Zirconium boride ceramic electrode material and preparation method thereof

Abstract

The present invention provides a zirconium boride ceramic electrode material and a preparation method thereof, which belongs to the field of zirconium boride ceramics. The preparation method of the zirconium boride ceramic electrode material consists of the following steps: preparing modified powder, preparing composite fiber material, mixing and molding, and spark plasma sintering. The zirconium boride ceramic electrode material and the preparation method thereof of the present invention can effectively avoid the problem that the doping material affects the overall stability of the zirconium boride ceramic electrode material, and leads to the reduction of the thermal stability and mechanical properties of the zirconium boride ceramic electrode material; improve the brittle defects and thermal cycle stability of the zirconium boride ceramic electrode material, and increase its effective service life.

Description

Technical Field

[0001] The invention relates to the field of zirconium boride ceramics, and in particular to a zirconium boride ceramic electrode material and a preparation method thereof. Background Art

[0002] With the continuous development of science and technology, human society has never stopped pursuing speed and energy. At present, in the fields of lithium batteries, high-speed cutting tools, spacecraft recovery, nuclear energy utilization, etc., due to their special working environment, the performance requirements for materials are getting higher and higher, but the existing traditional single materials can no longer meet the in-depth research and development and application needs in various fields.

[0003] With the continuous deepening of the study of high entropy effect, the exploration and expansion of high entropy materials are also ongoing. In 2015, American scholars first reported a rock salt structure oxide high entropy ceramic. Since then, various high entropy ceramic materials, such as borides, carbides, nitrides, etc. have been discovered; high entropy ceramic materials generally refer to ceramic materials with multiple components. The solid solution coupling effect between the multiple components can make the material have a higher entropy value, thereby effectively improving the phase stability of the ceramic material; at the same time, the significant solid solution strengthening effect can make the ceramic material have the characteristics of high hardness. Among high entropy ceramic materials, transition metal borides with high melting point, high hardness and high stability have received more and more attention and research in the field of high entropy ceramics. Due to its excellent performance, boride high entropy ceramics have good application prospects in special working conditions such as lithium batteries, aerospace, high-speed cutting tools, and nuclear energy utilization.

[0004] Transition metal borides also have high conductivity and electrochemical properties, and have great application potential in the field of electrochemistry. The prior art discloses relevant technical information on the application of zirconium boride ceramic electrodes in lithium-sulfur batteries and lithium-ion batteries; although the conductivity of zirconium boride ceramic electrodes is better than that of traditional ceramic materials, it still cannot meet the application requirements of certain high-conductivity electrodes. In order to further improve the conductivity of zirconium boride ceramic electrodes, the prior art usually dopes graphite materials, conductive metal materials, etc. into zirconium boride ceramic electrodes; although it can improve the conductivity of zirconium boride ceramic electrodes to a certain extent, the doping materials used will introduce interface problems, affecting the overall stability of zirconium boride ceramic electrode materials, and directly leading to reduced thermal stability and mechanical properties of zirconium boride ceramic electrode materials; under thermal cycle conditions, zirconium boride ceramic electrode materials are prone to microcracks and continue to expand, limiting their service life as electrodes.

[0005] At the same time, the existing zirconium boride ceramic electrode materials are very brittle and are prone to brittle fracture when subjected to mechanical stress (such as impact, vibration or thermal stress), which in turn leads to electrode failure. Summary of the invention

[0006] In order to solve the technical problems existing in the prior art, the present invention provides a zirconium boride ceramic electrode material and a preparation method thereof, which can effectively avoid the problem that the doping material affects the overall stability of the zirconium boride ceramic electrode material and causes the thermal stability and mechanical properties of the zirconium boride ceramic electrode material to be reduced; improve the brittle defects and thermal cycle stability of the zirconium boride ceramic electrode material, and increase its effective service life.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing a zirconium boride ceramic electrode material comprises the following steps: preparing a modified powder material, preparing a composite fiber material, mixing and molding, and spark plasma sintering.

[0009] The method for preparing the modified powder comprises the following steps: adding zirconium diboride powder, silicon carbide powder, titanium carbide powder, lanthanum oxide powder, yttrium oxide powder and ethanol solution into a high-energy ball mill, controlling the ball-to-material mass ratio to be 10-11:1, the ball milling speed to be 500-600 rpm, and performing a primary ball milling treatment for 5-6 hours; then spraying a titanate coupling agent GR-102 and tetrabutyl hafnium oxide at the same time, controlling the spraying of the titanate coupling agent GR-102 and the tetrabutyl hafnium oxide to be completed within 20-30 minutes, performing a secondary ball milling treatment for 5-6 hours, and obtaining a ball milled product; transferring the ball milled product into a vacuum drying device, drying at 85-90° C. to a constant weight under a vacuum degree of 0.05-0.06 MPa, and grinding the product evenly to obtain the modified powder.

