A carbon-carbon composite material and method of manufacture and use

Abstract

The application relates to the field of new materials, and discloses a carbon-carbon composite material, a preparation method and application. The carbon-carbon composite material comprises single carbon fibers and multilayer graphite sheets surrounding the periphery of the single carbon fibers, and nano metal particles are filled between any two adjacent graphite sheets, wherein the nano metal particles contain IA group, VB group, VIB group and VIII group metal elements. The carbon-carbon composite material is composed of layered graphite sheet clusters with a concentric structure in a microscale, contains various metal and nonmetal elements in the interior, and has the advantages of uniform distribution at an atomic scale. Furthermore, the carbon-carbon composite material also contains IA group, VB group, VIB group and VIII group metal elements, and has better electrochemical activity.

Description

Technical Field

[0001] This invention relates to the field of new materials, specifically to a carbon-carbon composite material, its preparation method, and its application. Background Technology

[0002] Carbon fiber possesses a comprehensive set of properties, including high tensile strength, high tensile modulus, low density, high temperature resistance, ablation resistance, corrosion resistance, high electrical and thermal conductivity, low thermal expansion, self-lubrication, and good biocompatibility. It is widely used in aerospace, automotive, building energy, and sporting goods industries. In Chapter 5, "Graphite Fiber," of He Fu's book *Carbon Fiber and Graphite Fiber* (first edition, September 2010), it states that graphite fiber generally refers to carbon fiber with a carbon content of over 99%. Graphite fiber can be obtained by graphitizing carbon fiber at high temperatures of 2200–3000℃. Graphite fiber not only has a high carbon content but also a high tensile modulus. It exhibits excellent properties such as a low coefficient of thermal expansion, good thermal stability, and dimensional stability, making it suitable for manufacturing rigid, thin, and dimensionally stable composite materials, widely used in aerospace applications, particularly in spacecraft. For example, high-modulus carbon fiber composites are used to manufacture the horn antennas of artificial satellites to ensure dimensional stability in the temperature-changing environment of space.

[0003] Carbon-carbon (C / C) composites refer to multiphase structural materials (CN112125690A) with carbon fiber or its fabric as the reinforcing phase and pyrolytic carbon or resin carbon or pitch carbon impregnated and carbonized by chemical vapor deposition as the matrix. They possess extremely high specific strength and specific modulus, and can be used at temperatures above 2000℃ in an inert atmosphere without degradation of mechanical properties, exhibiting characteristics unmatched by any other material. C / C composites are non-melting and non-flammable, exhibit uniform ablation, and are widely used in the outer wall materials of space shuttles, missile nose cones, and engine nozzles. C / C composites are excellent thermal conductors with a low coefficient of thermal expansion, and are resistant to friction and wear, making them widely used in aircraft braking systems. Typically, preforms made of long carbon fiber filaments or short-cut carbon fiber composite matrix carbon are used as the preform, which is then densified through liquid-phase impregnation and carbonization or chemical vapor deposition and chemical vapor infiltration to prepare C / C composites.

[0004] The fabrication of carbon-carbon composite materials integrates high-temperature technology and equipment. The key to its continuous graphitization preparation lies in suppressing and controlling the high-temperature oxidation and biochemical (evaporation) of the graphite heating element and the running fibers. Carbon-carbon composite materials exhibit macroscopically diverse morphologies due to their different stacking / arrangement in three-dimensional space. These diverse carbon materials are composed of microcrystals of varying sizes and orientations, and stacking states. Catalytically grown carbon nanofibers exhibit a variety of morphologies; different catalysts and raw materials produce tubular, herringbone-like, and planar carbon nanofibers with different structures.

[0005] CN111807853A discloses a preparation process and application of carbon-carbon composite parts, which uses carbon fiber, vapor-deposited carbon, and impregnated carbon composites to maintain good mechanical, thermal, and tribological properties at high temperatures, reduces costs by 50%, and allows for mass production. CN112125690A uses flake graphite and UV-cured silicone to prepare a mixed colloid, which is then filled between a mixed layer of carbon fiber and glass fiber to prepare an intermediate. The carbon-carbon composite material is prepared by hot-pressing, curing, and drying, and exhibits high tensile strength and high elasticity. CN112679950A discloses a method for preparing flexible carbon-carbon composite materials. After coating the surface of carbon fiber cloth with a thermosetting resin film, hot-pressing and curing are performed, followed by carbonization in an inert atmosphere. This method has the advantages of short processing time, simple process, no need for high-pressure equipment, and high production efficiency, enabling industrial production. CN113175565A discloses a thin-walled, high-strength carbon-carbon composite pipe and its preparation method. The pipe comprises a pipe body formed by carbon cloth, binder, and CVD lamination, and a dense layer located on the inner surface of the pipe body. This pipe has the advantage of reducing wall thickness while maintaining strength. CN113636854A discloses a carbon-carbon composite material with deposited carbon nanotubes. Short-cut carbon fibers are embedded within a carbon matrix and carbon fibers, and carbon nanotubes are deposited between them. This significantly improves the mechanical properties and oxidation resistance of the carbon-carbon composite material. CN113636855A discloses an internally oxidation-resistant carbon-carbon composite material, comprising a carbon matrix, carbon fiber reinforcement distributed within the carbon matrix, silicon carbide, zirconium oxide, and alumina. This material improves the ablation resistance and service life of the composite material. CN113683437A discloses a carbon-carbon composite material containing refractory metal, comprising a carbon matrix, carbon fiber reinforcement distributed within the carbon matrix, zirconium-fullerene composite nanoparticles, and silicon-rich silicon carbide, which has the advantages of improving the composite material's ablation resistance, service life, and oxidation resistance. CN115180969A discloses a high thermal conductivity carbon-carbon composite material and its preparation method, which utilizes electrophoresis to produce graphene / AlN reinforcement on the surface and inside of a carbon fiber needle-punched preform, impregnates it in benzoxazine resin, and after thermosetting and atmospheric pressure carbonization, exhibits excellent mechanical properties and good thermal conductivity. CN115231941A relates to a carbon-carbon composite material for ultra-high temperature environments and its preparation method, comprising a carbon matrix, carbon fiber reinforcement, ultra-high temperature ceramics, and carbon nanotubes. The prepared carbon-carbon composite material has excellent mechanical properties, high-temperature ablation resistance, and good thermal conductivity. CN213628313U discloses a carbon-carbon composite material sheet, which has the advantages of being lightweight and high-strength, having high thermal conductivity and low expansion, good friction performance, good thermal shock resistance, and high dimensional stability.

[0006] Existing publicly available patent research indicates that most current research on C / C composite materials focuses on improving and optimizing their preparation processes, addressing key technical challenges related to the functional properties and applications of C / C composites. However, the finished product forms of C / C composites disclosed in existing technologies are relatively uniform, and the main component element is only carbon. Furthermore, there are no reports on C / C composites with high aspect ratios and fiber rod-like morphologies. Summary of the Invention

[0007] The purpose of this invention is to overcome the problem that existing carbon-carbon composite materials have a single product form and are mainly composed of only carbon, and there are no carbon-carbon composite materials with high aspect ratio and fibrous rod-like form. This invention provides a carbon-carbon composite material, its preparation method and application. This carbon-carbon composite material has the advantages of being composed of layered graphite flakes with a concentric circle structure at the microscale, containing many types and amounts of metal and non-metal elements, and exhibiting a uniform distribution at the atomic scale.

[0008] To achieve the above objectives, the present invention provides a carbon-carbon composite material comprising a single carbon fiber and multiple layers of graphite sheets surrounding the single carbon fiber, wherein nano-metal particles are filled between any two adjacent layers of graphite sheets.

[0009] The nano-metal particles contain metal elements from Group IA, Group VB, Group VIB and Group VIII.

[0010] Preferably, the carbon-carbon composite material contains 45-92% by weight of carbon, 1.6-52% by weight of Group IA metals, 0.1-1% by weight of Group VB metals, 0.05-3% by weight of Group VIB metals and 2.2-33% by weight of Group VIII metals.

[0011] Preferably, the nano-metal particles contain sodium, potassium, nickel, lithium, platinum, iron, chromium, and vanadium.

[0012] Preferably, the carbon-carbon composite material contains 45-92% by weight of carbon, 0.7-18% by weight of sodium, 0.5-18% by weight of potassium, 0.5-15% by weight of nickel, 0.4-13% by weight of lithium, 1-10% by weight of platinum, 0.7-8% by weight of iron, 0.05-3% by weight of chromium, and 0.1-1% by weight of vanadium.

[0013] Preferably, the carbon-carbon composite material contains 50-90% by weight of carbon, 1-15% by weight of sodium, 1-15% by weight of potassium, 1-10% by weight of nickel, 1-10% by weight of lithium, 1-5% by weight of platinum, 1-5% by weight of iron, 0.1-1% by weight of chromium, and 0.1-0.5% by weight of vanadium.

[0014] Preferably, the number of graphite sheets surrounding the outer periphery of the single carbon fiber is 3-20 layers, more preferably 8-12 layers.

[0015] Preferably, the diameter of the single carbon fiber is 4-8 μm, more preferably 4.5-7.5 μm.

[0016] Preferably, the length of a single carbon fiber is 2-10 mm, and more preferably 3-9 mm.

[0017] Preferably, the thickness of the multilayer graphite sheets gradually increases from the inside to the outside.

[0018] Preferably, the ratio of the total thickness of the multilayer graphite sheets to the diameter of the single carbon fiber is 1-100:1.

[0019] Preferably, the carbon-carbon composite material is in a straight or curved shape.

[0020] Preferably, at least a portion of the surface of the carbon-carbon composite material is bamboo-like and / or raised.

[0021] Preferably, the diameter of the carbon-carbon composite material is 0.05-1 mm, and more preferably 0.1-0.3 mm.

[0022] Preferably, the length of the carbon-carbon composite material is 0.1-10 mm, and more preferably 1-5 mm.

[0023] Preferably, in the Raman spectrum of the carbon-carbon composite material, the ratio of the peak intensity of the D peak to the peak intensity of the G peak is 0.07-0.3:1.

[0024] Preferably, in the Raman spectrum of the carbon-carbon composite material, the ratio of the peak intensity of the 2D peak to the peak intensity of the G peak is 0.2-0.9:1.

[0025] A second aspect of the present invention provides a method for preparing carbon-carbon composite materials, the method comprising: reacting short-cut carbon fibers, a carbon source and a metal source at 1500-3500°C in the presence of an inert atmosphere, wherein the volumetric flow rate of the inert atmosphere is 50-500 mL / min.

