Multifunctional material for secondary battery and preparation method and application thereof

Abstract

The application discloses a multifunctional material for a secondary battery and a preparation method and application thereof, and belongs to the technical field of secondary batteries.The multifunctional material for the secondary battery comprises a core and a shell.The core comprises composite particles and catalyst particles.The composite particles comprise carrier material particles, an active substance and catalyst particles attached to the surface of the carrier.The active substance is attached to the surface of the carrier material particles to form an active substance coating layer.The active substance coating layer is in the form of closely arranged particles and / or a film.The catalyst particles are uniformly distributed between the composite particles and / or embedded in the surface of the carrier material particles.The shell is a carbon coating layer.The multifunctional material for the secondary battery can be applied to a secondary battery, so that the secondary battery has the advantages of high energy density, long cycle life and stable performance.

Description

Technical Field

[0001] This invention relates to the field of secondary battery materials technology, and in particular to a multifunctional material for secondary batteries, its preparation method, and its application. Background Technology

[0002] Electric vehicles and other electronic devices have driven the rapid development of rechargeable batteries. Their high energy density and fast charging speeds have made them popular. However, the rapid increase in battery volume and the growing demand for longer driving ranges in recent years have led to requirements for even higher energy density and better cost-effectiveness.

[0003] Current research on improving battery energy density mainly focuses on three directions: first, increasing the specific capacity and proportion of active materials; second, improving the utilization rate of the battery's internal space; and third, using additive materials. Among these three solutions, increasing the specific capacity and proportion of materials requires the development of new materials, including positive and negative electrode materials, conductive agents, and binders. Solutions for improving the utilization rate of the battery's internal structure generally involve process innovation, such as upgrading from winding to stacking, innovation in battery tabs (from all tabs to multiple tabs, or even tabless-free processes), and reducing foil and separator thickness, as well as increasing the proportion of active material. Solutions using additive materials include adding positive and negative electrodes to replenish active ions, and adding active ions through the separator.

[0004] While the aforementioned improvement schemes can improve the energy density of secondary batteries to some extent, the degree of improvement is limited. Furthermore, there are few reports of schemes that combine the advantages of both schemes. Therefore, it is necessary to develop a material that combines the above-mentioned schemes of increasing the proportion of active materials and using additive materials, so as to improve the energy density of the battery while maintaining the stability of the material. Summary of the Invention

[0005] This invention provides a multifunctional material for secondary batteries, its preparation method, and its application. The method involves uniformly mixing a solution of an active material precursor containing active ions with a carrier material, adding catalyst particles, continuing mixing, and then drying to obtain a mixture. The mixture is then subjected to high-temperature sintering to react the active material precursor to generate an active material, resulting in an aggregated core material. This core material is then carbon-coated to obtain the multifunctional material for secondary batteries. This material can simultaneously function as a conductive agent and an additive. The carbon-coated outer shell of the multifunctional material can replace part of the conductive agent, reducing the amount of conductive agent required. Therefore, it is not necessary to reduce the proportion of the positive electrode active material, effectively increasing the proportion of the positive electrode active material. Furthermore, this multifunctional material for secondary batteries can serve as a supplement... The use of active ion additives can improve the energy density of the battery. Furthermore, the core of the material consists of multiple composite particles, which are composed of a carrier material and surface-loaded active materials and catalyst particles. When the material is at a low potential, the catalyst can catalyze the full decomposition of the active materials, releasing more active ions to compensate for the irreversible loss of active ions. In addition, because the multifunctional material for secondary batteries provided by this invention has a carbon coating layer, it provides conductivity while isolating the active materials in the core from the air, ensuring the stability of the active materials and preventing them from reacting with water in the air to form inert substances containing active elements that require further catalysis. This ensures that the material can quickly release active ions during battery charge-discharge cycles.

[0006] The present invention provides a multifunctional material for secondary batteries. When applied in secondary batteries, the material can provide more active ions through the synergistic effect of active materials, catalyst particles and carbon coating layers. This replenishes the irreversible active ions consumed by the secondary battery during charge and discharge cycles, giving the secondary battery the advantages of high energy density, long cycle life and stable performance.

[0007] In a first aspect, embodiments of the present invention provide a multifunctional material for secondary batteries, the multifunctional material for secondary batteries comprising: a core and a shell;

[0008] The core comprises composite particles and catalyst particles; the composite particles comprise: carrier material particles, active material, and catalyst particles attached to the surface of the carrier.

[0009] The active substance is attached to the surface of the carrier material particles to form an active substance coating layer; the active substance coating layer is in the form of closely arranged particles and / or a thin film.

[0010] The catalyst particles are uniformly distributed between the composite particles and / or embedded on the surface of the carrier material particles;

[0011] The outer shell is a carbon coating.

[0012] Preferably, the active material includes any one of lithium oxide, sodium oxide, lithium sulfide, and sodium sulfide;

[0013] The catalyst particles include at least one of the following: elemental or compound elements of iron, cobalt, nickel, copper, zinc, chromium, palladium, cadmium, silver, gold, platinum, and rhodium, or alloys of the aforementioned metals.

[0014] The carrier material particles include one or more of the following: carbon materials, ceramic materials, metallic materials, and polymer materials;

[0015] The carbon materials include one or more of the following: carbon black, carbon microspheres, graphite, hard carbon, activated carbon, carbon fiber, carbon nanotubes, acetylene black, fullerene, and graphene.

[0016] The ceramic material includes one or more of the following: alumina, magnesium oxide, zirconium oxide, titanium oxide, silicon carbide, silicon nitride, silicon oxide, cordierite, silicates, aluminosilicates, and aluminum titanate;

[0017] The metallic materials include one or more of the following: elemental aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, and zinc, or alloys of the aforementioned metals.

[0018] The polymeric materials include one or more of the following: polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamine, polyoxymethylene, polyoxymethylene, polyphosphate, styrene-butadiene rubber, nitrile rubber, polymethyl methacrylate, epoxy resin, phenolic resin, polyurethane, polycarbonate, and polytetrafluoroethylene.

[0019] More preferably, the carrier material particles have a porous structure; the pore size of the carrier material particles is between 0.1 nm and 10 μm.

[0020] The active substance adheres to the surface and pores of the carrier material particles, forming an active substance coating layer.

