CN114824297A

CN114824297A - Preparation method of high-performance foam carbon electrode material applied to flow energy storage battery

Info

Publication number: CN114824297A
Application number: CN202210315834.6A
Authority: CN
Inventors: 周曦东; 刘兰英
Original assignee: Beijing Nastek Nano Technology Co ltd
Current assignee: Zhejiang Xingneng Electronic Materials Co ltd
Priority date: 2022-03-25
Filing date: 2022-03-25
Publication date: 2022-07-29

Abstract

The invention provides a preparation technology of a foam carbon electrode material applied to a liquid flow energy storage battery, which is used for preparing and producing one-dimensional, two-dimensional and three-dimensional porous foam carbon materials by selecting measures such as a proper foam carbon precursor molecular structure, element composition, purity, molding technology, a foam carbon graphitization process and the like, improving the electrical activity area of the materials by controlling the porosity, the pore size, the specific surface area of the materials and the like, and simultaneously improving and increasing the activity and the catalytic performance of the electrode material by depositing inorganic N, P elements and metals such as Bi, Cu, Mn, Ti, Ir, Ce, Cr and other simple substances or oxides thereof on the surface of the materials, thereby preparing the electrode with high current density, high current efficiency, long service life and high catalytic efficiency, and being applied to the fields of liquid flow energy storage batteries such as iron chromium, all vanadium, zinc selenium, all iron and the like.

Description

Preparation method of high-performance foam carbon electrode material applied to flow energy storage battery

Technical Field

The invention belongs to the field of preparation of materials of a liquid flow energy storage battery, and relates to a preparation method of a high-performance foam carbon electrode applied to the liquid flow energy storage battery; even more particularly, the present invention relates to the manufacture of carbon-based foam electrode materials comprising a conductive aid, a surface electrocatalyst and a modifier using a spinning, pressure spinning or casting process and a surface modification technique. The whole preparation process comprises the processes of mixing and preparing the carbon-based material and the composite auxiliary agent, spinning and felting or casting film forming, curing and pyrolyzing, and finally preparing the nano-fiber carbon felt and the foam film.

Background

Promoting the popularization and application of renewable energy sources becomes an important strategy for energy safety and economic sustainable development of countries in the world. But renewable energy power generation has obvious unsteady-state characteristics, and direct grid connection can cause the stable operation of a power grid system to be influenced. The high-efficiency energy storage battery is matched to ensure the continuity and stability of power generation and power supply, and the method is an important way for realizing the development strategy of renewable energy sources. The all-vanadium redox flow battery has the outstanding advantages of flexible structural design, easy scale production, safety, reliability, environmental friendliness and the like, and has wide application prospect and huge market potential.

In general, a carbon-based material sheet such as graphite is used as a current collector (support) on which a positive electrode material and a negative electrode material are attached in a flow energy storage battery, however, the carbon-based sheet has a two-dimensional structure and thus is inferior to a porous body in terms of the packing density for supporting an active material and an active material, specifically, the carbon-based material cannot be used as an electrode material in a manner in which the carbon-based material sheet contains an electroactive material and therefore the carbon-based material cannot suppress the disappearance of the electroactive material or the corrosion thereof, and therefore it is necessary to maintain sufficient electroactive and long-lasting stability on the carbon-based material to ensure its electrochemical performance and a certain length of service life in a flow battery; in addition, the wetting of the electrolyte among the active materials on the surface of the electrode material, the fluidity of the electrolyte and the like in the flow battery are all related to the surface performance of the electrode material and the structural characteristics of the electrode material; therefore, the preparation of electrode materials with a porous structure and special electrochemical properties is very important in the development and application of flow batteries, and high-activity electrodes such as porous foams, screens or expanded carbon substrate bodies have high and low capacitance and are easy to load surface catalysts and modifying substances, so that the preparation of electrode materials with a porous structure and special electrochemical properties is always a hot direction in academic research and industrial fields.

