Oligolytic cathode slurry, cathode and semi-solid state battery

Abstract

The present invention discloses an oligo-liquid positive electrode slurry, a positive electrode, and a semi-solid battery. The oligo-liquid positive electrode slurry is formed by homogenizing an electrolyte, a positive electrode active material, and a conductive agent; wherein the electrolyte contains a polymerizable monomer and an initiator, and the electrolyte accounts for no more than 10% by mass of the oligo-liquid positive electrode slurry. The oligo-liquid positive electrode slurry is binder-free and has a low electrolyte content (≤10%). It can be used in conjunction with a semi-solid process to form a positive electrode. There is no trace of liquid on the positive electrode side, making the coated positive electrode not only stably compatible with halide solid electrolytes or sulfide solid electrolytes, but also because the electrolyte is introduced on the positive electrode side, the lithium / sodium ion transmission on the positive electrode side is changed from solid-solid contact transmission to liquid transmission, thereby greatly improving battery performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of secondary batteries, and in particular relates to an oligo-liquid positive electrode slurry and a positive electrode for a semi-solid battery, and also relates to a semi-solid battery and a preparation method thereof. Background Art

[0002] Solid-state batteries, combining the high specific energy of lithium / sodium metal anodes with the inherent safety of solid-state electrolytes, represent a promising energy storage technology with high energy density and safety. Among the various solid-state electrolytes, halide or sulfide solid electrolytes are novel solid-state electrolyte materials, offering advantages such as high ionic conductivity, excellent ductility, and stability with cathode active materials. However, the interfacial contact between the cathode and halide or sulfide solid electrolytes in solid-state batteries remains problematic, hindering the commercialization of solid-state batteries using halide or sulfide solid electrolytes as the solid electrolyte layer. Furthermore, the slow interparticle transport of lithium / sodium ions on the cathode side of solid-state batteries significantly reduces transport efficiency and severely limits battery performance. Furthermore, halide or sulfide solid electrolytes are unstable in the electrolyte system and readily react with polar solvents (such as water), rendering the solid-state electrolyte ineffective. Consequently, the development of semi-solid-state batteries based on these solid-state electrolytes has been hindered.

[0003] Chinese patent application publication number CN114695965A reports an interfacial wetting agent for halide solid electrolytes. The interfacial wetting agent uses n-butyl ether or isobutyl ether as a solvent and lithium bis(trifluoromethanesulfonyl imide) as a lithium salt. The interfacial wetting agent has advantages such as a wide electrochemical window and high conductivity, thereby improving the performance of the solid-state battery. However, the presence of the interfacial wetting agent results in the presence of a liquid electrolyte in the solid-state battery system, which reduces the safety of the solid-state battery and does not solve the problem of difficult ion transport on the positive electrode side. Chinese patent application publication number CN115799621A proposes a composite solid electrolyte membrane. The membrane is obtained by uniformly mixing a polymer with a halide solid electrolyte and applying shear force to the resulting mixed powder to fiberize the polymer. This improves the interfacial contact between the positive electrode and the halide solid electrolyte, thereby improving the performance of the solid-state battery. However, this solution also uses solid particle transmission on the positive electrode side, which does not solve the problem of difficult ion transport on the positive electrode side and greatly reduces its performance. Summary of the Invention

[0004] In view of this, the primary purpose of the present invention is to provide an oligo-liquid positive electrode slurry, which contains no binder and has a low electrolyte content (≤10%). The positive electrode is formed by a semi-solid process, and there is no trace of liquid on the positive electrode side, so that the coated positive electrode is not only stably compatible with the halide / sulfide solid electrolyte, but also because the electrolyte is introduced on the positive electrode side, the lithium / sodium ions on the positive electrode side are changed from solid-solid contact transmission to liquid transmission, thereby greatly improving the battery performance.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention first provides an oligo-liquid positive electrode slurry, which is formed by homogenizing an electrolyte, a positive electrode active material and a conductive agent; wherein the electrolyte contains a polymerizable monomer and an initiator, and the mass proportion of the electrolyte in the oligo-liquid positive electrode slurry does not exceed 10%.

[0007] In a further embodiment, the polymerizable monomer is at least one of vinyl ethylene carbonate, methyl methacrylate, polyethylene glycol diacrylate, pentaerythritol tetraacrylate, 1,3-dioxolane, and 1,3,5-trioxane;

[0008] And / or, the initiator is azobisisobutyronitrile (AIBN) or a cationic polymerization initiator.

