Ion-electron mixed conductor material and preparation method and application thereof

Abstract

The invention relates to an ion-electron mixed conductor material and a preparation method and application thereof. The material comprises a multivalent oxide ion-electron mixed conductor and a carbon coating layer outside the multivalent oxide ion-electron mixed conductor. The chemical general formula of the multivalent oxide is AxGyJzDuEhO6X, wherein 0 < x < = 3, 0 < y < 5 / 3, 0 < = z < = 2, 0 < = u < = 2, 0 < = h < = 2, and z + u + h = 2; a is Li < + >, Na < + > and / or K < + >; g is a + 2 and / or + 3 valent cation; j, D and E are positive ions which take + 4, + 5 and + 6 valence as main valence states and have various reduction valence states, and at least one element in J, D and E simultaneously coexists with at least one reduction valence state in the main valence state of J, D and E; x is halogen or OH <->. The material has oxygen vacancies, and an element A is doped in holes of the carbon coating layer. According to the invention, the electronic conductivity is improved while high ionic conductivity is maintained, and the problem of insufficient electronic conductivity of an oxide electrolyte in an electrode material is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of electrode materials technology, and in particular to an ion-electron hybrid conductor material, its preparation method, and its application. Background Technology

[0002] In the development of battery technology, electrolyte materials, as one of the core components of batteries, directly affect the overall performance and safety of the battery. For example, traditionally, lithium-ion batteries mainly rely on organic liquid electrolytes. However, these electrolytes pose safety hazards such as flammability and volatility, limiting their application in high-safety-requirement fields such as large-scale energy storage and electric vehicles. Therefore, inorganic solid electrolytes, due to their non-flammability, wide electrochemical window, and potential compatibility with high-energy-density lithium metal anodes, have become a hot topic in the research and development of next-generation high-energy-density lithium batteries.

[0003] Among inorganic solid electrolytes, oxide electrolytes, such as lithium lanthanum zirconium oxide (LLZO), lithium lanthanum titanium oxide (LLTO), and lithium titanium aluminum phosphate (LATP), have attracted much attention due to their high ionic conductivity and are often used as electrolyte layers in batteries to effectively transport lithium ions and isolate electrons. However, when oxide electrolytes such as LLZO are attempted to be used in positive and negative electrode materials, their low electronic conductivity becomes a limiting factor. Positive and negative electrode materials not only need good ionic conductivity to support the rapid migration of lithium ions, but also need high electronic conductivity to ensure efficient electron transport, thereby achieving high power output and long cycle life of the battery. Low electronic conductivity of the electrolyte will hinder electron transport, increase the internal resistance of the battery, and reduce battery performance.

[0004] In existing technologies, although various methods have been attempted to improve the electronic conductivity of electrolyte materials, it is often difficult to achieve a significant increase in electronic conductivity while maintaining high ionic conductivity. Many methods, while introducing electronic conductivity, inevitably reduce ionic conductivity, or the degree of introduction of electronic conductivity is limited, failing to achieve sufficiently high electronic conductivity to meet the requirements of both positive and negative electrode materials. This "trading one for the other" phenomenon has become one of the key technical challenges restricting battery development. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a hybrid ionic-electronic conductor material, its preparation method, and its applications. The ionic-electronic hybrid conductor material provided by this invention retains the advantage of high ionic conductivity while improving electronic conductivity, effectively solving the problem of insufficient electronic conductivity when oxide electrolytes are used in positive and negative electrode materials.

[0006] To achieve the above objectives, in a first aspect, the present invention provides an ion-electron hybrid conductor material, the ion-electron hybrid conductor material comprising: a multivalent oxide ion-electron conductor material and a carbon coating layer covering the multivalent oxide ion-electron hybrid conductor material;

[0007] The chemical formula of the multivalent oxide ion-electron hybrid conductor material is A. x G y J z D u E h O6X; 0<x≤3, 0<y<5 / 3; 0≤z≤2, 0≤u≤2, 0≤h≤2, z+u+h=2;

[0008] A is Li + Na + or K + One or more of the following;

[0009] G is a +2 and / or +3 cation;

[0010] J is a cation with a predominantly +4 valence state and a reducing valence state with +3 and / or +2 valence states;

[0011] D is a cation with a predominantly +5 valence state and also has a reducing valence state of +4 and / or +3 and / or +2.

[0012] E is a cation with a predominantly +6 valence state, and also has reducing valence states of +5, +4, +3 and / or +2.

[0013] In A x G y J z D u E h In O6X, at least one of J, D and E coexists simultaneously with its principal valence state and at least one reduced valence state.

[0014] X is F - Cl - ,Br - I - or OH - One or more of the following;

[0015] The multivalent oxide ion-electron hybrid conductor material has oxygen vacancies, and the pores of the carbon coating layer are doped with element A.

[0016] Preferably, G is one or more of Sr, Ca, Mg, Ba, Zn, Al, Ga, In, La, Sc, Y, or lanthanides; J is one or more of Zr, Ti, Hf, Si, Ge, or Sn; D is one or more of Nb, Sb, Bi, V, or Ta; and E is one or more of W, Cr, Mo, or Mn.

[0017] Preferably, 0.5≤z≤1, 0.2≤u≤1, and 0.2≤h≤1.

[0018] In a second aspect, the present invention provides a method for preparing the ion-electron hybrid conductor material described in the first aspect above, the method comprising:

[0019] According to the general chemical formula A x G y J z D u E h The molar ratio of each element in O6X is used to mix and mill the A source, G source, J source, D source, E source, X source and the first solvent to obtain the first mixed slurry; wherein, 0 < x ≤ 3, 0 < y < 5 / 3; 0 ≤ z ≤ 2, 0 ≤ u ≤ 2, 0 ≤ h ≤ 2, z + u + h = 2;

[0020] The first mixed slurry was spray-dried to obtain the first precursor material;

[0021] The first precursor material is pre-sintered in an oxygen-containing atmosphere at a heating rate of 1℃ / min-20℃ / min to 300℃-800℃, held for 1h-12h, and then cooled to obtain the pre-sintered material.

[0022] The pre-sintered material is mixed with a second solvent and milled once. Then, a polymer and an alkali metal A salt are added and milled again to coat the surface of the pre-sintered material with the polymer and the alkali metal A salt, thus obtaining a second mixed slurry.

[0023] The second mixed slurry is spray-dried to obtain the second precursor material;

[0024] The second precursor material is subjected to sintering treatment, which includes two stages:

[0025] In the first stage, under an oxygen-free atmosphere, the temperature is increased to 600℃-1400℃ at a heating rate of 1℃ / min-20℃ / min and held for 1h-5h. During the sintering process, the pre-sintered material forms a multivalent oxide ion-electron hybrid conductor material. The polymer undergoes carbonization, forming a carbon coating layer on the surface of the multivalent oxide ion-electron hybrid conductor. Simultaneously, the reducing substances generated by the carbonization of the polymer cause some oxygen atoms in the multivalent oxide ion-electron hybrid conductor material to detach from their original positions, forming oxygen vacancies, and causing at least one element (J, D, or E) to undergo a partial reduction reaction, thus allowing both the primary and reduced valence states to coexist in the material. Simultaneously, the small molecule gas released during the thermal decomposition of the polymer during carbonization forms nanoscale pores in the carbon coating layer. The alkali metal A released during the thermal decomposition of the salt containing alkali metal A diffuses and embeds into the pores.

[0026] In the second stage, the temperature is maintained at 600℃-1400℃, an organic gas source is introduced, and the temperature is maintained for 1h-20h to further densify the carbon coating layer and enhance its conductivity, and to regulate the pore structure in the carbon coating layer. After cooling, an ion-electron hybrid conductor material is obtained.

[0027] Preferably, the G source is one or more cationic compounds with a +2 and / or +3 valence, and the G is one or more of Sr, Ca, Mg, Ba, Zn, Al, Ga, In, La, Sc, Y or lanthanides;

[0028] The J source is one or more of a +4 valent cationic compound, wherein J is one or more of Zr, Ti, Hf, Si, Ge or Sn;

[0029] The D source is one or more of a +5 valent cationic compound, and D is one or more of Nb, Sb, Bi, V or Ta;

[0030] The E source is one or more of a +6 valent cationic compound, and the E is one or more of W, Cr, Mo or Mn;

[0031] The A source is a compound containing A, including one or more of lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, sodium hydroxide, sodium oxalate, sodium acetate, potassium carbonate, potassium hydroxide, potassium oxalate, or potassium acetate.

