injected into a 2032 coin cell (the negative electrode of the cell is graphite, and the positive electrode is LiNi). 0.5 Co 0.2 Mn 0.3 In an atmosphere containing O2 (with a glass fiber separator), polymerization occurs upon heating at 50 °C for 12 hours, forming a solid electrolyte in the battery. The resulting solid polymer is insoluble in various solvents, indicating a cross-linked structure. Quantitative calculations also show a favorable environment for the formation of this cross-linked structure.

[0040] The battery was then subjected to a long-cycle test at room temperature, with a charge / discharge rate of 0.4 C and a voltage range of 3-4.3 V. After 200 cycles, the capacity retention rate was 92%.

[0041] Example 5: Take 0.5 g of the lithium salt with the aluminum-centered anion shown in the above structural formula and 0.5 g of LiDFOB, dissolve them together in a mixed solvent of 0.5 ml FEC and 0.5 ml ethyl methyl carbonate (EMC) (volume ratio 1:1), and inject into a 2032 coin cell (the negative electrode is lithium metal, and the positive electrode is LiNi). 0.8 Co 0.1 Mn 0.1 In an atmosphere containing O2 (with a glass fiber separator), polymerization occurs upon heating at 40 °C for 5 hours, forming a solid electrolyte within the battery. This electrolyte has a room temperature conductivity of 4.7 × 10⁻⁶. -3 S cm -1 The electrochemical window of this electrolyte is 5.3 V.

[0042] The battery was then subjected to a long-cycle test at room temperature, with a charge / discharge rate of 0.3 C and a voltage range of 3-4.3 V. After 100 cycles, the capacity retention rate was 97%.

[0043] Example 6: 0.5 g of the sodium salt of the aluminum-centered anion small molecule shown in the above structural formula and 0.5 g of NaDFOB were dissolved together in a mixed solvent of 0.5 ml FEC and 0.5 ml methyl ethyl carbonate (volume ratio 1:1). This solution was then injected into a 2032 coin cell (sodium metal as the negative electrode, sodium vanadium phosphate as the positive electrode, and PP2500 as the separator). Polymerization was achieved by heating at 55 °C for 4 hours, forming a solid electrolyte in the cell. The room temperature conductivity of this electrolyte is 1.4 × 10⁻⁶. -3 S cm -1 The resulting solid polymer is no longer soluble in various solvents, proving that a cross-linked structure has been obtained. Quantitative calculations also indicate a favorable environment for the formation of cross-linked structures.

[0044] The battery was then subjected to long-cycle testing at room temperature (see [reference]). Figure 5 The charge / discharge rate is 0.2 C, the voltage range is 2.2-3.8 V, and the capacity retention rate is 97.2% after 100 long cycles.

[0045] Example 7: Take 0.5 g of the sodium salt of the aluminum-centered anion small molecule shown in the above structural formula and 0.5 g of NaPF6 and dissolve them together in 0.5 ml of FEC and 0.5 ml of EC (volume ratio 1:1). Inject the solution into a 2032 coin cell (the negative electrode of the cell is sodium metal, the positive electrode is sodium manganate, and the separator is a glass fiber separator). The solution can be polymerized by heating at 60 °C for 18 hours to form a solid electrolyte in the cell.

[0046] The battery was then subjected to a long-cycle test at room temperature, with a charge / discharge rate of 0.3 C and a voltage range of 2.1-3.5 V. After 260 cycles, the capacity retention rate was 87%.

[0047] Example 8: Take 0.5 g of the potassium salt of the aluminum-centered anion small molecule shown in the above structural formula and 0.5 g of potassium difluorooxalate borate (KDFOB) and dissolve them together in a mixed solvent of 0.5 ml FMEC and 0.5 ml EC (volume ratio 1:1). Inject the solution into a 2032 coin cell (the negative electrode of the cell is potassium metal, the positive electrode is Prussian blue, and the separator is PP2500). Polymerize the solution by heating at 60 °C for 8 hours to form a solid electrolyte in the cell.

[0048] The battery was then subjected to a long-cycle test at room temperature, with a charge / discharge rate of 0.4 C and a voltage range of 2.2-4.0 V. After 100 cycles, the capacity retention was 97.2%.

[0049] Example 9: 0.5 g of the lithium salt with the aluminum-centered anion shown in the above structural formula and 0.5 g of LiClO4 were dissolved in a mixed solvent of 0.5 ml FEC and 0.5 ml PC (volume ratio 3:7), and then injected into a 2032 coin cell (the negative electrode of the cell is graphite, and the positive electrode is LiNi). 0.8 Co 0.1 Mn 0.1 In O2 (with a glass fiber separator), it can polymerize upon heating at 60 °C for 7 hours to form a solid electrolyte in the battery. The electrochemical window of this electrolyte was determined to be 5.5 V using the LSV method.

[0050] The battery was then subjected to a long-cycle test at 40°C with a charge / discharge rate of 0.2 C and a voltage range of 3-4.3 V. After 130 cycles, the capacity retention rate was 86%.