[0009] In a further embodiment, in the electrolyte, the amount of the polymerizable monomer added is between 0.5% and 50%; and the amount of the initiator added is between 0.5% and 5%.

[0010] In a further embodiment, the electrolyte solution further includes an electrolyte salt and an organic solvent.

[0011] In a further embodiment, the electrolyte salt is a lithium salt or a sodium salt.

[0012] In a further embodiment, the lithium salt is at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium perchlorate, lithium trifluoromethanesulfonate, lithium difluorophosphate, 2-trifluoromethyl-4,5-dicyanoimidazole lithium, lithium difluorooxalatoborate, lithium chlorotrifluoroborate, lithium trioxalatophosphate, lithium tetrafluorooxalatophosphate, and lithium bisoxalatoborate.

[0013] In a further embodiment, the sodium salt is at least one of sodium hexafluorophosphate, sodium hexafluoroarsenate, sodium tetrafluoroborate, sodium perchlorate, sodium trifluoromethanesulfonate, sodium difluorophosphate, sodium difluorooxalatoborate, sodium chlorotrifluoroborate, sodium trioxalatophosphate, sodium tetrafluorooxalatophosphate, and sodium bisoxalatoborate.

[0014] In a further embodiment, the concentration of the electrolyte salt in the electrolyte solution is 0.5 to 2.5 mol / L.

[0015] In a further embodiment, the organic solvent is at least one of low-polarity ethers, low-polarity esters, and low-polarity sulfones.

[0016] In a further embodiment, the low-polarity ether is at least one of n-propyl ether, ethyl butyl ether, ethyl isobutyl ether, n-butyl ether, isobutyl ether, n-pentyl ether, and isopentyl ether.

[0017] In a further embodiment, the low-polarity sulfone is at least one of propyl sulfone, isopropyl sulfone, butyl sulfone, isobutyl sulfone, dimethyl sulfoxide, and sulfolane.

[0018] In a further embodiment, the low-polarity ester solvent is at least one of ethyl acetate, isopropyl acetate, butyl acetate, pentyl acetate, and hexyl acetate.

[0019] In a further embodiment, the positive electrode active material is a lithium battery positive electrode active material or a sodium battery positive electrode active material.

[0020] In a further embodiment, the positive electrode active material of the lithium battery is one of lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium cobalt oxide, and lithium manganese iron phosphate.

[0021] In a further embodiment, the positive electrode active material of the sodium battery is one of sodium manganese oxide, sodium cobalt oxide, sodium nickel oxide, sodium iron phosphate, and sodium vanadium phosphate.

[0022] In a further embodiment, the conductive agent is at least one of conductive carbon black Super-P, Ketjen black, multi-walled carbon nanotubes, single-walled carbon nanotubes, and vapor-deposited carbon fibers.

[0023] In a further embodiment, the mass ratio of the positive electrode active material, the conductive agent and the electrolyte is (87~91):(3~6):(3~10).

[0024] The present invention further provides a positive electrode, which is obtained by coating the aforementioned oligo-liquid positive electrode slurry on a positive electrode current collector.

[0025] The present invention further provides a method for preparing a semi-solid-state battery, comprising the following steps:

[0026] Obtain a positive electrode as described above;

[0027] The positive electrode is assembled with a solid electrolyte and a negative electrode, and then solidified in situ, wherein the solid electrolyte is a halide solid electrolyte or a sulfide solid electrolyte.

[0028] In a further embodiment, the negative electrode is a metal M or an alloy thereof, and the metal M is lithium or sodium.

[0029] The present invention further provides a semi-solid-state battery, which is prepared using the aforementioned preparation method.

[0030] Beneficial effects of the present invention:

[0031] In the oligo-liquid positive electrode slurry of the present invention, the electrolyte content does not exceed 10%, which changes the ion transport in the semi-solid positive electrode obtained by coating it into liquid transport, which is faster than the inter-particle transport in solid-state batteries. In addition, due to the extremely low electrolyte content, the safety performance and energy density of the battery are improved.

[0032] The positive electrode obtained from the above-mentioned oligo-liquid positive electrode slurry of the present invention adopts a binder-free electrolyte slurry process, which can be well combined with an in-situ curing process. Compared with other in-situ curing semi-solid processes (curing in the pores of the electrode, which makes the uniformity of in-situ curing need to be improved), this can improve the uniformity of electrode curing.

