Functional materials for secondary batteries, their preparation methods, and applications

Abstract

This invention provides functional materials for secondary batteries, methods for preparing them, and their applications. [Solution] The functional material for secondary batteries comprises a carrier material and an active material. The carrier material is a porous material that catalytically acts on the active material under a voltage of 2.0V to 4.8V. The carrier material includes one or more of the following: porous metal material, porous ceramic material, porous carbon material, porous plastic, and molecular sieve. The active material includes a lithium-containing compound or a sodium-containing compound. The active material is uniformly distributed in the form of fine particles within the pores or on the surface of the carrier material. The particle size Dv50 of the active material particles is 0.1nm to 10μm, and the particle size Dv50 of the carrier material particles is 1nm to 100μm. When this functional material for secondary batteries is applied to a secondary battery, it is possible to replenish the irreversible active ions consumed during the charge-discharge cycle of the secondary battery, thereby giving the secondary battery the advantages of high capacity and long cycle life.

Description

[Technical Field]

[0001] [Cross reference] This application claims priority to the Chinese patent application filed with the China National Intellectual Property Office on March 27, 2023, with application number 202310300406.0, and the title of the invention is "Functional material for secondary batteries, method of preparation thereof, and application."

[0002] [Technical field] This invention relates to the technical field of materials for secondary batteries, and more particularly to functional materials for secondary batteries, methods for preparing the same, and their applications. [Background technology]

[0003] In recent years, as awareness of the environmental impact of fossil fuels has grown, there has been a gradual shift to electric energy in the fields of mobile devices, industrial equipment, and electric vehicles, leading to a surge in demand for highly efficient rechargeable batteries. Widespread use of these rechargeable batteries requires characteristics such as high energy density, high safety, and long lifespan.

[0004] Lithium-ion and sodium-ion batteries are the two main types of batteries used in energy storage and electronic product systems. While some products are already commercialized and in use, their energy density, lifespan, and safety do not fully meet people's needs. For example, in current lithium-ion and sodium-ion batteries, irreversible active ions are consumed during the initial charge and discharge cycle, resulting in low Coulomb efficiency in the first cycle of the battery, which affects the battery's energy density and lifespan.

[0005] To address the above problem, we will develop a functional material with superior properties that replenishes the consumed irreversible active ions, thereby solving the problem of irreversible active ion consumption during the initial charge-discharge cycle of a secondary battery, which reduces the Coulomb efficiency of the battery's first cycle and affects its energy density and lifespan. [Overview of the project] [Problems that the invention aims to solve]

[0006] Embodiments of the present invention provide functional materials for secondary batteries, methods for preparing the same, and applications. A functional material for secondary batteries is obtained by mixing a solution containing a precursor of a lithium or sodium active material with a carrier material, and then uniformly dispersing the active material in the form of small particles in the pores and on the surface of the carrier material through a physical process (e.g., shaking, dispersion stirring). This functional material for secondary batteries is a composite of two materials, an active material and a carrier material, by adsorbing the active material into the pores of the carrier material. Here, the carrier material catalyzes the reaction of the active material under the application of a voltage of 2.0V to 4.8V, which can lower the activation energy of the reaction of the active material. At the same time, because the active material exists in the form of small particles, it increases the number of reaction sites and the reaction area, thereby increasing the overall reaction activity of the material. When the functional material for secondary batteries provided in embodiments of the present invention is applied to a secondary battery, it can supply more active ions and replenish the irreversible active ions consumed during the charge-discharge cycle of the secondary battery, giving the secondary battery the advantages of high capacity and long cycle life. [Means for solving the problem]

[0007] In a first embodiment, an embodiment of the present invention provides a functional material for a secondary battery, the functional material for a secondary battery comprising a carrier material and an active material, The carrier material is a porous material that acts as a catalyst on the active material under a voltage of 2.0V to 4.8V, and the carrier material includes one or more of the following: porous metal material, porous ceramic material, porous carbon material, porous plastic, and molecular sieve. The active material comprises a lithium-containing compound or a sodium-containing compound, and the active material is uniformly distributed in the form of fine particles within the pores or on the surface of the carrier material. The particle size Dv50 of the active material particles is 0.1 nm to 10 μm, the particle size Dv50 of the carrier material particles is 1 nm to 100 μm, and the particle size Dv50 of the functional material particles for secondary batteries is 1 nm to 120 μm. The lithium-containing compound comprises one or more of the following: lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, lithium formate, lithium oxide, lithium peroxide, lithium sulfide, lithium fluoride, and lithium nitride. The aforementioned sodium-containing compound includes one or more of the following: sodium carbonate, sodium hydroxide, sodium oxalate, sodium acetate, sodium formate, sodium oxide, sodium peroxide, sodium sulfide, and sodium fluoride. The porous metal material includes one or more of the elements or alloys of these metals: aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, and zinc. The porous ceramic material includes one or more of the following: porous alumina, porous zirconia, porous magnesium oxide, porous silicon carbide, porous silicon nitride, cordierite, high silica silicate, aluminosilicate, and aluminum titanate. The porous carbon material comprises one or more of the following: activated carbon, expanded graphite, activated carbon fibers, carbon nanotubes, and porous acetylene black. The porous plastic includes one or more of the following: porous polyethylene, porous polystyrene, porous polyvinyl chloride, porous polypropylene, porous polyurethane, and porous phenolic resin. The molecular sieve comprises one or more of the following: cross-linked dextran, carbon molecular sieve, or zeolite. The functional material for secondary batteries is obtained after drying by adsorbing a clarified solution containing the precursor of the active material onto the pores of the carrier material, and the temperature of the drying process is 60°C to 300°C.

[0008] Preferably, the pore size of the carrier material is 0.1 nm to 20 μm. The specific surface area of ​​the carrier material is 5m². 2 / g~3000m 2 / g The mass ratio of the active material to the carrier material is 0.1:1 to 100:1.