[0026] The metal source includes Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source.

[0027] Preferably, the weight ratio of the metal source, the carbon source and the chopped carbon fibers is 20-100:30-200:1, and more preferably 30-70:50-150:1.

[0028] Preferably, the weight ratio of the group IA metal source, group VB metal source, group VIB metal source and group VIII metal source is 50-500:1:3-10:30-350.

[0029] Preferably, the metal source contains a sodium source, a potassium source, a nickel source, a lithium source, a platinum source, an iron source, a chromium source, and a vanadium source.

[0030] Preferably, the weight ratio of the sodium source, potassium source, nickel source, lithium source, platinum source, iron source, chromium source and vanadium source is 20-180:20-180:20-150:10-100:10-100:5-80:3-10:1.

[0031] Preferably, the sodium source is selected from one or more of Na2CO3, NaHCO3, NaNO3, NaCl, and NaF.

[0032] Preferably, the potassium source is selected from one or more of KCl, K2CO3, KF and KOH.

[0033] Preferably, the nickel source is selected from one or more of NiO, Ni(OH)2, NiF2 and NiCl2.

[0034] Preferably, the lithium source is selected from one or more of LiF, Li2O, LiOH and LiCl.

[0035] Preferably, the platinum source is selected from one or more of PtO, PtO2 and Pt(OH)2.

[0036] Preferably, the iron source is selected from one or more of FeO, Fe2O3, Fe3O4, Fe(OH)2, Fe(OH)3, FeCl2, FeCl3 and FePO4.

[0037] Preferably, the chromium source is selected from one or more of CrO3, Li2CrO4, K2CrO4 and BaCrO4.

[0038] Preferably, the vanadium source is selected from one or more of VO, V2O3, VO2 and V2O5.

[0039] Preferably, the carbon source is carbonized resin and / or graphite.

[0040] Preferably, the graphite is amorphous graphite.

[0041] Preferably, the reaction temperature is 1500-3000℃.

[0042] Preferably, the reaction time is 12-720 hours, more preferably 24-120 hours.

[0043] Preferably, the volumetric flow rate of the inert atmosphere is 100-300 mL / min.

[0044] Preferably, the length of the chopped carbon fiber is 0.1-10 mm, and more preferably 1-5 mm.

[0045] Preferably, the chopped carbon fiber has a specification of 12-320K, and more preferably 12-48K.

[0046] Preferably, the carbon content of the chopped carbon fibers is 85-95% by weight.

[0047] A third aspect of the present invention provides a carbon-carbon composite material prepared by the above method.

[0048] A fourth aspect of the present invention provides an application of the above-mentioned carbon-carbon composite material in graphite electrode materials.

[0049] The carbon-carbon composite material of the present invention has the advantages of being composed of layered graphite flakes with concentric circular structures at the microscale, containing a variety of metal and non-metal elements in varying amounts, and exhibiting a uniform distribution at the atomic scale. Furthermore, the carbon-carbon composite material also contains metal elements from Group IA, Group VB, Group VIB and Group VIII, thus exhibiting better electrochemical activity. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the macroscopic morphology of the carbon-carbon composite material in Example 1;

[0051] Figure 2 The energy spectrum of Na element inside the carbon-carbon composite material in Example 1;

[0052] Figure 3 The energy spectrum of K element inside the carbon-carbon composite material in Example 1;

[0053] Figure 4 The energy spectrum of Ni element inside the carbon-carbon composite material in Example 1;

[0054] Figure 5 The energy spectrum of Li element inside the carbon-carbon composite material in Example 1;

[0055] Figure 6 The energy spectrum of Pt element inside the carbon-carbon composite material in Example 1;

[0056] Figure 7The energy spectrum of Fe element inside the carbon-carbon composite material in Example 1;

[0057] Figure 8 The energy spectrum of Cr element inside the carbon-carbon composite material in Example 1;

[0058] Figure 9 The energy spectrum of V element inside the carbon-carbon composite material in Example 1;

[0059] Figure 10 This is a schematic diagram of the cross-sectional morphology of the carbon-carbon composite material in Example 1; Detailed Implementation

[0060] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0061] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0062] In one aspect, this invention provides a carbon-carbon composite material comprising a single carbon fiber and multiple layers of graphite sheets surrounding the single carbon fiber, wherein nano-metal particles are filled between any two adjacent layers of graphite sheets.

[0063] The nano-metal particles contain metal elements from Group IA, Group VB, Group VIB and Group VIII.

[0064] The carbon-carbon composite material provided by this invention has a unique microstructure. The core of the composite material is a single carbon fiber, surrounded by multiple concentric graphite sheets. Furthermore, the composite material contains nano-metal particles (non-carbon elements), which are uniformly distributed between any two adjacent layers of graphite sheets.

[0065] In this invention, in order to further improve the performance of carbon-carbon composite materials, in a preferred embodiment, the nano-metal particles contain metal elements from Group IA, Group VB, Group VIB and Group VIII.

[0066] In a preferred embodiment of the present invention, in order to enhance the conductivity and electrochemical activity of the carbon-carbon composite material, it is necessary to limit the content of each element in the carbon-carbon composite material.

[0067] Therefore, preferably, the carbon-carbon composite material contains 45-92% by weight of carbon, 1.6-52% by weight of Group IA metals, 0.1-1% by weight of Group VB metals, 0.05-3% by weight of Group VIB metals and 2.2-33% by weight of Group VIII metals.

[0068] More preferably, the nano-metal particles contain sodium, potassium, nickel, lithium, platinum, iron, chromium, and vanadium. When these metal elements are present, the electrode material can have excellent conductivity, improve its electrochemical activity, and benefit the electrocatalytic reaction of the graphite electrode.

[0069] In a preferred embodiment, the carbon-carbon composite material contains 45-92 wt% carbon, 0.7-18 wt% sodium, 0.5-18 wt% potassium, 0.5-15 wt% nickel, 0.4-13 wt% lithium, 1-10 wt% platinum, 0.7-8 wt% iron, 0.05-3 wt% chromium, and 0.1-1 wt% vanadium.

[0070] Preferably, the carbon-carbon composite material contains 50-90% by weight of carbon, 1-15% by weight of sodium, 1-15% by weight of potassium, 1-10% by weight of nickel, 1-10% by weight of lithium, 1-5% by weight of platinum, 1-5% by weight of iron, 0.1-1% by weight of chromium, and 0.1-0.5% by weight of vanadium.

[0071] In this invention, the number of graphite sheets with concentric circular structures surrounding the single carbon fiber is relatively large. Specifically, the number of graphite sheets surrounding the single carbon fiber is 3-20 layers, preferably 8-12 layers, and can specifically be 8, 9, 10, 11, or 12 layers. Having a large number of graphite sheets with concentric circular structures surrounding the single carbon fiber allows for a more uniform distribution of nano-metal particles among the graphite sheets, maintaining the dimensional stability of the carbon-carbon composite material.

[0072] In this invention, the diameter of the single carbon fiber can be a conventional choice in the art. Preferably, the diameter of the single carbon fiber is 4-8 μm, and more preferably 4.5-7.5 μm.

[0073] The length of the single carbon fiber is equivalent to the length of the carbon-carbon composite material. Preferably, the length of the single carbon fiber is 2-10 mm, and more preferably 3-9 mm.

[0074] The carbon-carbon composite material described in this invention has a unique microstructure. As can be seen from the scanning electron microscope, in the preferred case, the thickness of the multilayer graphite sheets gradually increases from the inside to the outside, which can improve the stability of the concentric circle structure of the carbon-carbon composite material.

[0075] The approximate ratio of carbon fiber and graphite content in a carbon-carbon composite material can be inferred from the ratio of the total thickness of the graphite sheets to the diameter of a single carbon fiber. In a preferred embodiment, the ratio of the total thickness of the multilayer graphite sheets to the diameter of the single carbon fiber can be 1-100:1, specifically 1:1, 20:1, 40:1, 60:1, 80:1, or 100:1. Limiting the ratio of the total thickness of the graphite sheets to the diameter of the single carbon fiber within this range enhances its electrical conductivity and electrochemical activity.

[0076] In this invention, the appearance of the carbon-carbon composite material is not limited and can take on various forms. Specifically, the carbon-carbon composite material is generally straight or curved.

[0077] The carbon-carbon composite material provided by this invention may also contain carbon particles that exist independently or in an aggregated state, wherein the carbon particles are uniformly distributed on the surface of each layer of graphite sheet. Preferably, the particle size of the carbon particles is 0.02-2 mm.

[0078] In this invention, the diameter of the carbon-carbon composite material is not uniform due to the presence of nano-metal particles or a combination of nano-metal particles and carbon particles. Specifically, at least a portion of the surface of the carbon-carbon composite material has a bamboo-like and / or protruding shape.

[0079] In a preferred embodiment of the present invention, the diameter of the carbon-carbon composite material is 0.05-1 mm, preferably 0.1-0.3 mm; and the length of the carbon-carbon composite material is 0.1-10 mm, preferably 1-5 mm.

[0080] In this invention, the ratio of the peak intensity of the D peak to the G peak of the carbon-carbon composite material can be 0.07-0.3:1, as determined by Raman spectroscopy. When the ratio of the peak intensity of the D peak to the G peak is within this range, the smaller the lattice defects of the carbon atoms, the higher the electrical conductivity of the carbon-carbon composite material.

[0081] In this invention, the ratio of the peak intensities of the 2D peak to the G peak in the Raman spectrum of the carbon-carbon composite material can be 0.2-0.9:1. When the ratio of the peak intensities of the 2D peak to the G peak is within this range, the graphitization degree of the carbon-carbon composite material is relatively complete, and the electrical conductivity is high.

[0082] In specific embodiments, the carbon-carbon composite material of the present invention is gray or black.

[0083] The carbon-carbon composite material of the present invention also contains small amounts of other metallic elements, including zinc, manganese, silver, barium, copper, magnesium, lead and strontium, with the content of each metallic element being less than 0.001 by weight.

[0084] A second aspect of the present invention provides a method for preparing carbon-carbon composite materials, the method comprising: reacting short-cut carbon fibers, a carbon source and a metal source at 1500-3500°C in the presence of an inert atmosphere, wherein the volumetric flow rate of the inert atmosphere is 50-500 mL / min.

[0085] The metal source includes Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source.