[0033] The oligo-liquid positive electrode slurry in the present invention enables the semi-solid battery assembled subsequently. Due to the extremely low content of electrolyte in the oligo-liquid positive electrode slurry, the semi-solid slurry positive electrode can stably and compatibly coexist with the halide solid electrolyte, which perfectly solves the problem of instability between the positive electrode containing electrolyte and the halide / sulfide solid electrolyte; and because the semi-solid slurry positive electrode has a high viscosity and a soft surface, the interface contact between the slurry positive electrode and the halide solid electrolyte in the semi-solid battery is better, the interface impedance is lower, and it has more excellent performance.

[0034] The semi-solid-state battery in the present invention adopts a binder-free oligo-liquid positive electrode slurry process, combines a halide / sulfide solid electrolyte and a metal negative electrode to construct a semi-solid-state battery. It is a unique technical route for developing high-energy-density, high-safety energy storage batteries by leveraging their strengths and avoiding their weaknesses. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the structure of a semi-solid-state battery in a preferred embodiment of the present invention.

[0036] Figure 2 This is a flow chart for preparing a semi-solid-state battery in a preferred embodiment of the present invention.

[0037] Figure 3 2 is a comparison chart of the battery cycle performance in Example 1 and Comparative Example 5. DETAILED DESCRIPTION

[0038] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0040] A first aspect of the present invention provides an oligo-liquid positive electrode slurry, which is formed by homogenizing an electrolyte, a positive electrode active material and a conductive agent; wherein the electrolyte contains a polymerizable monomer and an initiator, and the mass proportion of the electrolyte in the oligo-liquid positive electrode slurry does not exceed 10%.

[0041] The “oligo-liquid” mentioned herein refers to a low content of electrolyte in the positive electrode slurry, specifically referring to the content of electrolyte in the positive electrode slurry not exceeding 10%.

[0042] The oligo-liquid positive electrode slurry described herein is a clay-like slurry (solid content not less than 80%, viscosity not less than 15000 mPa·s) formed by homogenizing the electrolyte, positive electrode active material and conductive agent.

[0043] The oligo-liquid positive electrode slurry described herein does not contain a binder. The selection and amount of the positive electrode active material and the conductive agent can be adjusted according to conventional compositions. In some specific embodiments of the present invention, the mass ratio of the positive electrode active material, the conductive agent, and the electrolyte in the oligo-liquid positive electrode slurry is (87~91):(3~6):(3~10).

[0044] The following is a detailed description of the components in the oligo-liquid positive electrode slurry:

[0045] electrolyte

[0046] The electrolyte described herein refers to a conventional electrolyte with the addition of components capable of achieving in-situ curing, specifically, polymerizable monomers and initiators.

[0047] The term "polymerizable monomer" refers to a monomeric compound that can initiate a polymerization reaction and achieve curing under certain conditions. These conditions are defined as reaction conditions that at least do not alter the properties of the primary battery materials (e.g., the positive electrode, electrolyte, and negative electrode). Examples of polymerizable monomers include at least one of vinyl ethylene carbonate (VEC), methyl methacrylate (MMA), polyethylene glycol diacrylate (PEGDA), pentaerythritol tetraacrylate (PETEA), 1,3-dioxolane (DOL), and 1,3,5-trioxane (TXE).

[0048] The initiator herein refers to an auxiliary agent that can cooperate with the reaction conditions to initiate the polymerization reaction of the polymerizable monomer. The initiator can be selected according to the type of polymerizable monomer. Specific examples include azobisisobutyronitrile (AIBN) or various cationic polymerization initiators.

[0049] In addition, the addition amount of the polymerizable monomer and the initiator in the electrolyte can be adjusted according to actual needs. In some specific embodiments of the present invention, in the electrolyte, the addition amount of the polymerizable monomer is between 0.5% and 50%; the addition amount of the initiator is between 0.5% and 5%.

[0050] It is understandable that the electrolyte also includes the necessary components of a conventional electrolyte: electrolyte salt and organic solvent.

[0051] The electrolyte salt varies according to the type of battery.