[0009] In a second embodiment, the embodiment of the present invention provides a method for preparing a functional material for a secondary battery as described in the first embodiment, the preparation method being: A clear solution is obtained by dissolving a certain amount of the precursor of the active material in a solvent and stirring it uniformly. A solution of the composite material is obtained by adding a certain amount of carrier material to a clarified solution, dispersing it thoroughly and uniformly, and adsorbing the clarified solution into the pores of the carrier material. The process involves drying a solution of a composite material to remove the solvent, and then crystallizing the clarified solution within the pores of the composite material to form particulate active material, thereby ultimately obtaining a functional material for secondary batteries. Here, the carrier material includes one or more of the following: porous metal material, porous ceramic material, porous carbon material, porous plastic, and molecular sieve. The active material includes a lithium-containing compound or a sodium-containing compound.

[0010] Preferably, the lithium-containing compound comprises one or more of the following: lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, lithium formate, lithium oxide, lithium peroxide, lithium sulfide, lithium fluoride, and lithium nitride. The aforementioned sodium-containing compound includes one or more of the following: sodium carbonate, sodium hydroxide, sodium oxalate, sodium acetate, sodium formate, sodium oxide, sodium peroxide, sodium sulfide, and sodium fluoride. The solvent comprises one or more of the following: deionized water, ethanol, ether, acetone, N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), ethyl acetate, benzene, and chloroform. The mass ratio of the solvent to the active material is 5:1 to 200:1.

[0011] Preferably, the porous metal material contains one or more of aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, and zinc, either in elemental form or as alloy materials of these metals. The porous ceramic material contains one or more of porous alumina, porous zirconia, porous magnesium oxide, porous silicon carbide, porous silicon nitride, cordierite, high silica silicate, aluminosilicate, and aluminum titanate. The porous carbon material contains one or more of activated carbon, expanded graphite, carbon fiber, carbon nanotube, and porous acetylene black. The porous plastic contains one or more of porous polyethylene, porous polystyrene, porous polyvinyl chloride, porous polypropylene, porous polyurethane, and porous phenolic resin. The molecular sieve contains one or more of crosslinked dextran, carbon molecular sieve, or zeolite.

[0012] Preferably, the method for sufficiently dispersing includes one or a combination of shaking dispersion, stirring dispersion, ultrasonic dispersion, and ball mill dispersion. The apparatus for sufficiently dispersing includes one or a combination of a shaker, a stirrer, an ultrasonic disperser, or a ball mill device. The time for sufficiently dispersing is 0.5 hours to 72 hours.

[0013] Preferably, the method for the drying treatment includes one or a combination of rotary evaporation drying, stirring and heating drying, spray drying, vacuum heating drying, and air drying after filtration. The temperature for the drying treatment is 60°C to 300°C, and the time is 0.5 hours to 48 hours.

[0014] In a third aspect, an embodiment of the present invention provides a positive electrode plate including the functional material for a secondary battery described in the first aspect above.

[0015] In a fourth aspect, an embodiment of the present invention provides a secondary battery including the positive electrode plate described in the third aspect above.

Advantages of the Invention

[0016] Embodiments of the present invention provide a functional material for a secondary battery, a preparation method thereof, and an application. After mixing a solution containing a precursor of a lithium or sodium active material with a carrier material, the active material is uniformly dispersed in the pores and on the surface of the carrier material in the form of small particles through a physical process (such as methods like shaking and dispersion stirring), thereby obtaining a functional material for a secondary battery. This functional material for a secondary battery is a composite of two types of materials, an active material and a carrier material, by adsorbing the active material into the pores of the carrier material. Here, the carrier material can catalyze the active material to react under the application of voltage and reduce the activation energy of the reaction of the active material. At the same time, since the active material exists in the form of small particles, the reaction points are increased, the reaction area is increased, and the reaction activity of the whole material is enhanced. When the functional material for a secondary battery provided by the embodiments of the present invention is applied to a secondary battery, more active ions can be supplied to replenish the irreversible active ions consumed during the charge and discharge cycles of the secondary battery, enabling the secondary battery to have the advantages of high capacity and long cycle life.

[0017] The preparation method of the functional material for a secondary battery provided by the embodiments of the present invention is simple in operation, low in cost, and suitable for large-scale batch production.

Brief Description of the Drawings

[0018] Hereinafter, the technical solutions in the embodiments of the present invention will be described in more detail with reference to the drawings and embodiments.

[0019] [Figure 1] It is a flowchart of a preparation method of a functional material for a secondary battery according to an embodiment of the present invention. [Figure 2] It is a scanning electron microscope (SEM) image of a functional material for a secondary battery according to Embodiment 1 of the present invention. [Figure 3]This is a diagram of the initial cycle charge-discharge curve of a functional material for secondary batteries according to Example 1 of the present invention. [Figure 4] This is the X-ray diffraction (XRD) spectrum of lithium oxalate, a functional material and active material for secondary batteries according to Example 2 of the present invention. [Figure 5] This is a diagram of the initial cycle charge-discharge curve of a functional material for secondary batteries according to Example 2 of the present invention. [Figure 6] This is a comparative diagram of the initial cycle charge-discharge curves of the CR2032 button batteries assembled in Example 3 and Comparative Example 1 of the present invention. [Modes for carrying out the invention]

[0020] The present invention will be further described below with reference to the drawings and specific embodiments, but these embodiments are merely for the purpose of illustrating the present invention in more detail and should be understood as not intended to limit the present invention in any way, that is, they are not intended to limit the scope of protection of the present invention.

[0021] Embodiments of the present invention provide a functional material for secondary batteries comprising a carrier material and an active material, wherein the mass ratio of the active material to the carrier material is [0.1:1] to [100:1]. The active material is uniformly distributed in the form of fine particles within the pores or on the surface of the carrier material.

[0022] Here, the carrier material is a porous material that acts catalytically on the active material under a voltage of 2.0V to 4.8V. Specifically, the carrier material has strong ion adsorption properties, which can lower the activation energy of the reaction, accelerate the desorption of active ions, and achieve catalytic action. The particle size Dv50 of the carrier material particles is 1 nm to 100 μm, and the particle size Dv50 of the functional material particles for secondary batteries is 1 nm to 120 μm. The pore size of the carrier material is 0.1 nm to 20 μm, and the specific surface area of ​​the carrier material is 5 m². 2 / g~3000m 2 It is / g.