[0021] Preferably, the particle size Dv50 of the multifunctional material for the secondary battery is 10nm-100μm;

[0022] The particle size Dv50 of the carrier material is 1nm-50μm;

[0023] The active material coating layer consists of closely packed particles with a particle size Dv50 between 0.1 nm and 10 μm, or a thin film with a thickness of 0.1 nm to 10 μm.

[0024] The particle size Dv50 of the catalyst particles is 0.1 nm-5 μm;

[0025] The carbon coating layer is one or more layers of uniformly distributed continuous carbon film or carbon particle layer; the thickness of the carbon coating layer is 1 nm-10 μm.

[0026] Preferably, the active material accounts for 20%-96% of the total mass of the multifunctional material for secondary batteries;

[0027] The mass of the catalyst particles accounts for 0.1%-8% of the total mass of the multifunctional material for secondary batteries;

[0028] The mass of the carrier material particles accounts for 2%-80% of the total mass of the multifunctional material for secondary batteries; the mass of the carbon coating layer accounts for 0.5%-10% of the total mass of the multifunctional material for secondary batteries.

[0029] Secondly, embodiments of the present invention provide a method for preparing the multifunctional material for secondary batteries described in the first aspect above, the method comprising:

[0030] Weigh the carrier material particles and the precursor material of the active substance in proportion, and first dissolve the precursor material of the active substance in a solvent to obtain a transparent solution;

[0031] Carrier material particles are added to a transparent solution and dispersed in a dispersion device to obtain a mixed solution;

[0032] The catalyst particles are added to the mixed solution and dispersed further. After being mixed evenly, the mixture is dried to obtain the final mixture.

[0033] The mixture is sintered in a protective atmosphere to obtain an agglomerated core material;

[0034] Carbon coating is applied to the aggregated core material to form an outer shell, resulting in a multifunctional material for secondary batteries.

[0035] Preferably, the precursor material of the active substance includes one or more of the following: lithium hydroxide, lithium carbonate, lithium nitrate, lithium sulfate, lithium acetate, lithium oxalate, sodium hydroxide, sodium carbonate, sodium acetate, sodium oxalate, and sodium sulfite.

[0036] The catalyst particles include at least one of the following: elemental or compound elements of iron, cobalt, nickel, copper, zinc, chromium, palladium, cadmium, silver, gold, platinum, and rhodium, or alloys of the aforementioned metals.

[0037] The carrier material particles include one or more of the following: carbon materials, ceramic materials, metallic materials, and polymer materials;

[0038] The carbon materials include one or more of the following: carbon black, carbon microspheres, graphite, hard carbon, activated carbon, carbon fiber, carbon nanotubes, acetylene black, fullerene, and graphene.

[0039] The ceramic material includes one or more of the following: alumina, magnesium oxide, zirconium oxide, titanium oxide, silicon carbide, silicon nitride, silicon oxide, cordierite, silicates, aluminosilicates, and aluminum titanate;

[0040] The metallic materials include one or more of the following: elemental aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, and zinc, or alloys of the aforementioned metals.

[0041] The polymeric materials include one or more of the following: polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamine, polyoxymethylene, polyoxymethylene, polyphosphate, styrene-butadiene rubber, nitrile rubber, polymethyl methacrylate, epoxy resin, phenolic resin, polyurethane, polycarbonate, and polytetrafluoroethylene.

[0042] The solvent includes one or more of the following: deionized water, ethanol, diethyl ether, acetone, N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), ethyl acetate, benzene, and chloroform.

[0043] The mass ratio of the solvent to the precursor material of the active substance is 2:1 to 200:1.

[0044] Preferably, the protective atmosphere is any one or a mixture of nitrogen, argon, helium, or hydrogen atmosphere;

[0045] The dispersion treatment method includes one or more of the following: vibration dispersion, stirring dispersion, ultrasonic dispersion, and ball milling dispersion; the dispersion treatment equipment includes one or more of the following: a shaking table, a mixer, an ultrasonic disperser, or a ball mill; the dispersion treatment time is between 0.5 hours and 72 hours.

[0046] The drying method includes one or more of the following: rotary evaporation drying, stirring and heating drying, spray drying, vacuum heating drying, and filtration followed by forced air drying; the drying temperature is 60℃-300℃, and the time is 0.5 hours-48 hours.

[0047] The sintering temperature is 450℃-1400℃, and the holding time is 0.5 hours-20 hours.

[0048] Preferably, the carbon coating treatment method is gas-phase carbon coating or solid-phase carbon coating;

[0049] The carbon source gas for gaseous carbon coating includes one or more of methane, acetylene, propane, and propyne.

[0050] The carbon source material for solid-phase carbon coating includes one or more of glucose, sucrose, fructose, asphalt, starch, and polyethylene glycol.

[0051] Thirdly, embodiments of the present invention provide a secondary battery, the secondary battery comprising the multifunctional material for secondary batteries described in the first aspect above.

[0052] This invention provides a multifunctional material for secondary batteries, its preparation method, and its application. The multifunctional material includes a carbon-coated outer shell and a core containing composite particles and catalyst particles. The carbon-coated outer shell is capable of conducting electrons and functions as a conductive agent. The composite particles are a carrier material with an active material coating and catalyst particles attached to its surface. Because of the presence of catalyst particles, when the material is at a low potential, the catalyst can catalyze the complete decomposition of the active material, releasing more active ions to compensate for the irreversible loss of active ions. Therefore, the multifunctional material for secondary batteries of this invention can both replace part of the conductive agent to increase the proportion of the positive electrode active material and provide active ions, thereby improving the energy density of the battery.

[0053] The present invention provides a method for preparing a multifunctional material for secondary batteries, which is simple to operate, low in cost, and suitable for commercial mass production. Attached Figure Description

[0054] The technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0055] Figure 1 This is a cross-sectional structural diagram of a multifunctional material for secondary batteries provided in an embodiment of the present invention.

[0056] Figure 2 A flowchart illustrating the preparation method of a multifunctional material for secondary batteries provided in an embodiment of the present invention.

[0057] Figure 3 The X-ray diffraction (XRD) patterns of the multifunctional material for secondary batteries prepared in Example 1 of this invention after storage for 0 days and 7 days.

[0058] Figure 4 The XRD patterns of the functional material provided in Comparative Example 1 of this invention after 0 days and 7 days of storage.

[0059] Figure 5 Scanning electron microscope (SEM) images of multifunctional materials for secondary batteries provided in Embodiment 2 of the present invention.