[0032] The salt containing alkali metal A includes one or more of the following: lithium carbonate, lithium hydroxide, lithium acetate, lithium oxalate, lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium difluorooxalateborate (LiDFOB), sodium carbonate, sodium hydroxide, sodium oxalate, sodium acetate, potassium carbonate, potassium hydroxide, potassium oxalate, or potassium acetate.

[0033] X is F - Jl - ,Br - I - OH - One or more of the following, wherein the X source is a compound containing X, including: lanthanum fluoride, lithium fluoride, ammonium fluoride, titanium fluoride, hydrogen fluoride, calcium fluoride, potassium fluoride, sodium fluoride, magnesium fluoride, potassium fluorozirconate, ammonium fluorozirconate, potassium fluorotitanate, ammonium fluorotitanate, potassium fluoroaluminate, fluorozirconic acid, fluorotitanic acid, fluorosilicic acid, strontium fluoride, chromium fluoride, ammonium chloride, barium fluoride, lithium chloride, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, titanium tetrachloride, ammonium bromide, lithium bromide, sodium bromide, potassium bromide, or magnesium bromide;

[0034] The polymers include one or more of the following: polyacrylic acid, polymethyl methacrylate, polyacrylonitrile, polyethylene oxide, polyethylene glycol, polyvinylidene fluoride, polycarbonate, polyethylene, polypropylene, polyvinyl chloride, styrene-butadiene rubber, or cellulose and their derivatives.

[0035] The first solvent includes one or more of the following: deionized water, ethanol, N-methylpyrrolidone (NMP), isopropanol, or acetone;

[0036] The second solvent includes one or more of deionized water, ethanol, NMP, isopropanol, or acetone.

[0037] Preferably, the equipment used for sand milling is selected from any one of sand mill, stirred mill, air jet mill, three-roll mill, ball mill or high-speed disc disperser; the sand milling media used for sand milling is selected from one or more of glass beads, steel beads, zirconium silicate beads or zirconium oxide beads; wherein, the diameter of the sand milling media is 0.05mm-1mm;

[0038] The grinding speed is 1000rpm-3000rpm, and the grinding time is 1h-10h.

[0039] The equipment used for spray drying is selected from either an open spray dryer or a closed spray dryer.

[0040] The inlet temperature of the spray dryer is 180℃-260℃, and the outlet temperature is 60℃-120℃.

[0041] The sintering equipment used for pre-sintering the first precursor material and sintering the second precursor material is selected from any one of box furnace, tube furnace, pusher furnace, roller kiln, rotary furnace or fluidized bed.

[0042] The oxygen-containing atmosphere includes either air or oxygen.

[0043] The oxygen-free atmosphere includes one or more of nitrogen, argon, or an argon-hydrogen mixture containing no more than 5% hydrogen by volume.

[0044] The organic gas source includes one or more of ethane, acetylene, ethylene, propylene, or methane.

[0045] Preferably, the small molecule gas includes one or more of CO, CO2, H2O, or NH3.

[0046] Preferably, the solid content of the first mixed slurry is 5wt%-60wt%;

[0047] The mass of the polymer is 0.5wt%-10wt% of the mass of the pre-sintered material, and the mass of the metal salt containing A is 10wt%-50wt% of the mass of the polymer.

[0048] The solid content of the second mixed slurry is 5wt%-50wt%.

[0049] Thirdly, the present invention provides an application of an ion-electron hybrid conductor material, wherein at least one of the positive electrode, negative electrode, and electrode interface layer contains the ion-electron hybrid conductor material described in the first aspect above, or contains the ion-electron hybrid conductor material prepared by the preparation method described in the second aspect above.

[0050] Fourthly, the present invention provides a battery, wherein the battery pack is an ion battery, a metal battery, or a solid-state battery;

[0051] The battery comprises the ion-electron hybrid conductor material described in the first aspect above, or the ion-electron hybrid conductor material prepared by the preparation method described in the second aspect above.

[0052] The ion-electron hybrid conductor material provided in this invention comprises: a multivalent oxide ion-electron hybrid conductor material and a carbon coating layer covering the multivalent oxide ion-electron hybrid conductor material. On one hand, the formation of the carbon coating layer on the surface of the multivalent oxide ion-electron hybrid conductor material creates an electronic conductivity network, improving the material's electronic conductivity. Furthermore, at least one metal element exists simultaneously in both its primary and reduced states in the multivalent oxide ion-electron hybrid conductor material, and the presence of oxygen vacancies, along with the presence of both the primary and reduced states of the same metal element, increases the electron concentration, further enhancing the material's electronic conductivity. On the other hand, alkali metal elements are doped into the pores of the carbon coating layer, constructing excellent ion conduction channels within the carbon coating layer, which can improve ion conductivity. Therefore, the ion-electron hybrid conductor material provided by this invention retains the advantage of high ion conductivity while improving electronic conductivity. Batteries containing the ion-electron hybrid conductor material provided in the embodiments of the present invention have both high ion conductivity and high electronic conductivity. This material can be used in composite positive electrodes, composite negative electrodes and electrode interface layers in batteries, and can be applied to various battery devices such as ion batteries, metal batteries or solid-state batteries. Attached Figure Description

[0053] Figure 1 A flowchart illustrating the preparation method of the ion-electron hybrid conductor material provided in this embodiment of the invention. Detailed Implementation

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

[0055] The reagents and materials used in the following examples and comparative examples are all commercially available conventional reagent products, or can be prepared by conventional methods. Where specific experimental steps or conditions are not specified in the examples, they were performed according to conventional experimental steps and conditions in the art. Unless otherwise specified, all equipment used is conventional equipment currently available in the art.

[0056] This invention provides an ion-electron hybrid conductor material, comprising a multivalent ion-electron hybrid conductor material and a carbon coating layer encapsulating the multivalent oxide ion-electron hybrid conductor material. The general chemical formula of the multivalent ion-electron hybrid conductor material is A. x G y J z D u E h O6X; 0 < x ≤ 3, 0 < y < 5 / 3; 0 ≤ z ≤ 2, 0 ≤ u ≤ 2, 0 ≤ h ≤ 2, z + u + h = 2. Where A, G, J, D, and E need to satisfy the following conditions:

[0057] A is Li + Na + or K + One or more of the following;

[0058] G is a +2 and / or +3 cation;

[0059] J is a cation with a predominantly +4 valence state and a reducing valence state with +3 and / or +2 valence states;

[0060] D is a cation with a predominantly +5 valence state and also has a reducing valence state of +4 and / or +3 and / or +2.

[0061] E is a cation with a predominantly +6 valence state, and also has reducing valence states of +5, +4, +3 and / or +2.

[0062] In A x G y J z D u E h In O6X, at least one of J, D and E coexists simultaneously with its principal valence state and at least one reduced valence state.

[0063] X is F - Cl - ,Br - I - or OH - One or more of the following;

[0064] Multivalent oxide ion-electron hybrid conductor materials have oxygen vacancies, and the carbon coating layer contains A elements within its pores.

[0065] Wherein, G is one or more of Sr, Ca, Mg, Ba, Zn, Al, Ga, In, La, Sc, Y or lanthanides; J is one or more of Zr, Ti, Hf, Si, Ge or Sn; D is one or more of Nb, Sb, Bi, V or Ta; and E is one or more of W, Cr, Mo or Mn.

[0066] Preferably, 0.5≤z≤1, 0.2≤u≤1, and 0.2≤h≤1.

[0067] The ion-electron hybrid conductor material provided in this invention is a solid electrolyte material, comprising a multivalent oxide ion-electron hybrid conductor material and a carbon coating layer covering it. On one hand, the carbon coating layer formed on the surface of the multivalent oxide ion-electron hybrid conductor material creates an electronic conductivity network, improving the material's electronic conductivity. On the other hand, at least one metal element exists simultaneously in both its primary and reduced states within the multivalent oxide ion-electron hybrid conductor material, and oxygen vacancies are present within the material. The presence of oxygen vacancies and different valence states of the same metal element increases the electron concentration, promotes electron transfer, and further enhances the material's electronic conductivity. On the other hand, alkali metal elements are doped into the pores of the carbon coating layer, constructing ion conduction channels within the carbon coating layer and improving ion conductivity. This demonstrates that the ion-electron hybrid conductor material provided in this invention introduces electronic conductivity in two ways, ultimately forming an ion-electron dual-channel transport network, retaining the advantage of high ion conductivity while improving electronic conductivity. Batteries containing the ion-electron hybrid conductor material provided in the embodiments of the present invention have both high ion conductivity and high electronic conductivity. This material can be used in composite positive electrodes, composite negative electrodes and electrode interface layers in batteries, and can be applied to various battery devices such as ion batteries, metal batteries or solid-state batteries.