[0051] Example 10: Take 1 g of sodium salt of aluminum-centered anion small molecules as shown in the above structural formula, dissolve it in 2 ml FEC, inject it into a 2032 coin cell (the negative electrode of the cell is sodium metal, the positive electrode is sodium vanadium phosphate, and the separator is PP2500), and it can be polymerized by heating at 65 °C for 2 hours to form a solid electrolyte in the cell.

[0052] The battery was then subjected to a long-cycle test at room temperature, with a charge / discharge rate of 2 C and a voltage range of 2.2-3.8 V. After 70 cycles, the capacity retention rate was 93%.

[0053] Example 11: 1 g of lithium salt containing the aluminum-centered anion small molecule shown in the above structural formula was dissolved in 3 ml of FEMC and then injected into a 2032 coin cell (the negative electrode of the cell is graphite, and the positive electrode is LiNi). 0.6 Co 0.2 Mn 0.2 In O2 (with a glass fiber separator), it can be polymerized by heating at 70 °C for 1 hour to form a solid electrolyte in the battery.

[0054] The battery was then subjected to a long-cycle test at room temperature, with a charge / discharge rate of 0.7 C and a voltage range of 3-4.3 V. After 150 cycles, the capacity retention rate was 94%.

Claims

1. A single-ion solid electrolyte polymerized in situ, characterized in that: The solid electrolyte is obtained by in-situ polymerization of metal salt in the presence of solvent to obtain a single-ion solid electrolyte; wherein the metal salt contains a small molecule metal salt with an aluminum central anion as shown in Formula 1; the solvent includes fluorocarbonate; the mass ratio of the fluorocarbonate to the small molecule metal salt with an aluminum central anion as shown in Formula 1 is 1-10:1-10. The aluminum-central anion small molecule metal salt is shown in Formula 1. Set 1 T is selected from lithium, sodium, or potassium; Y1 is selected from halogen, O, S, or NR. 1 When Y1 is a halogen, there is no R group; Y2 and Y3 can be the same or different and are selected from O, S or NR. 1 ; R, R 1 Can be the same or different from C1-C 20 Alkyl, C1-C 20 Halogenated alkyl groups, C3-C 10 cycloalkyl, C3-C 10 A halogenated cycloalkyl group, unsubstituted or substituted benzene with at least one of the same or different substituents listed below, wherein the substituents are halogenated, C1-C 20 Alkyl, C1-C 20 Haloalkyl, C3-C 10 cycloalkyl, C3-C 10 Halogenated cycloalkyl groups; R 1 It can also be hydrogen; p1 is an integer from 0 to 10, p2 is an integer from 1 to 10, and the value of p1+p2 makes the anion exhibit a negative monovalent.

2. The in-situ polymerized single-ion solid electrolyte according to claim 1, characterized in that: The metal salt is an aluminum-centered anionic small molecule metal salt of Formula 1, or a mixture of an aluminum-centered anionic small molecule metal salt of Formula 1 and other anionic metal salts; wherein, when the metal salt is a mixture of an aluminum-centered anionic small molecule metal salt of Formula 1 and other anionic (central atom M) metal salts, it is polymerized in situ in the presence of a solvent; wherein, the central atom M in the other anionic metal salts is B, P, N, Cl, or As.

3. The in-situ polymerized single-ion solid electrolyte according to claim 2, characterized in that: The other anionic metal salts are selected from TPF6, TAsF6, TClO4, TTFSI, TFSI, TBOB, TDFOB, and TBF4, where T is lithium, sodium, or potassium.

4. The in-situ polymerized single-ion solid electrolyte according to claim 1, characterized in that: The solvent is a fluorocarbonate solvent, or a fluorocarbonate solvent and other solvents; Other solvents are selected from C3-C 10 Non-fluorinated linear carbonate solvents, C3-C 10 One or more of the following: non-fluorinated cyclic carbonate solvents, ether solvents, ester solvents, sulfone solvents, and nitrogen-containing solvents.

5. The in-situ polymerized single-ion solid electrolyte according to any one of claims 1-4, characterized in that: The mass ratio of fluorinated carbonate, other solvents, aluminum-centered anionic small molecule metal salts as shown in Formula 1, and other anionic metal salts in the solid electrolyte is 1-60:0-40:1-60:0-50.

6. A method for preparing an in-situ polymerized single-ion solid electrolyte, characterized in that: The raw materials of the single-ion solid electrolyte as described in claim 1 are injected into the battery and polymerized in situ at 30-80°C for 1-20 hours to obtain the in-situ polymerized single-ion solid electrolyte.

7. The application of the in-situ polymerized single-ion solid electrolyte as described in claim 1, characterized in that: Application of the in-situ polymerized single-ion solid electrolyte in batteries.

8. A battery comprising a positive electrode, a negative electrode, and an electrolyte between the positive and negative electrodes, characterized in that, The electrolyte is the in-situ polymerized single-ion solid electrolyte as described in claim 1.

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