[0023] The carrier material includes one or more of the following: porous metal materials, porous ceramic materials, porous carbon materials, porous plastics, and molecular sieves. The porous metal material includes one or more of the following: aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, zinc, or alloys of these metals. The porous ceramic material includes one or more of the following: porous alumina, porous zirconia, porous magnesium oxide, porous silicon carbide, porous silicon nitride, cordierite, high silica silicate, aluminosilicate, and aluminum titanate. The porous carbon material includes one or more of the following: activated carbon, expanded graphite, activated carbon fiber, carbon nanotubes, and porous acetylene black. The porous plastic includes one or more of the following: porous polyethylene, porous polystyrene, porous polyvinyl chloride, porous polypropylene, porous polyurethane, and porous phenolic resin. The molecular sieve includes one or more of the following: cross-linked dextran, carbon molecular sieve, or zeolite.

[0024] The active material contains a lithium-containing compound or a sodium-containing inorganic compound. The lithium-containing inorganic compound contains one or more of the following: lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, lithium formate, lithium oxide, lithium peroxide, lithium sulfide, lithium fluoride, and lithium nitride. The sodium-containing compound contains one or more of the following: sodium carbonate, sodium hydroxide, sodium oxalate, sodium acetate, sodium formate, sodium oxide, sodium peroxide, sodium sulfide, and sodium fluoride. The particle size Dv50 of the active material particles is 0.1 nm to 10 μm.

[0025] An embodiment of the present invention provides a method for preparing the above-mentioned functional material for secondary batteries, and specifically includes the following steps, as shown in Figure 1.

[0026] In step 110, a clear solution is obtained by dissolving a certain amount of the active material precursor in a solvent and stirring it uniformly.

[0027] Here, the precursor of the active material includes a raw material for a lithium-containing compound or a raw material for a sodium-containing compound. The lithium-containing compound includes one or more of the following: lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, lithium formate, lithium oxide, lithium peroxide, lithium sulfide, lithium fluoride, and lithium nitride. The sodium-containing compound includes one or more of the following: sodium carbonate, sodium hydroxide, sodium oxalate, sodium acetate, sodium formate, sodium oxide, sodium peroxide, sodium sulfide, and sodium fluoride.

[0028] The solvent includes one or more of the following: deionized water, ethanol, ether, acetone, N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), ethyl acetate, benzene, and chloroform.

[0029] The mass ratio of solvent to active material is [5:1] to [200:1].

[0030] The method for uniform stirring in this step is a conventional method, and it is sufficient to uniformly mix the active material and the solvent. The stirring device includes, but is not limited to, a stirrer, an ultrasonic disperser, or a high-speed fluid mixer.

[0031] In step 120, a certain amount of carrier material is added to the clarified solution and dispersed thoroughly and uniformly, and the clarified solution is adsorbed into the pores of the carrier material to obtain a solution of the composite material.

[0032] Here, the carrier material includes one or more of the following: porous metal materials, porous ceramic materials, porous carbon materials, porous plastics, and molecular sieves. Because the carrier material has a porous structure, it has stronger adsorption properties to the solute in the clarifying solution when adsorbing the clarifying solution.

[0033] Porous metal materials include one or more of the following elements or alloys: aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, and zinc.

[0034] Porous ceramic materials include one or more of the following: porous alumina, porous zirconia, porous magnesium oxide, porous silicon carbide, porous silicon nitride, cordierite, high silica silicate, aluminosilicate, and aluminum titanate.

[0035] Porous carbon materials include one or more of the following: activated carbon, expanded graphite, activated carbon fibers, carbon nanotubes, and porous acetylene black.

[0036] Porous plastics include one or more of the following: porous polyethylene, porous polystyrene, porous polyvinyl chloride, porous polypropylene, porous polyurethane, and porous phenolic resin.

[0037] Molecular sieves contain one or more of the following: cross-linked dextran, carbon molecular sieves, or zeolites.

[0038] Methods for sufficient dispersion include one or a combination of shaking dispersion, stirring dispersion, ultrasonic dispersion, and ball mill dispersion. Apparatus for sufficient dispersion includes one or a combination of a shaker, agitator, ultrasonic disperser, or ball mill apparatus. The time for sufficient dispersion is between 0.5 and 72 hours.

[0039] In step 130, the composite material solution is dried to remove the solvent, and the clarified solution within the pores of the composite material is crystallized to form particulate active material, thereby ultimately obtaining a functional material for secondary batteries.

[0040] Here, the drying method includes one or a combination of rotary evaporation drying, agitated heating drying, spray drying, vacuum heating drying, and forced air drying after filtration. The temperature of the drying process is 60°C to 300°C, and the duration is 0.5 hours to 48 hours.

[0041] In the functional materials for secondary batteries prepared according to the embodiments of the present invention, the active material is mainly distributed uniformly in the form of fine particles within the pores of the carrier material, and some is distributed on the surface of the carrier material, but does not form a coating layer structure.

[0042] In embodiments of the present invention, the functional material for secondary batteries prepared by the above preparation method can be used as an additive to the positive electrode active material in the manufacture of a positive electrode plate.

[0043] Here, the positive electrode plate mainly comprises a positive electrode current collector, a positive electrode active material, a functional material for secondary batteries, a conductive agent, and a binder.

[0044] The positive electrode current collector includes, but is not limited to, aluminum foil.

[0045] The cathode active material includes one of the following: lithium cobaltate, lithium manganate, lithium iron phosphate, nickel-cobalt-lithium manganate ternary material, sodium cobaltate, vanadium pentoxide, Prussian blue, olivine-structured sodium iron phosphate, NASICON-structured Na3V2(PO4)3, or layered-structured nickel-iron-manganate.

[0046] The conductive agent includes, but is not limited to, one or more of the following: carbon black, carbon nanotubes, acetylene black, and Ketjenblack.

[0047] The binder includes, but is not limited to, one or more of the following: polyvinylidene fluoride, poly(vinylidene fluoride-co-hexafluoropropylene), carboxymethylcellulose, sodium carboxymethylcellulose, polymethyl methacrylate, polyacrylate, polyacrylonitrile, styrene-butadiene rubber, polyvinyl alcohol, polytetrafluoroethylene, polyacrylamide, polyvinyl acetate, and polyurethane.

