A semi-solid electrode and a method of making the same

Abstract

The application discloses a kind of semi-solid electrode and preparation method thereof, belong to new material technical field.The method of the present application first polymerization initiator, monomer, high molecular weight prepolymer are sequentially added into electrolyte, stirring until monomer is completely dissolved;In the obtained mixed electrolyte, conductive agent is added, stirring until completely dispersed;Then add positive active material, stirring until completely dispersed to obtain mixed slurry;Finally, the obtained mixed slurry is coated to the surface of current collector, and is cured by ultraviolet light radiation and is wound, to obtain integrated semi-solid electrode.The application solves the interface problem of full solid electrolyte used in battery and positive electrode, while minimizing the content of electrolyte in battery, improving the safety performance of battery.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology, specifically relating to a semi-solid electrode and its preparation method. Background Technology

[0002] In recent years, due to the frequent combustion accidents of new energy electric vehicles, the use of solid electrolytes to replace the original flammable electrolytes and heat-sensitive separators to prepare all-solid-state batteries and improve battery safety has attracted widespread attention. Currently, solid electrolytes are mainly divided into oxide solid electrolytes, sulfide solid electrolytes, and polymer solid electrolytes. Among them, sulfide solid electrolytes are highly anticipated due to their high ionic conductivity and strong plasticity, which allow for close contact with active materials through cold pressing. Despite these advantages, sulfide all-solid-state batteries still face many difficulties in industrialization: 1) Sulfide solid electrolytes have a narrow electrochemical window and are easily oxidized by the positive electrode, leading to increased interfacial resistance; 2) During cycling, the stress caused by the volume change of the positive electrode leads to poor interfacial contact between the sulfide electrolyte and the active material, hindering lithium-ion transport; 3) Due to the difference in electrochemical potential between sulfides and the positive / negative electrode materials, a space charge layer is generated at the interface, hindering ion transport. Currently, a comprehensive and effective method is still lacking to solve the above-mentioned scientific problems and engineering challenges.

[0003] Based on this, adding a small amount of electrolyte to wet the positive electrode, in combination with an all-solid electrolyte, can reduce the content of flammable electrolyte to the greatest extent and prepare a semi-solid battery, which is a solution that can be quickly industrialized.

[0004] Common cathode materials are typically prepared by uniformly mixing active materials, conductive agents, and binders with a solvent, followed by coating. During battery assembly, the positive and negative electrodes and separator are pre-assembled, and then the electrolyte is injected. This method relies on the diffusion of the electrolyte during settling to wet the electrodes, requiring a specific electrolyte injection volume. Even with a solid electrolyte, this traditional preparation method still demands a high electrolyte injection volume to ensure lithium-ion transport within the electrodes, failing to minimize electrolyte content and fundamentally reduce the introduction of fuel combustion, thus hindering battery safety. Furthermore, the electrolyte within the electrodes faces the challenge of continuous decomposition and recombination during cycling due to the instability of the SEI / CEI film, leading to electrolyte depletion and decreased cycle performance.

[0005] Therefore, there is an urgent need for a positive / negative electrode preparation method that can stabilize the interface between the solid electrolyte and the electrode, and minimize the electrolyte content in the electrode while ensuring battery cycle performance. Summary of the Invention

[0006] To address the aforementioned issues, this invention discloses a semi-solid electrode and its preparation method, which solves the interface problem between the all-solid electrolyte and the positive electrode when used in a battery cell, while minimizing the electrolyte content within the battery cell and improving battery safety performance.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] This invention first provides a method for preparing a semi-solid electrode, the method comprising the following steps:

[0009] S1. Add the high molecular weight prepolymer, monomer, and initiator to the electrolyte in sequence and stir until the monomer is completely dissolved. The mass percentage of the prepolymer, monomer, and initiator in the electrolyte is as follows: high molecular weight prepolymer 0.5-30%, monomer 0.5-5%, and initiator 0.001-0.2%.

[0010] S2. Add a conductive agent to the mixed electrolyte obtained in step S1 and stir until completely dispersed; then add the positive electrode active material and stir until completely dispersed to obtain a mixed slurry. The amount added is 50-90% of the positive electrode active material, 0.5-5% of the conductive agent, and 9-50% of the mixed electrolyte obtained in step S1.