[0086] The method described in this invention is simple and easy to operate. It only requires mixing and contacting short-cut carbon fibers, a carbon source, and a metal source of a specific group to carry out the reaction.

[0087] In this invention, in order to obtain a carbon-carbon composite material with a suitable ratio of carbon to metal elements, a large number of graphite sheets surrounding the diameter of a single carbon fiber, and excellent electrical conductivity, the weight ratio of the metal source, the carbon source, and the chopped carbon fibers can be appropriately controlled.

[0088] Preferably, the weight ratio of the metal source, the carbon source, and the chopped carbon fibers is 20-100:30-200:1, and more preferably 30-70:50-150:1.

[0089] In this invention, the metal source serves to generate nano-metal particles and fill the spaces between graphite sheets. Therefore, the metal source simultaneously contains Group IA, Group VB, Group VIB, and Group VIII metal sources.

[0090] Preferably, the weight ratio of the group IA metal source, group VB metal source, group VIB metal source and group VIII metal source is 50-500:1:3-10:30-350.

[0091] In a preferred embodiment, the metal source contains sodium, potassium, nickel, lithium, platinum, iron, chromium, and vanadium. When these metal elements are present simultaneously, they not only provide a carrier for the electrochemical catalytic reaction and a medium for charge transfer, but the physical spatial effect induced by the metal particles also facilitates the diffusion of electrochemical reactants and the removal of products.

[0092] Preferably, the weight ratio of the sodium source, potassium source, nickel source, lithium source, platinum source, iron source, chromium source and vanadium source is 20-180:20-180:20-150:10-100:10-100:5-80:3-10:1.

[0093] In this invention, the sodium source can be a conventional choice in the art, and can be a sodium salt, sodium oxide or sodium hydroxide, specifically selected from one or more of Na2CO3, NaHCO3, NaNO3, NaCl and NaF.

[0094] In this invention, the potassium source can be a conventional choice in the art, and can be a potassium salt, potassium oxide or potassium hydroxide, specifically selected from one or more of KCl, K2CO3, KF and KOH.

[0095] In this invention, the nickel source can be a conventional choice in the art, and can be a nickel salt, nickel oxide or nickel hydroxide, specifically selected from one or more of NiO, Ni(OH)2, NiF2 and NiCl2.

[0096] In this invention, the lithium source can be a conventional choice in the art, and can be a lithium salt, lithium oxide or lithium hydroxide, specifically selected from one or more of LiF, Li2O, LiOH and LiCl.

[0097] In this invention, the platinum source can be a conventional choice in the art, and can be a platinum salt, platinum oxide or platinum hydroxide, specifically selected from one or more of PtO, PtO2 and Pt(OH)2.

[0098] In this invention, the iron source can be a conventional choice in the art, and can be an iron salt, iron oxide or iron hydroxide, specifically selected from one or more of FeO, Fe2O3, Fe3O4, Fe(OH)2, Fe(OH)3, FeCl2, FeCl3 and FePO4.

[0099] In this invention, the chromium source can be a conventional choice in the art, and can be a chromium salt, chromium oxide or chromium hydroxide, specifically selected from one or more of CrO3, Li2CrO4, K2CrO4 and BaCrO4.

[0100] In this invention, the vanadium source can be a conventional choice in the art, and can be a vanadium salt, vanadium oxide or vanadium hydroxide, specifically selected from one or more of VO, V2O3, VO2 and V2O5.

[0101] In the method described in this invention, the carbon source functions to form graphite sheets on the outer periphery of a single carbon fiber. The carbon source can be a conventional choice in the art; specifically, it can be a carbonized resin and / or graphite. Preferably, the carbonized resin is a resin-based carbide obtained through high-temperature carbonization. Preferably, the graphite is amorphous graphite.

[0102] To ensure that the chopped carbon fibers, the carbon source, and the metal source can form the aforementioned carbon-carbon composite material, the reaction needs to be carried out under an inert atmosphere. Specifically, the inert atmosphere is nitrogen and / or an inert gas; the purity of both nitrogen and the inert atmosphere is >99.9% by volume, and the oxygen content in the inert atmosphere is <50 ppm.

[0103] In this invention, the reaction can be carried out in a conventionally used high-temperature furnace. Specifically, isostatic graphite or highly oriented graphite is used as the heating element in the high-temperature furnace. Preferably, the high-temperature furnace is connected to a tail gas recovery system via a pipeline. A valve is installed on the pipeline connecting the high-temperature furnace and the tail gas recovery system. The inner diameter of the pipeline is between 5-20 mm. The valve is fully open, and a filter screen is installed before the valve along the gas flow direction. The selection of the pipeline, filter screen, and valve meets the temperature resistance requirements.

[0104] In a preferred embodiment of the present invention, the reaction temperature is 1500-3000℃. In a specific embodiment, the reaction temperature can be 1500℃, 2000℃, 2500℃, or 3000℃. To prepare carbon-carbon composite materials with a graphite structure, considering both the relationship between the growth rate of metal particles and temperature, as well as the economic efficiency of operating the high-temperature furnace, controlling the reaction temperature within the above-mentioned range is more suitable.

[0105] Preferably, the reaction time is 12-720 hours, more preferably 24-120 hours, and specifically, the reaction time can be 24 hours, 50 hours, 75 hours, 100 hours or 120 hours.

[0106] In a preferred embodiment of the present invention, the volumetric flow rate of the inert atmosphere is 100-300 mL / min, specifically 100 mL / min, 150 mL / min, 200 mL / min, 250 mL / min, or 300 mL / min. When the gas flow rate is low, the adsorbed oxygen on the surface of the raw materials cannot be completely replaced, causing oxidation and etching of the raw materials, which affects the preparation effect of the carbon-carbon composite material. When the gas flow rate is high, the chopped carbon fibers suspend and vibrate, preventing the gasified carbon and nano-metal particles from adhering and achieving steady-state growth.

[0107] In this invention, the single carbon fiber at the center of the carbon-carbon composite material is formed by chopped carbon fibers. In a specific embodiment, the length of the chopped carbon fibers is 0.1-10 mm, preferably 1-5 mm; the specifications of the chopped carbon fibers are 12-320 K, preferably 12-48 K.

[0108] In this invention, the carbon content of the chopped carbon fibers is 85-95% by weight. Specifically, it can be 85% by weight, 90% by weight, or 95% by weight.

[0109] A third aspect of the present invention provides a carbon-carbon composite material prepared by the above method.

[0110] A fourth aspect of the present invention provides an application of the above-mentioned carbon-carbon composite material in graphite electrode materials.

[0111] The carbon-carbon composite material described in this invention can be further processed as a raw material. Processing methods include, but are not limited to, blending / extrusion / granulation, strip forming, grinding / pulverizing, and calcination. Material products manufactured using the above processing methods, whose constituent elements and their contents fall within the scope defined by this invention, are all within the protection scope of this invention. Furthermore, as long as the types and contents of the contained elements are within the scope defined by this invention, regardless of whether they are raw materials or finished products, and the shape of the material is not limited to fibrous form, and is not limited by the material processing method, they are all within the protection scope of this invention.

[0112] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited thereto. In the following embodiments, the carbonized resin powder used is YKD-508 blood perfusion carbonized resin (carbon skeleton spherical porous adsorption resin) purchased from Henan Yinkai New Material Co., Ltd.

[0113] The testing methods used in this invention include:

[0114] 1. The surface and cross-sectional morphology of the carbon-carbon composite materials prepared in the examples and comparative examples were observed using a ZEISS Merlin field emission scanning electron microscope. The test conditions included: accelerating voltage 20-30 kV and electron beam current 10 pA-40 / 100 / 300 nA.

[0115] 2. The elemental composition, distribution, and particle size of the carbon-carbon composite materials prepared in the examples and comparative examples were analyzed using an X-ray energy dispersive spectroscopy (EDS) instrument configured with a field emission scanning electron microscope (FESS) from ZEISS Merlin, Germany. The area scanning mode testing conditions included: accelerating voltage of 20–30 kV and an effective probe working area of ​​150 mm². 2 The elemental range is Be to U, and the detection limit is approximately 0.1 wt.%.

[0116] 3. Raman Imaging Analysis of Carbon-Carbon Composite Material Cross-Sections: A laser micro-Raman spectrometer (RENISHAW, in-Via Raman microscope, UK, 532nm line, helium-neon laser, laser radiation model: QONTOR) was used to observe the cross-sectional morphology of the carbon-carbon composite materials prepared in the examples and comparative examples, and Raman imaging analysis was performed on the cross-sectional morphology. This allows for high-sensitivity spectral analysis under high-resolution conditions. The specific method includes: directly breaking the carbon-carbon composite material, observing the morphology after the cross-section is exposed, and using Live Track™ technology for real-time focusing. During the test, each point is acquired under focused conditions, and the Z-axis coordinate of each point is recorded to form a surface height image. The Raman imaging results can be superimposed on the height image. The in-situ Raman imaging area is 70µm*70µm, with a step size of 1µm, and the Raman spectrum recording range is 400-3100cm². -1 The integration time for each spectrum is 100 s. The cross-sectional morphology of the fibrous composite material was observed under a 20x objective lens, and Raman spectra were acquired at a specific location within a 1 μm x 1 μm region. This spectrum has a range of 1350 cm⁻¹. -1 Nearby D peak, 1582cm -1 Nearby G peak, and 2699cm -1 Nearby 2D peaks; also using Raman imaging, observe the intensity distribution of the D peaks at different points.

[0117] 4. The types and contents of non-carbon elements in the carbon-carbon composite materials prepared in the examples and comparative examples were tested using inductively coupled plasma atomic emission spectrometry.

[0118] The main instruments and reagents are as follows:

[0119] (1) Varian 725-ES inductively coupled plasma atomic emission spectrometer;

[0120] (2) Haoyue HMF1600-40 box furnace;

[0121] (3) LabTech Digiblock ST36 electrothermal digester;

[0122] (4) Multi-element standard solution: 1000ug / mL (Steel Research Institute Nake Testing Technology Co., Ltd.); Praseodymium standard stock solution: 1000ug / mL (National Nonferrous Metals and Electronic Materials Analysis and Testing Center); Vanadium standard stock solution: 1000ug / mL (National Nonferrous Metals and Electronic Materials Analysis and Testing Center); The ultrapure water used in the experiment was prepared by the Genie Purist intelligent ultrapure water system (resistivity = 18.2MΩcm, 25℃); Hydrogen peroxide (30wt%), hydrochloric acid, nitric acid and hydrofluoric acid were all of superior purity; Sulfuric acid was of process ultrapure purity (Sinopharm Chemical Reagent Co., Ltd.); Liquid argon (Chart Cryogenic Engineering Systems (Changzhou) Co., Ltd.).