[0048] Embodiments of the present invention provide a secondary battery, which includes a lithium-ion battery or a sodium-ion battery.

[0049] Specifically, a secondary battery consists of a positive electrode plate containing the above-mentioned functional material for secondary batteries, a separator, an electrolyte or solid electrolyte, and a negative electrode plate.

[0050] Here, the separator includes one of the following: a double-sided alumina separator, a separator containing a sodium ion solid electrolyte, or a separator containing a lithium ion solid electrolyte. The substrate film of the separator includes one of the following: a polyolefin film, a nonwoven fabric separator, a fiber separator, or a polyaramid separator.

[0051] The negative electrode plate includes either lithium foil, sodium foil, or a negative electrode current collector containing a negative electrode active material. Specifically, the negative electrode current collector includes, but is not limited to, copper foil or titanium foil. The active material layer on the surface of the negative electrode current collector further contains a conductive agent and a binder. The negative electrode active material includes, but is not limited to, carbon materials, tin-based negative electrode materials, silicon-based negative electrode materials, silicon-carbon composite materials, nanooxide materials, or titanate ester-based negative electrode materials. Carbon-based materials include graphite, hard carbon, carbon fiber, petroleum coke, or intermediate-phase carbon microbeads.

[0052] The electrolyte contains a solute and a solvent.

[0053] Here, the solute is a conductive salt and includes one of the following: sodium perchlorate (NaClO4), sodium tetrafluoroborate (NaBF4), sodium hexafluorophosphate (NaPF6), sodium hexafluoroarsenate (NaAsF6), sodium trifluoroacetate (CF3COONa), lithium perchlorate (LiCIO4), lithium hexafluorophosphate (LiPF6), lithium hexafluoroborate (LiBF6), or lithium hexafluoroarsenate (LiAsF6).

[0054] The solvents are ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), fluoroethylene carbonate (FEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), γ-butyrolactone (BL), methylpropionate (MP), methylbutyrolactone (B) It contains one of the following: ethyl acetate (MB), ethyl acetate (EA), ethyl propionate (EP), propyl propionate (PP), ethyl butyrate (EB), 1,3-dioxolane (DOL), ethylene glycol dimethyl ether (DME), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (TRGDME), tetraethylene glycol dimethyl ether (TEGDME), ethyl methanesulfonate (EMS), or dimethyl sulfoxide (DMSO).

[0055] To better understand the technical proposals of the present invention, the preparation process and characteristics of the functional materials for secondary batteries of the present invention will be explained below with reference to several specific examples.

[0056] Example 1 This embodiment provides a preparation process and characteristic testing of functional materials for secondary batteries, and the specific preparation steps are as follows.

[0057] In step 110, 120 g of deionized water is placed in a beaker, 8 g of sodium fluoride with a particle size Dv50 of 1 μm is dissolved in the 120 g of deionized water, and a clear solution is obtained by uniformly stirring with a magnetic stirrer.

[0058] In step 120, the particle size Dv50 is 20 μm and the specific surface area is 850 m². 2 8 g of porous zirconia at a concentration of / g is added to the above clarification solution, and then the solution is shaken and dispersed in a shaker at a frequency of 80 Hz for 48 hours to adsorb the active material into the pores of the carrier material, thereby obtaining a composite material solution.

[0059] In step 130, the solution of the composite material was placed in a rotary evaporator and concentrated into a concentrated liquid by rotary evaporation drying. Next, it was transferred to a forced-air dryer and dried at 120°C for 1 hour. After removal, it was polished and sieved to obtain a functional material for secondary batteries in which sodium fluoride was adsorbed inside the pores and on the surface of porous zirconia. Here, the particle size Dv50 of this functional material for secondary batteries is 20.2 μm.

[0060] Figure 2 shows an SEM image of the functional material for secondary batteries prepared in Example 1 of the present invention. As can be seen from Figure 2, the functional material for secondary batteries has an irregular shape overall, and at the same time, it was observed that the material surface has a relatively large pore diameter.

[0061] The functional material for secondary batteries prepared in this embodiment was used as the positive electrode active material to fabricate a positive electrode plate, a sodium-ion battery was assembled, and electrochemical properties tests were then performed on the sodium-ion battery. Specifically, the results are as follows.

[0062] In the preparation of the sodium-ion battery, the functional material for secondary batteries prepared in this example, polyvinylidene fluoride (PVDF), and conductive carbon black (SP) were slurryed in a mass ratio of 8:1:1, and then coated onto aluminum foil to prepare the positive electrode plate. Subsequently, it was assembled into a CR2032 type button cell according to a conventional method with sodium foil, a double-sided alumina separator, and electrolyte. Here, the electrolyte is an ethylene carbonate (EC) / dimethyl carbonate (DEC) solution (volume ratio 1:1) containing 1 mol / L sodium hexafluorophosphate (NaPF6).

[0063] The test method involved charging the battery to 4.0V at a rate of 0.1C, then charging it to 0.02C at a constant voltage of 4.0V, and finally discharging it to 2V at a rate of 0.1C. The initial cycle charge-discharge test curve is shown in Figure 3. From the figure, it can be seen that the charge ratio capacity of the battery in its first cycle was 296.9mAh / g, and the discharge ratio capacity was 58.3mAh / g. This example demonstrates that a battery prepared using only functional materials for secondary batteries as the positive electrode active material can release a large amount of active sodium ions during the first cycle of charging, further demonstrating that the functional materials for secondary batteries according to the embodiment of the present invention can be used as functional materials to replenish active sodium ions in sodium-ion batteries.

[0064] Control test of Example 1 In this comparative example, a positive electrode plate was prepared using sodium fluoride, the active material of Example 1, as the positive electrode active material, a sodium-ion battery was assembled, and electrochemical properties were tested on the sodium-ion battery. The battery assembly and testing methods were the same as in Example 1. As a result of the test, the charge ratio capacity in the first cycle of the battery was 0.42 mAh / g, and the discharge ratio capacity was 0.39 mAh / g, which were much smaller than the test value of the charge ratio capacity in the first cycle of Example 1. Further comparison showed that the functional material for secondary batteries prepared in Example 1 of the present invention was able to release a large amount of active sodium ions during the first cycle of charging.