[0052] For lithium batteries, the electrolyte salt is a lithium salt, and specific examples of the lithium salt include lithium hexafluorophosphate (LiPF6), lithium hexafluoroarsenate (LiAsF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium trifluoromethanesulfonate (LiCF3SO3), lithium difluorophosphate (LiPO2F2), 2-trifluoromethyl-4,5-dicyanoimidazole lithium (LiN4C6F3), lithium difluorooxalatoborate (LiBC2O4F2), lithium chlorotrifluoroborate (LiBF3Cl), lithium trioxalatophosphate (LiP(CO2CO2)3), lithium tetrafluorooxalatophosphate (LiPF4(CO2CO2)), lithium bis(oxalatoborate) (LiB(C2O4)2) and LiN(C6F3). x F 2x+1 SO2) (C y F 2y+1 SO2) (x and y are each independently an integer of 0 to 5), but is not limited thereto.

[0053] For sodium batteries, the electrolyte salt is a sodium salt. Specific examples of the sodium salt include at least one of sodium hexafluorophosphate, sodium hexafluoroarsenate, sodium tetrafluoroborate, sodium perchlorate, sodium trifluoromethanesulfonate, sodium difluorophosphate, sodium difluorooxalatoborate, sodium chlorotrifluoroborate, sodium trioxalatophosphate, sodium tetrafluorooxalatophosphate, and sodium bisoxalatoborate, but are not limited thereto.

[0054] The specific concentration of the electrolyte salt can be the conventional addition amount in the art. In some specific embodiments of the present invention, the concentration of the electrolyte salt is 0.5-2.5 mol / L.

[0055] Furthermore, the organic solvent is at least one of low-polarity ethers, low-polarity esters, and low-polarity sulfones.

[0056] The low polarity ethers may be highly sterically hindered ether compounds containing a single oxygen atom. Specific examples include at least one of n-propyl ether, ethyl butyl ether, ethyl isobutyl ether, n-butyl ether, isobutyl ether, n-pentyl ether, and isopentyl ether, but are not limited thereto.

[0057] For low-polarity esters, it can be at least one of ethyl acetate, isopropyl acetate, butyl acetate, pentyl acetate, and hexyl acetate;

[0058] The low-polarity sulfone may be at least one of propyl sulfone, isopropyl sulfone, butyl sulfone, isobutyl sulfone, dimethyl sulfoxide, and sulfolane.

[0059] It should be noted that the electrolyte can be prepared by conventional methods in the art, that is, all components are fully dissolved and mixed uniformly under the condition of isolating water and oxygen, which will not be elaborated here one by one.

[0060] positive electrode active material

[0061] The positive electrode active materials herein are conventional active materials in the art, and vary depending on the type of battery:

[0062] For lithium batteries, the positive electrode active material can be lithium nickel cobalt manganese oxide (LiNi x Co y Mn z O2, x+y+z=1), lithium iron phosphate (LiFePO4), lithium cobalt oxide (LiCoO2), lithium iron manganese phosphate (LiMn x Fe 1-x PO4), but not limited thereto.

[0063] For sodium batteries, the positive electrode active material may be one of sodium manganese oxide (NaMnO2), sodium cobalt oxide (NaCoO2), sodium nickel oxide (NaNiO2), sodium iron phosphate (NaFePO4), and sodium vanadium phosphate (NaVPO4), but is not limited thereto.

[0064] Conductive agent

[0065] The conductive agent described in this article is an auxiliary agent with conductive ability commonly used in secondary batteries in the field. Specific examples include at least one of conductive carbon black Super-P, Ketjen black, multi-walled carbon nanotubes, single-walled carbon nanotubes, and vapor-deposited carbon fibers, but are not limited thereto.

[0066] The second aspect of the present invention provides a positive electrode, which is obtained by coating the oligo-liquid positive electrode slurry described in the first aspect of the present invention on a positive electrode current collector.

[0067] In some specific embodiments of the present invention, the positive electrode current collector is evenly coated by die pressing. The positive electrode current collector can be made of conventional materials in the art, such as aluminum foil, but is not limited thereto.

[0068] A third aspect of the present invention provides a method for preparing a semi-solid-state battery, comprising the following steps:

[0069] Obtaining the positive electrode according to the second aspect of the present invention;

[0070] The positive electrode is assembled with a solid electrolyte and a negative electrode, and then solidified in situ, wherein the solid electrolyte is a halide solid electrolyte or a sulfide solid electrolyte.

[0071] The in-situ curing reaction conditions (such as temperature, time, etc.) are adjusted based on the types of polymerizable monomers and initiators in the electrolyte. In some specific embodiments of the present invention, the in-situ curing is achieved by heating at a temperature of 55° C. for 8 hours.