In order to achieve higher output, higher capacity, longer life, and the like, electrode bodies that are three-dimensional porous bodies such as foams or non-woven fabrics have been proposed, and three-dimensional reticulated porous carbon matrix electrode materials for positive electrodes, which provide secondary batteries with higher output and higher capacity, have been described in japanese patent application laid-open nos. 11-233151, 2000-19552, 2005-078991, 2006-032144, and 11-154517-4534033, require current collectors with three-dimensional structures that are more porous than two-dimensional structures. In particular, since the positive electrode current collector is easily oxidized by the electrolyte at a high charge-discharge voltage, a positive electrode current collector having sufficiently high oxidation resistance and electrolyte resistance is also required.

Chinese patents CN 103249850B and CN 110656403a respectively describe methods of preparing carbon-based porous materials and plating metal on the surface or doping conductive metal substances to improve the conductivity of electrode materials, but these methods cannot meet various environmental requirements of high-capacity liquid flow energy storage batteries, such as current density, service life, and the like.

Chinese patents CN 110656403A and CN202010947905.5 introduce an easily conductive metal-doped polyacrylonitrile carbon fiber and a preparation method thereof, and the technology only provides a method for changing the conductivity of the carbon fiber, but the method has no way of meeting the requirements of the capacity and the coulombic efficiency of the flow energy storage battery, and has high cost and strict equipment requirements.

The prior art discloses that the application of carbon-based materials in the field of current is very wide, and the application comprises carbon nanofibers for improving the surface area and the void ratio of an electrode material, a foam carbon film material production technology and other material surface composite modification; titanium dioxide, copper, bismuth, manganese, titanium carbide, copper, bismuth, manganese oxide, surface nitriding or oxidation treatment.

Polymeric micro-and nanofibers fabricated by electrospinning were first reported decades ago. However, the first carbon-based nanofibers made by electrospinning were produced in the relatively recent 2003. However, those nanofibers are not flexible. Even more recently flexible carbon-based materials comprising electrospun nanofibers have been previously reported, approximately from 2006, for example see U.S. patent publication No. 2006034948.

U.S. Pat. Nos. 5358802A, 6033506A and 10170749B2 describe methods for producing high-surface-area, multi-porosity carbon foam materials from pitch and polyacrylonitrile carbon sources, while CN 101849302 and CN201780033472.9 describe techniques for doping carbon nanotubes, silicon (Si), bismuth (Ge), tin (Sn), lead (Pb), tellurium (Sb), bismuth (Bi), zinc (Zn), aluminum (A1) and cadmium (Cd) in carbon-based materials for use in proton batteries as electrode materials.

In the above technologies, although various methods for producing carbon-based porous foam materials are introduced or applied to relevant battery materials, the liquid flow energy storage battery and the materials have respective limitations because of their own specificities, which can meet the requirements of low material cost, high current density, high coulombic efficiency and long service life. One of the main objects of the invention realized in the present application is to prepare carbon-based porous foam flow energy storage battery electrodes using spinning or tape casting. The material that is the subject of the present application will be referred to hereinafter as the flow energy storage battery foam carbon electrode, i.e. carbon-based nanofiber mats and porous flexible foam films, or flexible samples that typically use these carbon-based nanofibers. In general, spinning of carbon-based produces rigid non-woven mats of carbon-based micro-and nanofibers that are not continuous and sheet-like and, in addition, require a substrate that acts as a mechanical support, the present invention overcomes all of the disadvantages of the prior art.

One of the other main objects of the invention realized in the present application is to change the surface electrical activity or catalytic performance of the carbon-based bulk material by melt blending doping, microwave-assisted technology or vapor deposition technology, so as to make the electrode of the carbon-based porous foam flow energy storage battery have high current capacity, current density and coulombic force to meet the development requirements of the flow energy storage battery.

The invention specifically aims to provide fiber raw materials based on asphalt, PAN and plant fiber, which meet the requirements of an electrode of a liquid flow energy storage battery by modifying the raw materials in the aspects of material conductivity, porosity, pore diameter and the like, and have the characteristics of simulating the porosity of the real surface, depositing and modifying the electrochemical properties of the surface of the electrode material by compounds such as metal elements bismuth, titanium, copper, bismuth, manganese and the like, thereby ensuring that the electrode is used as the liquid flow energy storage battery with large capacity, high current density and high coulomb conversion rate in the aspects of series such as macroscopic composition, microstructure and the like.