[0065] Example 2 This embodiment provides a preparation process and characteristic testing for functional materials for secondary batteries. The specific preparation steps are as follows:

[0066] In step 110, 12 g of lithium oxalate with a particle size Dv50 of 6 μm is dissolved in 200 g of deionized water, placed in a disperser, and dispersed and stirred at a rotation speed of 500 rpm for 30 minutes to obtain a clear solution by uniform stirring.

[0067] In step 120, the particle size Dv50 is 2 μm and the specific surface area is 920 m². 28 g of porous polyurethane at a concentration of / g is added to the above clarified solution, and then dispersed and stirred in a disperser for 40 hours to adsorb the active material into the pores of the carrier material, thereby obtaining a composite material solution.

[0068] In step 130, the solution of the composite material was transferred to a heated mixer, concentrated into a thick liquid by heating and stirring, then transferred to a forced-air dryer and dried at 110°C for 2 hours, removed, polished, and sieved to obtain a functional material for secondary batteries in which lithium oxalate was adsorbed inside the pores and on the surface of porous polyurethane. Here, the particle size Dv50 of this functional material for secondary batteries is 2 μm.

[0069] Figure 4 shows the XRD pattern of the functional material for secondary batteries prepared in Example 2 of the present invention. From Figure 4, it can be seen that the characteristic peak of the functional material for secondary batteries coincides with the characteristic peak of lithium oxalate, the active material. This indicates that the crystal structure of lithium oxalate, the active material, did not change after it was supported on porous polyurethane, the carrier material.

[0070] Using the functional materials for secondary batteries prepared in this embodiment, positive electrode plates were prepared, a lithium-ion battery was assembled, and electrochemical properties tests were conducted. Specifically, the tests were as follows:

[0071] In the preparation of the lithium-ion battery, the functional material for secondary batteries prepared in this example, polyvinylidene fluoride (PVDF), and conductive carbon black (SP) were slurryed in a mass ratio of 8:1:1, and then coated onto aluminum foil to prepare the positive electrode plate. Subsequently, it was assembled into a CR2032 type button cell according to a conventional method with sodium foil, a double-sided alumina separator, and electrolyte. Here, the electrolyte is a solution of ethylene carbonate (EC) / dimethyl carbonate (DEC) containing 1 mol / L of LiPF6 (the volume ratio of EC to DEC is 1:1).

[0072] The test method involved charging the battery to 4.4V at a rate of 0.1C, then charging it to 0.02C at a constant voltage of 4.4V, and finally discharging it to 3V at a rate of 0.1C. The initial cycle charge-discharge test curve is shown in Figure 5. From the figure, it can be seen that the charge ratio capacity of the material in the first cycle was 461.7mAh / g, and the discharge ratio capacity was 32.6mAh / g. This example demonstrates that a lithium-ion battery manufactured using only functional materials for secondary batteries as the positive electrode active material can release a large amount of active lithium ions during the first cycle of charging, further demonstrating that the functional materials for secondary batteries according to the embodiment of the present invention can be used as functional materials to replenish the active lithium ions in lithium-ion batteries.

[0073] Control test of Example 2 In this comparative example, lithium oxalate, the active material of Example 2, was used as the positive electrode active material to prepare a positive electrode plate, a lithium-ion battery was assembled, and an electrochemical properties test was performed on the lithium-ion battery. The battery assembly and testing methods were the same as in Example 2. As a result of the test, the charge ratio capacity in the first cycle of the battery was 36.8 mAh / g, and the discharge ratio capacity was 1.2 mAh / g, which were much smaller than the test value of the charge ratio capacity in the first cycle of Example 2. Further comparison showed that the functional material for secondary batteries prepared in Example 2 of the present invention was able to release a large amount of active lithium ions during the first cycle of charging.

[0074] Example 3 This embodiment provides a preparation process and characteristic testing of functional materials for secondary batteries, and the specific preparation steps are as follows.

[0075] In step 110, 1.8 kg of lithium carbonate with a particle size Dv50 of 500 nm and 20 kg of deionized water are placed in a stirring tank and stirred for 2 hours until completely dissolved to obtain a clarified solution.

[0076] In step 120, the particle size Dv50 is 5 μm and the specific surface area is 880 m². 21.2 kg of cross-linked dextran at a concentration of / g is added to the above clarified solution, and then the mixture is continuously stirred in a stirring tank for 24 hours to adsorb lithium carbonate, the active material, into the pores of the cross-linked dextran, the carrier material, thereby obtaining a composite material solution.

[0077] In step 130, a solution of the composite material was placed in a spray dryer and sprayed at an inlet temperature of 250°C and an outlet temperature of 120°C to form particles, thereby obtaining a functional material for secondary batteries in which lithium carbonate is adsorbed inside the pores and on the surface of cross-linked dextran. Here, the particle size Dv50 of this functional material for secondary batteries is 5 μm.

[0078] Using the functional materials for secondary batteries prepared in this embodiment, positive electrode plates were prepared, a lithium-ion battery was assembled, and electrochemical properties tests were conducted. Specifically, the tests were as follows:

[0079] In the preparation of the lithium-ion battery, the functional material for secondary batteries prepared in this example, polyvinylidene fluoride (PVDF), conductive carbon black (SP), and ternary cathode material NCM811 were slurryed in a mass ratio of 5:2:2:91, and then coated onto aluminum foil to prepare the cathode plate. Subsequently, it was assembled into a CR2032 type button cell according to a conventional method with sodium foil, a double-sided alumina separator, and electrolyte. The electrolyte is an ethylene carbonate (EC) / dimethyl carbonate (DEC) solution containing 1 mol / L of LiPF6 (the volume ratio of EC to DEC is 1:1).