[0072] The halide solid electrolyte or sulfide solid electrolyte described herein may be a conventional composition in the art. Specifically, the halide solid electrolyte described herein refers to a composition of A a M b X c A solid electrolyte, wherein A is Li or Na, M is at least one of Al, Y, In, Sc, Zr, Ti, Hf, a lanthanide or actinide transition element, and X is a halogen element; a, b, and c can be adjusted according to the specific valence state of the element.

[0073] The sulfide solid electrolytes described herein refer to binary sulfide electrolytes composed of A2S and P2S5; or ternary sulfide electrolytes composed of A2S, P2S5, and MS2; or lithium / sodium argyrodite electrolytes, particularly A6PS5X electrolytes, where A is Li or Na, M is at least one of Si, Ge, Sn, and Al, and X is a halogen element, Cl, Br, or I.

[0074] A fourth aspect of the present invention provides a semi-solid-state battery, which is prepared using the preparation method described in the third aspect of the present invention.

[0075] The present invention is described below by means of specific examples. It should be noted that the following specific examples are for illustrative purposes only and do not limit the scope of the present invention in any way. In addition, unless otherwise specified, methods without specific conditions or steps are conventional methods, and the reagents and materials used are all commercially available.

[0076] Example 1

[0077] This embodiment first provides an oligo-liquid positive electrode slurry, and the specific preparation steps are as follows:

[0078] (1) Preparation of electrolyte

[0079] The electrolyte was prepared at room temperature in a glove box with a water and oxygen content of less than 0.1 ppm. Using n-butyl ether as the solvent, the solution was sealed and placed in a refrigerator. After cooling to -10°C, it was transferred to the glove box. LiPF6 was added to a concentration of 1 mol / L. VEC and PEGDA monomers were added at a 10% mass fraction, and the initiator AIBN was present at a concentration of 2% of the total electrolyte mass.

[0080] (2) Preparation of oligo-liquid cathode slurry

[0081] The positive electrode active material LiNi0.8Co0.1Mn0.1O2, the conductive agent Ketjen Black (KB) and the electrolyte in step (1) are mixed in a mass ratio of 87:3:10, added to a mixing device, and stirred at high speed to form a uniform slurry with a viscosity of not less than 15000 mPa·s.

[0082] This embodiment further provides a semi-solid-state battery, the structure and preparation process of which can be referred to Figure 1 and Figure 2 , the specific preparation method is as follows:

[0083] (1) Preparation of positive electrode

[0084] The oligo-liquid positive electrode slurry obtained above was evenly coated on an aluminum foil by die pressure coating, wherein the die size was a stainless steel plate with a thickness of 200 μm and a circular hole with a diameter of 14 mm inside the steel plate to obtain a positive electrode.

[0085] (2) Preparation of solid electrolyte

[0086] The solid electrolyte layer is prepared by powder die-casting process. The halide solid electrolyte Li2Al2Cl6 is added to the corresponding 16mm mold and die-casted at a pressure of 350MPa to serve as the electrolyte layer of the semi-solid battery.

[0087] (3) The metal negative electrode uses a lithium disc with a diameter of 15.6 mm and a thickness of 0.45 mm.

[0088] (4) Battery assembly

[0089] The positive electrode, solid electrolyte layer, protective layer and negative electrode are assembled in sequence, as shown in FIG. Figure 1 As shown in the figure, a sulfide solid electrolyte, Li6PS5Cl, was introduced as a protective layer for the metal anode to prevent reaction between the halide solid electrolyte and the metal anode; this sulfide solid electrolyte was used in all examples. After assembly, the battery was heated in a 55°C oven for 8 hours to complete the in-situ curing process, resulting in a semi-solid-state battery.

[0090] Example 2

[0091] The oligo-liquid positive electrode slurry in this embodiment adopts the same implementation as that in Example 1, with the only difference being that the content of the electrolyte in the oligo-liquid positive electrode slurry is 5%; see Table 1 for details, and the other steps and parameters as well as the preparation of the semi-solid state battery are the same as those in Example 1.

[0092] Example 3

[0093] The oligo-liquid positive electrode slurry in this embodiment adopts the same implementation as that in Example 1, with the only difference being that the content of the electrolyte in the oligo-liquid positive electrode slurry is 3%; for details, please refer to Table 1. The other steps and parameters as well as the preparation of the semi-solid state battery are the same as those in Example 1.