[0010] In the preparation of the modified powder, the weight ratio of zirconium diboride powder, silicon carbide powder, titanium carbide powder, lanthanum oxide powder, yttrium oxide powder, ethanol solution, titanate coupling agent GR-102, and tetrabutyl hafnium oxide is 55-58:20-21:12-12.5:3-3.3:1.5-1.8:50-53:6-6.5:2.5-3;

[0011] The volume concentration of the ethanol solution is 85-90%.

[0012] The preparation of the composite fiber material comprises the following steps: in-situ composite treatment and in-situ reduction treatment.

[0013] The in-situ composite treatment method comprises the following steps: placing a carbon fiber with a diameter of 8-10 μm in a treatment chamber of a low-temperature plasma device, controlling the low-temperature plasma treatment power to be 400-500 W and the low-temperature plasma treatment frequency to be 11-12 MHz in an argon atmosphere environment, performing the low-temperature plasma treatment for 10-20 minutes, completing the low-temperature plasma treatment, chopping the carbon fiber to 0.8-1 cm, and obtaining pretreated fibers; then putting the pretreated fibers, copper nitrate trihydrate, nickel nitrate hexahydrate, and terephthalic acid into a high-pressure reactor containing N,N-dimethylformamide, stirring for 30-40 minutes, sealing the high-pressure reactor, heating the temperature to 110-120° C. at a heating rate of 0.4-0.6° C. / min, maintaining the temperature for reaction for 22-24 hours, cooling to room temperature, opening the high-pressure reactor to take out the reaction mixture, performing centrifugal separation to obtain solids, and washing the solids with N,N-dimethylformamide and deionized water in turn, and then drying to obtain the in-situ composite.

[0014] In the in-situ composite treatment, the weight ratio of the pretreated fiber, copper nitrate trihydrate, nickel nitrate hexahydrate, terephthalic acid, and N,N-dimethylformamide is 12-13:3-3.3:0.9-1.1:3.5-3.6:60-65.

[0015] The in-situ reduction treatment method comprises the following steps: putting the in-situ composite into deionized water, stirring for 10-20 minutes, heating the mixture to 45-50° C., dripping an ascorbic acid solution having a concentration of 0.1-0.12 mol / L while keeping the temperature, and controlling the dripping time of the ascorbic acid solution to be 50-60 minutes; after the ascorbic acid solution is dripped, continuing to keep the temperature and stir for 3-4 hours, cooling the mixture naturally to room temperature, and centrifuging to obtain a solid, washing the solid with deionized water, and then drying the solid to obtain a composite fiber material.

[0016] In the in-situ reduction treatment, the mass ratio of the in-situ composite, deionized water, and ascorbic acid solution is 11-11.5:100:78-82.

[0017] The mixing and molding method comprises the following steps: putting the modified powder and the composite fiber material into a high-speed mixer, controlling the mixing speed to be 1100-1300 rpm, mixing them evenly, and obtaining a mixture; then transferring the mixture into a mold, sealing it, placing it in a cold isostatic pressing molding machine, controlling the cold isostatic pressing molding pressure to be 200-220 MPa, performing cold isostatic pressing molding for 20-30 minutes, and demolding to obtain a green body.

[0018] In the mixed molding, the weight ratio of the modified powder material to the composite fiber material is 10:1.3-1.4.

[0019] The spark plasma sintering method comprises the following steps: placing a green body in a graphite mold of the same size, and then transferring the green body into a spark plasma sintering device, introducing a mixed gas of nitrogen and argon, adjusting the pressure in the spark plasma sintering device to 33-35 MPa, heating the green body to 1100-1200° C., and sintering the green body at the temperature for 8-10 minutes; further heating the green body to 1700-1750° C., and sintering the green body at the temperature for 8-10 minutes; naturally cooling the green body to room temperature, and demolding the green body to obtain a zirconium boride ceramic electrode material.

[0020] In the spark plasma sintering, the volume ratio of nitrogen to argon in the mixed gas is 1:2-2.5.