[0068] The aforementioned ion-electron hybrid conductor material can be prepared by the following method, specifically as follows: Figure 1 As shown, the main steps include:

[0069] Step 110, according to general chemical formula A x G y J z D u E h The molar ratio of each element in O6X is used to mill source A, source G, source J, source D, source E, source X and the first solvent to obtain the first mixed slurry.

[0070] Among them, 0<x≤3, 0<y<5 / 3; 0≤z≤2, 0≤u≤2, 0≤h≤2, z+u+h=2.

[0071] Source A is a compound containing A, including one or more of the following: lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, sodium hydroxide, sodium oxalate, sodium acetate, potassium carbonate, potassium hydroxide, potassium oxalate, or potassium acetate.

[0072] The source of G is one or more of a +2 and / or +3 valent cation compound, and G is one or more of Sr, Ca, Mg, Ba, Zn, Al, Ga, In, La, Sc, Y or a lanthanide element.

[0073] J source is one or more of a +4 valent cation compound, where J is one or more of Zr, Ti, Hf, Si, Ge, or Sn.

[0074] The source D is one or more of a +5 valent cation compound, where D is one or more of Nb, Sb, Bi, V, or Ta.

[0075] The E source is one or more of a +6 valent cation compound, where E is one or more of W, Cr, Mo, or Mn.

[0076] X is F - Cl - ,Br - I - or OH - One or more of the following, wherein the source X is a compound containing X, including: lanthanum fluoride, lithium fluoride, ammonium fluoride, titanium fluoride, hydrogen fluoride, calcium fluoride, potassium fluoride, sodium fluoride, magnesium fluoride, potassium fluorozirconate, ammonium fluorozirconate, potassium fluorotitanate, ammonium fluorotitanate, potassium fluoroaluminate, fluorozirconic acid, fluorotitanic acid, fluorosilicic acid, strontium fluoride, chromium fluoride, ammonium chloride, barium fluoride, lithium chloride, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, titanium tetrachloride, ammonium bromide, lithium bromide, sodium bromide, potassium bromide, or magnesium bromide.

[0077] The first solvent includes one or more of the following: deionized water, ethanol, N-methylpyrrolidone (NMP), isopropanol, or acetone.

[0078] The ion-electron hybrid conductor material prepared by this invention is a solid electrolyte. The purpose of this step is to break up the agglomeration of raw material particles through mechanical force, mix the raw materials evenly and refine the particles, providing an active interface for subsequent solid-phase reactions and avoiding impurities in the product phase due to component segregation. In the sand milling process, the equipment used is selected from any one of a sand mill, stirred mill, air jet mill, three-roll mill, ball mill, or high-speed disc disperser; the milling media used is selected from one or more of glass beads, steel beads, zirconium silicate beads, or zirconium oxide beads; wherein the diameter of the milling media is 0.05 mm-1 mm.

[0079] Furthermore, during the sand milling process, the preferred process parameters are: a sand milling speed of 1000 rpm to 3000 rpm, a sand milling time of 1 h to 10 h, and a solid content of 5 wt% to 60 wt% in the first mixed slurry.

[0080] Step 120: Spray dry the first mixed slurry to obtain the first precursor material.

[0081] The purpose of this step is to improve the fluidity of the material, which facilitates subsequent sintering, and at the same time reduce agglomeration. In this step, the equipment used for spray drying is selected from either an open spray dryer or a closed spray dryer, preferably a closed spray dryer.

[0082] Furthermore, in this step, during the spray drying process, the preferred process parameters are: the inlet temperature of the spray dryer is 180℃-260℃, and the outlet temperature is 60℃-120℃.

[0083] Step 130: The first precursor material is pre-sintered by heating it to 300℃-800℃ in an oxygen-containing atmosphere at a heating rate of 1℃ / min-20℃ / min, holding it at that temperature for 1h-12h, and then cooling it to obtain the pre-sintered material.

[0084] The purpose of pre-sintering is to initiate solid-phase reactions between raw materials, combining them into a whole, and preventing particle separation during the sand milling process in step 140, which would lead to component segregation and impurity in the product phase. This step is carried out in an oxidizing environment to promote the oxidation and removal of low-valence impurities while avoiding excessive reduction of high-valence elements. In this step, the equipment used for pre-sintering is selected from any one of a box furnace, tube furnace, pusher furnace, roller kiln, rotary kiln, or fluidized bed; the oxygen-containing atmosphere includes air or oxygen. In step 130, compressed air or compressed oxygen is introduced, meaning that pre-sintering is carried out in an air atmosphere or an oxygen atmosphere.

[0085] Step 140: The pre-sintered material is mixed with the second solvent and milled. Then, a polymer and an alkali metal A salt are added and milled again to coat the surface of the pre-sintered material with the polymer and the alkali metal A salt, thus obtaining a second mixed slurry.

[0086] In this step, the added polymer is 0.5wt%-10wt% of the mass of the pre-sintered material, while the salt containing alkali metal A is 10wt%-50wt% of the mass of the polymer.

[0087] The second solvent includes one or more of the following: deionized water, ethanol, NMP, isopropanol, or acetone.

[0088] Salts containing alkali metal A include one or more of the following: lithium carbonate, lithium hydroxide, lithium acetate, lithium oxalate, lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium difluorooxalateborate (LiDFOB), sodium carbonate, sodium hydroxide, sodium oxalate, sodium acetate, potassium carbonate, potassium hydroxide, potassium oxalate, or potassium acetate.

[0089] The polymers include one or more of the following: polyacrylic acid, polymethyl methacrylate, polyacrylonitrile, polyethylene oxide, polyethylene glycol, polyvinylidene fluoride, polycarbonate, polyethylene, polypropylene, polyvinyl chloride, styrene-butadiene rubber, or cellulose and their derivatives.

[0090] In this step, the pre-sintered material formed by sintering the first precursor material is first dispersed by sand milling. The purpose is to reduce the particle size of the pre-sintered material and to achieve uniform dispersion in the solvent, that is, to further refine the particles and mix them uniformly, breaking up any particle agglomeration that may form during pre-sintering, ensuring the exposure of surface active sites, and providing a foundation for the subsequent preparation of the carbon coating layer. A polymer and an alkali metal A-containing salt are added and the sand milling continues. The purpose is to coat the surface of the pre-sintered material with the polymer and the alkali metal A-containing salt. The polymer serves as a carbon source precursor, which is subsequently carbonized to form a conductive carbon layer, while the alkali metal A-containing salt provides the alkali metal ions required for ion conduction channels. In this step, the sand milling equipment used for the two sand milling processes can be the same or different, and can be selected from any of the following: sand mill, stirred mill, air jet mill, three-roll mill, ball mill, or high-speed disc disperser, preferably a sand mill. The abrasive media used in the two abrasive milling processes can be the same or different. Preferably, the abrasive media used in the abrasive milling process are selected from one or more of glass beads, steel beads, zirconium silicate beads or zirconium oxide beads. The diameter of the abrasive media is 0.05mm-1mm.

[0091] Furthermore, during the sand milling process, the preferred process parameters are: a milling speed of 1000 rpm to 3000 rpm and a milling time of 1 hour to 10 hours. It should be noted that the milling speed and milling time can be the same or different for two milling cycles.

[0092] The final second mixed slurry has a solids content of 5wt%-50wt%.

[0093] Step 150: Spray dry the second mixed slurry to obtain the second precursor material.

[0094] The purpose of this step is to transform the coated slurry into a second precursor material, forming core-shell structured particles. This ensures that the carbon source and the alkali metal A salt are uniformly coated on the surface of the core material, providing a structural basis for subsequent sintering. In this step, the spray drying equipment is selected from either an open spray dryer or a closed spray dryer, preferably a closed spray dryer. It should be noted that the types of drying equipment used in steps 120 and 150 can be the same or different.

[0095] Furthermore, in this step, the inlet temperature of the spray dryer is 180℃-260℃, and the outlet temperature is 60℃-120℃.