[0060] Figure 6 The first-week charge-discharge curves are shown for the multifunctional material for secondary batteries provided in Embodiment 2 of the present invention and the functional material in Comparative Example 2.

[0061] Figure 7The first-week charge-discharge curves are shown for the multifunctional material for secondary batteries provided in Embodiment 3 of the present invention and the functional material in Comparative Example 3.

[0062] Figure 8 The first-week charge-discharge curves are shown for the multifunctional material for secondary batteries provided in Embodiment 4 of the present invention, and for the functional materials provided in Comparative Examples 4 and 5. Detailed Implementation

[0063] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. However, it should be understood that these embodiments are only for more detailed description and should not be construed as limiting the present invention in any way, that is, not intended to limit the scope of protection of the present invention.

[0064] This invention provides a multifunctional material for secondary batteries, comprising a core and a shell; the particle size Dv50 of the multifunctional material for secondary batteries is between 10 nm and 100 μm.

[0065] The core comprises composite particles and catalyst particles; the composite particles include: carrier material particles, active material, and catalyst particles attached to the surface of the carrier.

[0066] The outer shell is a carbon coating layer with a thickness of 1nm-10μm.

[0067] The mass percentages of each component in the multifunctional material for secondary batteries are as follows:

[0068] The active material accounts for 20%-96% of the total mass of the multifunctional material for secondary batteries, preferably 30%-96%; the catalyst particles account for 0.1%-8% of the total mass of the multifunctional material for secondary batteries, preferably 0.1%-5%; the support material particles account for 2%-80% of the total mass of the multifunctional material for secondary batteries, preferably 5%-72%; and the carbon coating layer accounts for 0.5%-10% of the total mass of the multifunctional material for secondary batteries, preferably 0.5%-8%.

[0069] The structure of the multifunctional material for secondary batteries of the present invention is as follows: the active material is attached to the surface of the carrier material particles to form an active material coating layer; the active material coating layer is in the form of closely arranged particles and / or thin films; the catalyst particles are uniformly distributed between the composite particles and / or embedded in the surface of the carrier material particles; the carbon coating layer is one or more layers of uniformly distributed continuous carbon thin films or carbon particle layers.

[0070] The particle size Dv50 of the carrier material is 1nm-50μm; the active material coating layer consists of closely packed particles with a particle size Dv50 between 0.1nm-10μm or a thin film with a thickness of 0.1nm-10μm; the particle size Dv50 of the catalyst particles is 0.1nm-5μm.

[0071] A schematic diagram of one structural configuration of the multifunctional material for secondary batteries provided in this embodiment of the invention is shown below. Figure 1 As shown, the multifunctional material has a two-layer structure of core and shell. The core is composed of multiple composite particles, including carrier material particles, active substances and catalyst particles. The active substances are attached to the surface of the carrier material particles to form a tightly packed granular coating layer. The catalyst particles are embedded in the surface of the carrier material particles, and some catalyst particles are evenly distributed among the internal composite particles, forming the core together with multiple composite particles. The shell is a carbon coating layer, which is a layer of uniformly distributed continuous carbon particles.

[0072] The specific classification of each component in the multifunctional material for secondary batteries provided in this invention is as follows:

[0073] The active material includes any one of lithium oxide, sodium oxide, lithium sulfide, and sodium sulfide.

[0074] The catalyst particles include at least one of the following: elemental or compound elements of iron, cobalt, nickel, copper, zinc, chromium, palladium, cadmium, silver, gold, platinum, and rhodium, or alloys of the aforementioned metals.

[0075] The carrier material particles include one or more of the following: carbon materials, ceramic materials, metallic materials, and polymeric materials; wherein, carbon materials include one or more of the following: carbon black, carbon microspheres, graphite, hard carbon, activated carbon, carbon fiber, carbon nanotubes, acetylene black, fullerene, and graphene; ceramic materials include one or more of the following: alumina, magnesium oxide, zirconium oxide, titanium oxide, silicon carbide, silicon nitride, silicon oxide, cordierite, silicates, aluminosilicates, and aluminum titanate; metallic materials include one or more of the following: elemental aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, and zinc, or alloys of the aforementioned metals; polymeric materials include one or more of the following: polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamine, polyoxymethylene, polyoxymethylene, polyphosphate, styrene-butadiene rubber, nitrile rubber, polymethyl methacrylate, epoxy resin, phenolic resin, polyurethane, polycarbonate, and polytetrafluoroethylene.

[0076] In an optional embodiment, the aforementioned carrier material particles can have a porous structure with pore sizes between 0.1 nm and 10 μm. When the carrier material particles have a porous structure, the active material adheres to the surface of the carrier material particles to form a coating layer, and some of the active material is distributed within the pores of the carrier material particles. Carrier material particles with a porous structure can load a greater amount of active material.

[0077] This invention provides a method for preparing the above-mentioned multifunctional material for secondary batteries, such as... Figure 2 As shown, the specific steps include:

[0078] Step 210: Weigh the carrier material particles and the precursor material of the active substance according to the proportion. First, dissolve the precursor material of the active substance in a solvent to obtain a transparent solution.

[0079] The mass ratio of the carrier material particles to the precursor material of the active substance is [1-4]:[1-68];

[0080] The precursor materials for the active substance include one or more of the following: lithium hydroxide, lithium carbonate, lithium nitrate, lithium sulfate, lithium acetate, lithium oxalate, sodium hydroxide, sodium carbonate, sodium acetate, sodium oxalate, and sodium sulfite.

[0081] The carrier material particles include one or more of the following: carbon materials, ceramic materials, metallic materials, and polymeric materials; specifically, carbon materials include one or more of the following: carbon black, carbon microspheres, graphite, hard carbon, activated carbon, carbon fiber, carbon nanotubes, acetylene black, fullerene, and graphene; ceramic materials include one or more of the following: alumina, magnesium oxide, zirconium oxide, titanium oxide, silicon carbide, silicon nitride, silicon oxide, cordierite, silicates, aluminosilicates, and aluminum titanate; metallic materials include one or more of the following: elemental aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, and zinc, or alloys of the aforementioned metals; polymeric materials include one or more of the following: polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamine, polyoxymethylene, polyoxymethylene, polyphosphate, styrene-butadiene rubber, nitrile rubber, polymethyl methacrylate, epoxy resin, phenolic resin, polyurethane, polycarbonate, and polytetrafluoroethylene.