[0123] The instrument's operating conditions are as follows:

[0124] Instrument operating parameters: High-frequency power: 1100W; Plasma gas flow rate: 15L / min -1 Auxiliary gas flow rate: 1.5 L / min -1 Atomizing gas flow rate: 0.75L / min -1 Sample injection pump speed: 15 rpm; observation height: 10 mm.

[0125] The experimental method is as follows:

[0126] (1) Accurately weigh 0.1g of sample into a clean quartz crucible, place it in a box furnace, and gradually heat it to 930℃ for ashing treatment to obtain ash. The percentage of weight loss of the sample during the calcination process is the carbon content of the fibrous carbon-carbon composite material in this invention;

[0127] (2) Use a small amount of ultrapure water to transfer all the ash to a PFA test tube, add aqua regia, hydrogen peroxide, sulfuric acid and hydrofluoric acid in sequence, cover and place in an electric digestion apparatus to heat until the sample is completely digested;

[0128] (3) Remove the test tube and cool it to room temperature. Transfer it to a 50 mL volumetric flask using ultrapure water and make up to volume for testing.

[0129] (4) Prepare mixed standard solutions of elements, plot test spectra, use inductively coupled plasma optical emission spectrometer to detect the test solution, and calculate the content of each element according to the plotted test spectra;

[0130] Inductively coupled plasma atomic emission spectrometry (ICP-AES) allows for the simultaneous selection of multiple characteristic spectral lines for each element and features synchronous background correction. Therefore, in this experiment, four spectral lines were selected for each element to be measured. By comprehensively analyzing the intensity, interference, and stability, analytical lines with less spectral interference and higher precision were chosen.

[0131] Example 1

[0132] Methods for preparing carbon-carbon composite materials include:

[0133] Short-cut carbon fibers (12K specification, 3mm length, 90% carbon content by weight), carbonized resin powder, and a metal source were reacted in a high-temperature furnace for 48 hours in the presence of nitrogen (gas flow rate of 100mL / min).

[0134] The weight ratio of metal source, carbonized resin powder and short-cut carbon fiber is 50:100:1. The metal sources are sodium source (NaCl), potassium source (KCl), nickel source (NiF2), lithium source (LiF), platinum source (Pt(OH)2), iron source (FeCl3), chromium source (Li2CrO4) and vanadium source (V2O3). The weight ratio of sodium source, potassium source, nickel source, lithium source, platinum source, iron source, chromium source and vanadium source is 55:35:20:15:15:20:3:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 105:1:3:55.

[0135] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2200℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 40 ppm.

[0136] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0137] The carbon-carbon composite material prepared in this embodiment (macromorphological diagram as shown) Figure 1 As shown in the figure, the carbon-carbon composite material (which appears as black fibers) has the following characteristics:

[0138] (1) The cross-sectional morphology of the carbon-carbon composite material was measured using scanning electron microscopy, such as... Figure 10 As shown, the center consists of a single carbon fiber with a diameter of 5 μm and a length of 3 mm. The outer periphery of the single carbon fiber is surrounded by 12 concentric graphite sheets, with the thickness of the 12 graphite sheets gradually increasing from the inside out. The ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 25:1. Nanoscale metal particles are filled between any two adjacent graphite sheets. The carbon-carbon composite material has a diameter of 0.25 mm and a length of 3 mm.

[0139] (2) The carbon-carbon composite material is black, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.07 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.162:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.483:1.

[0140] (3) The main elements contained in carbon-carbon composite materials include: carbon content of 50 wt%; sodium content of 10.2 wt%; potassium content of 6.3 wt%; nickel content of 3.3 wt%; lithium content of 2.9 wt%; platinum content of 2.7 wt%; iron content of 3.1 wt%; chromium content of 0.1 wt%; vanadium content of 0.2 wt%; that is, carbon-carbon composite materials contain 50 wt% carbon, 19.4 wt% of Group IA metals, 0.2 wt% of Group VB metals, 0.1 wt% of Group VIB metals and 9.1 wt% of Group VIII metals; elements with a content of less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead and strontium.

[0141] The features of steps (1) and (2) were obtained by analysis using a ZEISS Merlin field emission scanning electron microscope and an X-ray energy dispersive spectrometer configured with a ZEISS Merlin field emission scanning electron microscope.

[0142] from Figures 2-9 As can be seen from the elemental energy spectrum, the Na(2,4-dimethylformamide) in the carbon-carbon composite material prepared in this embodiment contains... Figure 2 ), K( Figure 3 ), Ni ( Figure 4 ), Li ( Figure 5 ), Pt( Figure 6 ), Fe( Figure 7 ) and Cr( Figure 8 ) and V( Figure 9 It is uniformly distributed and consists of nanoparticles.

[0143] Example 2

[0144] Methods for preparing carbon-carbon composite materials include:

[0145] Short-cut carbon fibers (24K, 6mm in length, 95% carbon by weight), amorphous graphite, and a metal source were reacted in a high-temperature furnace for 100 hours in the presence of nitrogen (gas flow rate of 200 mL / min).

[0146] The weight ratio of metal source, amorphous graphite and chopped carbon fiber is 36:70:1. The metal sources are sodium source (NaF), potassium source (KF), nickel source (NiCl2), lithium source (LiOH), platinum source (PtO2), iron source (Fe2O3), chromium source (K2CrO4) and vanadium source (VO2). The weight ratio of sodium source, potassium source, nickel source, lithium source, platinum source, iron source, chromium source and vanadium source is 70:95:55:32:50:40:3:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 197:1:3:145.

[0147] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2200℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 40 ppm.

[0148] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 5mm, and a filter screen is installed before the valve along the gas flow direction.

[0149] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0150] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 6 mm; the outer periphery of the single carbon fiber is surrounded by 9 layers of concentric graphite sheets, the thickness of the 9 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 9 graphite sheets to the diameter of the single carbon fiber is 59:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.6 mm and a length of 6 mm.

[0151] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 1.6 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.161:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.479:1.

[0152] (3) The main elements contained in carbon-carbon composite materials include: carbon (53 wt%), sodium (6.9 wt%), potassium (9.3 wt%), nickel (5.2 wt%), lithium (3.1 wt%), platinum (4.7 wt%), iron (4.2 wt%), chromium (0.3 wt%), and vanadium (0.1 wt%). That is, carbon-carbon composite materials contain 53 wt% carbon, 19.3 wt% Group IA metals, 0.1 wt% Group VB metals, 0.3 wt% Group VIB metals, and 14.1 wt% Group VIII metals. Elements with a content less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead, and strontium.

[0153] Example 3

[0154] Methods for preparing carbon-carbon composite materials include:

[0155] Short-cut carbon fibers (50K specification, 9mm length, 90% carbon content), carbonized resin powder, and a metal source were reacted in a high-temperature furnace for 80 hours in the presence of nitrogen (gas flow rate of 300mL / min).

[0156] The weight ratio of metal source, carbonized resin powder and short-cut carbon fiber is 35:50:1. The metal sources are sodium source (NaCl), potassium source (KCl), nickel source (NiF2), lithium source (LiF), platinum source (Pt(OH)2), iron source (FeCl3), chromium source (Li2CrO4) and vanadium source (V2O3). The weight ratio of sodium source, potassium source, nickel source, lithium source, platinum source, iron source, chromium source and vanadium source is 40:30:25:30:20:15:3:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 100:1:3:60.

[0157] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2800℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 30 ppm.

[0158] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 15mm, and a filter screen is installed before the valve along the gas flow direction.

[0159] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0160] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 9 mm; the outer periphery of the single carbon fiber is surrounded by 8 layers of concentric graphite sheets, the thickness of the 8 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 8 graphite sheets to the diameter of the single carbon fiber is 39:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.4 mm and a length of 9 mm.

[0161] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.08 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.182:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.540:1.

[0162] (3) The main elements contained in carbon-carbon composite materials include: carbon (65 wt%), sodium (7.2 wt%), potassium (5.3 wt%), nickel (4.1 wt%), lithium (6.2 wt%), platinum (3.5 wt%), iron (3.1 wt%), chromium (0.5 wt%), and vanadium (0.2 wt%). That is, carbon-carbon composite materials contain 65 wt% carbon, 18.7 wt% Group IA metals, 0.2 wt% Group VB metals, 0.5 wt% Group VIB metals, and 10.7 wt% Group VIII metals. Elements with a content less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead, and strontium.

[0163] Example 4

[0164] Methods for preparing carbon-carbon composite materials include:

[0165] Short-cut carbon fibers (12K specification, 6mm length, 95% carbon content), amorphous graphite, and a metal source were reacted in a high-temperature furnace for 120 hours in the presence of nitrogen (gas flow rate of 300mL / min).

[0166] The weight ratio of metal source, amorphous graphite and chopped carbon fiber is 32:65:1. The metal sources are sodium source (NaF), potassium source (KF), nickel source (NiCl2), lithium source (LiOH), platinum source (PtO2), iron source (Fe2O3), chromium source (K2CrO4) and vanadium source (VO2). The weight ratio of sodium source, potassium source, nickel source, lithium source, platinum source, iron source, chromium source and vanadium source is 25:20:20:20:10:10:3:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 65:1:3:40.

[0167] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2800℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 40 ppm.

[0168] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 20mm, and a filter screen is installed before the valve along the gas flow direction.

[0169] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0170] (1) The center is a single carbon fiber with a diameter of 7 μm and a length of 6 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 43:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.6 mm and a length of 6 mm.

[0171] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 1.3 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.180:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.551:1.

[0172] (3) The main elements contained in carbon-carbon composite materials include: carbon (58 wt%), sodium (7.0 wt%), potassium (5.1 wt%), nickel (3.9 wt%), lithium (6.0 wt%), platinum (3.2 wt%), iron (2.8 wt%), chromium (0.7 wt%), and vanadium (0.3 wt%). That is, carbon-carbon composite materials contain 58 wt% carbon, 18.1 wt% Group IA metals, 0.3 wt% Group VB metals, 0.7 wt% Group VIB metals, and 9.9 wt% Group VIII metals. Elements with a content less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead, and strontium.