[0094] Examples 4-6

[0095] The oligo-liquid positive electrode slurry in this embodiment adopts the same implementation as that in Example 2, with the only difference being that in the electrolyte, the polymerizable monomers are 1,3-dioxolane, 1,3,5-trioxane, and MMA, respectively. For details, see Table 1. The other steps and parameters, as well as the preparation of the semi-solid-state battery, are the same as those in Example 2.

[0096] Examples 7-9

[0097] The oligo-liquid positive electrode slurry in this embodiment adopts the same implementation as that in Example 2, with the only difference being that the organic solvents in the electrolyte are cyclobutane sulfone, ethyl acetate, and ethyl butyl ether, respectively; see Table 1 for details. The other steps and parameters, as well as the preparation of the semi-solid-state battery, are the same as those in Example 2.

[0098] Examples 10-11

[0099] The oligo-liquid positive electrode slurry in this embodiment adopts the same implementation as that in Example 2, with the only difference being that the positive electrode active materials in the oligo-liquid positive electrode slurry are LiFePO4 and LiCoO2, respectively; see Table 1 for details, and the other steps and parameters as well as the preparation of the semi-solid state battery are the same as those in Example 2.

[0100] Examples 12-13

[0101] The preparation of the semi-solid-state battery in this embodiment adopts the same implementation method as that in Example 2, with the only difference being that the halide solid electrolytes used are Li3InCl6 and Li3YBr6 respectively; the other steps and parameters as well as the preparation of the oligo-liquid positive electrode slurry are the same as those in Example 2.

[0102] Example 14

[0103] The preparation of the semi-solid-state battery in this embodiment adopts the same implementation method as that of Examples 12-13, with the only difference being that the halide solid electrolyte is replaced by the sulfide solid electrolyte Li6PS5Cl; the other steps and parameters and the preparation of the oligo-liquid positive electrode slurry are the same as those of Examples 12-13.

[0104] Comparative Example 1-2

[0105] The cathode slurry in this comparative example was prepared in the same manner as in Example 2, with the only difference being that the electrolyte accounted for 20% and 30% of the cathode slurry. All other steps and parameters, as well as the preparation of the semi-solid-state battery, were the same as in Example 2.

[0106] Comparative Example 3

[0107] The oligo-liquid cathode slurry in this comparative example was prepared in the same manner as in Example 1, with the only difference being that the organic solvent in the electrolyte was a mixture of EC and DEC in a volume ratio of 1:1. All other steps and parameters, as well as the preparation of the semi-solid-state battery, were the same as in Example 1.

[0108] Comparative Example 4

[0109] The oligo-liquid cathode slurry in this comparative example was prepared in the same manner as in Example 2, with the only difference being that the organic solvent in the electrolyte was a mixture of EC and DEC in a volume ratio of 1:1. All other steps and parameters, as well as the preparation of the semi-solid-state battery, were the same as in Example 2.

[0110] Comparative Example 5

[0111] The battery in this comparative example was assembled in a conventional manner, wherein the positive electrode was formed by coating an aluminum foil of the same thickness as in Example 1 with a positive electrode slurry (the positive electrode slurry was composed of a mixture of positive electrode active material LiNi0.8Co0.1Mn0.1O2, a conductive agent Ketjen Black (KB), and PVDF in a mass ratio of 87:3:10, added to a mixing device, and stirred at high speed to form a uniform slurry with a viscosity of not less than 15000 mPa·s).

[0112] After being fully infiltrated with the same electrolyte as in Example 1, the battery was assembled, and the solid electrolyte layer was replaced with a traditional PP separator, while the negative electrode composition remained unchanged.

[0113] Table 1 Composition of oligo-liquid positive electrode slurries in Examples 1-11 and Comparative Examples 1-4

[0114]

[0115] Performance Testing

[0116] The electrochemical performance of the CR2032 button-type battery prepared in the example was tested, wherein the charge and discharge voltage range was 3.0-4.3 V. The battery was activated at a 0.1C rate for three cycles and then cycled at a 0.3C rate. The results are shown in Table 2.

[0117] Table 2 Interface between slurry positive electrode and halide solid electrolyte and battery status in Examples 1-14 and Comparative Examples 1-4

[0118]

[0119] Note: “ / ” in Table 2 indicates that the halide solid electrolyte reacts with the positive electrode, causing the battery to fail to operate normally.