Disclosure of Invention

The present invention provides an electrode based on monolithic 3D carbon nanotube-carbon-metal hybrid carbon foam for liquid flow energy storage batteries (vanadium or iron chromium based) and a process for producing such an electrode directly from carbon fiber precursor raw materials. The process is surprisingly simple, rapid, cost effective, and environmentally friendly. The invention also provides a liquid flow energy storage battery containing the unique electrode.

In a preferred embodiment, the vanadium-based or iron-chromium-based has an anode, a cathode, an anode half cell, a cathode half cell, a proton exchange membrane, wherein the cathode and anode comprise a monolithic 3D carbon nanotube-carbon-metal hybrid foam comprised of a plurality of pores, pore walls, and elemental metal or compound located on the surface of the pore walls (e.g., as nanoparticles embedded in the pores or as a coating deposited on the surface of the pore walls), and wherein the metal (for a flow energy storage cell) is selected from Au, Ag, Mg, Zn, Ti, Mn, Co, Ni, Sn, V, Cr, or alloys thereof, and is present in an amount of 0.1% to 50% of the total hybrid foam weight or volume. The pore walls comprise single or few-layered carbon nanotube sheets chemically bonded by a carbon material, having a carbon material to carbon nanotube weight ratio of from 1/200 to 1/2, wherein the few-layered carbon nanotube sheets have 2-10 stacked carbon nanotube planar layers with an interplanar spacing d002 of from 0.3354nm to 0.40nm as measured by X-ray diffraction, and the single or few-layered carbon nanotube sheets comprise a native carbon nanotube material having substantially zero% non-carbon elements or a non-native carbon nanotube material having 0.001% to 25% non-carbon elements by weight, wherein the non-native carbon nanotubes are selected from the group consisting of graphene oxide, reduced oxidized carbon nanotubes, fluorinated carbon nanotubes, chlorinated carbon nanotubes, brominated carbon nanotubes, iodinated carbon nanotubes, hydrogenated carbon nanotubes, doped carbon nanotubes, chemically functionalized carbon nanotubes, Or a combination thereof.

In general, a three-dimensional carbon-based material structure with high porosity is prepared by these means): the low conductivity porous nanofiber or foam is rendered conductive, such desired or foam precursor materials are doped with a predetermined amount of carbon nanotubes, and if desired, the pore-forming is performed by adding a pore-forming agent, followed by firing. The invention prepares the carbon-based material porous body by adding carbon source precursor resin such as asphalt, PAN resin and plant fiber into polymer microspheres and low-phase-splitting transforming agent, mixing and then removing the pore-forming agent, and simultaneously prepares the liquid flow energy storage battery electrode by forming a carbon-based material coating containing micro-particles on the surface of a porous carbon-based material substrate and performing compression molding, wherein the micro-particles have a surface structure with high hydrophilicity.

To form the carbon component of the resulting carbon nanotube-carbon hybrid foam, polymer particles having a high carbon yield or char yield (e.g., > 30% by weight) may be selected. Carbon yield is the weight percentage of the polymer structure that is converted by heat into a solid carbon phase rather than becoming part of a volatile gas. The high carbon yielding polymer may be selected from the group consisting of phenolic resins, polyfurfuryl alcohol, polyacrylonitrile, polyimides, polyamides, polyoxadiazoles, polybenzoxazoles, polybenzobisoxazoles, polythiazoles, polybenzothiazoles, polybenzobisoxazoles, poly (p-phenylene vinylenes), polybenzimidazoles, polybenzobisoxazoles, copolymers thereof, polymer blends thereof, or combinations thereof.