[0011] S3. Coat the mixed slurry obtained in step S2 onto the surface of the current collector, cure it with ultraviolet light, and roll it up to obtain an integrated semi-solid electrode.

[0012] Furthermore, the thickness of the coating mixture in step S3 is 1–200 μm, and the thickness of the current collector layer used in step S3 is 1–30 μm.

[0013] Furthermore, the high molecular weight prepolymer described in step S1 is a macromolecule containing >C=C< structural groups, and is composed of repeating units having the following: Wherein R1 and R2 include, but are not limited to, one or more groups containing carbon and / or oxygen and / or hydrogen and / or nitrogen elements from -CH2, -CH2CH2, -NH, -CH2CO, -O, -CH, -COCH, and -CH2CH; R3 includes, but is not limited to, one or more groups containing carbon and / or nitrogen and / or fluorine and / or hydrogen and / or oxygen elements from -NH2, -CF3, -F, and -CN; n≥50.

[0014] Furthermore, the molecular weight of the high molecular weight prepolymer described in step S1 is between 10,000 and 100,000, and the molecular weight of the monomer is between 50 and 1,000.

[0015] Furthermore, the monomer described in step S1 has two or more groups with a >C=C< structure.

[0016] Further, the monomers mentioned in step S1 include, but are not limited to, one of the following: tripropylene glycol diacrylate, triethylene glycol diacrylate, ethylene glycol dimethacrylate, dipropylene glycol diacrylate, dipropylene adipate, 1,10-bis(acryloyloxy)decane, 1,4-bis(acryloyloxy)butane, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, and trimethylolpropane trimethacrylate.

[0017] Further, the initiator described in step S1 includes, but is not limited to, one of 4-methylbenzophenone, 1-hydroxycyclohexylphenyl ketone, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methyl-1-phenylpropanone, and 4,4'-bis(diethylamino)benzophenone.

[0018] Further, the electrolyte in step S1 includes, but is not limited to, one or a mixture of several of the following: ethylene carbonate (EC), dimethyl carbonate (DMC), propylene carbonate (PC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), ethyl propionate, propylene carbonate (PC), methyl formate (MF), propyl formate, 1,2-dimethoxyethane (DME), dimethyl phthalate (DMP), and 1,3-dioxolane (DOL);

[0019] Furthermore, the conductive agent mentioned in step S2 includes, but is not limited to, one or a combination of carbon nanotubes, graphite, carbon particles, carbon black, and carbon microspheres.

[0020] Furthermore, the positive electrode active material mentioned in step S2 includes, but is not limited to, one of the following: nickel-cobalt-manganese ternary positive electrode material, nickel-cobalt-aluminum ternary positive electrode material, lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, sulfur, and sulfur composite materials.

[0021] Furthermore, the ultraviolet light wavelength in step S3 is between 100-400nm, and the photocuring time is between 20-60min.

[0022] The present invention also provides a semi-solid electrode prepared by the above method.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. In contrast to conventional assembly-then-liquid-injection preparation methods, the present invention provides a semi-solid electrode preparation method. During the positive electrode homogenization process, the high molecular weight prepolymer and monomer are used to replace the binder, and the electrolyte is used to replace the solvent. The electrolyte is directly coated onto the surface of the current collector and a gel-state electrode is formed through in-situ polymerization. The electrolyte is pre-locked inside the positive electrode before the cell is assembled. No subsequent liquid injection is required, and the amount of electrolyte in the positive electrode can be pre-controlled during homogenization, which can minimize the electrolyte content in the battery and improve battery safety performance.

[0025] 2. To address the uniformity problem typically faced by gel electrolytes, this invention involves uniformly mixing the high molecular weight prepolymer, monomer, active material, and electrolyte during homogenization, and then directly coating and polymerizing them. This method does not rely on traditional static diffusion to wet the electrode, thus improving the wettability of the positive electrode active material, enhancing ion transport within the positive electrode, and ensuring a uniform distribution of the electrolyte within the electrode.