[0173] Example 5

[0174] Methods for preparing carbon-carbon composite materials include:

[0175] Short-cut carbon fibers (12K specification, 6mm length, 95% carbon content), amorphous graphite, and a metal source were reacted in a high-temperature furnace for 36 hours in the presence of nitrogen (gas flow rate of 300mL / min).

[0176] The weight ratio of metal source, amorphous graphite and chopped carbon fiber is 35:50:1. The metal sources are sodium source (NaF), potassium source (KF), nickel source (NiCl2), lithium source (LiOH), platinum source (PtO2), iron source (Fe2O3), chromium source (K2CrO4) and vanadium source (VO2). The weight ratio of sodium source, potassium source, nickel source, lithium source, platinum source, iron source, chromium source and vanadium source is 180:180:120:100:85:35:10:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 460:1:10:240.

[0177] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2800℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 30 ppm.

[0178] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0179] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0180] (1) The center is a single carbon fiber with a diameter of 7 μm and a length of 6 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 57:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.8 mm and a length of 6 mm.

[0181] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 1.3 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.187:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.555:1.

[0182] (3) The main elements contained in carbon-carbon composite materials include: carbon (73 wt%), sodium (9.2 wt%), potassium (6.2 wt%), nickel (2.3 wt%), lithium (2.1 wt%), platinum (1.7 wt%), iron (1.7 wt%), chromium (0.3 wt%), and vanadium (0.2 wt%). That is, carbon-carbon composite materials contain 73 wt% carbon, 17.5 wt% Group IA metals, 0.2 wt% Group VB metals, 0.3 wt% Group VIB metals, and 5.7 wt% Group VIII metals. Elements with a content less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead, and strontium.

[0183] Example 6

[0184] Methods for preparing carbon-carbon composite materials include:

[0185] Short-cut carbon fibers (12K specification, 6mm length, 95% carbon content), amorphous graphite, and a metal source were reacted in a high-temperature furnace for 120 hours in the presence of nitrogen (gas flow rate of 100mL / min).

[0186] The weight ratio of metal source, amorphous graphite and chopped carbon fiber is 31:65:1. The metal sources are sodium source (NaF), potassium source (KF), nickel source (NiCl2), lithium source (LiOH), platinum source (PtO2), iron source (Fe2O3), chromium source (K2CrO4) and vanadium source (VO2). The weight ratio of sodium source, potassium source, nickel source, lithium source, platinum source, iron source, chromium source and vanadium source is 180:170:110:100:40:20:10:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 450:1:10:170.

[0187] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2800℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 20 ppm.

[0188] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0189] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0190] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 6 mm; the outer periphery of the single carbon fiber is surrounded by 10 layers of concentric graphite sheets, the thickness of the 10 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 10 graphite sheets to the diameter of the single carbon fiber is 98:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 1.0 mm and a length of 6 mm.

[0191] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 1.5 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.187:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.553:1.

[0192] (3) The main elements contained in carbon-carbon composite materials include: 55% by weight of carbon; 11.2% by weight of sodium; 8.3% by weight of potassium; 5.3% by weight of nickel; 7.1% by weight of lithium; 2.2% by weight of platinum; 1.1% by weight of iron; 0.5% by weight of chromium; and 0.15% by weight of vanadium. That is, carbon-carbon composite materials contain 55% by weight of carbon, 26.6% by weight of Group IA metals, 0.15% by weight of Group VB metals, 0.5% by weight of Group VIB metals, and 8.6% by weight of Group VIII metals. Elements with a content of less than 0.001% by weight include: zinc, manganese, silver, barium, copper, magnesium, lead, and strontium.

[0193] Example 7

[0194] Methods for preparing carbon-carbon composite materials include:

[0195] Short-cut carbon fibers (12K specification, 6mm length, 95% carbon content), amorphous graphite, and a metal source were reacted in a high-temperature furnace for 120 hours in the presence of nitrogen (gas flow rate of 200mL / min).

[0196] The weight ratio of metal source, amorphous graphite and chopped carbon fiber is 32:66:1. The metal sources are sodium source (NaF), potassium source (KF), nickel source (NiCl2), lithium source (LiOH), platinum source (PtO2), iron source (Fe2O3), chromium source (K2CrO4) and vanadium source (VO2). The weight ratio of sodium source, potassium source, nickel source, lithium source, platinum source, iron source, chromium source and vanadium source is 180:180:150:100:60:40:10:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 460:1:10:250.

[0197] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2800℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 20 ppm.

[0198] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0199] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0200] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 6 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 39:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.4 mm and a length of 6 mm.

[0201] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.6 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.182:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.553:1.

[0202] (3) The main elements contained in carbon-carbon composite materials include: carbon (54 wt%), sodium (12.2 wt%), potassium (10.3 wt%), nickel (6.3 wt%), lithium (8.1 wt%), platinum (1.8 wt%), iron (1.2 wt%), chromium (0.7 wt%), and vanadium (0.3 wt%). That is, carbon-carbon composite materials contain 54 wt% carbon, 30.6 wt% Group IA metals, 0.3 wt% Group VB metals, 0.7 wt% Group VIB metals, and 9.3 wt% Group VIII metals. Elements with a content less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead, and strontium.

[0203] Example 8

[0204] Methods for preparing carbon-carbon composite materials include:

[0205] Short-cut carbon fibers (12K specification, 6mm length, 95% carbon content), amorphous graphite, and a metal source were reacted in a high-temperature furnace for 72 hours in the presence of nitrogen (gas flow rate of 300mL / min).

[0206] The weight ratio of metal source, amorphous graphite and chopped carbon fiber is 58:115:1. The metal sources are sodium (NaF), potassium (KF), nickel (NiCl2), lithium (LiOH), platinum (PtO2), iron (Fe2O3), chromium (K2CrO4) and vanadium (VO2). The weight ratio of sodium, potassium, nickel, lithium, platinum, iron, chromium and vanadium sources is 110:80:50:30:20:10:6:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 220:1:6:80.

[0207] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2800℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 20 ppm.

[0208] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0209] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0210] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 6 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 50:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.5 mm and a length of 6 mm.

[0211] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 1.0 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.182:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.554:1.

[0212] (3) The main elements contained in carbon-carbon composite materials include: carbon (69 wt%), sodium (7.2 wt%), potassium (5.3 wt%), nickel (3.2 wt%), lithium (2.2 wt%), platinum (1.2 wt%), iron (2.7 wt%), chromium (0.4 wt%), and vanadium (0.37 wt%). That is, carbon-carbon composite materials contain 69 wt% carbon, 14.7 wt% Group IA metals, 0.37 wt% Group VB metals, 0.4 wt% Group VIB metals, and 7.1 wt% Group VIII metals. Elements with a content less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead, and strontium.

[0213] Example 9

[0214] Methods for preparing carbon-carbon composite materials include:

[0215] Short-cut carbon fibers (12K specification, 6mm length, 95% carbon content), amorphous graphite, and a metal source were reacted in a high-temperature furnace for 48 hours in the presence of nitrogen (gas flow rate of 300mL / min).

[0216] The weight ratio of metal source, amorphous graphite and chopped carbon fiber is 70:140:1. The metal sources are sodium source (NaF), potassium source (KF), nickel source (NiCl2), lithium source (LiOH), platinum source (PtO2), iron source (Fe2O3), chromium source (K2CrO4) and vanadium source (VO2). The weight ratio of sodium source, potassium source, nickel source, lithium source, platinum source, iron source, chromium source and vanadium source is 45:30:25:10:20:15:3:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 85:1:3:60.

[0217] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2800℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 20 ppm.

[0218] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0219] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0220] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 6 mm; the outer periphery of the single carbon fiber is surrounded by 10 layers of concentric graphite sheets, the thickness of the 10 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 10 graphite sheets to the diameter of the single carbon fiber is 89:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.9 mm and a length of 6 mm.

[0221] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 1.2 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.180:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.555:1.

[0222] (3) The main elements contained in carbon-carbon composite materials include: carbon (87 wt%), sodium (2.2 wt%), potassium (1.5 wt%), nickel (1.2 wt%), lithium (1.5 wt%), platinum (1.0 wt%), iron (1.7 wt%), chromium (0.1 wt%), and vanadium (0.35 wt%). That is, carbon-carbon composite materials contain 87 wt% carbon, 5.2 wt% Group IA metals, 0.35 wt% Group VB metals, 0.1 wt% Group VIB metals, and 3.9 wt% Group VIII metals. Elements with a content less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead, and strontium.

[0223] Example 10

[0224] The method of Example 1 was implemented, except that the metal source was a potassium source, a nickel source, a lithium source, a platinum source, an iron source, a chromium source, and a vanadium source, but no sodium source was used.

[0225] Methods for preparing carbon-carbon composite materials include:

[0226] Short-cut carbon fibers (12K specification, 3mm length, 90% carbon content by weight), carbonized resin powder, and a metal source were reacted in a high-temperature furnace for 48 hours in the presence of nitrogen (gas flow rate of 100mL / min).

[0227] The weight ratio of metal source, carbonized resin powder and short-cut carbon fiber is 50:100:1. The metal sources are potassium source (KCl), nickel source (NiF2), lithium source (LiF), platinum source (Pt(OH)2), iron source (FeCl3), chromium source (Li2CrO4) and vanadium source (V2O3). The weight ratio of potassium source, nickel source, lithium source, platinum source, iron source, chromium source and vanadium source is 35:20:15:15:20:3:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 50:1:3:55.

[0228] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2200℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 40 ppm.

[0229] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0230] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0231] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 3 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 25:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.25 mm and a length of 3 mm.

[0232] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.07 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.162:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.483:1.

[0233] (3) The main elements contained in carbon-carbon composite materials include: carbon content of 50 wt%; potassium content of 6.4 wt%; nickel content of 3.1 wt%; lithium content of 2.7 wt%; platinum content of 2.9 wt%; iron content of 3.5 wt%; chromium content of 0.3 wt%; and vanadium content of 0.3 wt%. That is, carbon-carbon composite materials contain 50 wt% carbon, 9.1 wt% of Group IA metals, 0.3 wt% of Group VB metals, 0.3 wt% of Group VIB metals, and 9.5 wt% of Group VIII metals; elements with a content of less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead, and strontium.

[0234] Example 11

[0235] The method of Example 1 was implemented, except that the metal source was sodium, nickel, lithium, platinum, iron, chromium and vanadium, but not potassium.