[0021] A zirconium boride ceramic electrode material is prepared by the above-mentioned preparation method.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The method for preparing the zirconium boride ceramic electrode material of the present invention comprises the following steps: in the preparation of the modified powder, zirconium diboride powder, silicon carbide powder, titanium carbide powder, lanthanum oxide and yttrium oxide are subjected to primary ball milling treatment, and then ball milling modification (i.e., secondary ball milling treatment) is performed using a titanate coupling agent GR-102 and tetrabutyl hafnium oxide, thereby improving the dispersibility of the powder raw materials and the interface bonding between the raw materials, and improving the mechanical strength, toughness and thermal stability of the zirconium boride ceramic electrode material; at the same time, by reducing the interface resistance, the effective active area of ​​the zirconium boride ceramic electrode is optimized, the electrochemical performance is improved, and the conductivity of the electrode material is improved. In the preparation of composite fiber materials, low-temperature plasma is first used to treat the surface of carbon fiber to improve the surface roughness of carbon fiber, realize surface activation of carbon fiber, and improve the bonding performance of carbon fiber with metal organic framework material in subsequent operation; then the pretreated fiber is contacted with copper nitrate trihydrate, nickel nitrate hexahydrate, and terephthalic acid, and the pretreated fiber is composited with Cu / Ni metal organic framework material in an in-situ composite manner to obtain an in-situ composite; ascorbic acid solution is used as a reducing agent to perform in-situ reduction treatment on the in-situ composite to obtain a carbon fiber material composited with nano-metal clusters; in this process, the Cu / Ni metal organic clusters pre-compounded on the surface of the pretreated fiber are The machine framework material is used as a template, and on the basis of retaining its metal organic framework structure and high specific surface area characteristics, in-situ reduction is performed to obtain uniformly distributed nano metal clusters; it is combined with modified powder for use in the preparation of zirconium boride ceramic electrode materials, while avoiding adverse effects on the overall stability of the zirconium boride ceramic electrode materials, through the conductive network formed by it, the charge transfer performance and conductivity of the zirconium boride ceramic electrode materials are further improved, the effective active area of ​​the zirconium boride ceramic electrode materials is further optimized, and its electrochemical performance is improved; and the mechanical properties, toughness and thermal stability of the zirconium boride ceramic electrode are improved, avoiding the reduction of electrochemical performance caused by possible microcracks or structural damage in thermal cycling conditions. In the mixing molding and spark plasma sintering, the modified powder and the composite fiber material are mixed and molded, and then the zirconium boride ceramic electrode material is prepared; the aforementioned technical means cooperate and work synergistically with each other, which can effectively avoid the problem that the doping material affects the overall stability of the zirconium boride ceramic electrode material, and causes the thermal stability and mechanical properties of the zirconium boride ceramic electrode material to decrease; improve the brittle defects and thermal cycle stability of the zirconium boride ceramic electrode material, and increase its effective service life.

[0024] (2) The zirconium boride ceramic electrode material of the present invention has a Vickers hardness HV of 27.1-27.5 GPa, a fracture toughness of 5.04-5.13 MPa, and a charge / discharge specific capacitance of up to 61.4 / 54.1 F / cm 2 , Coulomb efficiency can reach 94%, and the room temperature resistivity is (2.47-2.61)×10 -7 Ω·m.

[0025] (3) After 20 cycles of rapid temperature change from room temperature to 1000°C, the Vickers hardness HV of the zirconium boride ceramic electrode material of the present invention can still reach 26.4 GPa, the fracture toughness can still reach 4.94 MPa, and the charge / discharge specific capacitance can still reach 60.0 / 52.9 F / cm 2 ; and no cracks appeared in the zirconium boride ceramic electrode material. DETAILED DESCRIPTION

[0026] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described.

[0027] Example 1

[0028] This embodiment provides a method for preparing a zirconium boride ceramic electrode material, specifically:

[0029] 1. Preparation of modified powder

[0030] Zirconium diboride powder, silicon carbide powder, titanium carbide powder, lanthanum oxide powder, yttrium oxide powder and ethanol solution are put into a high-energy ball mill, the ball-to-material mass ratio is controlled to be 10:1, the ball milling speed is 500rpm, and the primary ball milling treatment is carried out for 5 hours; then, titanate coupling agent GR-102 and tetrabutyl hafnium oxide are sprayed at the same time, and the spraying of titanate coupling agent GR-102 and tetrabutyl hafnium oxide is controlled to be completed within 20 minutes, and the secondary ball milling treatment is carried out for 5 hours to obtain a ball-milled product; the ball-milled product is transferred to a vacuum drying device, dried at 85°C to constant weight under a vacuum degree of 0.05MPa, and ground evenly to obtain a modified powder.

[0031] Among them, the weight ratio of zirconium diboride powder, silicon carbide powder, titanium carbide powder, lanthanum oxide powder, yttrium oxide powder, ethanol solution, titanate coupling agent GR-102, and tetrabutyl hafnium oxide is 55:20:12:3:1.5:50:6:2.5.

[0032] The volume concentration of the ethanol solution is 85%.