[0096] Step 160: The second precursor material is sintered to obtain an ion-electron hybrid conductor material.

[0097] In this step, the sintering equipment used is selected from any one of the following: box furnace, tube furnace, pusher furnace, roller kiln, rotary furnace, or fluidized bed furnace. It may be the same as or different from the sintering equipment used in pre-sintering. Specifically, the sintering process in this step includes two stages:

[0098] In the first stage, under an oxygen-free atmosphere, the temperature is increased to 600℃-1400℃ at a heating rate of 1℃ / min-20℃ / min, and held for 1h-5h. The purpose of the first-stage sintering is to carbonize the polymer and the alkali metal A-containing salt thermal decomposition. During the sintering process, the pre-sintered material forms a multivalent oxide ion-electron mixed conductor material, while the polymer undergoes a series of complex chemical reactions upon heating (e.g., decomposition, dehydrogenation, cyclization, etc.), ultimately forming carbonized products and a carbon coating layer on the surface of the multivalent oxide-ion mixed conductor material. Carbon materials possess a certain degree of electronic conductivity, which helps to improve the electronic conductivity of the material.

[0099] During the carbonization process, polymer molecules release small molecule gases (such as CO, CO2, H2O, and NH3) through thermal decomposition. These gases, as they escape, create nanoscale pores within the carbon coating. Furthermore, the carbonized material contains reducing agents that remove oxygen ions from the material, creating oxygen vacancies. Simultaneously, these reducing agents cause partial reduction reactions of at least one metal element (J, D, or E), resulting in the simultaneous presence of both the dominant and reduced states of that metal element within the material. The presence of oxygen vacancies and both the dominant and reduced states of the same metal element increases the electron concentration, further enhancing the material's electronic conductivity.

[0100] During high-temperature sintering, the salt containing alkali metal A releases alkali metal elements through thermal decomposition. These alkali metal elements diffuse and embed into the pores, thereby constructing good ion conduction channels within the carbon coating layer and improving the ionic conductivity of the material.

[0101] It should be noted that an oxygen-free environment is required during the first stage of sintering to prevent the carbon layer from being oxidized. The oxygen-free gas includes one or more of nitrogen, argon, or an argon-hydrogen mixture with a volume ratio not exceeding 5%. Furthermore, the grain growth rate is closely related to high temperature; the higher the temperature, the easier it is for the grains to grow. In traditional sintering processes, high external heating temperatures are often required to reach the reaction temperature, which easily leads to rapid grain growth. However, in the preparation method provided in this embodiment of the invention, the heat released during the carbonization of the polymer reduces the external heating temperature required for the multivalent oxide ion-electron hybrid conductor material. That is, the exothermic reaction from the carbonization of the polymer provides some of the reaction heat for the multivalent oxide ion-electron hybrid conductor material, thereby reducing the need for external heating temperature. Sintering is carried out at a relatively lower temperature, weakening the driving force for grain growth. Because grain growth is a thermally activated process, lower temperatures slow down the atomic diffusion rate, indirectly slowing down the grain size growth of the multivalent oxide ion-electron hybrid conductor material. In addition, after the carbon coating layer is formed, it will coat the surface of the multivalent oxide ion-electron hybrid conductor material particles. This carbon coating acts as a physical barrier, limiting direct contact and aggregation between particles, thereby inhibiting further particle growth; in other words, the carbon coating can also inhibit particle size growth.

[0102] Smaller grain size helps increase the specific surface area of ​​a material, increasing the contact area between the material and ions and electrons, thereby improving the material's ion-electron mixed conductivity. At the same time, smaller grains can reduce the obstruction of grain boundaries to ion and electron transport, improving the overall conductivity of the material.

[0103] In the second stage of sintering, the temperature is maintained at 600℃-1400℃, an organic gas source is introduced, and the temperature is held. The purpose of the second stage of sintering is the thermal decomposition of the organic gas source. At high temperatures, the organic gas source undergoes a thermal decomposition reaction, generating various small molecules, such as hydrocarbon fragments, carbon monoxide, and hydrogen. Simultaneously, some solid or semi-solid carbonaceous residues may also be produced. These carbonaceous residues deposit on the surface of the existing carbon coating layer and in its internal pores. As carbon continues to deposit, the originally relatively loose carbon coating layer structure is gradually filled, making the carbon coating layer denser.

[0104] The carbon atoms produced by the decomposition of organic gas increase the content of conductive carbon in the carbon coating layer, which means an increase in conductive channels, thereby reducing the resistance of the carbon coating layer and improving its conductivity.

[0105] Furthermore, the substances produced by the thermal decomposition of organic gas sources can interact with carbon atoms in the carbon coating layer, promoting the reconstruction of the carbon layer structure. Active carbon atoms or groups from the decomposition of organic gas sources can participate in the growth and arrangement of the carbon coating layer, forming new carbon-carbon bonds and thus altering its microstructure. This structural change affects the connectivity and distribution of pores; some previously interconnected pores may become partially closed due to the reconstruction of the carbon coating layer, or new connecting channels may form, thereby regulating the pore structure.

[0106] In summary, sintering in this step consists of two stages:

[0107] In the first sintering stage, through the sintering process, the pre-sintered material forms a multivalent oxide ion-electron hybrid conductor material; the polymer undergoes carbonization, forming a carbon coating layer on the surface of the multivalent oxide ion-electron hybrid conductor material; simultaneously, the reducing substances generated by the carbonization of the polymer cause some oxygen atoms in the multivalent oxide ion-electron hybrid conductor material to detach from their original positions to form oxygen vacancies, and cause at least one element among J, D, or E to undergo a partial reduction reaction, thus resulting in the simultaneous existence of the main valence state and the reduced state in the material; at the same time, the small molecule gas released by the thermal decomposition of the polymer during the carbonization process forms nanoscale pores in the carbon coating layer; the alkali metal A released by the thermal decomposition of the salt containing alkali metal A diffuses and embeds itself in the pores.

[0108] In the second stage, the temperature is maintained at 600℃-1400℃, an organic gas source is introduced, and the temperature is maintained for 1h-20h to further densify the carbon coating layer and enhance its conductivity, and to regulate the pore structure in the carbon coating layer. After cooling, an ion-electron hybrid conductor material is obtained.

[0109] The method for preparing ion-electron hybrid conductor materials provided by this invention has several aspects. Firstly, by carbonizing a polymer, a carbon coating layer is formed on the surface of the multivalent oxide ion-electron hybrid conductor material, creating an electronic conductive network and improving the material's electronic conductivity. Secondly, the reducing substances formed during carbonization reduce at least one metal element in the multivalent oxide ion-electron hybrid conductor material from a high-valence state to a low-valence state, allowing the main valence state and the reduced state to coexist. Simultaneously, the reducing substances cause oxygen atoms within the material to detach from their original positions, forming oxygen vacancies. The presence of oxygen vacancies and different valence states of the same metal element increases the electron concentration, promotes electron transfer, and further improves the material's electronic conductivity. Thirdly, the alkali metal element released from the thermal decomposition of an alkali metal A salt at high temperatures diffuses and embeds into the pores of the carbon coating layer, constructing ion-conducting channels within the carbon coating layer and improving ion conductivity. Finally, the carbon atoms generated from the thermal decomposition of an organic gas source at high temperatures make the carbon coating layer more compact and increase the content of conductive carbon in the carbon coating layer, thereby improving its electronic conductivity. The final result is a material possessing both high ionic conductivity and high electronic conductivity. Specifically, the ion-electron hybrid conductor material prepared by the method provided in this invention improves electronic conductivity while retaining the advantage of high ionic conductivity. When applied to batteries, this material enables the battery to possess both high ionic conductivity and high electronic conductivity. The ion-electron hybrid conductor material prepared by this invention can be used in composite positive electrodes, composite negative electrodes, and electrode interface layers in batteries, specifically in various battery devices such as ion batteries, metal batteries, or solid-state batteries.

[0110] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0111] Example 1

[0112] (1) According to the molecular formula Li 1.5 Al 0.63 Ti 0.7 NbW 0.3 The molar ratios of various elements in O6F were extracted from lithium carbonate, aluminum oxide, titanium dioxide, niobium pentoxide, tungsten trioxide, and ammonium fluoride. These were then added to a sand mill with ethanol for the first sand milling and mixing, resulting in a first mixed slurry with a solid content of 30 wt%. The specific conditions for the first sand milling were: 0.3 mm zirconia balls as the milling media, a milling time of 3 hours, and a milling speed of 2000 rpm.