[0082] Solvents include one or more of the following: deionized water, ethanol, diethyl ether, acetone, N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), ethyl acetate, benzene, and chloroform.

[0083] The mass ratio of solvent to precursor material of active substance is 2:1-200:1.

[0084] Step 220: Add carrier material particles to the transparent solution and place it in a dispersion device for dispersion treatment to obtain a mixed solution;

[0085] The dispersion treatment methods include one or more of the following: vibration dispersion, stirring dispersion, ultrasonic dispersion, and ball milling dispersion; the dispersion treatment equipment includes one or more of the following: a shaking table, a mixer, an ultrasonic disperser, or a ball mill; and the dispersion treatment time is between 0.5 hours and 72 hours.

[0086] Step 230: Add catalyst particles to the mixed solution, continue dispersion treatment, mix evenly, and then dry to obtain a mixture.

[0087] The catalyst particles include at least one of the following: elemental or compound elements of iron, cobalt, nickel, copper, zinc, chromium, palladium, cadmium, silver, gold, platinum, and rhodium, or alloys of the aforementioned metals.

[0088] The method for dispersion processing in this step is the same as that for dispersion processing in step 220.

[0089] The drying methods include one or more of the following: rotary evaporation drying, stirring and heating drying, spray drying, vacuum heating drying, and filtration followed by forced air drying; the drying temperature is 60℃-300℃, and the time is 0.5 hours-48 hours.

[0090] Step 240: The mixture is sintered in a protective atmosphere to obtain an agglomerated core material;

[0091] The protective atmosphere is any one or a mixture of nitrogen, argon, helium or hydrogen atmosphere.

[0092] The sintering temperature is 450℃-1400℃, and the holding time is 0.5 hours-20 hours.

[0093] Step 250: Carbon coating is applied to the aggregated core material to form an outer shell, resulting in a multifunctional material for secondary batteries;

[0094] Among them, the carbon coating treatment methods are gas phase carbon coating or solid phase carbon coating;

[0095] The carbon source gases for gaseous carbon coating include one or more of methane, acetylene, propane, and propyne.

[0096] The carbon source materials for solid-phase carbon coating include one or more of glucose, sucrose, fructose, pitch, starch, and polyethylene glycol.

[0097] In the preparation of the multifunctional material for secondary batteries, this application first mixes a solution of an active substance precursor containing active ions with a support material, allowing the active substance precursor to occupy or adsorb onto easily bonded sites on the support material particles. Then, catalyst particles are added, distributing the catalyst particles between the composite particles and / or embedding them on the surface of the support material particles. The multifunctional material for secondary batteries prepared by the above method can be used as an additive in the preparation of positive electrode active materials.

[0098] The aforementioned positive electrode sheet mainly includes a positive current collector, a positive active material, a multifunctional material for secondary batteries, a conductive agent, and a binder.

[0099] Positive current collectors include, but are not limited to, aluminum foil.

[0100] A positive electrode active material, a multifunctional material for secondary batteries, a conductive agent, a binder, and a solvent are mixed to prepare a positive electrode slurry. This slurry is then coated onto a positive electrode current collector using conventional methods and dried to obtain a positive electrode sheet.

[0101] The positive electrode active materials include any one of the following: lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium nickel cobalt manganese oxide ternary materials, sodium cobalt oxide, vanadium pentoxide, Prussian blue, sodium iron phosphate with olivine structure, Na3V2(PO4)3 with NASICON structure, and sodium nickel iron manganese oxide with layered structure.

[0102] The conductive agent includes, but is not limited to, one or more of the following: carbon black, carbon nanotubes, acetylene black, and Ketjen black; the mass percentage of the conductive agent in the positive electrode slurry is 0-10%.

[0103] The adhesives include, but are not limited to, one or more of the following: polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, carboxymethyl cellulose, sodium carboxymethyl cellulose, polymethyl methacrylate, polyacrylate, polyacrylonitrile, styrene-butadiene rubber, polyvinyl alcohol, polytetrafluoroethylene, polyacrylamide, polyvinyl acetate, and polyurethane.

[0104] This invention provides a secondary battery, which includes a lithium-ion battery or a sodium-ion battery.

[0105] Specifically, a secondary battery is assembled from a positive electrode sheet containing multifunctional materials for secondary batteries, a separator, an electrolyte or solid electrolyte, and a negative electrode sheet.

[0106] The separator includes, but is not limited to, any one of double-sided alumina separator, separator containing sodium ion solid electrolyte, and separator containing lithium ion solid electrolyte; the base membrane of the separator includes, any one of polyolefin membrane, non-woven membrane, fiber membrane, and polyaramid membrane.

[0107] The negative electrode sheet includes any one of lithium sheet, sodium sheet, or negative electrode current collector containing negative electrode active material; specifically, the negative electrode current collector includes, but is not limited to, copper foil or titanium foil, and the active material layer on the surface of the negative electrode current collector also includes a conductive agent and a binder; the negative electrode active material includes, but is not limited to, any one of carbon materials, tin-based negative electrode materials, silicon-based negative electrode materials, silicon-carbon composite materials, nano-oxide materials, and titanate ester negative electrode materials; carbon materials include any one of graphite, hard carbon, carbon fiber, petroleum coke, and mesophase carbon microspheres.

[0108] The electrolyte comprises a solute and a solvent; the solute is a conductive salt, including: sodium perchlorate (NaClO4), sodium tetrafluoroborate (NaBF4), sodium hexafluorophosphate (NaPF6), sodium hexafluoroarsenate (NaAsF6), sodium trifluoroacetate (CF3COONa), lithium perchlorate (LiClO4), lithium hexafluorophosphate (LiPF6), and lithium hexafluoroborate (Li... The solvent includes any one of BF6 and lithium hexafluoroarsenate (LiAsF6); the solvent includes any one of ethylene carbonate (EC), propylene carbonate (PC), butenyl carbonate (BC), vinylene carbonate (VC), fluoroethylene carbonate (FEC), methyl ethyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), γ-butyrolactone (BL), methyl propionate (MP), methyl butyrate (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).

[0109] To better understand the technical solution provided by this invention, the following examples illustrate the preparation process and characteristics of the multifunctional material for secondary batteries.