[0033] 2. Preparation of composite fiber materials

[0034] 1) In-situ composite treatment

[0035] A carbon fiber with a diameter of 9 μm is placed in a treatment chamber of a low-temperature plasma device. In an argon atmosphere environment, the low-temperature plasma treatment power is controlled to be 400 W, the low-temperature plasma treatment frequency is controlled to be 11 MHz, and the low-temperature plasma treatment is performed for 10 minutes. After the low-temperature plasma treatment is completed, the carbon fiber is chopped to 0.8 cm to obtain pretreated fibers; then the pretreated fibers, copper nitrate trihydrate, nickel nitrate hexahydrate, and terephthalic acid are put into a high-pressure reactor filled with N,N-dimethylformamide, and after stirring for 30 minutes, the high-pressure reactor is sealed and heated to 110°C at a heating rate of 0.4°C / min. After the reaction is kept warm for 22 hours, it is cooled to room temperature, the high-pressure reactor is opened to take out the reaction mixture, and solid matter is obtained by centrifugal separation. The solid matter is washed with N,N-dimethylformamide and deionized water in turn and then dried to obtain an in-situ composite.

[0036] The weight ratio of the pretreated fiber, copper nitrate trihydrate, nickel nitrate hexahydrate, terephthalic acid and N,N-dimethylformamide is 12:3:0.9:3.5:60.

[0037] 2) In-situ reduction treatment

[0038] The in-situ composite was put into deionized water, stirred for 10 minutes, then heated to 45°C with stirring, and an ascorbic acid solution with a concentration of 0.1 mol / L was dripped into the solution while keeping the temperature constant, and the dripping time of the ascorbic acid solution was controlled to be 50 minutes. After the ascorbic acid solution was added, the solution was kept warm and stirred for 3 hours, then naturally cooled to room temperature, and solid matter was obtained by centrifugation. The solid matter was washed with deionized water and then dried to obtain a composite fiber material.

[0039] The mass ratio of the in-situ composite, deionized water, and ascorbic acid solution is 11:100:78.

[0040] 3. Mixing and molding

[0041] The modified powder and composite fiber material are put into a high-speed mixer, the mixing speed is controlled to be 1100rpm, and the mixture is evenly mixed to obtain a mixture; then the mixture is transferred into a mold and sealed, and then placed in a cold isostatic pressing machine, the cold isostatic pressing pressure is controlled to be 200MPa, and after cold isostatic pressing for 20 minutes, demolding is carried out to obtain a green body.

[0042] In the mixed molding, the weight ratio of the modified powder material to the composite fiber material is 10:1.3.

[0043] 4. Spark plasma sintering

[0044] The green body was placed in a graphite mold of the same size, and then transferred to a spark plasma sintering device, a mixed gas of nitrogen and argon was introduced, the pressure in the spark plasma sintering device was adjusted to 33 MPa, the temperature was raised to 1100°C, and the temperature was kept for sintering for 8 minutes; the temperature was further raised to 1700°C, and the temperature was kept for sintering for 8 minutes; it was naturally cooled to room temperature, demolded, and the boride zirconium ceramic electrode material was obtained.

[0045] The volume ratio of nitrogen to argon in the mixed gas is 1:2.

[0046] This embodiment also provides a zirconium boride ceramic electrode material prepared by the aforementioned method.

[0047] Example 2

[0048] This embodiment provides a method for preparing a zirconium boride ceramic electrode material, specifically:

[0049] 1. Preparation of modified powder

[0050] Zirconium diboride powder, silicon carbide powder, titanium carbide powder, lanthanum oxide powder, yttrium oxide powder and ethanol solution are put into a high-energy ball mill, the ball-to-material mass ratio is controlled to be 10.5:1, the ball milling speed is 550rpm, and the primary ball milling treatment is carried out for 5.5 hours; then, titanate coupling agent GR-102 and tetrabutyl hafnium oxide are sprayed at the same time, and the spraying of titanate coupling agent GR-102 and tetrabutyl hafnium oxide is controlled to be completed within 25 minutes, and the secondary ball milling treatment is carried out for 5.5 hours to obtain a ball-milled product; the ball-milled product is transferred to a vacuum drying device, dried to constant weight at 87°C under a vacuum degree of 0.058MPa, and ground evenly to obtain a modified powder.

[0051] Among them, the weight ratio of zirconium diboride powder, silicon carbide powder, titanium carbide powder, lanthanum oxide powder, yttrium oxide powder, ethanol solution, titanate coupling agent GR-102, and tetrabutyl hafnium oxide is 57:20.6:12.2:3.2:1.6:51:6.3:2.8.

[0052] The volume concentration of the ethanol solution is 88%.