It is noted that these polymers (high carbon yield and low carbon yield) convert to carbon material that nucleates preferentially near the edges of the carbon nanotube sheet when heated at temperatures between 300 ℃ and 2,500 ℃. Such carbon materials serve to bridge the gaps between graphene sheets, thereby forming an interconnected electron-conducting path. In other words, the resulting carbon nanotube-carbon hybrid foam is composed of an integral 3D network of carbon-bonded carbon nanotube sheets, allowing for continuous transport of electrons and phonons (quantized lattice vibrations) between carbon nanotube sheets or domains without interruption. Upon further heating at a temperature above 2,500 ℃, the carbon phase incorporating the carbon nanotubes may be graphitized, provided that the carbon phase is "soft carbon" or graphitizable. In this case, both the electrical conductivity and the thermal conductivity are further increased.

Thus, in certain embodiments, the step of pyrolyzing comprises carbonizing the polymer at a temperature of from 200 ℃ to 2,500 ℃ to obtain a carbon-bonded carbon nanotube sheet. Optionally, the carbon-bonded carbon nanotube sheet may be subsequently graphitized at a temperature of from 2,500 ℃ to 3,200 ℃ to obtain a graphite-bonded carbon nanotube sheet.

It may be noted that pyrolysis of the polymer tends to result in the formation of pores in the carbon phase of the resulting polymer due to the release of those volatile gas molecules such as CO2 and H2O. However, if the polymer is not restricted upon carbonization, such pores also have a high tendency to become collapsed. We have unexpectedly found that carbon nanotube sheets surrounding polymer particles can limit carbon pore wall shrinkage and collapse, while some carbon species also penetrate into the gaps between the carbon nanotube sheets, where they bind the carbon nanotube sheets together. The pore size and pore volume (porosity level) of the resulting 3D monolithic carbon nanotube foam depends on the starting polymer size and carbon yield of the polymer, and to a lesser extent on the pyrolysis temperature.

In certain preferred embodiments, the curing step comprises imitating or casting a mass of these carbon nanotube-coated polymers into a desired shape. For example, a green body of a film can be easily formed by extruding the large amount of the carbon nanotube-coated resin to a doctor blade of a casting apparatus. The polymer may be rapidly heated and melted, the green body slightly compressed to slightly fuse the polymer particles together by heat, and rapidly cooled to solidify the green body. This cured green body is then subjected to a pyrolysis treatment (carbonization and graphitization of the polymer).

In some alternative embodiments, the solidifying step comprises melting the polymer particles to form a polymer melt mixture having graphene sheets dispersed therein, forming the polymer melt mixture into a desired shape, and solidifying the shape into a carbon nanotube-polymer composite structure. This shape may be a rod, a film (thin or thick film, wide or narrow, monolithic or in roll form), a fiber (staple or continuous length), a sheet, or any regular or odd shape. Then pyrolyzing the carbon nanotube-polymer composite shape preferably, the curing step may include compacting the carbon nanotube-coated polymer particles into a porous green compact having macroscopic pores and then infiltrating or impregnating the pores with an additional carbon source material selected from: petroleum pitches, coal tar pitches, aromatic organic materials (e.g., naphthalene or other pitch derivatives), monomers, organic polymers, or combinations thereof. The organic polymer may contain a high carbon-yielding polymer selected from: phenolic resins, polyfurfuryl alcohol, polyacrylonitrile, polyimides, polyamides, polyoxadiazoles, polybenzoxazoles, polybenzdioxazoles, polythiazoles, polybenzothiazoles, poly (p-phenylene vinylene), polybenzimidazole, polybenzobimidazole, copolymers thereof, polymer blends thereof, or combinations thereof. When infiltrated green compacts of carbon nanotube-coated polymer particles are subjected to pyrolysis, these species become additional sources of carbon if higher amounts of carbon in the hybrid foam are desired.

It may be noted that there is no limitation on the shape or size of the carbon nanotube-carbon hybrid foam of the present invention. In a preferred embodiment, the unitary carbon nanotube-carbon hybrid foam is made in the form of a continuous length rolled sheet (roll of continuous foam sheet) having a thickness of not less than 100nm and not greater than 10cm and a length of at least 1 meter long, preferably at least 2 meters, further preferably at least 10 meters, and most preferably at least 100 meters. The sheet roll is produced by a roll-to-roll process. There is no prior art carbon nanotube-based foam made in the form of a roll of sheets. It has not previously been found or suggested to have a possible roll-to-roll process for producing continuous length carbon nanotube foams (either virgin or non-virgin based).