[0026] 3. The high molecular weight prepolymer used in this invention can resist oxidation of the positive electrode, ensuring its wettability. Simultaneously, due to the gel's flexibility, it can maintain good contact with the positive electrode active material and solid electrolyte during cycling, improving battery cycle performance. The high molecular weight prepolymer and monomer used in this invention can be used simultaneously as a gel framework and positive electrode binder after polymerization, reducing the use of auxiliary materials within the electrode and improving ionic / electronic conductivity.

[0027] 4. The high molecular weight prepolymer selected in this invention has certain oxidation resistance and flexibility, which can effectively alleviate the problems of chemical instability and poor physical contact at the interface between the solid electrolyte and the positive electrode. It also has adhesion, oxidation resistance and liquid retention properties, and can be used as a binder. While locking in the liquid, it improves the interface problem between the solid electrolyte and the positive electrode. Attached Figure Description

[0028] Figure 1 This is a flowchart illustrating the preparation process of a semi-solid electrode according to the present invention. Detailed Implementation

[0029] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0030] Example 1

[0031] like Figure 1 As shown, a method for preparing a semi-solid electrode in this embodiment specifically includes the following steps:

[0032] S1. Weigh the raw materials according to the following mass ratio: a total of 100 parts solution, including 97.94 parts electrolyte, 1.5 parts high molecular weight prepolymer, 0.5 parts monomer, and 0.06 parts initiator. The electrolyte is selected as (1.0M LiPF6 dissolved in a mixed solution of EC:DMC:DEC = 1:1:1 vol%); the high molecular weight prepolymer is selected with the following structural formula:

[0033] The prepolymer is a given product, wherein R1 is -CH2, R2 is -CH2CH, R3 is -CN, and n is 150; the monomer is ethylene glycol dimethacrylate, and the initiator is 4-methylbenzophenone.

[0034] S1-1: Add the high molecular weight prepolymer to the electrolyte and stir continuously with magnetic force until it is completely dissolved;

[0035] S1-2: Add ethylene glycol dimethacrylate to the mixed electrolyte obtained in step S1-1, and stir continuously with magnetic force until completely dissolved;

[0036] S1-3: Add 4-methylbenzophenone to the mixed electrolyte obtained in step S1-2 and stir magnetically until completely dissolved.

[0037] S2. Weigh the raw materials according to the following ratio: a total of 100 parts slurry, including 30 parts of the mixed electrolyte obtained in step S1, 69 parts of the positive electrode material, and 1 part of the conductive additive. The positive electrode material is NCM811, and the conductive additive is carbon black.

[0038] S2-1: Add carbon black to step S1-3 and stir mechanically until completely dispersed;

[0039] S2-2: Add NCM811 to the mixed solution obtained in step S2-1 and stir mechanically until completely dispersed.

[0040] S3. The mixed slurry obtained in S2-2 is coated onto the current collector to a thickness of 100 μm, and then irradiated with UV light at a wavelength of 100 nm for 40 min. This yields a semi-solid electrode as described in this invention.

[0041] The application of a semi-solid electrode obtained in this embodiment: Li6PS5Cl / SBR composite electrolyte membrane is selected as solid electrolyte, lithium foil is used as negative electrode, and the electrode prepared above is used as semi-solid positive electrode. The electrode is assembled into a mold battery and pressed to obtain battery LB-01. The electrochemical performance of the battery obtained in this embodiment is tested, and the test results are shown in Table 1.

[0042] Example 2

[0043] like Figure 1As shown, a method for preparing a semi-solid electrode in this embodiment specifically includes the following steps:

[0044] S1. Weigh the raw materials according to the following mass ratio: a total of 100 parts solution, including 82.5 parts electrolyte, 15 parts high molecular weight prepolymer, 1.5 parts monomer, and 0.1 parts initiator. The electrolyte is selected as (1.0M LiPF6 dissolved in a mixed solution of EC:DMC:DEC = 1:1:1 vol%); the high molecular weight prepolymer is selected with the following structural formula:

[0045] The prepolymer is a given product, wherein R1 is -CH2, R2 is -CH2CH, R3 is -CN, and n is 150; the monomer is ethylene glycol dimethacrylate, and the initiator is 4-methylbenzophenone.