[0080] The test method involved charging the material to 4.4V at a rate of 0.1C, then charging it to 0.02C at a constant voltage of 4.4V, and finally discharging it to 3V at a rate of 0.1C. The initial cycle charge-discharge test curve is shown in Figure 6. From the figure, it can be seen that the charge ratio capacity of the material in the first cycle was 239.5mAh / g, the discharge ratio capacity was 210.4mAh / g, and the Coulomb efficiency in the first cycle was 87.8%.

[0081] To better illustrate the effects of the embodiments of the present invention, Comparative Example 1 was compared with Example 3.

[0082] Comparative Example 1 The difference between this comparative example and Example 3 is that functional materials for secondary batteries were not used in the preparation of the positive electrode plate; the rest of the battery assembly method was the same. PVDF, SP, and the ternary positive electrode material NCM811 were slurryed in a mass ratio of 2:2:96, then applied to prepare the positive electrode plate. This was assembled into a CR2032 type button battery according to the method of Example 3 and tested according to the procedure of Example 3.

[0083] Figure 6 shows the first-cycle charge-discharge curve obtained by testing the battery assembled in this comparative example. From the figure, it can be seen that the charge ratio capacity of the material in the first cycle was 225.2 mAh / g, the discharge ratio capacity was 209.8 mAh / g, and the Coulomb efficiency in the first cycle was 93.2%.

[0084] The initial cycle charge ratio capacity of the battery in Example 3 was greater than that of the material in Comparative Example 1, indicating that the material can release a large amount of active lithium ions during the initial charge cycle. Although the initial cycle Coulomb efficiency of Example 3 appears lower than that of Comparative Example 1, half-cell testing showed that, with the same lithium insertion capacity, the lithium desorption capacity of the battery in Example 3 using the functional material for secondary batteries was larger, resulting in lower efficiency during the initial cycle and demonstrating the role of the functional material for secondary batteries. The difference in charge ratio capacity between the two was 14.3 mAh / g, which translates to 511.2 mAh / g when converted to the functional material for secondary batteries, indicating that the functional material for secondary batteries in Example 3 plays a role in providing a high compensation ratio capacity.

[0085] Example 4 This embodiment provides a preparation process and characteristic testing of functional materials for secondary batteries, and the specific preparation steps are as follows.

[0086] In step 110, 5 g of sodium acetate with a particle size Dv50 of 1 μm is dissolved in 180 g of ethanol, placed in a disperser, and dispersed and stirred for 20 minutes until homogeneous to obtain a clarified solution.

[0087] In step 120, the particle size Dv50 is 20 μm and the specific surface area is 80 m². 2 15 g of cordierite at a concentration of / g is added to the above clarified solution, then placed in a ball mill apparatus and dispersed for 16 hours. By adsorbing sodium acetate, the active material, into the pores of the cordierite, the carrier material, a solution of the composite material is obtained.

[0088] In step 130, the solution of the composite material was transferred to a heated mixer, concentrated into a thick liquid by heating and stirring, then transferred to a forced-air dryer and dried at 90°C for 1 hour. After removal, it was polished and sieved to obtain a functional material for secondary batteries in which sodium acetate was adsorbed in the pores and on the surface of the cordierite. Here, the particle size Dv50 of this functional material for secondary batteries is 6 μm.

[0089] A positive electrode plate was fabricated using the functional material for secondary batteries prepared in this embodiment, a sodium-ion battery was assembled, and electrochemical characteristics tests were conducted. The manufacturing process and test methods for the sodium-ion battery were the same as in Example 1. As a result of the tests, the charge ratio capacity of the sodium-ion battery in the first cycle was 353.3 mAh / g, indicating a relatively large desodium ratio capacity.

[0090] To better illustrate the effects of the embodiments of the present invention, Comparative Example 2 was compared with Example 4.

[0091] Comparative Example 2 The difference between this comparative example and Example 4 is that a functional material for secondary batteries is not used in the preparation of the positive electrode plate, and the other battery assembly methods are the same. After slurrying sodium acetate powder material, PVDF, and SP in a mass ratio of 8:1:1, it was coated to prepare a positive electrode plate. The electrode plate was assembled into a battery in the same manner as in Example 4 and tested according to the procedure of Example 4. As a result of the test, the initial cycle charge specific capacity of the material was only 0.92 mAh / g. This is because in Comparative Example 2, a functional material for secondary batteries was not used, the catalytic action on sodium acetate could not be exerted, sodium acetate was not decomposed, and its capacity could not be exhibited.

[0092] From the comparison results of the initial cycle charge specific capacities of the materials in Example 4 and Comparative Example 2, it can be seen that the functional material in Example 4 has a large sodium deintercalation capacity and, when supported on cordierite, which is a porous ceramic material, it has achieved a good catalytic decomposition effect on the decomposition of the active component.

[0093] Example 5 This example provides a preparation process and characteristic test of a functional material for secondary batteries. The specific preparation steps are as follows.

[0094] In Step 110, 250 g of benzene is placed in a three-neck flask, and then 10 g of lithium nitride with a particle size Dv50 of 3 μm is added. It is put into an ultrasonic disperser and ultrasonically dispersed for 1 hour to completely dissolve lithium nitride in benzene, thereby obtaining a clear solution.

[0095] In Step 120, 15 g of porous titanium with a particle size Dv50 of 720 nm and a specific surface area of 670 m 2 / g is added to the above clear solution, and then continuously dispersed with an ultrasonic disperser for 24 hours. By adsorbing lithium nitride, which is an active material, into the pores of porous titanium, which is a carrier material, a solution of the composite material is obtained.

[0096] In step 130, the solution of the composite material was transferred to a rotary evaporator, rotated and evaporated under negative pressure, and after removal, polished and sieved to obtain a functional material for secondary batteries in which lithium nitride was adsorbed inside the pores and on the surface of porous titanium. Here, the particle size Dv50 of this functional material for secondary batteries is 746 nm.