[0110] Example 1

[0111] This embodiment provides a preparation process and performance testing of a multifunctional material for secondary batteries. The specific preparation steps are as follows:

[0112] (1) Weigh lithium carbonate, the precursor material of the active material, and carbon nanotube material with a particle size Dv50 of 2.4 μm at a mass ratio of 1:0.4. First, dissolve lithium carbonate in deionized water at 20℃ to obtain a transparent solution, wherein the mass ratio of deionized water at 20℃ to lithium carbonate is 100:1.3.

[0113] (2) Add carbon nanotube material to the transparent solution and place it in an ultrasonic dispersion device for ultrasonic dispersion for 32 hours to obtain a mixed solution.

[0114] (3) Add nickel sulfate particles with a catalyst particle size Dv50 of 50 nm to the mixed solution, continue to disperse, mix evenly and then spray dry to obtain a mixture, wherein the mass of nickel sulfate accounts for 2% of the mass of the mixture.

[0115] (4) Place the mixture in a rotary kiln, introduce 3L / min of inert argon gas, heat the rotary kiln to 1350℃, and keep it at that temperature for 2 hours, so that lithium carbonate undergoes a chemical reaction to be converted into active material lithium oxide, and obtain agglomerated core material.

[0116] (5) After the heat preservation in step (4) is completed, adjust the temperature of the rotary kiln to 800℃, and then switch the atmosphere to a mixture of argon and acetylene with a volume ratio of 1:2. Continue to keep warm for 5 hours to form a 3nm carbon coating layer on the surface of the agglomerated core material (the thickness of the carbon coating layer is characterized by transmission electron microscopy TEM) to obtain a multifunctional material for secondary batteries with a particle size Dv50 of 7.5μm.

[0117] The carbon content in the multifunctional material for secondary batteries was determined to be 56.3 wt% using a carbon-sulfur analyzer.

[0118] The XRD pattern of the multifunctional material for secondary batteries prepared in this embodiment is shown below. Figure 3 As shown.

[0119] The XRD pattern of the multifunctional material for secondary batteries prepared in this embodiment after being stored in a normal temperature and pressure environment for 7 days is shown below. Figure 3 As shown.

[0120] Comparative Example 1

[0121] To better illustrate the effects of the embodiments of the present invention, Comparative Example 1 was used as the control group experiment of Example 1: The difference between the preparation process of the functional material prepared in Comparative Example 1 and the preparation process of the multifunctional material for secondary batteries in Example 1 is that no carbon coating treatment was performed in the preparation process of Comparative Example 1, and the other steps were the same as those in Example 1.

[0122] The XRD pattern of the functional material prepared in this comparative example, and its XRD pattern after being stored in a normal temperature and pressure environment for 7 days, are shown below. Figure 4 As shown.

[0123] go through Figure 3 and Figure 4 XRD pattern analysis showed that the XRD pattern of the secondary battery multifunctional material prepared in Example 1 remained unchanged after 7 days of storage at room temperature and pressure, indicating that the crystal structure of the secondary battery multifunctional material did not change. However, the XRD pattern of the functional material in Comparative Example 1 changed from the lithium oxide peak to the lithium hydroxide peak after 7 days of storage at room temperature and pressure, indicating that the stability of the functional material in Comparative Example 1 was inferior to that of the secondary battery multifunctional material in Example 1. This demonstrates that the secondary battery multifunctional material with a carbon coating structure prepared in Example 1 has higher air stability.

[0124] Example 2

[0125] This embodiment provides a preparation process and performance testing of a multifunctional material for secondary batteries. The specific preparation steps are as follows:

[0126] (1) Weigh lithium acetate, the precursor material of the active material, and alumina carrier material particles with a particle size Dv50 of 3.3 μm at a mass ratio of 1:0.3. First, dissolve lithium acetate in deionized water to obtain a transparent solution, wherein the mass ratio of deionized water to lithium acetate is 20:1.

[0127] (2) Add alumina carrier material particles to the transparent solution, place it in a shaking shaker and shake it at a frequency of 80Hz for 48 hours to obtain a mixed solution.

[0128] (3) Cobalt nitrate particles with a catalyst Dv50 of 30 nm were added to the mixed solution and the mixture was further dispersed by shaking. After being mixed evenly, the mixture was evaporated and dried to obtain a mixture, wherein the mass of cobalt nitrate accounted for 3% of the mass of the mixture.

[0129] (4) Place the mixture in an atmosphere box furnace, introduce 4L / min of inert argon gas, and heat the atmosphere box furnace to 750°C and keep it at that temperature for 6 hours, so that lithium acetate undergoes a chemical reaction to transform into the active material lithium oxide, and obtain the agglomerated core material.

[0130] (5) The aggregated core material and the carbon source material glucose were mixed evenly in an argon atmosphere at a mass ratio of 1:0.1, and then transferred to an atmosphere box furnace, heated to 850°C, and held for 4 hours to carbonize the carbon source material on the surface of the aggregated core material to form a 250nm coating layer (the thickness of the carbon coating layer was characterized by transmission electron microscopy TEM) to obtain a multifunctional material for secondary batteries with a particle size Dv50 of 8.4μm.

[0131] The carbon content in the multifunctional material for secondary batteries, as determined by a carbon-sulfur analyzer, is 4.03 wt%.

[0132] SEM image of the multifunctional material for secondary batteries prepared in this embodiment, as shown below. Figure 5 As shown in the figure, the material surface is covered with a large amount of carbon particles.

[0133] The multifunctional secondary battery material prepared in this embodiment was used as the positive electrode active material to prepare the positive electrode sheet, and a lithium half-cell was assembled. Then, the electrochemical performance of the battery was tested. The specific test steps are as follows:

[0134] Preparation of lithium-ion half-cells: The secondary battery prepared in this embodiment was mixed with multifunctional material, polyvinylidene fluoride (PVDF) and conductive carbon black (SP) in a mass ratio of 8:1:1 to form a slurry, which was then coated on aluminum foil to form a positive electrode. The positive electrode was then assembled with lithium sheet, 12μm PE separator and 1mol / L lithium hexafluorophosphate LiPF6 in ethylene carbonate (EC) / dimethyl carbonate (DMC) (EC to DMC volume ratio of 1:1) electrolyte according to conventional methods to form a CR2032 coin cell.