[0113] (2) The first mixed slurry is dried by a closed spray dryer to obtain the first precursor material. The specific drying conditions are: the inlet temperature is 200℃ and the outlet temperature is 80℃.

[0114] (3) The first precursor material is placed in a box furnace and heated to 600°C at a heating rate of 5°C / min under air atmosphere. The temperature is held for 5 hours and then cooled to obtain the pre-sintered material.

[0115] (4) The pre-sintered material was mixed with ethanol, and then milled a second time in a sand mill. Polyvinyl alcohol and Li TFSI were then added to the sand mill for a third milling to ensure thorough mixing with the pre-sintered material, resulting in a second mixed slurry with a solid content of 20 wt%. The mass of polyvinyl alcohol was 2 wt% of the pre-sintered material, and the mass of lithium salt Li TFSI was 15 wt% of the polyvinyl alcohol. The specific conditions for the second milling were: milling for 4 hours, using 0.2 mm zirconia balls as the milling medium, and a milling speed of 2200 rpm. The specific conditions for the third milling were: milling for 3 hours, using 0.2 mm zirconia balls as the milling medium, and a milling speed of 2200 rpm.

[0116] (5) The second mixed slurry is passed through a closed spray drying device to obtain the second precursor material. The specific drying conditions are: inlet temperature of 200℃ and outlet temperature of 80℃.

[0117] (6) The second precursor material is placed in a box furnace and heated to 850°C at a heating rate of 8°C / min. It is then kept at this temperature in nitrogen for 3 hours, followed by ethylene infusion for 5 hours. After cooling, the ion-electron hybrid conductor material is obtained.

[0118] Example 2

[0119] (1) According to the molecular formula Li 1.5 La 0.63 Ti 0.7 NbW 0.3 The molar ratios of various elements in O6F were extracted from lithium carbonate, lanthanum oxide, titanium dioxide, niobium pentoxide, tungsten trioxide, and ammonium fluoride. These were then added to a sand mill with deionized water for the first sand milling and mixing, yielding a first mixed slurry with a solid content of 40 wt%. The specific conditions for the first sand milling were: 0.3 mm zirconia balls as the milling media, a milling time of 3 hours, and a milling speed of 2000 rpm.

[0120] (2) The first mixed slurry is passed through a closed spray drying device to obtain the first precursor material. The specific drying conditions are: the inlet temperature is 180℃ and the outlet temperature is 100℃.

[0121] (3) The first precursor material is placed in a box furnace and heated to 300°C at a heating rate of 1°C / min under air atmosphere and held for 10 hours. After cooling, the pre-sintered material is obtained.

[0122] (4) The pre-sintered material was mixed with ethanol, and then milled a second time in a sand mill. Polyvinyl alcohol and Li TFSI were then added to the sand mill for a third milling to ensure thorough mixing with the pre-sintered material, resulting in a second mixed slurry with a solid content of 30 wt%. The mass of polyvinyl alcohol was 4 wt% of the pre-sintered material, and the mass of lithium salt Li TFSI was 10 wt% of the polyvinyl alcohol. The specific conditions for the second milling were: milling for 4 hours, using 0.2 mm zirconia balls as the milling medium, and a milling speed of 2200 rpm. The specific conditions for the third milling were: milling for 3 hours, using 0.2 mm zirconia balls as the milling medium, and a milling speed of 2200 rpm.

[0123] (5) The second mixed slurry is passed through a closed spray drying device to obtain the second precursor material. The specific drying conditions are: the inlet temperature is 180℃ and the outlet temperature is 100℃.

[0124] (6) The second precursor material is placed in a box furnace and heated to 600°C at a heating rate of 15°C / min. It is then kept at this temperature in nitrogen for 5 hours, followed by acetylene infusion for 20 hours. After cooling, the ion-electron hybrid conductor material is obtained.

[0125] Example 3

[0126] (1) According to the molecular formula Li 1.5 La 0.63 Zr 0.7 NbW 0.3 The molar ratios of various elements in O6Cl were extracted from lithium carbonate, lanthanum oxide, zirconium dioxide, niobium pentoxide, tungsten trioxide, and ammonium chloride. These were then added to a sand mill with deionized water for the first sand milling and mixing to obtain a first mixed slurry with a solid content of 30 wt%. The specific conditions for the first sand milling were: 1 mm zirconium oxide balls as the milling media, a milling time of 5 hours, and a milling speed of 1500 rpm.

[0127] (2) The mixed slurry is passed through a closed-loop spray dryer to obtain the first precursor material. The specific drying conditions are: inlet temperature of 200℃ and outlet temperature of 80℃.

[0128] (3) The first precursor material is placed in a box furnace and heated to 300°C at a heating rate of 10°C / min under air atmosphere and held for 12 hours. After cooling, the pre-sintered material is obtained.

[0129] (4) The pre-sintered material was mixed with deionized water, and then milled a second time in a sand mill. Polyvinyl alcohol and Li TFSI were then added to the sand mill, and milling continued a third time to ensure thorough mixing with the pre-sintered material, resulting in a second mixed slurry with a solid content of 40 wt%. The mass of polyvinyl alcohol was 1 wt% of the pre-sintered material, and the mass of lithium salt Li TFSI was 20 wt% of the polyvinyl alcohol. The specific conditions for the second milling were: milling for 4 hours, using 0.8 mm zirconia balls as the milling medium, and a milling speed of 2500 rpm. The specific conditions for the third milling were: milling for 2 hours, using 0.8 mm zirconia balls as the milling medium, and a milling speed of 2500 rpm.

[0130] (5) The second mixed slurry is passed through a closed spray drying device to obtain the second precursor material. The specific drying conditions are: inlet temperature of 200℃ and outlet temperature of 80℃.

[0131] (6) The second precursor material is placed in a box furnace and heated to 1000°C at a heating rate of 12°C / min. It is then kept at this temperature in nitrogen for 2 hours, followed by acetylene infusion for 5 hours. After cooling, the ion-electron hybrid conductor material is obtained.

[0132] Example 4

[0133] (1) According to the molecular formula Li 1.5 La 0.5 The molar ratios of various elements in ZrNbO6F were extracted from lithium carbonate, lanthanum oxide, zirconium dioxide, niobium pentoxide, and ammonium fluoride. These were then added to a sand mill with deionized water for the first sand milling mixing, yielding a first mixed slurry with a solid content of 5 wt%. The specific conditions for the first sand milling were: 0.3 mm zirconium oxide balls as the milling media, a milling time of 3 hours, and a milling speed of 2000 rpm.

[0134] (2) The first mixed slurry is passed through a closed spray drying device to obtain the first precursor material. The specific drying conditions are: the inlet temperature is 260℃ and the outlet temperature is 120℃.

[0135] (3) The first precursor material is placed in a box furnace and heated to 800°C in an oxygen atmosphere at a heating rate of 20°C / min. The temperature is held for 5 hours and then cooled to obtain the pre-sintered material.

[0136] (4) The pre-sintered material was mixed with deionized water, and then milled a second time in a sand mill. Polyvinyl alcohol and Li TFSI were then added to the sand mill, and milling continued a third time to ensure thorough mixing with the pre-sintered material, resulting in a second mixed slurry with a solid content of 5 wt%. The mass of polyvinyl alcohol was 3 wt% of the pre-sintered material, and the mass of lithium salt Li TFSI was 40 wt% of the polyvinyl alcohol. The specific conditions for the second milling were: milling for 4 hours, using 0.2 mm zirconia balls as the milling medium, and a milling speed of 2200 rpm. The specific conditions for the third milling were: milling for 3 hours, using 0.2 mm zirconia balls as the milling medium, and a milling speed of 2200 rpm.

[0137] (5) The second mixed slurry is passed through a closed spray drying device to obtain the second precursor material. The specific drying conditions are: inlet temperature of 260℃ and outlet temperature of 120℃.

[0138] (6) The second precursor material is placed in a box furnace and heated to 1200°C at a heating rate of 15°C / min. It is then kept at this temperature in nitrogen for 1 hour, followed by acetylene infusion for 10 hours. After cooling, the ion-electron hybrid conductor material is obtained.