[0046] S1-1: Add the high molecular weight prepolymer to the electrolyte and stir continuously with magnetic force until it is completely dissolved;

[0047] S1-2: Add ethylene glycol dimethacrylate to the mixed electrolyte obtained in S1-1, and stir continuously with magnetic force until completely dissolved;

[0048] S1-3: Add 4-methylbenzophenone to the mixed electrolyte obtained in S1-2 and stir magnetically until completely dissolved.

[0049] S2. Weigh the raw materials according to the following ratio: a total of 100 parts slurry, including 30 parts of the mixed electrolyte obtained in step S1, 69 parts of the positive electrode material, and 1 part of the conductive additive. The positive electrode material is NCM811, and the conductive additive is carbon black.

[0050] S2-1: Add carbon black to the mixed electrolyte obtained in S1-3 and stir mechanically until it is completely dispersed;

[0051] S2-2: Add NCM811 to the mixed solution obtained in S2-1 and stir mechanically until completely dispersed.

[0052] S3. The mixed slurry obtained in S2-2 is coated onto the current collector to a thickness of 100 μm, and then irradiated with UV light at a wavelength of 100 nm for 40 min. This yields a semi-solid electrode as described in this invention.

[0053] The application of a semi-solid electrode obtained in this embodiment: Li6PS5Cl / SBR composite electrolyte membrane is selected as solid electrolyte, lithium foil is used as negative electrode, and the electrode prepared above is used as semi-solid positive electrode. The electrode is assembled into a mold battery and pressed to obtain battery LB-02. The electrochemical performance of the battery obtained in this embodiment is tested, and the test results are shown in Table 1.

[0054] Example 3

[0055] like Figure 1 As shown, a method for preparing a semi-solid electrode in this embodiment specifically includes the following steps:

[0056] S1. Weigh the raw materials according to the following mass ratio: a total of 100 parts solution, including 88.5 parts electrolyte, 10 parts high molecular weight prepolymer, 0.5 parts monomer, and 0.1 parts initiator. The electrolyte is selected as a mixed solution of 1.0M LiPF6 dissolved in EC:DMC:DEC = 1:1:1 (vol%); the high molecular weight prepolymer is selected with the following structural formula:

[0057] The prepolymer of which R1 is -NH, R2 is -CH2CH, R3 is -CF3, and n is 300; the monomer is triethylene glycol diacrylate, and the initiator is 1-hydroxycyclohexylphenyl ketone.

[0058] S1-1: Add the high molecular weight prepolymer to the electrolyte and stir continuously with magnetic force until it is completely dissolved;

[0059] S1-2: Add triethylene glycol diacrylate to the mixed electrolyte obtained in S1-1, and stir continuously with magnetic force until completely dissolved;

[0060] S1-3: Add 1-hydroxycyclohexylphenyl ketone to the mixed electrolyte obtained in S1-2 and stir magnetically until completely dissolved.

[0061] S2. Weigh the raw materials according to the following ratio: a total of 100 parts slurry, including 10 parts of the mixed electrolyte obtained in step S1, 88 parts of the positive electrode material, and 2 parts of the conductive additive. The positive electrode material is NCM811, and the conductive additive is carbon black.

[0062] S2-1: Add carbon black to the mixed electrolyte obtained in step S1 and stir mechanically until it is completely dispersed;

[0063] S2-2: Add NCM811 to the mixed solution obtained in S2-1 and stir mechanically until completely dispersed.

[0064] S3. Coat the mixed slurry obtained in S2-2 onto the current collector to a thickness of 100 μm, and irradiate with UV light at a wavelength of 200 nm for 50 min. This yields a semi-solid electrode as described in this invention.

[0065] The application of a semi-solid electrode obtained in this embodiment: Li6PS5Cl / SBR composite electrolyte membrane is selected as solid electrolyte, lithium foil is used as negative electrode, and the electrode prepared above is used as semi-solid positive electrode. The electrode is assembled into a mold battery and pressed to obtain battery LB-03. The electrochemical performance of the battery obtained in this embodiment is tested, and the test results are shown in Table 1.