[0120] Figure 3 The figure shows a comparison of the cycling performance of the batteries in Example 1 and Comparative Example 5. It can be seen that the semi-solid-state battery in Example 1 has higher capacity utilization and cycling stability. This is mainly due to the better ion transport effect of the electrolyte slurry and the better uniformity of solidification in the electrolyte slurry.

[0121] Example 15

[0122] In this embodiment, a sodium oligomeric positive electrode slurry is first provided, and the specific preparation steps are as follows:

[0123] (1) Preparation of electrolyte

[0124] The electrolyte was prepared at room temperature in a glove box with a water and oxygen content of less than 0.1 ppm. Using n-butyl ether as the solvent, the solution was sealed and placed in a refrigerator. After cooling to -10°C, it was transferred to the glove box and NaPF6 was added to a concentration of 1 mol / L. VEC and PEGDA monomers were added at a 10% mass fraction, and the initiator AIBN was added at a concentration of 2% of the total electrolyte mass.

[0125] (2) Preparation of oligo-liquid cathode slurry

[0126] The positive electrode active material sodium vanadium phosphate, the conductive agent Ketjen black (KB) and the electrolyte in step (1) are mixed in a mass ratio of 87:3:10, added to a mixing device, and stirred at high speed to form a uniform slurry with a viscosity of not less than 15000 mPa·s.

[0127] This embodiment further provides a semi-solid-state battery, and the specific preparation method is as follows:

[0128] (1) Preparation of positive electrode

[0129] The oligo-liquid positive electrode slurry obtained above was evenly coated on an aluminum foil by die pressure coating, wherein the die size was a stainless steel plate with a thickness of 200 μm and a circular hole with a diameter of 14 mm inside the steel plate to obtain a positive electrode.

[0130] (2) Preparation of solid electrolyte

[0131] The solid electrolyte layer is prepared by powder die-casting process. The halide solid electrolyte Na2Al2Cl6 is added to the corresponding 16mm mold and die-casted at a pressure of 350MPa to serve as the electrolyte layer of the semi-solid battery.

[0132] (3) The metal negative electrode uses a sodium disc with a diameter of 15.6 mm and a thickness of 0.45 mm.

[0133] (4) Battery assembly

[0134] The positive electrode, solid electrolyte layer, protective layer, and negative electrode were assembled in sequence. To prevent reaction between the halide solid electrolyte and the metal negative electrode, a sulfide solid electrolyte, Na6PS5Cl, was introduced as the negative electrode protective layer. This sulfide solid electrolyte was used in all examples. After assembly, the battery was heated in a 55°C oven for 8 hours to complete the in-situ curing process, resulting in a semi-solid-state battery.

[0135] Example 16

[0136] The preparation of the oligo-liquid positive electrode slurry in this example was the same as in Example 15, with the only difference being that the mass ratio of the positive electrode active material, sodium vanadium phosphate, the conductive agent, Ketjen Black (KB), and the electrolyte was 90:5:5. All other steps and parameters, as well as the preparation of the semi-solid-state battery, were the same as in Example 15.

[0137] Comparative Examples 6-7

[0138] The cathode slurry in this comparative example was prepared in the same manner as in Example 15, with the only difference being that the electrolyte content in the cathode slurry was 20% and 30%. All other steps and parameters, as well as the preparation of the semi-solid-state battery, were the same as in Example 15.

[0139] Comparative Example 8

[0140] The oligo-liquid cathode slurry in this comparative example was prepared in the same manner as in Example 15, with the only difference being that the organic solvent in the electrolyte was a mixture of EC and DEC in a volume ratio of 1:1. All other steps and parameters, as well as the preparation of the semi-solid-state battery, were the same as in Example 15.

[0141] Comparative Example 9

[0142] The oligo-liquid cathode slurry in this comparative example was prepared in the same manner as in Example 16, with the only difference being that the organic solvent in the electrolyte was a mixture of EC and DEC in a volume ratio of 1:1. All other steps and parameters, as well as the preparation of the semi-solid-state battery, were the same as in Example 16.

[0143] In the present invention, the compatibility of the semi-solid process with the halide solid electrolyte Na2Al2Cl6 in the sodium metal semi-solid battery was investigated. The results are shown in Table 3.