[0139] Example 5

[0140] (1) Take out lithium carbonate, lanthanum oxide, titanium dioxide and ammonium fluoride according to the molar ratio of each element in the molecular formula Li2LaTi2O6F, and then put them into a sand mill with deionized water for the first sand milling and mixing to obtain a first mixed slurry with a solid content of 30wt%. The specific conditions for the first sand milling are: the sand milling medium is 0.05mm zirconia balls, the sand milling time is 8h, and the sand milling speed is 1000rpm.

[0141] (2) The first mixed slurry is passed through a closed spray drying equipment to obtain the first precursor material; the drying conditions are as follows: the inlet temperature is 200℃ and the outlet temperature is 80℃.

[0142] (3) The first precursor material is placed in a box furnace and heated to 800°C in an oxygen atmosphere at a heating rate of 2°C / min. The temperature is held for 1 hour and then cooled to obtain the pre-sintered material.

[0143] (4) The pre-sintered material was mixed with deionized water and then milled for the first time in a sand mill. Polyvinyl alcohol and LiTFSI were then added to the sand mill, and a third milling was performed to ensure thorough mixing with the pre-sintered material, resulting in a second mixed slurry with a solid content of 20 wt%. The mass of polyvinyl alcohol was 0.05 wt% of the pre-sintered material, and the mass of lithium salt LiTFSI was 30 wt% of the polyvinyl alcohol. The specific conditions for the second milling were: milling for 2 hours, using 0.1 mm zirconia balls as the milling medium, and a milling speed of 3000 rpm. The specific conditions for the third milling were: milling for 1 hour, using 0.1 mm zirconia balls as the milling medium, and a milling speed of 3000 rpm.

[0144] (5) The second mixed slurry is passed through a closed spray drying device to obtain the second precursor material. The specific drying conditions are: inlet temperature of 200℃ and outlet temperature of 80℃.

[0145] (6) The second precursor material is placed in a box furnace and heated to 1000°C at a heating rate of 1°C / min. It is kept at this temperature in nitrogen for 1 hour, and then acetylene is introduced and kept at this temperature for 5 hours. After cooling, the ion-electron hybrid conductor material is obtained.

[0146] Example 6

[0147] (1) According to the molecular formula Na 1.5 Al 0.63 Ti 0.7 NbW 0.3 The molar ratios of various elements in O6F were determined by extracting sodium carbonate, aluminum oxide, titanium dioxide, niobium pentoxide, tungsten trioxide, and ammonium fluoride. These were then added to a sand mill with ethanol for the first sand milling and mixing, yielding a first mixed slurry with a solid content of 20 wt%. The specific conditions for the first sand milling were: 0.3 mm zirconia balls as the milling media, a milling time of 4 hours, and a milling speed of 2300 rpm.

[0148] (2) The first mixed slurry is passed through a closed spray drying equipment to obtain the first precursor material; the drying conditions are as follows: the inlet temperature is 220℃ and the outlet temperature is 60℃.

[0149] (3) The first precursor material is placed in a box furnace and heated to 700°C at a heating rate of 12°C / min under air atmosphere. The temperature is held for 10 hours and then cooled to obtain the pre-sintered material.

[0150] (4) The pre-sintered material is mixed with ethanol, and then milled a second time in a sand mill. Polyvinyl alcohol and sodium oxalate are then added to the sand mill and milled a third time to ensure thorough mixing with the pre-sintered material, resulting in a second mixed slurry with a solid content of 20 wt%. The mass of polyvinyl alcohol is 10 wt% of the pre-sintered material, and the mass of lithium salt sodium oxalate is 5 wt% of the polyvinyl alcohol. The specific conditions for the second milling are: milling for 4 hours, milling media is 0.2 mm zirconia balls, and milling speed is 2200 rpm. The specific conditions for the third milling are: milling for 3 hours, milling media is 0.2 mm zirconia balls, and milling speed is 2200 rpm. (5) The second mixed slurry is passed through a closed spray drying device to obtain the second precursor material. The specific drying conditions are: inlet temperature is 220℃, and outlet temperature is 60℃.

[0151] (6) The second precursor material is placed in a box furnace and heated to 1400°C at a heating rate of 20°C / min. It is then kept at this temperature in nitrogen for 3 hours, followed by ethylene infusion for 1 hour. After cooling, the ion-electron hybrid conductor material is obtained.

[0152] Example 7

[0153] (1) According to the molecular formula K 1.5 Al 0.63 Ti 0.7 NbW 0.3 The molar ratios of various elements in O6F were taken out as follows: potassium carbonate, aluminum oxide, titanium dioxide, niobium pentoxide, tungsten trioxide, and ammonium fluoride. These were then added to a sand mill with ethanol for the first sand milling and mixing to obtain a first mixed slurry with a solid content of 60 wt%. The specific conditions for the first sand milling were: 0.2 mm zirconia balls as the milling media, 10 h for the milling time, and 1200 rpm for the milling speed.

[0154] (2) The mixed slurry is passed through a closed-loop spray drying equipment to obtain the first precursor material. The specific drying conditions are: the inlet temperature is 200℃ and the outlet temperature is 80℃.

[0155] (3) The first precursor material is placed in a box furnace and heated to 700°C at a heating rate of 5°C / min under air atmosphere. The temperature is held for 5 hours and then cooled to obtain the pre-sintered material.

[0156] (4) The pre-sintered material is mixed with ethanol, and then milled a second time in a sand mill. Polyvinyl alcohol and potassium oxalate are then added to the sand mill, and milling is performed a third time to ensure thorough mixing with the pre-sintered material, resulting in a second mixed slurry with a solid content of 50 wt%. The mass of polyvinyl alcohol is 5 wt% of the pre-sintered material, and the mass of potassium oxalate is 50 wt% of the polyvinyl alcohol. The specific conditions for the second milling are: milling for 10 hours, milling media of 0.2 mm zirconia balls, and milling speed of 1000 rpm. The specific conditions for the third milling are: milling for 10 hours, milling media of 0.2 mm zirconia balls, and milling speed of 1000 rpm.

[0157] (5) The second mixed slurry is dried by a closed spray drying equipment. The specific drying conditions are: the inlet temperature is 200℃ and the outlet temperature is 80℃.

[0158] (6) The second precursor material is placed in a box furnace and heated to 800°C at a heating rate of 10°C / min. It is then kept at this temperature for 4 hours in argon gas, followed by ethylene gas and kept at this temperature for 10 hours. After cooling, the ion-electron hybrid conductor material is obtained.

[0159] Comparative Example 1

[0160] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 did not add the polymer polyvinyl alcohol and lithium salt Li TFSI in step (4), the sintering process was carried out in an air atmosphere, and the sintering in step (6) only had the first stage of sintering. The material prepared did not have a carbon coating layer and multivalent metals.

[0161] (1) According to the molecular formula Li 1.5 Al 0.63 Ti 0.7 NbW 0.3 The molar ratios of various elements in O6F were extracted from lithium carbonate, aluminum oxide, titanium dioxide, niobium pentoxide, tungsten trioxide, and ammonium fluoride. These were then added to a sand mill with ethanol for the first sand milling and mixing, resulting in a first mixed slurry with a solid content of 30 wt%. The specific conditions for the first sand milling were: 0.3 mm zirconia balls as the milling media, a milling time of 3 hours, and a milling speed of 2000 rpm.

[0162] (2) The first mixed slurry is dried by a closed spray dryer to obtain the first precursor material. The specific drying conditions are: the inlet temperature is 200℃ and the outlet temperature is 80℃.

[0163] (3) The first precursor material is placed in a box furnace and heated to 600°C at a heating rate of 5°C / min under air atmosphere. The temperature is held for 5 hours and then cooled to obtain the pre-sintered material.

[0164] (4) The pre-sintered material is mixed with ethanol, and then subjected to a second sand milling to obtain a second mixed slurry. The specific conditions for the second sand milling are: sand milling for 4 hours, sand milling media being 0.2 mm zirconia balls, and sand milling speed being 2200 rpm.

[0165] (5) The second mixed slurry is passed through a closed spray drying device to obtain the second precursor material. The specific drying conditions are: inlet temperature of 200℃ and outlet temperature of 80℃.

[0166] (6) The second precursor material is placed in a box furnace and heated to 850°C at a heating rate of 8°C / min. It is kept in air for 6 hours and then cooled to obtain the target powder.