[0097] Embodiments of the present invention provide a functional material for secondary batteries, a method for preparing the same, and its applications. A functional material for secondary batteries is obtained by mixing a solution containing a precursor of a lithium or sodium active material with a carrier material, and then uniformly dispersing the active material in the form of small particles in the pores and on the surface of the carrier material through a physical process (e.g., shaking, dispersion stirring). This functional material for secondary batteries is a composite of two materials, an active material and a carrier material, by adsorbing the active material into the pores of the carrier material. Here, the carrier material catalyzes the reaction of the active material under the application of voltage, thereby lowering the activation energy of the reaction of the active material. At the same time, because the active material exists in the form of small particles, it increases the number of reaction sites and the reaction area, thereby increasing the overall reaction activity of the material. When the functional material for secondary batteries provided in embodiments of the present invention is applied to a secondary battery, it is possible to supply more active ions and replenish the irreversible active ions consumed during the charge-discharge cycle of the secondary battery, thereby giving the secondary battery the advantages of high capacity and long cycle life.

[0098] The method for preparing functional materials for secondary batteries according to the embodiment of the present invention is easy to operate, low-cost, and suitable for large-scale batch production.

[0099] The specific embodiments described above further elaborate on the objectives, technical proposals, and beneficial effects of the present invention. It should be understood that these are merely specific embodiments of the present invention and are not intended to limit the scope of protection. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention shall be included within the scope of protection.

[0100] [Note] [Note 1] A functional material for secondary batteries, The functional material for secondary batteries includes a carrier material and an active material. The carrier material is a porous material that acts as a catalyst on the active material under a voltage of 2.0V to 4.8V, and the carrier material includes one or more of the following: porous metal material, porous ceramic material, porous carbon material, porous plastic, and molecular sieve. The active material comprises a lithium-containing compound or a sodium-containing compound, and the active material is uniformly distributed in the form of fine particles within the pores or on the surface of the carrier material. The particle size Dv50 of the active material particles is 0.1 nm to 10 μm, the particle size Dv50 of the carrier material particles is 1 nm to 100 μm, and the particle size Dv50 of the functional material particles for secondary batteries is 1 nm to 120 μm. The lithium-containing compound comprises one or more of the following: lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, lithium formate, lithium oxide, lithium peroxide, lithium sulfide, lithium fluoride, and lithium nitride. The aforementioned sodium-containing compound includes one or more of the following: sodium carbonate, sodium hydroxide, sodium oxalate, sodium acetate, sodium formate, sodium oxide, sodium peroxide, sodium sulfide, and sodium fluoride. The porous metal material includes one or more of the elements or alloys of these metals: aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, and zinc. The porous ceramic material includes one or more of the following: porous alumina, porous zirconia, porous magnesium oxide, porous silicon carbide, porous silicon nitride, cordierite, high silica silicate, aluminosilicate, and aluminum titanate. The porous carbon material comprises one or more of the following: activated carbon, expanded graphite, activated carbon fibers, carbon nanotubes, and porous acetylene black. The porous plastic includes one or more of the following: porous polyethylene, porous polystyrene, porous polyvinyl chloride, porous polypropylene, porous polyurethane, and porous phenolic resin. The molecular sieve comprises one or more of the following: cross-linked dextran, carbon molecular sieve, or zeolite. The functional material for secondary batteries is obtained by adsorbing a clarified solution containing the precursor of the active material onto the pores of the carrier material, followed by a drying process, with the drying temperature being 60°C to 300°C. A functional material for secondary batteries characterized by the following features.

[0101] [Note 2] The pore size of the carrier material is 0.1 nm to 20 μm. The specific surface area of ​​the carrier material is 5m². 2 / g~3000m 2 / g The mass ratio of the active material to the carrier material is 0.1:1 to 100:1. A functional material for secondary batteries as described in Appendix 1, characterized by the features described herein.

[0102] [Note 3] A method for preparing functional materials for secondary batteries as described in Appendix 1 or 2, The aforementioned preparation method is A clear solution is obtained by dissolving a certain amount of the precursor of the active material in a solvent and stirring it uniformly. A solution of the composite material is obtained by adding a certain amount of carrier material to a clarified solution, dispersing it thoroughly and uniformly, and adsorbing the clarified solution into the pores of the carrier material. The process involves drying a solution of composite materials to remove the solvent, and then crystallizing the clarified solution within the pores of the composite material to form particulate active materials, ultimately obtaining a functional material for secondary batteries. Includes, Here, the carrier material includes one or more of the following: porous metal material, porous ceramic material, porous carbon material, porous plastic, and molecular sieve. The precursor of the active material includes a raw material for a lithium-containing compound or a raw material for a sodium-containing compound. A preparation method characterized by the above.

[0103] [Note 4] The raw materials for the lithium-containing compound include one or more of the following: lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, lithium formate, lithium oxide, lithium peroxide, lithium sulfide, lithium fluoride, and lithium nitride. The raw materials for the sodium-containing compound include one or more of the following: sodium carbonate, sodium hydroxide, sodium oxalate, sodium acetate, sodium formate, sodium oxide, sodium peroxide, sodium sulfide, and sodium fluoride. The solvent comprises one or more of the following: deionized water, ethanol, ether, acetone, N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), ethyl acetate, benzene, and chloroform. The mass ratio of the solvent to the active material is 5:1 to 200:1. The preparation method described in Appendix 3, characterized by the features described herein.

[0104] [Note 5] The porous metal material includes one or more of the elements or alloys of these metals: aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, and zinc. The porous ceramic material includes one or more of the following: porous alumina, porous zirconia, porous magnesium oxide, porous silicon carbide, porous silicon nitride, cordierite, high silica silicate, aluminosilicate, and aluminum titanate. The porous carbon material comprises one or more of the following: activated carbon, expanded graphite, activated carbon fibers, carbon nanotubes, and porous acetylene black. The porous plastic includes one or more of the following: porous polyethylene, porous polystyrene, porous polyvinyl chloride, porous polypropylene, porous polyurethane, and porous phenolic resin. The molecular sieve comprises one or more of the following: cross-linked dextran, carbon molecular sieve, or zeolite. The preparation method described in Appendix 3, characterized by the features described herein.

[0105] [Note 6] The method for sufficient dispersion includes one or a combination of shaking dispersion, stirring dispersion, ultrasonic dispersion, and ball mill dispersion. The aforementioned apparatus for sufficient dispersion includes one of a shaker, a stirrer, an ultrasonic disperser, or a ball mill apparatus, or a combination thereof. The aforementioned time for sufficient distribution is between 0.5 hours and 72 hours. The preparation method described in Appendix 3, characterized by the features described herein.