[0053] 2. Preparation of composite fiber materials

[0054] 1) In-situ composite treatment

[0055] A carbon fiber with a diameter of 9 μm is placed in a processing chamber of a low-temperature plasma device. In an argon atmosphere environment, the low-temperature plasma processing power is controlled to be 450 W, and the low-temperature plasma processing frequency is controlled to be 11.3 MHz. After the low-temperature plasma treatment is performed for 15 minutes, the low-temperature plasma treatment is completed, and the carbon fiber is chopped to 0.8 cm to obtain pretreated fibers; then the pretreated fibers, copper nitrate trihydrate, nickel nitrate hexahydrate, and terephthalic acid are put into a high-pressure reactor containing N,N-dimethylformamide, and after stirring for 35 minutes, the high-pressure reactor is sealed, and the temperature is increased to 115°C at a heating rate of 0.5°C / min. After the reaction is kept warm for 23 hours, it is cooled to room temperature, the high-pressure reactor is opened to take out the reaction mixture, and solid matter is obtained by centrifugal separation. The solid matter is washed with N,N-dimethylformamide and deionized water in turn and then dried to obtain an in-situ composite.

[0056] Wherein, the weight ratio of the pretreated fiber, copper nitrate trihydrate, nickel nitrate hexahydrate, terephthalic acid and N,N-dimethylformamide is 12.7:3.2:1:3.6:62.

[0057] 2) In-situ reduction treatment

[0058] The in-situ composite was put into deionized water, stirred for 15 minutes, then heated to 47°C with stirring, and an ascorbic acid solution with a concentration of 0.11 mol / L was dripped into the water while keeping the temperature constant, and the dripping time of the ascorbic acid solution was controlled to be 55 minutes. After the ascorbic acid solution was added, the mixture was kept warm and stirred for 3.5 hours, then naturally cooled to room temperature, and solid matter was obtained by centrifugation. The solid matter was washed with deionized water and then dried to obtain a composite fiber material.

[0059] The mass ratio of the in-situ composite, deionized water, and ascorbic acid solution is 11.3:100:80.

[0060] 3. Mixing and molding

[0061] The modified powder and composite fiber material are put into a high-speed mixer, the mixing speed is controlled to be 1200rpm, and the mixture is mixed evenly to obtain a mixture; then the mixture is transferred into a mold and sealed, and then placed in a cold isostatic pressing machine, the cold isostatic pressing pressure is controlled to be 215MPa, and after cold isostatic pressing for 25 minutes, demolding is carried out to obtain a green body.

[0062] In the mixed molding, the weight ratio of the modified powder material to the composite fiber material is 10:1.35.

[0063] 4. Spark plasma sintering

[0064] The green body was placed in a graphite mold of the same size, and then transferred to a spark plasma sintering device, a mixed gas of nitrogen and argon was introduced, the pressure in the spark plasma sintering device was adjusted to 34 MPa, the temperature was raised to 1150°C, and the temperature was kept for 9 minutes; the temperature was further raised to 1720°C, and the temperature was kept for 9 minutes; it was naturally cooled to room temperature, demolded, and the boride zirconium ceramic electrode material was obtained.

[0065] The volume ratio of nitrogen to argon in the mixed gas is 1:2.3.

[0066] This embodiment also provides a zirconium boride ceramic electrode material prepared by the aforementioned method.

[0067] Example 3

[0068] This embodiment provides a method for preparing a zirconium boride ceramic electrode material, specifically:

[0069] 1. Preparation of modified powder

[0070] Zirconium diboride powder, silicon carbide powder, titanium carbide powder, lanthanum oxide powder, yttrium oxide powder and ethanol solution are put into a high-energy ball mill, the ball-to-material mass ratio is controlled to be 11:1, the ball milling speed is 600 rpm, and the primary ball milling treatment is carried out for 6 hours; then, titanate coupling agent GR-102 and tetrabutyl hafnium oxide are sprayed at the same time, and the spraying of titanate coupling agent GR-102 and tetrabutyl hafnium oxide is controlled to be completed within 30 minutes, and the secondary ball milling treatment is carried out for 6 hours to obtain a ball-milled product; the ball-milled product is transferred to a vacuum drying device, dried at 90°C to constant weight under a vacuum degree of 0.06 MPa, and ground evenly to obtain a modified powder.

[0071] Among them, the weight ratio of zirconium diboride powder, silicon carbide powder, titanium carbide powder, lanthanum oxide powder, yttrium oxide powder, ethanol solution, titanate coupling agent GR-102, and tetrabutyl hafnium oxide is 58:21:12.5:3.3:1.8:53:6.5:3.

[0072] The volume concentration of the ethanol solution is 90%.