[0167] Comparative Example 2

[0168] The difference between Comparative Example 2 and Example 1 is that Comparative Example 2 did not add the polymer polyvinyl alcohol and lithium salt Li TFSI in step (4), but the final sintering step only had the first stage sintering, and it was carried out in a reducing atmosphere. The material prepared did not have a carbon coating layer, but it had the main valence state and the reduced valence state of the same metal element.

[0169] (1) According to the molecular formula Li 1.5 Al 0.63 Ti 0.7 NbW 0.3 The molar ratios of various elements in O6F were extracted from lithium carbonate, aluminum oxide, titanium dioxide, niobium pentoxide, tungsten trioxide, and ammonium fluoride. These were then added to a sand mill with ethanol for the first sand milling and mixing, resulting in a first mixed slurry with a solid content of 30 wt%. The specific conditions for the first sand milling were: 0.3 mm zirconia balls as the milling media, a milling time of 3 hours, and a milling speed of 2000 rpm.

[0170] (2) The first mixed slurry is passed through a closed spray drying device to obtain the first precursor material. The specific drying conditions are: the inlet temperature is 200℃ and the outlet temperature is 80℃.

[0171] (3) The first precursor material is placed in a box furnace and heated to 600°C at a heating rate of 5°C / min under air atmosphere. The temperature is held for 5 hours and then cooled to obtain the pre-sintered material.

[0172] (4) The pre-sintered material is mixed with ethanol, and then a second sand milling is performed to obtain a second mixed slurry. The specific conditions for the second sand milling are: sand milling for 4 hours, sand milling media are 0.2 mm zirconia balls, and sand milling speed is 2200 rpm.

[0173] (5) The second mixed slurry is passed through a closed spray drying device to obtain the second precursor material. The specific drying conditions are: inlet temperature of 200℃ and outlet temperature of 80℃.

[0174] (6) The second precursor material is placed in a box furnace and heated to 850°C at a heating rate of 8°C / min. It is then kept at this temperature for 6 hours in an argon-hydrogen mixture and cooled to obtain the target powder.

[0175] Comparative Example 3

[0176] The difference between Comparative Example 3 and Example 1 is that no lithium salt Li TFSI was added in step (4) of Comparative Example 3. The material prepared has a carbon coating layer, but no lithium is present in the carbon coating layer.

[0177] (1) According to the molecular formula Li 1.5 Al 0.63 Ti 0.7 NbW 0.3 The molar ratios of various elements in O6F were extracted from lithium carbonate, aluminum oxide, titanium dioxide, niobium pentoxide, tungsten trioxide, and ammonium fluoride. These were then added to a sand mill with ethanol for the first sand milling and mixing, resulting in a first mixed slurry with a solid content of 30 wt%. The specific conditions for the first sand milling were: 0.3 mm zirconia balls as the milling media, a milling time of 3 hours, and a milling speed of 2000 rpm.

[0178] (2) The mixed slurry is passed through a closed-loop spray drying equipment to obtain the first precursor material. The specific drying conditions are: the inlet temperature is 200℃ and the outlet temperature is 80℃.

[0179] (3) The first precursor material is placed in a box furnace and heated to 600°C in air atmosphere at a heating rate of 5°C / min. The temperature is held for 5 hours and then cooled to obtain the pre-sintered material.

[0180] (4) The pre-sintered material is mixed with ethanol, and then milled a second time in a sand mill. Polyvinyl alcohol is then added to the sand mill for a third milling process to ensure thorough mixing with the pre-sintered material, resulting in a second mixed slurry. The mass of polyvinyl alcohol is 2 wt% of the pre-sintered material, and milling continues for 3 hours. The specific conditions for the second milling are: milling for 4 hours, using 0.2 mm zirconia balls as the milling medium, and a milling speed of 2200 rpm. The specific conditions for the third milling are: milling for 3 hours, using 0.2 mm zirconia balls as the milling medium, and a milling speed of 2200 rpm.

[0181] (5) The second mixed slurry is passed through a closed spray drying device to obtain the second precursor material. The specific drying conditions are: inlet temperature of 200℃ and outlet temperature of 80℃.

[0182] (6) The second precursor material is placed in a box furnace and heated to 850°C at a heating rate of 8°C / min. It is then kept at this temperature in nitrogen for 3 hours, followed by ethylene infusion for 5 hours. After cooling, the target powder is obtained.

[0183] The properties of the materials prepared in the above embodiments and comparative examples were characterized.

[0184] First, the ionic conductivity and electronic conductivity of the materials obtained in step (6) of each of the above embodiments and comparative examples are tested as target powders.

[0185] Ionic conductivity:

[0186] Take 5g of the prepared powder. Using a 15mm diameter mold, apply a pressure of 15MPa in a benchtop powder press, hold for 20 minutes, and then demold to obtain a thin sheet. Place the thin sheet in a sintering furnace, heat to 1300℃ at a rate of 5℃ / min, and hold for 20 hours. This will yield a ceramic sheet of the target powder. Gently polish the surface of the ceramic sheet with 1000-grit sandpaper moistened with alcohol using a cross-grit method to remove surface impurities and ensure uniform thickness of the electrolyte at all locations. Measure the thickness L of the ceramic sheet using calipers, deposit a gold-plated blocking electrode using an ion sputtering apparatus, and test the ionic conductivity using AC impedance spectroscopy. Record the test data in Table 1.

[0187] Electron conductivity:

[0188] Based on the principle of the four-probe method for testing the electronic conductivity of powder, the electronic conductivity of the target powder was tested. 10g of the target powder was added to a powder resistance tester for testing. A pressure of 300MPa was applied, and the electronic conductivity of the sample was tested. The test data was recorded in Table 1.

[0189]

[0190] Table 1

[0191] According to the data in Table 1, compared with Comparative Example 1, the ionic conductivity of the materials obtained in Comparative Example 1 and Example 1 is not significantly different. However, the electronic conductivity of Comparative Example 1 is very low. This is mainly because no polymer was added to Comparative Example 1, and the sintering was carried out under compressed air. Because no polymer was added, a carbon coating layer could not be formed on the material surface, and an electronic conductivity network could not be formed. Furthermore, sintering in an oxygen-containing atmosphere prevented the reduction of high-valence metal elements, thus failing to increase the electron concentration and consequently, the electronic conductivity.

[0192] Compared to Example 1, Comparative Example 2 showed little difference in ionic conductivity, but its electronic conductivity was significantly lower. This was mainly because no polymer was added, resulting in the absence of a carbon coating layer on the surface and consequently, lower electronic conductivity compared to Example 1. However, the final sintering step was performed under a reducing atmosphere, which partially reduced high-valence metal elements to low-valence states. Furthermore, some oxygen atoms in the material detached from their situ, forming oxygen vacancies. The presence of these oxygen vacancies and different valence states of the same metal element increased the electron concentration and improved the electronic conductivity of the material. Therefore, Comparative Example 2 exhibited a substantial increase in electronic conductivity compared to Comparative Example 1.

[0193] Compared with Example 1, the electronic conductivity of the materials obtained in Comparative Example 3 and Example 1 is not much different. However, the ionic conductivity of Comparative Example 3 is very low. This is because no lithium salt was added when adding the polymer to Comparative Example 3, resulting in a carbon coating layer on the surface of the sintered material. However, the carbon coating layer does not contain lithium metal elements and fails to form a good ion conduction channel. Therefore, the ionic conductivity is significantly lower than that of Example 1. However, the addition of the polymer can form a carbon coating layer on the surface of the material, forming an electronic conduction network, which makes the electronic conductivity significantly higher than that of Comparative Example 1 and Comparative Example 2.

[0194] The preparation method provided by this invention yields an ion-electron hybrid conductor material that retains the advantage of high ion conductivity while improving electronic conductivity. When applied in batteries, this material enables the battery to possess both high ion conductivity and high electronic conductivity. The ion-electron hybrid conductor material prepared by this invention can be used in composite positive electrodes, composite negative electrodes, and electrode interface layers in batteries, specifically in various battery devices such as ion batteries, metal batteries, or solid-state batteries.