[0236] Methods for preparing carbon-carbon composite materials include:

[0237] Short-cut carbon fibers (12K specification, 3mm length, 90% carbon content by weight), carbonized resin powder, and a metal source were reacted in a high-temperature furnace for 48 hours in the presence of nitrogen (gas flow rate of 100mL / min).

[0238] The weight ratio of metal source, carbonized resin powder and short-cut carbon fiber is 50:100:1. The metal sources are sodium source (NaCl), nickel source (NiF2), lithium source (LiF), platinum source (Pt(OH)2), iron source (FeCl3), chromium source (Li2CrO4) and vanadium source (V2O3). The weight ratio of sodium source, nickel source, lithium source, platinum source, iron source, chromium source and vanadium source is 55:20:15:15:20:3:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 70:1:3:55.

[0239] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2200℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 40 ppm.

[0240] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0241] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0242] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 3 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 25:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.25 mm and a length of 3 mm.

[0243] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.07 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.162:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.483:1.

[0244] (3) The main elements contained in carbon-carbon composite materials include: carbon content of 50 wt%; sodium content of 10.5 wt%; nickel content of 3.2 wt%; lithium content of 2.6 wt%; platinum content of 2.6 wt%; iron content of 3.3 wt%; chromium content of 0.1 wt%; and vanadium content of 0.4 wt%. That is, carbon-carbon composite materials contain 50 wt% carbon, 13.1 wt% of Group IA metals, 0.4 wt% of Group VB metals, 0.1 wt% of Group VIB metals, and 9.1 wt% of Group VIII metals. Elements with a content of less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead, and strontium.

[0245] Example 12

[0246] The method of Example 1 is implemented, except that the metal source is a sodium source, a potassium source, a lithium source, a platinum source, an iron source, a chromium source, and a vanadium source, but does not include a nickel source.

[0247] Methods for preparing carbon-carbon composite materials include:

[0248] Short-cut carbon fibers (12K specification, 3mm length, 90% carbon content by weight), carbonized resin powder, and a metal source were reacted in a high-temperature furnace for 48 hours in the presence of nitrogen (gas flow rate of 100mL / min).

[0249] The weight ratio of metal source, carbonized resin powder and short-cut carbon fiber is 50:100:1. The metal sources are sodium source (NaCl), potassium source (KCl), lithium source (LiF), platinum source (Pt(OH)2), iron source (FeCl3), chromium source (Li2CrO4) and vanadium source (V2O3). The weight ratio of sodium source, potassium source, lithium source, platinum source, iron source, chromium source and vanadium source is 55:35:15:15:20:3:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 105:1:3:35.

[0250] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2200℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 40 ppm.

[0251] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0252] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0253] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 3 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 25:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.25 mm and a length of 3 mm.

[0254] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.07 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.162:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.483:1.

[0255] (3) The main elements contained in carbon-carbon composite materials include: carbon content of 50 wt%; sodium content of 10.7 wt%; potassium content of 6.7 wt%; lithium content of 2.8 wt%; platinum content of 2.8 wt%; iron content of 3.4 wt%; chromium content of 0.2 wt%; and vanadium content of 0.1 wt%. That is, carbon-carbon composite materials contain 50 wt% carbon, 20.2 wt% of Group IA metals, 0.1 wt% of Group VB metals, 0.2 wt% of Group VIB metals, and 6.2 wt% of Group VIII metals; elements with a content of less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead, and strontium.

[0256] Example 13

[0257] The method of Example 1 was implemented, except that the metal source was sodium, potassium, nickel, platinum, iron, chromium and vanadium, and no lithium source was used.

[0258] Methods for preparing carbon-carbon composite materials include:

[0259] Short-cut carbon fibers (12K specification, 3mm length, 90% carbon content by weight), carbonized resin powder, and a metal source were reacted in a high-temperature furnace for 48 hours in the presence of nitrogen (gas flow rate of 100mL / min).

[0260] The weight ratio of metal source, carbonized resin powder and short-cut carbon fiber is 50:100:1. The metal sources are sodium source (NaCl), potassium source (KCl), nickel source (NiF2), platinum source (Pt(OH)2), iron source (FeCl3), chromium source (Li2CrO4) and vanadium source (V2O3). The weight ratio of sodium source, potassium source, nickel source, platinum source, iron source, chromium source and vanadium source is 55:35:20:15:20:3:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 90:1:3:55.

[0261] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2200℃, the purity of the nitrogen atmosphere is 99.99% by volume, and the oxygen content is 40ppm.

[0262] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0263] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0264] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 3 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 25:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.25 mm and a length of 3 mm.

[0265] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.07 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.162:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.483:1.

[0266] (3) The main elements contained in carbon-carbon composite materials include: carbon content of 50 wt%; sodium content of 10.4 wt%; potassium content of 6.5 wt%; nickel content of 3.5 wt%; platinum content of 2.5 wt%; iron content of 3.6 wt%; chromium content of 0.2 wt%; and vanadium content of 0.1 wt%. That is, carbon-carbon composite materials contain 50 wt% carbon, 16.9 wt% of Group IA metals, 0.1 wt% of Group VB metals, 0.2 wt% of Group VIB metals, and 9.6 wt% of Group VIII metals; elements with a content of less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead, and strontium.

[0267] Example 14

[0268] The method of Example 1 was implemented, except that the metal source was a sodium source, a potassium source, a nickel source, a lithium source, an iron source, a chromium source, and a vanadium source, but no platinum source was used.

[0269] Methods for preparing carbon-carbon composite materials include:

[0270] Short-cut carbon fibers (12K specification, 3mm length, 90% carbon content by weight), carbonized resin powder, and a metal source were reacted in a high-temperature furnace for 48 hours in the presence of nitrogen (gas flow rate of 100mL / min).

[0271] The weight ratio of metal source, carbonized resin powder and short-cut carbon fiber is 50:100:1. The metal sources are sodium source (NaCl), potassium source (KCl), nickel source (NiF2), lithium source (LiF), iron source (FeCl3), chromium source (Li2CrO4) and vanadium source (V2O3). The weight ratio of sodium source, potassium source, nickel source, lithium source, iron source, chromium source and vanadium source is 55:35:20:15:20:3:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 105:1:3:40.

[0272] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2200℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 40 ppm.

[0273] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0274] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0275] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 3 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 25:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.25 mm and a length of 3 mm.

[0276] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.07 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.162:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.483:1.

[0277] (3) The main elements contained in carbon-carbon composite materials include: carbon content of 50 wt%; sodium content of 10.6 wt%; potassium content of 6.5 wt%; nickel content of 3.4 wt%; lithium content of 2.5 wt%; iron content of 3.2 wt%; chromium content of 0.3 wt%; vanadium content of 0.3 wt%; that is, carbon-carbon composite materials contain 50 wt% carbon, 19.6 wt% group IA metal elements, 0.3 wt% group VB metal elements, 0.3 wt% group VIB metal elements and 6.6 wt% group VIII metal elements; elements with a content of less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead and strontium.

[0278] Example 15

[0279] The method of Example 1 was implemented, except that the metal source was a sodium source, a potassium source, a nickel source, a lithium source, a platinum source, a chromium source, and a vanadium source, but no iron source was used.

[0280] Methods for preparing carbon-carbon composite materials include:

[0281] Short-cut carbon fibers (12K specification, 3mm length, 90% carbon content by weight), carbonized resin powder, and a metal source were reacted in a high-temperature furnace for 48 hours in the presence of nitrogen (gas flow rate of 100mL / min).

[0282] The weight ratio of metal source, carbonized resin powder and short-cut carbon fiber is 50:100:1. The metal sources are sodium source (NaCl), potassium source (KCl), nickel source (NiF2), lithium source (LiF), platinum source (Pt(OH)2), chromium source (Li2CrO4) and vanadium source (V2O3). The weight ratio of sodium source, potassium source, nickel source, lithium source, platinum source, chromium source and vanadium source is 55:35:20:15:15:3:1, that is, the weight ratio of Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source is 105:1:3:35.

[0283] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2200℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 40 ppm.

[0284] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0285] The carbon-carbon composite material prepared in this embodiment has the following characteristics:

[0286] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 3 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 25:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.25 mm and a length of 3 mm.

[0287] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.07 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.162:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.483:1.

[0288] (3) The main elements contained in carbon-carbon composite materials include: carbon content of 50 wt%; sodium content of 10.4 wt%; potassium content of 6.2 wt%; nickel content of 3.3 wt%; lithium content of 2.7 wt%; platinum content of 2.4 wt%; chromium content of 0.1 wt%; and vanadium content of 0.2 wt%. That is, carbon-carbon composite materials contain 50 wt% carbon, 19.3 wt% of Group IA metals, 0.2 wt% of Group VB metals, 0.1 wt% of Group VIB metals, and 5.7 wt% of Group VIII metals. Elements with a content of less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead, and strontium.

[0289] Comparative Example 1

[0290] The method of Example 1 was carried out, except that short-cut carbon fibers were not added; a composite material was obtained.

[0291] The composite material prepared in this comparative example is in block form and contains 99.9% carbon by weight. It does not contain sodium, potassium, nickel, lithium, platinum, iron, chromium, or vanadium. Elements present in amounts less than 0.001% by weight include zinc, manganese, silver, barium, copper, magnesium, and strontium. Due to the lack of short-cut carbon fibers, metal particles cannot form growth attachment points; instead, carbon vapor can only grow into blocky carbonaceous materials with extremely high carbon content on the surface of the high-temperature furnace inner wall.

[0292] Since short-cut carbon fibers were not used in this comparative example, the carbon-carbon composite material described in this invention could not be obtained.

[0293] Comparative Example 2

[0294] The method was carried out according to Example 1, except that no inert atmosphere was used for protection during the reaction; a composite material was obtained.

[0295] The composite material prepared in this comparative example contains 99.9% by weight of carbon and does not contain sodium, potassium, nickel, lithium, platinum, iron, chromium, or vanadium. Elements with a content of less than 0.001% by weight include zinc, manganese, silver, barium, copper, magnesium, and strontium.

[0296] Since there was no inert atmosphere protection in this comparative example, the carbon-carbon composite material described in this invention could not be obtained.

[0297] Comparative Example 3

[0298] The method was implemented according to Example 1, except that no carbonized resin powder and metal source were added to the high-temperature furnace.

[0299] No product was generated in this comparative example.