[0106] [Note 7] The drying method includes one or a combination thereof of rotary evaporation drying, stirring and heating drying, spray drying, vacuum heating drying, and forced air drying after filtration. The temperature of the drying process is 60°C to 300°C, and the duration is 0.5 hours to 48 hours. The preparation method described in Appendix 3, characterized by the features described herein.

[0107] [Note 8] A positive electrode plate characterized by containing the functional material for secondary batteries described in Appendix 1 or 2.

[0108] [Note 9] A secondary battery characterized by including the positive electrode plate described in Appendix 8.

Claims

1. A functional material for secondary batteries, The functional material for secondary batteries includes a carrier material and an active material. The carrier material is a porous material that acts as a catalyst on the active material under a voltage of 2.0V to 4.8V, and the carrier material includes one or more of the following: porous metal material, porous ceramic material, porous carbon material, porous plastic, and molecular sieve. The active material comprises a lithium-containing compound or a sodium-containing compound, and the active material is uniformly distributed in the form of fine particles within the pores or on the surface of the carrier material. The particle size Dv50 of the active material particles is 0.1 nm to 10 μm, the particle size Dv50 of the carrier material particles is 1 nm to 100 μm, and the particle size Dv50 of the functional material particles for secondary batteries is 1 nm to 120 μm. The lithium-containing compound comprises one or more of the following: lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, lithium formate, lithium oxide, lithium peroxide, lithium sulfide, lithium fluoride, and lithium nitride. The aforementioned sodium-containing compound includes one or more of the following: sodium carbonate, sodium hydroxide, sodium oxalate, sodium acetate, sodium formate, sodium oxide, sodium peroxide, sodium sulfide, and sodium fluoride. The porous metal material includes one or more of the elements or alloys of these metals: aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, and zinc. The porous ceramic material includes one or more of the following: porous alumina, porous zirconia, porous magnesium oxide, porous silicon carbide, porous silicon nitride, cordierite, high silica silicate, aluminosilicate, and aluminum titanate. The porous carbon material comprises one or more of the following: activated carbon, expanded graphite, activated carbon fibers, carbon nanotubes, and porous acetylene black. The porous plastic includes one or more of porous polyethylene, porous polystyrene, porous polyvinyl chloride, porous polypropylene, porous polyurethane, and porous phenolic resin. The molecular sieve comprises one or more of the following: cross-linked dextran, carbon molecular sieve, or zeolite. The functional material for secondary batteries is obtained by adsorbing a clarified solution containing the precursor of the active material onto the pores of the carrier material, followed by a drying process, the drying temperature of which is 60°C to 300°C. A functional material for secondary batteries characterized by the following features.

2. The pore size of the carrier material is 0.1 nm to 20 μm. The specific surface area of ​​the carrier material is 5 m². ２ / g to 3000m ２ / g, The mass ratio of the active material to the carrier material is 0.1:1 to 100:

1. The functional material for secondary batteries according to feature 1.

3. A method for preparing a functional material for a secondary battery according to claim 1 or 2, The aforementioned preparation method is A clear solution is obtained by dissolving a certain amount of the precursor of the active material in a solvent and stirring it uniformly. A solution of the composite material is obtained by adding a certain amount of carrier material to a clarified solution, dispersing it thoroughly and uniformly, and adsorbing the clarified solution into the pores of the carrier material. The process involves drying a solution of composite materials to remove the solvent, and then crystallizing the clarified solution within the pores of the composite material to form particulate active materials, ultimately obtaining a functional material for secondary batteries. Includes, Here, the carrier material includes one or more of the following: porous metal material, porous ceramic material, porous carbon material, porous plastic, and molecular sieve. The precursor of the active material includes a raw material for a lithium-containing compound or a raw material for a sodium-containing compound. A preparation method characterized by the above.

4. The raw materials for the lithium-containing compound include one or more of the following: lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, lithium formate, lithium oxide, lithium peroxide, lithium sulfide, lithium fluoride, and lithium nitride. The raw materials for the sodium-containing compound include one or more of the following: sodium carbonate, sodium hydroxide, sodium oxalate, sodium acetate, sodium formate, sodium oxide, sodium peroxide, sodium sulfide, and sodium fluoride. The solvent comprises one or more of the following: deionized water, ethanol, ether, acetone, N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), ethyl acetate, benzene, and chloroform. The mass ratio of the solvent to the active material is 5:1 to 200:

1. The preparation method according to feature 3.

5. The porous metal material includes one or more of the elements or alloys of these metals: aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, and zinc. The porous ceramic material includes one or more of the following: porous alumina, porous zirconia, porous magnesium oxide, porous silicon carbide, porous silicon nitride, cordierite, high silica silicate, aluminosilicate, and aluminum titanate. The porous carbon material comprises one or more of the following: activated carbon, expanded graphite, activated carbon fibers, carbon nanotubes, and porous acetylene black. The porous plastic includes one or more of porous polyethylene, porous polystyrene, porous polyvinyl chloride, porous polypropylene, porous polyurethane, and porous phenolic resin. The molecular sieve comprises one or more of the following: cross-linked dextran, carbon molecular sieve, or zeolite. The preparation method according to feature 3.

6. The method for sufficient dispersion includes one or a combination of shaking dispersion, stirring dispersion, ultrasonic dispersion, and ball mill dispersion. The aforementioned apparatus for sufficient dispersion includes one of a shaker, a stirrer, an ultrasonic disperser, or a ball mill apparatus, or a combination thereof. The aforementioned time for sufficient distribution is between 0.5 hours and 72 hours. The preparation method according to feature 3.

7. The drying method includes one or a combination thereof of rotary evaporation drying, stirring and heating drying, spray drying, vacuum heating drying, and forced air drying after filtration. The temperature of the drying process is 60°C to 300°C, and the duration is 0.5 hours to 48 hours. The preparation method according to feature 3.

8. A positive electrode plate characterized by comprising the functional material for secondary batteries described in claim 1 or 2.

9. A secondary battery characterized by including the positive electrode plate described in claim 8.

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