[0066] Example 4

[0067] like Figure 1 As shown, a method for preparing a semi-solid electrode in this embodiment specifically includes the following steps:

[0068] S1. Weigh the raw materials according to the following mass ratio: a total of 100 parts solution, including 88.5 parts electrolyte, 10 parts high molecular weight prepolymer, 0.5 parts monomer, and 0.1 parts initiator. The electrolyte is selected as a mixed solution of 1.0M LiPF6 dissolved in EC:DMC:DEC = 1:1:1 (vol%); the high molecular weight prepolymer is selected with the following structural formula: The prepolymer of which R1 is -NH, R2 is -COCH, R3 is -CF3, and n is 400; the monomer is dipropylene glycol diacrylate, and the initiator is 1-hydroxycyclohexylphenyl ketone.

[0069] S1-1: Add the high molecular weight prepolymer to the electrolyte and stir continuously with magnetic force until it is completely dissolved;

[0070] S1-2: Add triethylene glycol diacrylate to the mixed electrolyte obtained in S1-1, and stir continuously with magnetic force until completely dissolved;

[0071] S1-3: Add 1-hydroxycyclohexylphenyl ketone to the mixed electrolyte obtained in S1-2 and stir magnetically until completely dissolved.

[0072] S2. Weigh the raw materials according to the following ratio: a total of 100 parts slurry, including 10 parts of the mixed electrolyte obtained in step S1, 88 parts of the positive electrode material, and 2 parts of the conductive additive. The positive electrode material is NCM811, and the conductive additive is carbon black.

[0073] S2-1: Add carbon black to the mixed electrolyte obtained in step S1 and stir mechanically until it is completely dispersed;

[0074] S2-2: Add NCM811 to the mixed solution obtained in S2-1 and stir mechanically until completely dispersed.

[0075] S3. Coat the mixed slurry obtained in S2-2 onto the current collector to a thickness of 100 μm, and irradiate with UV light at a wavelength of 200 nm for 50 min. This yields a semi-solid electrode as described in this invention.

[0076] The application of a semi-solid electrode obtained in this embodiment: Li6PS5Cl / SBR composite electrolyte membrane is selected as solid electrolyte, lithium foil is used as negative electrode, and the electrode prepared above is used as semi-solid positive electrode. The electrode is assembled into a mold battery and pressed to obtain battery LB-04. The electrochemical performance of the battery obtained in this embodiment is tested, and the test results are shown in Table 1.

[0077] Example 5

[0078] like Figure 1 As shown, a method for preparing a semi-solid electrode in this embodiment specifically includes the following steps:

[0079] S1. Weigh the raw materials according to the following mass ratio: a total of 100 parts solution, including 77.85 parts electrolyte, 20 parts high molecular weight prepolymer, 2 parts monomer, and 0.15 parts initiator. The electrolyte is selected as (1.0M LiPF6 dissolved in a mixed solution of EC:DMC:DEC = 1:1:1 vol%); the high molecular weight prepolymer is selected with the following structural formula:

[0080] The prepolymer is a prepolymer in which R1 is -CH2CH2, R2 is -N, R3 is CN, and n is 200; the monomer is 1,6-hexanediol diacrylate, and the initiator is 2-hydroxy-2-methyl-1-phenylpropanone.

[0081] S1-1: Add the high molecular weight prepolymer to the electrolyte and stir continuously with magnetic force until it is completely dissolved;

[0082] S1-2: Add 1,6-hexanediol diacrylate to the mixed electrolyte obtained in S1-1 and stir continuously with magnetic force until completely dissolved.

[0083] S1-3: Add 2-hydroxy-2-methyl-1-phenylpropanone to the mixed electrolyte obtained in S1-2 and stir magnetically until completely dissolved.

[0084] S2. Weigh the raw materials according to the following ratio: a total of 100 parts slurry, including 40 parts of the mixed electrolyte obtained in step S1, 57 parts of the positive electrode material, and 3 parts of the conductive additive. The positive electrode material is NCM811, and the conductive additive is carbon black.

[0085] S2-1: Add carbon black to the mixed electrolyte obtained in S1-3 and stir mechanically until it is completely dispersed;

[0086] S2-2: Add NCM811 to the mixed solution obtained in S2-1 and stir mechanically until completely dispersed.

[0087] S3. Coat the mixed slurry obtained in S2-2 onto the current collector to a thickness of 100 μm, and irradiate with UV light at a wavelength of 300 nm for 60 min. This yields a semi-solid electrode as described in this invention.