[0135] Test method: The test was conducted by charging at a rate of 0.1C to 4.5V, then charging at a constant voltage of 4.5V to 0.02C, and finally discharging at a rate of 0.1C to 3V. The charge-discharge test curves for the first week are shown below. Figure 6 As shown in the figure, the battery assembled in Example 2 has a first-week charging specific capacity of 360.5 mAh / g and a discharge specific capacity of 48.0 mAh / g. This indicates that the battery prepared in this example using only secondary battery functional materials as positive electrode active materials can release more active lithium ions during the first-week charging process. This further illustrates that the secondary battery functional materials provided in this embodiment can be used as functional materials to supplement active lithium ions in lithium-ion batteries.

[0136] Comparative Example 2

[0137] To better illustrate the effects of the embodiments of the present invention, Comparative Example 2 was used as the control group for Example 2: The difference between the process of preparing the functional material in Comparative Example 2 and the process in Example 2 is that no cobalt nitrate particles were added as a catalyst during the preparation process of Comparative Example 2, while the other steps were the same.

[0138] The functional material prepared in Comparative Example 2 was used as the positive electrode active material to prepare the positive electrode sheet, and a lithium half-cell was assembled. The electrochemical performance of the battery was then tested. The specific battery preparation process and testing steps were the same as in Example 2. The charge-discharge test curves for the first week are shown below. Figure 6 As shown in the figure, the first-week charge specific capacity of the battery assembled in Comparative Example 2 is 205.6 mAh / g, and the discharge specific capacity is 19.6 mAh / g, both of which are less than the charge-discharge specific capacity of Example 2. This indicates that the catalyst particles in the multifunctional material for secondary batteries prepared in Example 2 can catalyze the decomposition of active materials during the first-week charge of the battery, thereby improving the charge-discharge specific capacity of the battery.

[0139] Example 3

[0140] This embodiment provides a preparation process and performance testing of a multifunctional material for secondary batteries. The specific preparation steps are as follows:

[0141] (1) Weigh lithium hydroxide, the precursor material of the active substance, and granular activated carbon, the carrier material with a particle size Dv50 of 6.2 μm, at a mass ratio of 1:0.36. First, dissolve lithium hydroxide in deionized water to obtain a transparent solution, wherein the mass ratio of deionized water to lithium hydroxide is 15:1.

[0142] (2) Add activated carbon carrier material particles to the transparent solution, place it in a shaking shaker and shake it at a frequency of 80 Hz for 48 hours to obtain a mixed solution.

[0143] (3) Cobalt nitrate particles with a catalyst Dv50 of 30 nm were added to the mixed solution and the mixture was further dispersed by shaking. After being mixed evenly, the mixture was evaporated and dried to obtain a mixture, wherein the mass of cobalt nitrate accounted for 3% of the mass of the mixture.

[0144] (4) Place the mixture in a tube furnace, introduce inert nitrogen gas at a rate of 1 L / min, and heat the atmosphere box furnace to 900°C and keep it at that temperature for 4 hours, so that lithium hydroxide undergoes a chemical reaction to transform into active lithium oxide and obtain agglomerated core material.

[0145] (5) After the heat preservation in step (4) is completed, adjust the temperature of the rotary kiln to 950°C, and then switch the atmosphere to a mixture of argon and acetylene with a volume ratio of 1:2. Continue to keep warm for 3 hours to form a 2nm carbon coating layer on the surface of the agglomerated core material (the thickness of the carbon coating layer is characterized by transmission electron microscopy TEM) to obtain a multifunctional material for secondary batteries with a particle size Dv50 of 12.6μm.

[0146] The carbon content in the multifunctional material for secondary batteries was determined to be 53.3 wt% using a carbon-sulfur analyzer.

[0147] The multifunctional secondary battery material prepared in this embodiment was used as an additive material for the positive electrode active material to prepare a positive electrode sheet with lithium cobalt oxide (LCO), and a lithium half-cell was assembled. Then, the electrochemical performance of the battery was tested. The specific test steps are as follows:

[0148] Preparation of lithium-ion half-cells: The secondary battery prepared in this embodiment was mixed with multifunctional materials, PVDF, SP, and LCO in a mass ratio of 5:5:5:85 to form a slurry, which was then coated onto aluminum foil to prepare a positive electrode sheet. The positive electrode sheet was cut into 14mm round pieces, and then assembled into a CR2032 coin cell using conventional methods with a lithium sheet, a 12μm PE separator, and an electrolyte of 1mol / L lithium hexafluorophosphate (LiPF6) in ethylene carbonate (EC) / dimethyl carbonate (DMC) (the volume ratio of EC to DMC is 1:1).

[0149] Test method: The test was conducted by charging at a rate of 0.1C to 4.6V, then charging at a constant voltage of 4.6V to 0.02C, and finally discharging at a rate of 0.1C to 3V. The charge-discharge test curves for the first week are shown below. Figure 7 As shown in the figure, the battery assembled in Example 3 has a first-week charge specific capacity of 251.5 mAh / g and a discharge specific capacity of 213.8 mAh / g.

[0150] Comparative Example 3

[0151] To better illustrate the effects of the embodiments of the present invention, Comparative Example 3 was used as the control group experiment for Example 3:

[0152] The battery assembled in Comparative Example 3 does not contain the multifunctional material for secondary batteries prepared in Example 3. The specific battery preparation process is as follows: lithium cobalt oxide, conductive carbon black and polyvinylidene fluoride are mixed into a slurry in a mass ratio of 90:5:5, and then assembled into a coin cell in the manner of Example 3, and tested according to the same test procedure as in Example 3.

[0153] The charge-discharge curves of the battery assembled in Comparative Example 3 during the first week are as follows: Figure 7 As shown, the charging specific capacity of Comparative Example 3 battery is 232.1 mAh / g, and the discharging specific capacity is 215.7 mAh / g. The charging specific capacity of Example 3 battery is 19.1 mAh / g larger than that of Comparative Example 3 battery, while the discharging specific capacity is basically the same. This indicates that the multifunctional material used in the secondary battery releases more lithium ions during the battery charging process and plays a greater role in providing active lithium ions.

[0154] Example 4

[0155] This embodiment provides a preparation process and performance testing of a multifunctional material for secondary batteries. The specific preparation steps are as follows:

[0156] (1) Weigh sodium oxalate, the precursor material of the active substance, and aluminum foam, a porous metal material with a particle size Dv50 of 8.5 μm, at a mass ratio of 1:0.25. First, dissolve sodium oxalate in deionized water to obtain a transparent solution, wherein the mass ratio of deionized water to sodium oxalate is 30:1.