[0300] Comparative Example 4

[0301] The method was implemented according to Example 1, except that the core temperature of the high-temperature furnace was 1200°C. At this temperature, the reaction temperature was too low to allow the carbon in the carbonized resin powder to volatilize and grow further on the carbon fiber surface, and the metal particles could not adhere to the carbon fiber surface.

[0302] Therefore, no product was generated in this comparative example.

[0303] Comparative Example 5

[0304] The method was implemented according to Example 1, except that the gas flow rate was 2000 mL / min. At this time, due to the large gas flow rate, the microenvironment for stable growth of graphite sheets could not be maintained, and metal particles could not adhere to the surface of carbon fibers or graphite sheets.

[0305] Therefore, no product was generated in this comparative example.

[0306] Comparative Example 6

[0307] The method was carried out according to Example 1, except that the gas flow rate was 10 mL / min;

[0308] The carbon-carbon composite material prepared in this comparative example has the following characteristics:

[0309] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 3 mm; the outer periphery of the single carbon fiber is surrounded by two concentric graphite sheets with the thickness of the two graphite sheets gradually increasing from the inside to the outside, and the ratio of the total thickness of the two graphite sheets to the diameter of the single carbon fiber is 3:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.03 mm and a length of 3 mm.

[0310] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.02 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.161:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.474:1.

[0311] (3) The main elements contained in carbon-carbon composite materials include: carbon content of 96 wt%; sodium content of 0.2 wt%; potassium content of 0.3 wt%; nickel content of 0.3 wt%; lithium content of 0.5 wt%; platinum content of 0.1 wt%; iron content of 0.1 wt%; chromium content of 0.1 wt%; vanadium content of 0.2 wt%; that is, carbon-carbon composite materials contain 96 wt% carbon, 1 wt% of Group IA metal elements, 0.2 wt% of Group VB metal elements, 0.1 wt% of Group VIB metal elements and 0.5 wt% of Group VIII metal elements. Elements with a content of less than 0.001 wt% include: zinc, manganese, silver, barium, copper, magnesium, lead and strontium.

[0312] Comparative Example 7

[0313] The method of Example 1 was implemented, except that no metal source was added.

[0314] The carbon-carbon composite material prepared in this comparative example has the following characteristics:

[0315] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 3 mm; the outer periphery of the single carbon fiber is surrounded by 9 layers of concentric graphite sheets, the thickness of the 9 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 9 graphite sheets to the diameter of the single carbon fiber is 19:1; the carbon-carbon composite material has a diameter of 0.2 mm and a length of 3 mm.

[0316] (2) The carbon-carbon composite material is gray, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.07 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.159:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.479:1.

[0317] (3) The main elements contained in carbon-carbon composite materials include: carbon content of 99.9% by weight; elements with content less than 0.001% by weight include: zinc, manganese, silver, barium, copper, lithium, magnesium and strontium.

[0318] Comparative Example 8

[0319] The method of Example 1 was implemented, except that no carbonized resin powder was added.

[0320] No product was generated in this comparative example.

[0321] Comparative Example 9

[0322] The method was implemented according to Example 1, except that there was no sodium, potassium, or lithium source among the metal sources, i.e., no Group IA metal source.

[0323] Methods for preparing carbon-carbon composite materials include:

[0324] Short-cut carbon fibers (12K specification, 3mm length, 90% carbon content by weight), carbonized resin powder, and a metal source were reacted in a high-temperature furnace for 48 hours in the presence of nitrogen (gas flow rate of 100mL / min).

[0325] The weight ratio of metal source, carbon resin powder and short-cut carbon fiber is 50:100:1. The metal sources are nickel source (NiF2), platinum source (Pt(OH)2), iron source (FeCl3), chromium source (Li2CrO4) and vanadium source (V2O3). The weight ratio of nickel source, platinum source, iron source, chromium source and vanadium source is 20:15:20:3:1, that is, the weight ratio of group VB metal source, group VIB metal source and group VIII metal source is 1:3:55.

[0326] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2200℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 40 ppm.

[0327] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0328] The carbon-carbon composite material prepared in this comparative example has the following characteristics:

[0329] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 3 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 18:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.20 mm and a length of 3 mm.

[0330] (2) The carbon-carbon composite material is black, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.03 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.161:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.482:1.

[0331] (3) The main elements contained in carbon-carbon composite materials include: carbon content of 50% by weight; nickel content of 3.5% by weight; platinum content of 2.8% by weight; iron content of 3.2% by weight; chromium content of 0.1% by weight; and vanadium content of 0.2% by weight. That is, carbon-carbon composite materials contain 50% by weight of carbon, 0.2% by weight of group VB metal elements, 0.1% by weight of group VIB metal elements and 9.5% by weight of group VIII metal elements; elements with a content of less than 0.001% by weight include: zinc, manganese, silver, barium, magnesium, lead and strontium.

[0332] Comparative Example 10

[0333] The method was implemented according to Example 1, except that there was no iron source, platinum source and nickel source in the metal source, that is, no group VIII metal source.

[0334] Methods for preparing carbon-carbon composite materials include:

[0335] Short-cut carbon fibers (12K specification, 3mm length, 90% carbon content by weight), carbonized resin powder, and a metal source were reacted in a high-temperature furnace for 48 hours in the presence of nitrogen (gas flow rate of 100mL / min).

[0336] The weight ratio of metal source, carbon resin powder and short-cut carbon fiber is 50:100:1. The metal sources are sodium source (NaCl), potassium source (KCl), lithium source (LiF), chromium source (Li2CrO4) and vanadium source (V2O3). The weight ratio of sodium source, potassium source, lithium source, chromium source and vanadium source is 55:35:15:3:1, that is, the weight ratio of group IA metal source, group VB metal source and group VIB metal source is 105:1:3.

[0337] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2200℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 40 ppm.

[0338] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0339] The carbon-carbon composite material prepared in this comparative example has the following characteristics:

[0340] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 3 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 18:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.18 mm and a length of 3 mm.

[0341] (2) The carbon-carbon composite material is black, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.02 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.160:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.481:1.

[0342] (3) The main elements contained in carbon-carbon composite materials include: carbon content of 50% by weight; sodium content of 10.3% by weight; potassium content of 6.5% by weight; lithium content of 3.1% by weight; chromium content of 0.1% by weight; and vanadium content of 0.2% by weight. That is, carbon-carbon composite materials contain 50% by weight of carbon, 19.9% ​​by weight of Group IA metals, 0.2% by weight of Group VB metals and 0.1% by weight of Group VIB metals. Elements with a content of less than 0.001% by weight include: zinc, manganese, silver, barium, magnesium, lead and strontium.

[0343] Comparative Example 11

[0344] The method of Example 1 is implemented, except that there is no vanadium source in the metal source, that is, no group VB metal source.

[0345] Methods for preparing carbon-carbon composite materials include:

[0346] Short-cut carbon fibers (12K specification, 3mm length, 90% carbon content by weight), carbonized resin powder, and a metal source were reacted in a high-temperature furnace for 48 hours in the presence of nitrogen (gas flow rate of 100mL / min).

[0347] The weight ratio of metal source, carbonized resin powder and short-cut carbon fiber is 50:100:1. The metal sources are sodium source (NaCl), potassium source (KCl), nickel source (NiF2), lithium source (LiF), platinum source (Pt(OH)2), iron source (FeCl3) and chromium source (Li2CrO4). The weight ratio of sodium source, potassium source, nickel source, lithium source, platinum source, iron source and chromium source is 55:35:20:15:15:20:3, that is, the weight ratio of Group IA metal source, Group VIB metal source and Group VIII metal source is 105:3:55.

[0348] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2200℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 40 ppm.

[0349] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0350] The carbon-carbon composite material prepared in this comparative example has the following characteristics:

[0351] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 3 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 18:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.19 mm and a length of 3 mm.

[0352] (2) The carbon-carbon composite material is black, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.03 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.162:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.483:1.

[0353] (3) The main elements contained in carbon-carbon composite materials include: carbon content of 50 wt%; sodium content of 10.3 wt%; potassium content of 6.4 wt%; nickel content of 3.4 wt%; lithium content of 2.7 wt%; platinum content of 2.5 wt%; iron content of 3.0 wt%; and chromium content of 0.1 wt%. That is, carbon-carbon composite materials contain 50 wt% carbon, 19.4 wt% group IA metals, 0.1 wt% group VIB metals and 8.9 wt% group VIII metals. Elements with a content of less than 0.001 wt% include: zinc, manganese, silver, barium, magnesium, lead and strontium.

[0354] Comparative Example 12

[0355] The method is implemented according to Example 1, except that there is no chromium source in the metal source, that is, no group VIB metal source.

[0356] Methods for preparing carbon-carbon composite materials include:

[0357] Short-cut carbon fibers (12K specification, 3mm length, 90% carbon content by weight), carbonized resin powder, and a metal source were reacted in a high-temperature furnace for 48 hours in the presence of nitrogen (gas flow rate of 100mL / min).

[0358] The weight ratio of metal source, carbonized resin powder and short-cut carbon fiber is 50:100:1. The metal sources are sodium source (NaCl), potassium source (KCl), nickel source (NiF2), lithium source (LiF), platinum source (Pt(OH)2), iron source (FeCl3) and vanadium source (V2O3). The weight ratio of sodium source, potassium source, nickel source, lithium source, platinum source, iron source and vanadium source is 55:35:20:15:15:20:1, that is, the weight ratio of group IA metal source, group VB metal source and group VIII metal source is 105:1:55.

[0359] The high-temperature furnace uses isostatically pressed graphite as the heating element. The core operating temperature of the high-temperature furnace is 2200℃, and the purity of the nitrogen atmosphere is 99.99% by volume, with an oxygen content of 40 ppm.

[0360] A valve is installed on the pipe connecting the high-temperature furnace and the exhaust gas recovery system. The valve is fully open, the pipe has an inner diameter of 10mm, and a filter screen is installed before the valve along the gas flow direction.

[0361] The carbon-carbon composite material prepared in this comparative example has the following characteristics:

[0362] (1) The center is a single carbon fiber with a diameter of 5 μm and a length of 3 mm; the outer periphery of the single carbon fiber is surrounded by 12 layers of concentric graphite sheets, the thickness of the 12 graphite sheets gradually increases from the inside to the outside, and the ratio of the total thickness of the 12 graphite sheets to the diameter of the single carbon fiber is 18:1; nano-metal particles are filled between any two adjacent graphite sheets; the carbon-carbon composite material has a diameter of 0.22 mm and a length of 3 mm.