[0088] The application of a semi-solid electrode obtained in this embodiment: Li6PS5Cl / SBR composite electrolyte membrane is selected as solid electrolyte, lithium foil is used as negative electrode, and the electrode prepared above is used as semi-solid positive electrode. The electrode is assembled into a mold battery and pressed to obtain battery LB-05. The electrochemical performance of the battery obtained in this embodiment is tested, and the test results are shown in Table 1.

[0089] Example 6

[0090] like Figure 1 As shown, a method for preparing a semi-solid electrode in this embodiment specifically includes the following steps:

[0091] S1. Weigh the raw materials according to the following mass ratio: a total of 100 parts solution, including 77.85 parts electrolyte, 20 parts high molecular weight prepolymer, 2 parts monomer, and 0.15 parts initiator. The electrolyte is selected as (1.0M LiPF6 dissolved in a mixed solution of EC:DMC:DEC = 1:1:1 vol%); the high molecular weight prepolymer is selected with the following structural formula:

[0092] The prepolymer is a prepolymer in which R1 is -O, R2 is -CH2CH, R3 is CN, and n is 200; the monomer is 1,6-hexanediol diacrylate, and the initiator is 2-hydroxy-2-methyl-1-phenylpropanone.

[0093] S1-1: Add the high molecular weight prepolymer to the electrolyte and stir continuously with magnetic force until it is completely dissolved;

[0094] S1-2: Add 1,6-hexanediol diacrylate to the mixed electrolyte obtained in S1-1 and stir continuously with magnetic force until completely dissolved.

[0095] S1-3: Add 2-hydroxy-2-methyl-1-phenylpropanone to the mixed electrolyte obtained in S1-2 and stir magnetically until completely dissolved.

[0096] S2. Weigh the raw materials according to the following ratio: a total of 100 parts slurry, including 20 parts of the mixed electrolyte obtained in step S1, 76 parts of the positive electrode material, and 4 parts of the conductive additive. The positive electrode material is NCM811, and the conductive additive is carbon black.

[0097] S2-1: Add carbon black to the mixed electrolyte obtained in step S1 and stir mechanically until it is completely dispersed;

[0098] S2-2: Add NCM811 to the mixed solution obtained in S2-1 and stir mechanically until completely dispersed.

[0099] S3. Coat the mixed slurry obtained in S2-2 onto the current collector to a thickness of 100 μm, and irradiate with UV light at a wavelength of 300 nm for 60 min. This yields a semi-solid electrode as described in this invention.

[0100] The application of a semi-solid electrode obtained in this embodiment: Li6PS5Cl / SBR composite electrolyte membrane is selected as solid electrolyte, lithium foil is used as negative electrode, and the electrode prepared above is used as semi-solid positive electrode. The electrode is assembled into a mold battery and pressed to obtain battery LB-06. The electrochemical performance of the battery obtained in this embodiment is tested, and the test results are shown in Table 1.

[0101] Comparative Example 1

[0102] This comparative example is designed as a basic experiment without any additives. The difference between this comparative example and Examples 1-6 is that this comparative example is assembled into an all-solid-state battery, with NCM811 and Li6PS5Cl as the positive electrode, lithium foil as the negative electrode, and Li6PS5Cl / SBR composite electrolyte membrane in the middle. It is assembled into a mold battery and made into an all-solid-state battery LB-07.

[0103] Battery cycle performance test

[0104] Cyclic performance tests were conducted on the batteries LB-01 to LB-07 prepared in the above embodiments and comparative examples, with a current density of 0.33C selected.

[0105] The cycle performance of solid-state batteries LB-01 to LB-07 was tested using the above methods, and the results are shown in Table 1.

[0106] Table 1. Needle penetration test results of batteries LB-01 to LB-14

[0107] Example 1 100 80％ Example 2 100 84％ Example 3 100 82％ Example 4 100 81％ Example 5 100 80％ Example 6 100 82％ Comparative Example 1 100 50％

[0108] The above is merely a preferred embodiment of the present invention. The electrolyte in step S1 of the present invention contains additives, including but not limited to: vinylene carbonate (VC), lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonylimide) (LiTFSI), lithium tetrafluoroborate (LiBF4), trimethyl phosphate (TMP), lithium hexafluoroarsenate (LiAsF6), vinyl sulfate (DTD), fluoroethylene carbonate (FEC), and lithium nitrate (LiNO3), or a mixture thereof. The nickel-cobalt-manganese ternary cathode material of the present invention can be NCM111, NCM523, NCM622, or NCM811, etc. The high molecular weight prepolymer 1, monomer 2, initiator, cathode active material, and conductive agent of the present invention can all be freely selected within the scope of the claims without affecting the product performance of the present invention.