[0073] 2. Preparation of composite fiber materials

[0074] 1) In-situ composite treatment

[0075] A carbon fiber with a diameter of 9 μm is placed in a processing chamber of a low-temperature plasma device. In an argon atmosphere environment, the low-temperature plasma processing power is controlled to be 500 W, the low-temperature plasma processing frequency is controlled to be 12 MHz, and the low-temperature plasma treatment is performed for 20 minutes. After the low-temperature plasma treatment is completed, the carbon fiber is chopped to 0.8 cm to obtain pretreated fibers; then the pretreated fibers, copper nitrate trihydrate, nickel nitrate hexahydrate, and terephthalic acid are put into a high-pressure reactor containing N,N-dimethylformamide, and after stirring for 40 minutes, the high-pressure reactor is sealed and heated to 120°C at a heating rate of 0.6°C / min. After the reaction is kept warm for 24 hours, it is cooled to room temperature, the high-pressure reactor is opened to take out the reaction mixture, and solid matter is obtained by centrifugal separation. The solid matter is washed with N,N-dimethylformamide and deionized water in turn and then dried to obtain an in-situ composite.

[0076] Wherein, the weight ratio of the pretreated fiber, copper nitrate trihydrate, nickel nitrate hexahydrate, terephthalic acid and N,N-dimethylformamide is 13:3.3:1.1:3.6:65.

[0077] 2) In-situ reduction treatment

[0078] The in-situ composite was put into deionized water, stirred for 20 minutes, then heated to 50°C with stirring, and an ascorbic acid solution with a concentration of 0.12 mol / L was dripped into the solution while keeping the temperature high, and the dripping time of the ascorbic acid solution was controlled to be 60 minutes. After the ascorbic acid solution was added, the solution was kept warm and stirred for 4 hours, then naturally cooled to room temperature, and solid matter was obtained by centrifugation. The solid matter was washed with deionized water and then dried to obtain a composite fiber material.

[0079] Wherein, the mass ratio of the in-situ composite, deionized water, and ascorbic acid solution is 11.5:100:82.

[0080] 3. Mixing and molding

[0081] The modified powder and composite fiber material are put into a high-speed mixer, the mixing speed is controlled to be 1300rpm, and the mixture is evenly mixed to obtain a mixture; then the mixture is transferred into a mold and sealed, and then placed in a cold isostatic pressing machine, the cold isostatic pressing pressure is controlled to be 220MPa, and after cold isostatic pressing for 30 minutes, demolding is carried out to obtain a green body.

[0082] In the mixed molding, the weight ratio of the modified powder material to the composite fiber material is 10:1.4.

[0083] 4. Spark plasma sintering

[0084] The green body was placed in a graphite mold of the same size, and then transferred to a spark plasma sintering device, a mixed gas of nitrogen and argon was introduced, the pressure in the spark plasma sintering device was adjusted to 35 MPa, the temperature was raised to 1200°C, and the temperature was kept for 10 minutes; the temperature was further raised to 1750°C, and the temperature was kept for 10 minutes; it was naturally cooled to room temperature, demolded, and the boride zirconium ceramic electrode material was obtained.

[0085] The volume ratio of nitrogen to argon in the mixed gas is 1:2.5.

[0086] This embodiment also provides a zirconium boride ceramic electrode material prepared by the aforementioned method.

[0087] Comparative Example 1

[0088] The technical scheme of Example 2 is adopted, but the differences are as follows: 1) in the preparation of the modified powder, the addition of titanate coupling agent GR-102 and tetrabutyl hafnium ester is omitted, and a ball-milled product is obtained after a primary ball milling treatment for 11 hours; the ball-milled product is vacuum dried and ground evenly to obtain a modified powder; 2) in the in-situ composite treatment, the low-temperature plasma treatment of the carbon fiber is omitted, and the carbon fiber is chopped to replace the pretreated fiber for the subsequent operation of this step.

[0089] Comparative Example 2

[0090] The technical solution of Example 2 is adopted, but the differences are as follows: 1) in the step of preparing modified powder, copper powder is used instead of lanthanum oxide powder, and nickel powder is used instead of yttrium oxide powder; 2) in the in-situ composite treatment, the subsequent treatment of the pretreated fiber in this step is omitted, and the in-situ reduction treatment step is omitted; the pretreated fiber is used instead of the composite fiber material for the subsequent mixing and molding.

[0091] The Vickers hardness HV, fracture toughness, charge / discharge specific capacitance, coulomb efficiency, and room temperature resistivity of the zirconium boride ceramic electrode materials of Examples 1-3 and Comparative Examples 1-2 were tested. The Vickers hardness HV was measured by a micro-Vickers hardness tester on 10 test points at the same position of each zirconium boride ceramic electrode material, and the minimum value was taken. The fracture toughness was measured by a micro-Vickers hardness tester by an indentation method, and the test load was controlled to be 49N and the loading time was 15s; after loading was completed, the diagonal length of the crack was measured by a scanning electron microscope to obtain the corresponding fracture toughness.