[0144] Table 3 Electrolyte mass ratios and their compatibility with Na2Al2Cl6 in Examples 14-15 and Comparative Examples 6-9

[0145]

[0146] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0147] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for preparing a semi-solid-state battery, characterized in that: The following steps are involved: Obtaining a positive electrode, wherein the positive electrode is obtained by coating the oligo-liquid positive electrode slurry on a positive electrode current collector; After assembling the positive electrode with a solid electrolyte and a negative electrode, in-situ curing is performed to obtain a semi-solid-state battery, wherein the solid electrolyte is a halide solid electrolyte or a sulfide solid electrolyte; The oligo-liquid positive electrode slurry is formed by homogenizing an electrolyte, a positive electrode active material, and a conductive agent, and has a solid content of not less than 80% and a viscosity of not less than 15,000 mPa·s. The electrolyte is composed of an electrolyte salt, an organic solvent, a polymerizable monomer, and an initiator, and the electrolyte accounts for 3% to 5% by weight of the oligo-liquid positive electrode slurry. The organic solvent is at least one of low-polarity ethers, low-polarity esters, and low-polarity sulfones, the low-polarity ether is at least one of n-propyl ether, ethyl butyl ether, ethyl isobutyl ether, n-butyl ether, isobutyl ether, n-pentyl ether, and isopentyl ether; the low-polarity sulfone is at least one of propyl sulfone, isopropyl sulfone, butyl sulfone, isobutyl sulfone, dimethyl sulfoxide, and cyclopentane; the low-polarity ester solvent is at least one of ethyl acetate, isopropyl acetate, butyl acetate, pentyl acetate, and hexyl acetate.

2. The method for preparing a semi-solid-state battery according to claim 1, wherein: The polymerizable monomer is at least one of vinyl ethylene carbonate, methyl methacrylate, polyethylene glycol diacrylate, pentaerythritol tetraacrylate, 1,3-dioxolane, and 1,3,5-trioxane; And / or, the initiator is azobisisobutyronitrile or a cationic polymerization initiator.

3. The method for preparing a semi-solid-state battery according to claim 1, wherein: In the electrolyte, the added amount of the polymerizable monomer is between 0.5% and 50%; the added amount of the initiator is between 0.5% and 5%.

4. The method for preparing a semi-solid-state battery according to claim 1, wherein: The electrolyte salt is a lithium salt or a sodium salt.

5. The method for preparing a semi-solid-state battery according to claim 4, wherein: The lithium salt is at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium perchlorate, lithium trifluoromethanesulfonate, lithium difluorophosphate, 2-trifluoromethyl-4,5-dicyanoimidazole lithium, lithium difluorooxalatoborate, lithium chlorotrifluoroborate, lithium trioxalatophosphate, lithium tetrafluorooxalatophosphate, and lithium bisoxalatoborate.

6. The method for preparing a semi-solid-state battery according to claim 4, wherein: The sodium salt is at least one of sodium hexafluorophosphate, sodium hexafluoroarsenate, sodium tetrafluoroborate, sodium perchlorate, sodium trifluoromethanesulfonate, sodium difluorophosphate, sodium difluorooxalatoborate, sodium chlorotrifluoroborate, sodium trioxalatophosphate, sodium tetrafluorooxalatophosphate, and sodium bisoxalatoborate.

7. The method for preparing a semi-solid-state battery according to claim 1, wherein: In the electrolyte solution, the concentration of the electrolyte salt is 0.5-2.5 mol / L.

8. The method for preparing a semi-solid-state battery according to claim 1, wherein: The positive electrode active material is a lithium battery positive electrode active material or a sodium battery positive electrode active material.

9. The method for preparing a semi-solid-state battery according to claim 8, wherein: The lithium battery positive electrode active material is one of lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium cobalt oxide, and lithium manganese iron phosphate.

10. The method for preparing a semi-solid-state battery according to claim 8, wherein: The sodium battery positive electrode active material is one of sodium manganese oxide, sodium cobalt oxide, sodium nickel oxide, sodium iron phosphate, and sodium vanadium phosphate.

11. The method for preparing a semi-solid-state battery according to claim 1, wherein: The conductive agent is at least one of conductive carbon black Super-P, Ketjen black, multi-walled carbon nanotubes, single-walled carbon nanotubes, and vapor-deposited carbon fibers.

12. The method for preparing a semi-solid-state battery according to claim 1, wherein: In the oligo-liquid positive electrode slurry, the mass ratio of the positive electrode active material, the conductive agent and the electrolyte is (87-91): (3-6): (3-5).

13. The method for preparing a semi-solid-state battery according to claim 1, wherein: The negative electrode is a metal M or an alloy thereof, and the metal M is lithium or sodium.

14. A semi-solid-state battery, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 13.

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