For battery electrode applications, the carbon nanotube-carbon foam preferably has a non-carbon content of less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.5% by weight, of oxygen, nitrogen, titanium, copper, bismuth, manganese, bismuth, copper, and the like, and the pore walls have stacked carbon nanotube planes with inter-carbon nanotube spacing of less than 0.35nm, thermal conductivity of at least 250W/mK per specific gravity, and/or electrical conductivity of no less than 2,500S/cm per specific gravity.

In another preferred embodiment, the carbon nanotube-carbon hybrid foam has an oxygen content or non-carbon content of less than 0.01% by weight and the pore walls contain stacked carbon nanotube planes having an inter-carbon nanotube spacing of less than 0.34nm, a thermal conductivity of at least 300W/mK per specific gravity, and/or an electrical conductivity of not less than 3,000S/cm per specific gravity.

In yet another preferred embodiment, the carbon nanotube-carbon hybrid foam has an oxygen content or non-carbon content of no greater than 0.01% by weight, and the cell walls contain stacked carbon nanotube planes having an inter-carbon nanotube spacing of less than 0.336nm, a mosaic spread value of no greater than 0.7, a thermal conductivity of at least 350W/mK per specific gravity, and/or an electrical conductivity of no less than 3,500S/cm per specific gravity.

In yet another preferred embodiment, the carbon nanotube foam has pore walls comprising stacked carbon nanotube planes having an inter-carbon nanotube spacing of less than 0.336nm, a mosaicism spread value of no greater than 0.4, a thermal conductivity of greater than 400W/mK per specific gravity, and/or an electrical conductivity of greater than 4,000S/cm per specific gravity.

In a preferred embodiment, the pore walls contain stacked planes of carbon nanotubes having an inter-carbon nanotube spacing of less than 0.337nm and a mosaic spread value of less than 1.0. In preferred embodiments, the carbon nanotube foam exhibits a degree of graphitization of not less than 80% (preferably not less than 90%) and/or a mosaic spread value of less than 0.4. In a preferred embodiment, the pore walls contain a 3D network of interconnected carbon nanotube planes.

Another embodiment of the invention relates to the method for manufacturing the carbon-based material porous body, wherein the heat-treated carbon-based material porous body further contains, as a component thereof, less than or equal to 10 mass% of phosphorus.

Another embodiment of the present invention relates to a carbon-based material porous body including a plating layer containing at least titanium, copper, bismuth, manganese, and an alloy, wherein the carbon-based material porous body has been subjected to vapor deposition or electrolytic oxidation treatment by plating in a liquid, thereby having stronger corrosion resistance.

Another embodiment of the invention relates to the carbon-based material porous body, wherein the carbon-based material porous body has a titanium, copper, bismuth, and manganese content of 60 mass% or more and 95 mass% or less and a bismuth content of 5 mass% or more and 40 mass% or less.

Another embodiment of the present invention relates to a method for manufacturing a carbon-based material porous body including an alloy containing at least titanium, copper, bismuth, manganese, and tin, the method including the step of coating the titanium, copper, bismuth, and manganese porous body with a carbon-based material containing at least tin; and then performing an etching treatment to diffuse tin into the titanium, copper, bismuth, manganese porous body.

Another embodiment of the present invention relates to a method for manufacturing a carbon-based material porous body, wherein the titanium, copper, bismuth, manganese porous body is obtained by coating a porous substrate that has been provided with electrical conductivity with titanium, copper, bismuth, manganese, roughening by solution etching, removing the porous substrate, and then reducing the titanium, copper, bismuth, manganese.