[0092] For the detection of the electrochemical properties of zirconium boride ceramic electrode materials, each zirconium boride ceramic electrode material was first cut and processed into a test sample for standby use; the charge / discharge specific capacitance and coulomb efficiency were detected by using an Autolab electrochemical workstation to measure the electrochemical properties of each zirconium boride ceramic electrode material. The workstation adopted a three-electrode system, with a sodium chloride solution with a concentration of 3.5wt% as the electrolyte, the zirconium boride ceramic electrode material as the working electrode, a saturated calomel electrode as the reference electrode, and a platinum mesh as the auxiliary electrode; the area current density of the constant current charge and discharge was controlled to be 0.1mA / cm 2 The room temperature resistivity of each zirconium boride ceramic electrode material was tested using a direct current resistance test method.

[0093] The specific results are shown in the following table:

[0094]

[0095] Further, the boronized zirconium ceramic electrode materials and tantalum boronized ceramics of Example 2 and Comparative Examples 1-2 were placed in a calcining furnace, heated to 1000°C at a heating rate of 15°C / min in a nitrogen atmosphere, kept warm for 5 hours, and then rapidly cooled to room temperature within 1 hour; the aforementioned heating and cooling process was a rapid temperature change cycle, and after 20 consecutive times, the Vickers hardness HV, fracture toughness, and charge / discharge specific capacitance of each boronized zirconium ceramic electrode material were tested, and it was observed whether each boronized zirconium ceramic electrode material had cracks after 20 rapid temperature change cycles. The specific results are shown in the following table:

[0096]

[0097] It can be seen that the preparation method of the zirconium boride ceramic electrode material of the present invention, in the preparation of the modified powder, uses zirconium diboride powder, silicon carbide powder, titanium carbide powder, lanthanum oxide, and yttrium oxide for primary ball milling treatment, and then uses titanate coupling agent GR-102 and tetrabutyl hafnium ester for ball milling modification (i.e., secondary ball milling treatment), which improves the dispersibility of the powder raw materials while improving the interface bonding between the raw materials, and improves the mechanical strength, toughness and thermal stability of the zirconium boride ceramic electrode material; at the same time, by reducing the interface resistance, the effective active area of ​​the zirconium boride ceramic electrode is optimized, its electrochemical properties are improved, and the conductivity of the electrode material is improved. In the preparation of composite fiber materials, low-temperature plasma is first used to treat the surface of carbon fiber to improve the surface roughness of carbon fiber, realize surface activation of carbon fiber, and improve the bonding performance of carbon fiber with metal organic framework material in subsequent operation; then the pretreated fiber is contacted with copper nitrate trihydrate, nickel nitrate hexahydrate, and terephthalic acid, and the pretreated fiber is composited with Cu / Ni metal organic framework material in an in-situ composite manner to obtain an in-situ composite; ascorbic acid solution is used as a reducing agent to perform in-situ reduction treatment on the in-situ composite to obtain a carbon fiber material composited with nano-metal clusters; in this process, the Cu / Ni metal organic clusters pre-compounded on the surface of the pretreated fiber are The machine framework material is used as a template, and on the basis of retaining its metal organic framework structure and high specific surface area characteristics, in-situ reduction is performed to obtain uniformly distributed nano metal clusters; it is combined with modified powder for use in the preparation of zirconium boride ceramic electrode materials, while avoiding adverse effects on the overall stability of the zirconium boride ceramic electrode materials, through the conductive network formed by it, the charge transfer performance and conductivity of the zirconium boride ceramic electrode materials are further improved, the effective active area of ​​the zirconium boride ceramic electrode materials is further optimized, and its electrochemical performance is improved; and the mechanical properties, toughness and thermal stability of the zirconium boride ceramic electrode are improved, avoiding the reduction of electrochemical performance caused by possible microcracks or structural damage in thermal cycling conditions. In the mixing molding and spark plasma sintering, the modified powder and the composite fiber material are mixed and molded, and then the zirconium boride ceramic electrode material is prepared; the aforementioned technical means cooperate and work synergistically with each other, which can effectively avoid the problem that the doping material affects the overall stability of the zirconium boride ceramic electrode material, and causes the thermal stability and mechanical properties of the zirconium boride ceramic electrode material to decrease; improve the brittle defects and thermal cycle stability of the zirconium boride ceramic electrode material, and increase its effective service life.

[0098] Unless otherwise specified, all percentages used in the present invention are by mass.