[0109] Without departing from the principles of this invention, several improvements and modifications can be made, all of which fall within the protection scope of the claims of this invention.

Claims

1. A method for preparing a semi-solid electrode, characterized in that, The method includes the following steps: S1. Add the high molecular weight prepolymer, monomer, and initiator to the electrolyte in sequence and stir until the monomer is completely dissolved. The mass percentage of the high molecular weight prepolymer, monomer, and initiator in the electrolyte is as follows: high molecular weight prepolymer 0.5-30%, monomer 0.5-5%, and initiator 0.001-0.2%. S2. Add a conductive agent to the mixed electrolyte obtained in step S1 and stir until completely dispersed; then add the positive electrode active material and stir until completely dispersed to obtain a mixed slurry. The amount added is 50-90% of the positive electrode active material, 0.5-5% of the conductive agent, and 9-50% of the mixed electrolyte obtained in step S1. S3. Coat the mixed slurry obtained in step S2 onto the surface of the current collector, cure it with ultraviolet light radiation and roll it up to obtain an integrated semi-solid electrode. The high molecular weight prepolymer mentioned in step S1 is a macromolecule containing >C=C< structural groups, and is composed of repeating units having the following: R1 and R2 include one of -CH2, -CH2CH2, -NH, -CH2CO, -O, -CH, -COCH, and -CH2CH; R3 includes one of -NH2, -CF3, -F, and -CN; n≥50; The monomers mentioned in step S1 include one of the following: tripropylene glycol diacrylate, triethylene glycol diacrylate, ethylene glycol dimethacrylate, dipropylene glycol diacrylate, dipropylene adipate, 1,10-bis(acryloyloxy)decane, 1,4-bis(acryloyloxy)butane, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, and trimethylolpropane trimethacrylate.

2. The method for preparing a semi-solid electrode according to claim 1, characterized in that, The thickness of the coating mixture in step S3 is 1~200μm, and the thickness of the current collector layer used in step S3 is 1~30μm.

3. The method for preparing a semi-solid electrode according to claim 1, characterized in that, The molecular weight of the high molecular weight prepolymer mentioned in step S1 is between 10,000 and 100,000, and the molecular weight of the monomer is between 50 and 1,000.

4. The method for preparing a semi-solid electrode according to claim 1, characterized in that, The initiator described in step S1 includes one of 4-methylbenzophenone, 1-hydroxycyclohexylphenyl ketone, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methyl-1-phenylpropanone, and 4,4'-bis(diethylamino)benzophenone.

5. The method for preparing a semi-solid electrode according to claim 1, characterized in that, The electrolyte in step S1 includes one or a mixture of several of the following: ethylene carbonate (EC), dimethyl carbonate (DMC), propylene carbonate (PC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), ethyl propionate, propylene carbonate (PC), methyl formate (MF), propyl formate, 1,2-dimethoxyethane (DME), dimethyl phthalate (DMP), and 1,3-dioxolane (DOL).

6. The method for preparing a semi-solid electrode according to claim 1, characterized in that, The conductive agent in step S2 includes one or more of the following: carbon nanotubes, graphite, carbon particles, carbon black, and carbon microspheres.

7. The method for preparing a semi-solid electrode according to claim 1, characterized in that, The positive electrode active material mentioned in step S2 includes one of the following: nickel-cobalt-manganese ternary positive electrode material, nickel-cobalt-aluminum ternary positive electrode material, lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, sulfur, and sulfur composite materials.

8. The method for preparing a semi-solid electrode according to claim 1, characterized in that, The ultraviolet light wavelength in step S3 is between 100-400 nm, and the photocuring time is between 20-60 min.

9. A semi-solid electrode prepared by the method according to any one of claims 1-8.

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