[0157] (2) Add porous metal foam aluminum to the transparent solution, and then place it in a shaking shaker at a frequency of 80 Hz for 10 hours to disperse it, so as to obtain a mixed solution.

[0158] (3) Platinum black particles with a catalyst Dv50 of 30 nm were added to the mixed solution and the mixture was further dispersed by shaking. After being mixed evenly, the mixture was spray-dried to obtain a mixture, wherein the mass of platinum black accounted for 1% of the mass of the mixture.

[0159] (4) Place the mixture in a rotary kiln, introduce flowing argon and hydrogen gas with a volume ratio of 95:5, and heat the atmosphere box furnace to 980°C and keep it at that temperature for 6 hours, so that sodium oxalate undergoes a chemical reaction to be converted into active sodium oxide, and agglomerated core material is obtained.

[0160] (5) After the heat preservation in step (4) is completed, adjust the temperature of the rotary kiln to 850°C, and then switch the atmosphere to a mixture of carbon source gas methane and argon with a volume ratio of 1:3. Continue to keep it warm for 3 hours to form a 2nm carbon coating layer on the surface of the agglomerated core material (the thickness of the carbon coating layer is characterized by transmission electron microscopy TEM) to obtain a multifunctional material for secondary batteries with a particle size Dv50 of 12.6μm.

[0161] The carbon content in the multifunctional material used in secondary batteries was determined to be 0.7 wt% using a carbon-sulfur analyzer.

[0162] The secondary battery multifunctional material prepared in this embodiment was used as an additive material for the positive electrode active material and sodium nickel iron manganese oxide was used to prepare the positive electrode sheet. A sodium half-cell was then assembled, and the electrochemical performance of the battery was tested. The specific test steps are as follows:

[0163] Preparation of lithium-ion half-cells: The secondary battery functional materials prepared in this embodiment are mixed with PVDF, SP and sodium nickel iron manganese oxide cathode materials in a mass ratio of 5:5:5:85 to form a slurry, which is then coated on aluminum foil to prepare a cathode sheet. The cathode sheet is cut into 14mm round pieces, and then assembled into CR2032 coin cells with sodium sheet, 12μm PE separator and 1mol / L sodium hexafluorophosphate NaPF6 in an electrolyte of ethylene carbonate (EC) / dimethyl carbonate (DMC) (the volume ratio of EC to DMC is 1:1) according to conventional methods.

[0164] Test method: The test was conducted following a procedure of charging to 4.0V at a 0.1C rate, then charging at 4.0V constant voltage to 0.02C, and finally discharging to 2V at a 0.1C rate. The charge / discharge test curves for the first week are shown below. Figure 8 As shown in the figure, the battery assembled in Example 4 has a first-week charge specific capacity of 130.9 mAh / g and a discharge specific capacity of 109.8 mAh / g.

[0165] Comparative Example 4

[0166] To better illustrate the effects of the embodiments of the present invention, Comparative Example 4 was used as the control group experiment for Example 4:

[0167] The battery assembled in Comparative Example 4 does not contain the multifunctional material for secondary batteries prepared in Example 4. The specific battery preparation process is as follows: sodium nickel iron manganese oxide, conductive carbon black and polyvinylidene fluoride are mixed into a slurry in a mass ratio of 90:5:5, and then assembled into a coin cell in the manner of Example 4, and tested according to the same test procedure as in Example 4.

[0168] The charge-discharge curves of the battery assembled in Comparative Example 4 during the first week are as follows: Figure 8 As shown, the charging specific capacity of Comparative Example 4 battery is 124.4 mAh / g, and the discharging specific capacity is 110.1 mAh / g. The charging specific capacity of Example 4 battery is 6.5 mAh / g larger than that of Comparative Example 4 battery, while the discharging specific capacity is basically the same. This indicates that the multifunctional material used in the secondary battery releases more sodium ions during the battery charging process, thus playing a significant role in providing active sodium ions.

[0169] Comparative Example 5

[0170] To better illustrate the effects of the embodiments of the present invention, Comparative Example 5 was used as the control group for Example 4. The specific steps for preparing the functional material in Comparative Example 5 are as follows:

[0171] (1) Weigh sodium oxalate, the precursor material of the active substance, and aluminum foam, a porous metal material with a particle size Dv50 of 8.5 μm, at a mass ratio of 1:0.25. First, dissolve sodium oxalate in deionized water to obtain a transparent solution, wherein the mass ratio of deionized water to sodium oxalate is 30:1.

[0172] (2) Add porous metal foam aluminum to the transparent solution, and then place it in a shaking shaker at a frequency of 80 Hz for 10 hours to disperse it, so as to obtain a mixed solution.

[0173] (3) The mixed solution is spray-dried to obtain a mixture of materials, and sodium oxalate is adsorbed in the pores and on the surface of porous aluminum foam as a functional material.

[0174] The secondary battery multifunctional material prepared in this embodiment was used as an additive material for the positive electrode active material and sodium nickel iron manganese oxide was used to prepare the positive electrode sheet. The sodium half-cell was then assembled and the electrochemical performance of the battery was tested. The battery assembly process and the testing process were the same as in Example 4.

[0175] The charge-discharge curves of the battery assembled in Comparative Example 5 during the first week are as follows: Figure 8As shown, the charging specific capacity of Comparative Example 5 is 128.8 mAh / g, and the discharging specific capacity is 110.0 mAh / g, which is basically the same as the discharging capacity of Example 4. However, the charging capacity is 2.1 mAh / g smaller than that of Example 4 and 4.4 mAh / g larger than that of Comparative Example 4. This indicates that although the functional material prepared in Comparative Example 5 can provide more active sodium ions during the first week of charging, its ability to provide active sodium ions is less than that of the multifunctional material for secondary batteries in Example 4.