[0195] 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. An ion-electron hybrid conductor material, characterized in that, The ion-electron hybrid conductor material includes: a multivalent oxide ion-electron hybrid conductor material and a carbon coating layer covering the multivalent oxide ion-electron hybrid conductor material; The chemical formula of the multivalent oxide ion-electron hybrid conductor material is A. x G y J z D u E h O6X; 0<x≤3, 0<y<5 / 3; 0≤z≤2, 0≤u≤2, 0≤h≤2, z+u+h=2; A is Li + Na + or K + One or more of the following; G is a +2 and / or +3 cation; J is a cation with a predominantly +4 valence state and also has a reducing valence state of +3 and / or +2. D is a cation with a predominantly +5 valence state and also has a reducing valence state of +4 and / or +3 and / or +2. E is a cation with a predominantly +6 valence state, and also has reducing valence states of +5, +4, +3 and / or +2. In A x G y J z D u E h In O6X, at least one of J, D and E coexists simultaneously with its principal valence state and at least one reduced valence state. X is F - Cl - ,Br - I - or OH - One or more of the following; The multivalent oxide ion-electron hybrid conductor has oxygen vacancies, and the pores of the carbon coating are doped with element A.

2. The ion-electron hybrid conductor material according to claim 1, characterized in that, G is one or more of Sr, Ca, Mg, Ba, Zn, Al, Ga, In, La, Sc, Y, or lanthanides; J is one or more of Zr, Ti, Hf, Si, Ge, or Sn; D is one or more of Nb, Sb, Bi, V, or Ta; and E is one or more of W, Cr, Mo, or Mn.

3. The ion-electron hybrid conductor material according to claim 1, characterized in that, 0.5≤z≤1, 0.2≤u≤1, 0.2≤h≤1.

4. A method for preparing the ion-electron hybrid conductor material according to any one of claims 1-3, characterized in that, The preparation method includes: According to the general chemical formula A x G y J z D u E h The molar ratio of each element in O6X is used to mix and mill the A source, G source, J source, D source, E source, X source and the first solvent to obtain the first mixed slurry; wherein, 0 < x ≤ 3, 0 < y < 5 / 3; 0 ≤ z ≤ 2, 0 ≤ u ≤ 2, 0 ≤ h ≤ 2, z + u + h = 2; The first mixed slurry is spray-dried to obtain the first precursor material; The first precursor material is pre-sintered in an oxygen-containing atmosphere by heating it to 300℃-800℃ at a heating rate of 1℃ / min-20℃ / min, holding it at that temperature for 1h-12h, and then cooling it to obtain the pre-sintered material. The pre-sintered material is mixed with a second solvent and milled. Then, a polymer and an alkali metal A salt are added and milling is continued to coat the surface of the pre-sintered material with the polymer and the alkali metal A salt to obtain a second mixed slurry. The second mixed slurry is spray-dried to obtain the second precursor material; The second precursor material is subjected to a sintering process, which includes two stages. In the first stage, under an oxygen-free atmosphere, the temperature is increased to 600℃-1400℃ at a heating rate of 1℃ / min-20℃ / min and held for 1h-5h. During the sintering process, the pre-sintered material forms a multivalent oxide ion-electron hybrid conductor material. The polymer undergoes carbonization, forming a carbon coating layer on the surface of the multivalent oxide ion-electron hybrid conductor material. Simultaneously, the reducing substances generated by the carbonization of the polymer cause some oxygen atoms in the multivalent oxide ion-electron hybrid conductor material to detach from their original positions, forming oxygen vacancies, and causing at least one element (J, D, or E) to undergo a partial reduction reaction, thus resulting in the simultaneous presence of both the primary and reduced valence states in the material. Furthermore, the small molecule gases released during the thermal decomposition of the polymer during carbonization form nanoscale pores in the carbon coating layer. The alkali metal A released during the thermal decomposition of the salt containing alkali metal A diffuses and embeds into the pores. In the second stage, the temperature is maintained at 600℃-1400℃, an organic gas source is introduced, and the temperature is maintained for 1h-20h to further densify the carbon coating layer and enhance its conductivity, and to regulate the pore structure in the carbon coating layer. After cooling, an ion-electron hybrid conductor material is obtained.

5. The preparation method according to claim 4, characterized in that, The G source is one or more cationic compounds with a +2 and / or +3 valence, and the G is one or more of Sr, Ca, Mg, Ba, Zn, Al, Ga, In, La, Sc, Y or lanthanides; The J source is one or more of a +4 valent cationic compound, wherein J is one or more of Zr, Ti, Hf, Si, Ge or Sn; The D source is one or more of a +5 valent cationic compound, and D is one or more of Nb, Sb, Bi, V or Ta; The E source is one or more of a +6 valent cationic compound, and the E is one or more of W, Cr, Mo or Mn; The A source is a compound containing A, including one or more of lithium carbonate, lithium hydroxide, lithium oxalate, lithium acetate, sodium hydroxide, sodium oxalate, sodium acetate, potassium carbonate, potassium hydroxide, potassium oxalate, or potassium acetate. The salt containing alkali metal A includes one or more of the following: lithium carbonate, lithium hydroxide, lithium acetate, lithium oxalate, lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium difluorooxalateborate (LiDFOB), sodium carbonate, sodium hydroxide, sodium oxalate, sodium acetate, potassium carbonate, potassium hydroxide, potassium oxalate, or potassium acetate. X is F - Cl - ,Br - I - OH - One or more of the following, wherein the X source is a compound containing X, including: lanthanum fluoride, lithium fluoride, ammonium fluoride, titanium fluoride, hydrogen fluoride, calcium fluoride, potassium fluoride, sodium fluoride, magnesium fluoride, potassium fluorozirconate, ammonium fluorozirconate, potassium fluorotitanate, ammonium fluorotitanate, potassium fluoroaluminate, fluorozirconic acid, fluorotitanic acid, fluorosilicic acid, strontium fluoride, chromium fluoride, ammonium chloride, barium fluoride, lithium chloride, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, titanium tetrachloride, ammonium bromide, lithium bromide, sodium bromide, potassium bromide, or magnesium bromide; The polymers include one or more of the following: polyacrylic acid, polymethyl methacrylate, polyacrylonitrile, polyethylene oxide, polyethylene glycol, polyvinylidene fluoride, polycarbonate, polyethylene, polypropylene, polyvinyl chloride, styrene-butadiene rubber, or cellulose and their derivatives. The first solvent includes one or more of the following: deionized water, ethanol, N-methylpyrrolidone (NMP), isopropanol, or acetone; The second solvent includes one or more of deionized water, ethanol, NMP, isopropanol, or acetone.

6. The preparation method according to claim 4, characterized in that, The equipment used for the sand mill is selected from any one of a sand mill, stirred mill, air jet mill, three-roll mill, ball mill, or high-speed disc disperser; the sand milling media used for the sand mill is selected from one or more of glass beads, steel beads, zirconium silicate beads, or zirconium oxide beads; wherein the diameter of the sand milling media is 0.05mm-1mm. The grinding speed is 1000rpm-3000rpm, and the grinding time is 1h-10h; The equipment used for spray drying is selected from either an open spray dryer or a closed spray dryer. The inlet temperature of the spray dryer is 180℃-260℃, and the outlet temperature is 60℃-120℃. The sintering equipment used for pre-sintering the first precursor material and sintering the second precursor material is selected from any one of box furnace, tube furnace, pusher furnace, roller kiln, rotary furnace or fluidized bed. The oxygen-containing atmosphere includes either air or oxygen. The oxygen-free atmosphere includes one or more of nitrogen, argon, or hydrogen in an argon-hydrogen mixture with a volume ratio not exceeding 5%; The organic gas source includes one or more of ethane, acetylene, ethylene, propylene, or methane.

7. The preparation method according to claim 4, characterized in that, The small molecule gas includes one or more of CO, CO2, H2O, or NH3.

8. The preparation method according to claim 4, characterized in that, The solid content of the first mixed slurry is 5wt%-60wt%; The mass of the polymer is 0.5wt%-10wt% of the mass of the pre-sintered material, and the mass of the metal salt containing A is 10wt%-50wt% of the mass of the polymer. The solid content of the second mixed slurry is 5wt%-50wt%.

9. An application of an ion-electron hybrid conductor material, characterized in that, At least one of the positive electrode, negative electrode, and electrode interface layer contains the ion-electron hybrid conductor material as described in any one of claims 1-3, or contains the ion-electron hybrid conductor material prepared by the preparation method described in any one of claims 4-8.

10. A battery, characterized in that, The battery is an ion battery, a metal battery, or a solid-state battery; The battery comprises the ion-electron hybrid conductor material according to any one of claims 1-3, or the ion-electron hybrid conductor material prepared by the preparation method according to any one of claims 4-8.

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