[0363] (2) The carbon-carbon composite material is black, and each graphite sheet has independently existing carbon particles distributed on its surface. The particle size of the carbon particles is 0.02 mm. The carbon-carbon composite material is curved in the axial direction, and some of its surfaces are covered with blocky protrusions. In the Raman imaging spectrum of the carbon-carbon composite material, the average ratio of the peak intensity of the D peak to the G peak is 0.159:1, and the average ratio of the peak intensity of the 2D peak to the G peak is 0.478:1.

[0364] (3) The main elements contained in carbon-carbon composite materials include: carbon content of 50 wt%; sodium content of 10.4 wt%; potassium content of 6.5 wt%; nickel content of 3.6 wt%; lithium content of 2.6 wt%; platinum content of 2.4 wt%; iron content of 3.1 wt%; and vanadium content of 0.2 wt%. That is, carbon-carbon composite materials contain 50 wt% carbon, 19.5 wt% group IA metal elements, 0.2 wt% group VB metal elements, and 9.1 wt% group VIII metal elements. Elements with a content of less than 0.001 wt% include: zinc, manganese, silver, barium, magnesium, lead, and strontium.

[0365] Test Example 1

[0366] The carbon-carbon composite materials prepared in the examples and the composite materials obtained in the comparative examples, as well as the electrochemical properties of the carbon-carbon composite materials, were tested according to the following method (wherein, the corresponding electrochemical properties could not be measured in comparative examples 3-5 and comparative example 8 because no products were generated).

[0367] The catalytic activity was tested using a Chenhua electrochemical workstation (CHI760E) coupled with a rotating disk electrode. The test was conducted in a conventional three-electrode system, including a working electrode (rotating disk electrode), a reference electrode (saturated calomel electrode, Hg / HgO), and a counter electrode (platinum wire), with 0.1M KOH as the electrolyte.

[0368] The electrode potential is converted to the potential relative to the standard hydrogen electrode. Before testing, the working electrode needs to be rigorously polished by sequentially polishing it with alumina powder of different particle sizes (1µm, 0.3µm and 0.05µm) until it is shiny, and then cleaning it with ethanol and water and drying it before use.

[0369] First, N2 or O2 is bubbled into the electrolyte for at least 30 minutes until the gas is saturated. Then, the prepared working electrode coated with carbon-carbon composite material is immersed in the electrolyte. Within the potential range of 0-1.2V, the electrode is saturated at 100mV / s. -1 The working electrode is surface-cleaned at a rate of 10 mV / s, and then cleaned at 50 mV / s. -1 The rate was tested. Based on the integrated area of ​​the desorption peak region, the electrochemically active area (ECSA) of the carbon-carbon composite material can be calculated.

[0370] The calculation formula is as follows:

[0371]

[0372] Among them, Q H The first value represents the amount of charge desorbed, in mC; 0.21 represents the amount of charge adsorbed and desorbed by hydrogen per unit area of ​​a Pt atom, in mC / cm². -2 m represents the Pt loading on the working electrode, in grams.

[0373] The results are shown in Table 1:

[0374] Table 1

[0375]

[0376]

[0377] The results above show that the carbon-carbon composite material of the present invention includes a single carbon fiber and multiple layers of graphite sheets surrounding the single carbon fiber. Nanoscale metal particles are filled between any two adjacent layers of graphite sheets, and all of them have a high electrochemical active surface area. The high active surface area can improve the accumulation concentration and migration rate of mobile charges, which is beneficial to increasing the conductivity of the electrode material and has a better effect.

[0378] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A carbon-carbon composite material, characterized by, The carbon-carbon composite material comprises single carbon fibers and multi-layer graphite sheets surrounding the periphery of the single carbon fibers, and nano metal particles are filled between any two adjacent graphite sheets, The nano metal particles contain Group IA, Group VB, Group VIB and Group VIII metal elements. The carbon-carbon composite material contains 45-92% by weight of carbon elements, 1.6-52% by weight of Group IA metal elements, 0.1-1% by weight of Group VB metal elements, 0.05-3% by weight of Group VIB metal elements and 2.2-33% by weight of Group VIII metal elements.

2. The carbon-carbon composite material of claim 1, wherein The nano metal particles contain sodium elements, potassium elements, nickel elements, lithium elements, platinum elements, iron elements, chromium elements and vanadium elements.

3. The carbon-carbon composite of claim 2, wherein The carbon-carbon composite material contains 45-92% by weight of carbon elements, 0.7-18% by weight of sodium elements, 0.5-18% by weight of potassium elements, 0.5-15% by weight of nickel elements, 0.4-13% by weight of lithium elements, 1-10% by weight of platinum elements, 0.7-8% by weight of iron elements, 0.05-3% by weight of chromium elements and 0.1-1% by weight of vanadium elements.

4. The carbon-carbon composite of claim 3, wherein The carbon-carbon composite material contains 50-90% by weight of carbon elements, 1-15% by weight of sodium elements, 1-15% by weight of potassium elements, 1-10% by weight of nickel elements, 1-10% by weight of lithium elements, 1-5% by weight of platinum elements, 1-5% by weight of iron elements, 0.1-1% by weight of chromium elements and 0.1-0.5% by weight of vanadium elements.

5. The carbon-carbon composite of any of claims 1-4, wherein, The number of layers of graphite sheets surrounding the periphery of the single carbon fibers is 3-20 layers.

6. The carbon-carbon composite of claim 5, wherein The number of layers of graphite sheets surrounding the periphery of the single carbon fibers is 8-12 layers.

7. The carbon-carbon composite of any of claims 1-4, wherein the carbon-carbon composite has a density of at least 1.8 g / cm3. The diameter of the single carbon fibers is 4-8um.

8. The carbon-carbon composite of claim 7, wherein The diameter of the single carbon fibers is 4.5-7.5um.

9. The carbon-carbon composite of claim 7, wherein The length of the single carbon fibers is 2-10mm.

10. The carbon-carbon composite of claim 9, wherein, The length of the single carbon fibers is 3-9mm.

11. The carbon-carbon composite of any of claims 1-4, wherein, The thickness of the multi-layer graphite sheets gradually increases from inside to outside.

12. The carbon-carbon composite of any of claims 1-4, wherein The ratio of the total thickness of the multi-layer graphite sheets to the diameter of the single carbon fibers is 1-100:

1.

13. The carbon-carbon composite of any of claims 1-4, wherein The carbon-carbon composite material is in a straight line or a curved shape.

14. The carbon-carbon composite of any of claims 1-4, wherein At least part of the surface of the carbon-carbon composite material is in a bamboo joint shape and / or a convex shape.

15. The carbon-carbon composite of any of claims 1-4, wherein The diameter of the carbon-carbon composite material is 0.05-1mm.

16. The carbon-carbon composite of claim 15, wherein, The diameter of the carbon-carbon composite material is 0.1-0.3mm.

17. The carbon-carbon composite of any of claims 1-4, wherein The length of the carbon-carbon composite material is 0.1-10mm.

18. The carbon-carbon composite of claim 17, wherein, The length of the carbon-carbon composite material is 1-5mm.

19. The carbon-carbon composite of any of claims 1-4, wherein In the Raman spectrum of the carbon-carbon composite material, the ratio of the peak intensity of the D peak to the G peak is 0.07-0.3:

1.

20. The carbon-carbon composite of claim 19, wherein, In the Raman spectrum of the carbon-carbon composite material, the ratio of the peak intensity of the 2D peak to the G peak is 0.2-0.9:

1.

21. A method of making a carbon-carbon composite material, characterized by, The method comprises: reacting chopped carbon fibers, a carbon source and a metal source at 1500-3500℃ in the presence of an inert atmosphere, and the volume flow rate of the inert atmosphere is 50-500mL / min; The metal source contains Group IA metal source, Group VB metal source, Group VIB metal source and Group VIII metal source. The weight ratio of the amount of the metal source, the carbon source and the chopped carbon fiber is 20-100:30-200:

1. The weight ratio of the amount of the Group IA metal source, the Group VB metal source, the Group VIB metal source and the Group VIII metal source is 50-500:1:3-10:30-350.

22. The method of claim 21, wherein, The weight ratio of the amount of the metal source, the carbon source and the chopped carbon fiber is 30-70:50-150:

1.

23. The method of claim 21 or 22, wherein, The metal source contains a sodium source, a potassium source, a nickel source, a lithium source, a platinum source, an iron source, a chromium source and a vanadium source.

24. The method of claim 23, wherein, The weight ratio of the amount of the sodium source, the potassium source, the nickel source, the lithium source, the platinum source, the iron source, the chromium source and the vanadium source is 20-180:20-180:20-150:10-100:10-100:5-80:3-10:

1.

25. The method of claim 23, wherein, The sodium source is selected from one or more of Na2CO3, NaHCO3, NaNO3, NaCl and NaF; and / or, The potassium source is selected from one or more of KCl, K2CO3, KF and KOH; and / or, The nickel source is selected from one or more of NiO, Ni(OH)2, NiF2and NiCl2; and / or, The lithium source is selected from one or more of LiF, Li2O, LiOH and LiCl; and / or, The platinum source is selected from one or more of PtO, PtO2and Pt(OH)2; and / or, The iron source is selected from one or more of FeO, Fe2O3, Fe3O4, Fe(OH)2, Fe(OH)3, FeCl2, FeCl3and FePO4; and / or, The chromium source is selected from one or more of CrO3, Li2CrO4, K2CrO4and BaCrO4; and / or, The vanadium source is selected from one or more of VO, V2O3, VO2and V2O5.

26. The method of claim 21 or 22, wherein, The carbon source is carbonized resin and / or graphite.

27. The method of claim 26, wherein, The graphite is amorphous graphite.

28. The method of claim 21 or 22, wherein, The temperature of the reaction is 1500-3000°C; and / or, The time of the reaction is 12-720 hours; and / or, The volume flow rate of the inert atmosphere is 100-300 mL / min.

29. The method of claim 21 or 22, wherein, The length of the chopped carbon fiber is 0.1-10 mm; and / or, The specification of the chopped carbon fiber is 12-320K; and / or, The carbon content of the chopped carbon fiber is 85-95 wt%.

30. The carbon-carbon composite material prepared by the method of any one of claims 21-29.

31. The use of the carbon-carbon composite material of any one of claims 1-20 or the carbon-carbon composite material of claim 30 in graphite electrode material.

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