[0176] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multifunctional material for secondary batteries, characterized in that, The multifunctional material for the secondary battery includes: a core and a shell; The core comprises composite particles and catalyst particles; the composite particles comprise: carrier material particles, active material, and catalyst particles attached to the surface of the carrier. The active substance is attached to the surface of the carrier material particles to form an active substance coating layer; the active substance coating layer is in the form of closely arranged particles and / or a thin film. The catalyst particles are uniformly distributed between the composite particles and / or embedded on the surface of the carrier material particles; The outer shell is a carbon coating layer; The active material includes any one of lithium oxide, sodium oxide, lithium sulfide, and sodium sulfide; The catalyst particles include at least one of the following: elemental or compound elements of iron, cobalt, nickel, copper, zinc, chromium, palladium, cadmium, silver, gold, platinum, and rhodium, or alloys of the aforementioned metals. The carrier material particles include one or more of the following: carbon materials, ceramic materials, metallic materials, and polymer materials; The carbon materials include one or more of the following: carbon black, carbon microspheres, graphite, hard carbon, activated carbon, carbon fiber, carbon nanotubes, acetylene black, fullerene, and graphene. The ceramic material includes one or more of the following: alumina, magnesium oxide, zirconium oxide, titanium oxide, silicon carbide, silicon nitride, silicon oxide, cordierite, silicates, aluminosilicates, and aluminum titanate; The metallic materials include one or more of the following: elemental aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, and zinc, or alloys of the aforementioned metals. The polymeric materials include one or more of the following: polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamine, polyoxymethylene, polyoxymethylene, polyphosphate, styrene-butadiene rubber, nitrile rubber, polymethyl methacrylate, epoxy resin, phenolic resin, polyurethane, polycarbonate, and polytetrafluoroethylene. The secondary battery uses a multifunctional material as an additive to supplement active ions.

2. The multifunctional material for secondary batteries according to claim 1, characterized in that, The carrier material particles have a porous structure; the pore size of the carrier material particles is between 0.1 nm and 10 μm. The active substance adheres to the surface and pores of the carrier material particles, forming an active substance coating layer.

3. The multifunctional material for secondary batteries according to claim 1, characterized in that, The particle size Dv50 of the multifunctional material for the secondary battery is 10nm-100μm; The particle size Dv50 of the carrier material is 1nm-50μm; The active material coating layer consists of closely packed particles with a particle size Dv50 between 0.1 nm and 10 μm, or a thin film with a thickness of 0.1 nm to 10 μm. The particle size Dv50 of the catalyst particles is 0.1 nm-5 μm; The carbon coating layer is one or more layers of uniformly distributed continuous carbon film or carbon particle layer; the thickness of the carbon coating layer is 1 nm-10 μm.

4. The multifunctional material for secondary batteries according to claim 1, characterized in that, The active material accounts for 20%-96% of the total mass of the multifunctional material for secondary batteries; The mass of the catalyst particles accounts for 0.1%-8% of the total mass of the multifunctional material for secondary batteries; The mass of the carrier material particles accounts for 2%-80% of the total mass of the multifunctional material for secondary batteries; the mass of the carbon coating layer accounts for 0.5%-10% of the total mass of the multifunctional material for secondary batteries.

5. A method for preparing a multifunctional material for secondary batteries according to any one of claims 1-4, characterized in that, The preparation method includes: Weigh the carrier material particles and the precursor material of the active substance in proportion, and first dissolve the precursor material of the active substance in a solvent to obtain a transparent solution; Carrier material particles are added to a transparent solution and dispersed in a dispersion device to obtain a mixed solution; The catalyst particles are added to the mixed solution and dispersed further. After being mixed evenly, the mixture is dried to obtain the final mixture. The mixture is sintered in a protective atmosphere to obtain an agglomerated core material; Carbon coating is applied to the aggregated core material to form an outer shell, resulting in a multifunctional material for secondary batteries.

6. The preparation method according to claim 5, characterized in that, The precursor materials of the active substance include one or more of the following: lithium hydroxide, lithium carbonate, lithium nitrate, lithium sulfate, lithium acetate, lithium oxalate, sodium hydroxide, sodium carbonate, sodium acetate, sodium oxalate, and sodium sulfite. The catalyst particles include at least one of the following: elemental or compound elements of iron, cobalt, nickel, copper, zinc, chromium, palladium, cadmium, silver, gold, platinum, and rhodium, or alloys of the aforementioned metals. The carrier material particles include one or more of the following: carbon materials, ceramic materials, metallic materials, and polymer materials; The carbon materials include one or more of the following: carbon black, carbon microspheres, graphite, hard carbon, activated carbon, carbon fiber, carbon nanotubes, acetylene black, fullerene, and graphene. The ceramic material includes one or more of the following: alumina, magnesium oxide, zirconium oxide, titanium oxide, silicon carbide, silicon nitride, silicon oxide, cordierite, silicates, aluminosilicates, and aluminum titanate; The metallic materials include one or more of the following: elemental aluminum, copper, iron, silver, titanium, nickel, tungsten, cobalt, molybdenum, platinum, magnesium, lead, and zinc, or alloys of the aforementioned metals. The polymeric materials include one or more of the following: polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamine, polyoxymethylene, polyoxymethylene, polyphosphate, styrene-butadiene rubber, nitrile rubber, polymethyl methacrylate, epoxy resin, phenolic resin, polyurethane, polycarbonate, and polytetrafluoroethylene. The solvent includes one or more of the following: deionized water, ethanol, diethyl ether, acetone, N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), ethyl acetate, benzene, and chloroform. The mass ratio of the solvent to the precursor material of the active substance is 2:1 to 200:

1.

7. The preparation method according to claim 5, characterized in that, The protective atmosphere is any one or a mixture of nitrogen, argon, helium or hydrogen atmosphere. The dispersion treatment method includes one or more of the following: vibration dispersion, stirring dispersion, ultrasonic dispersion, and ball milling dispersion; the dispersion treatment equipment includes one or more of the following: a shaking table, a mixer, an ultrasonic disperser, or a ball mill; the dispersion treatment time is between 0.5 hours and 72 hours. The drying method includes one or more of the following: rotary evaporation drying, stirring and heating drying, spray drying, vacuum heating drying, and filtration followed by forced air drying; the drying temperature is 60℃-300℃, and the time is 0.5 hours-48 hours. The sintering temperature is 450℃-1400℃, and the holding time is 0.5 hours-20 hours.

8. The preparation method according to claim 5, characterized in that, The carbon coating treatment method is gas phase carbon coating or solid phase carbon coating; The carbon source gas for gaseous carbon coating includes one or more of methane, acetylene, propane, and propyne. The carbon source material for solid-phase carbon coating includes one or more of glucose, sucrose, fructose, asphalt, starch, and polyethylene glycol.

9. A secondary battery, characterized in that, The secondary battery includes the multifunctional material for secondary batteries as described in any one of claims 1-4.

Images