[0099] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a zirconium boride ceramic electrode material, characterized in that: The method comprises the following steps: preparing modified powder material, preparing composite fiber material, mixing and molding, and spark plasma sintering; The method for preparing the modified powder comprises: performing primary ball milling on zirconium diboride powder, silicon carbide powder, titanium carbide powder, lanthanum oxide powder, yttrium oxide powder and ethanol solution, and then spraying titanate coupling agent GR-102 and tetrabutyl hafnium oxide into the mixture, performing secondary ball milling to obtain a ball milled product; and drying and grinding the ball milled product to obtain the modified powder. The preparation of the composite fiber material comprises the following steps: in-situ composite treatment and in-situ reduction treatment; The in-situ composite treatment method comprises the following steps: the carbon fibers are treated with low-temperature plasma and then chopped to obtain pretreated fibers; the pretreated fibers, copper nitrate trihydrate, nickel nitrate hexahydrate, and terephthalic acid are added to N,N-dimethylformamide, mixed evenly, heated to 110-120° C. in a closed environment, kept warm for reaction, and then solids are obtained by separation; the solids are washed and dried to obtain an in-situ composite; The in-situ reduction treatment method comprises the following steps: putting the in-situ composite into deionized water, mixing uniformly, heating to 45-50° C., and dripping an ascorbic acid solution while keeping the temperature constant; after the ascorbic acid solution is dripped, continuing to keep the temperature constant and stirring, separating and obtaining a solid, and washing and drying the solid to obtain a composite fiber material; The mixing and molding method comprises: uniformly mixing the modified powder material and the composite fiber material, and then performing cold isostatic pressing to obtain a green body; The green body is subjected to spark plasma sintering to obtain a zirconium boride ceramic electrode material.

2. The method for preparing the zirconium boride ceramic electrode material according to claim 1, characterized in that: In the preparation of the modified powder, the weight ratio of zirconium diboride powder, silicon carbide powder, titanium carbide powder, lanthanum oxide powder, yttrium oxide powder, ethanol solution, titanate coupling agent GR-102, and tetrabutyl hafnium oxide is 55-58:20-21:12-12.5:3-3.3:1.5-1.8:50-53:6-6.5:2.5-3; The volume concentration of the ethanol solution is 85-90%.

3. The method for preparing the zirconium boride ceramic electrode material according to claim 1, characterized in that: In the preparation of the modified powder, the ball-to-material mass ratio is 10-11:1, the ball milling speed is 500-600rpm, the primary ball milling treatment time is 5-6h, and the secondary ball milling treatment time is 5-6h; The spraying time of titanate coupling agent GR-102 and tetrabutyl hafnium ester is 20-30 minutes.

4. The method for preparing the zirconium boride ceramic electrode material according to claim 1, characterized in that: In the in-situ composite treatment, the low-temperature plasma treatment atmosphere is argon, the low-temperature plasma treatment power is 400-500W, the low-temperature plasma treatment frequency is 11-12MHz, and the low-temperature plasma treatment time is 10-20min; The diameter of the carbon fiber is 8-10 μm; the length after chopped is 0.8-1 cm.

5. The method for preparing the zirconium boride ceramic electrode material according to claim 1, characterized in that: In the in-situ composite treatment, the weight ratio of the pretreated fiber, copper nitrate trihydrate, nickel nitrate hexahydrate, terephthalic acid, and N,N-dimethylformamide is 12-13:3-3.3:0.9-1.1:3.5-3.6:60-65; The heating rate to 110-120°C is 0.4-0.6°C / min; The reaction time at 110-120℃ is 22-24h.

6. The method for preparing the zirconium boride ceramic electrode material according to claim 1, characterized in that: In the in-situ reduction treatment, the mass ratio of the in-situ composite, deionized water, and ascorbic acid solution is 11-11.5:100:78-82.

7. The method for preparing the zirconium boride ceramic electrode material according to claim 1, characterized in that: In the in-situ reduction treatment, the concentration of the ascorbic acid solution is 0.1-0.12 mol / L; The ascorbic acid solution was added for 50-60 min. After the ascorbic acid solution is added dropwise, the stirring time is continued for 3-4 hours.

8. The method for preparing the zirconium boride ceramic electrode material according to claim 1, characterized in that: In the mixed material molding, the cold isostatic pressing pressure is 200-220MPa, and the cold isostatic pressing time is 20-30min; The weight ratio of the modified powder material to the composite fiber material is 10:1.3-1.

4.

9. The method for preparing the zirconium boride ceramic electrode material according to claim 1, characterized in that: The spark plasma sintering comprises placing the green body in a mold and transferring it into a spark plasma sintering device, introducing a mixed gas of nitrogen and argon, adjusting the spark plasma sintering pressure to 33-35 MPa, heating to 1100-1200° C., and sintering at the temperature for 8-10 minutes; then heating to 1700-1750° C., and sintering at the temperature for 8-10 minutes to obtain a zirconium boride ceramic electrode material; The volume ratio of nitrogen to argon in the mixed gas is 1:2-2.

5.

10. A zirconium boride ceramic electrode material, characterized in that: The method is prepared by the method according to any one of claims 1 to 9.

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