Another embodiment of the present invention relates to a method for manufacturing a carbon-based material porous body containing at least elements and compounds of titanium, copper, bismuth, manganese, and the like, the method including the steps of: a step of plating a porous substrate having conductivity with titanium, copper, bismuth, manganese to form a titanium, copper, bismuth, manganese plating layer, followed by washing the titanium, copper, bismuth, manganese plating layer, and then continuously plating the surface of the titanium, copper, bismuth, manganese plating layer with an alloy containing at least titanium, copper, bismuth, manganese, and bismuth or an alloy containing at least titanium, copper, bismuth, manganese, and tin without drying the surface of the titanium, copper, bismuth, manganese plating layer to form an alloy plating layer; a step of removing the porous substrate by heating in an oxidizing atmosphere; and then performing an etching treatment in a reducing atmosphere to reduce the carbon-based material, wherein the step of removing the porous base material and the step of reducing the carbon-based material are performed to diffuse bismuth or tin in the alloy plating layer into the titanium, copper, bismuth, manganese plating layer.

Another embodiment of the present invention relates to the method for manufacturing a carbon-based material porous body, further including, after the step of reducing the carbon-based material: etching treatment is performed in a nitrogen atmosphere or a reducing atmosphere to nitride the surface metal, thereby improving the acid corrosion resistance effect.

Another embodiment of the invention relates to the method for manufacturing a carbon-based material porous body, wherein after the step of reducing the carbon-based material, the carbon-based material porous body has a titanium, copper, bismuth, manganese content of greater than or equal to 60 mass% and less than or equal to 95 mass% and a bismuth content of greater than or equal to 5 mass% and less than or equal to 40 mass%.

Detailed Description

The method for manufacturing the carbon-based material porous body according to the first embodiment of the invention includes: coating an alloy containing bismuth on a carbon foam electrode doped with conductive material such as titanium, copper, bismuth, and manganese; and a step of subsequently performing an etching treatment to roughen the clad surface. By coating the porous foam electrode serving as a high-electric-activity material in such a way, the phenomena of hydrogen evolution and oxygen evolution in the half-cell can be stably inhibited, and the service life and the electrochemical activity of the electrode are ensured; further, by performing the etching treatment in an inert atmosphere or a reducing atmosphere, bismuth can be diffused in the titanium, copper, bismuth, or manganese porous body.

The titanium, copper, bismuth and manganese doped porous body foam carbon electrode body can be manufactured by the following method: subjecting the surface of the porous substrate to a conductive treatment to form a conductive film (hereinafter referred to as "conductive coating layer"); subsequently, bismuth and manganese electroplating is carried out on the conductive coating layer, so that an electroplated layer is formed on the surface of the porous base material; the porous substrate is subsequently removed and then titanium, copper, bismuth, manganese are reduced.

The porous substrate used in the first embodiment may be porous, and may be any of various carbon felts such as PAN-based, pitch-based or viscose-based soft felts produced by publicly known methods, but is characterized by adding carbon nanotubes or substances of titanium, copper, manganese elements at the time of production. For example, resin foam, nonwoven fabric, felt, woven fabric, etc. may be used, and these substrates may be used in combination if necessary, but must be flexible; however, materials that can be plated with carbon-based materials and subsequently removed by firing are preferred and thus, the materials are preferably flexible with PAN-based preference in view of material cost.

The porosity of the porous substrate is not limited, and is generally greater than or equal to about 60% and less than or equal to about 97%, and preferably greater than or equal to about 80% and less than or equal to about 96%. The thickness of the porous substrate is not limited and is appropriately determined depending on the application and the like; however, the thickness is generally greater than or equal to about 2-10rm and less than or equal to about 8mm, and preferably greater than or equal to about 3rm and less than or equal to about 6mm m.

The present invention will be described below with reference to examples in which resin foam is used as a porous substrate. (conductive treatment)

The conductive treatment is not limited as long as a layer having conductivity can be formed on the surface of the resin foam. Examples of the material for forming such a layer having conductivity (conductive clad layer) include: carbon-based carbon nanotubes, titanium, copper, bismuth, manganese, and the like.

As specific examples of the conductive treatment, for example, when a carbon-based material of titanium, copper, bismuth, manganese, or the like is used, preferable examples include electroless plating and gas-phase treatments such as sputtering, vapor deposition, and ion plating. Alternatively, for example, when an alloy carbon-based material or graphite is used as the material, a mixture prepared by mixing fine powder of such a material with a binder is preferably applied to the surface of the resin foam.

The porous foam film can be treated by, for example, an activating solution (a cleaning solution produced by JAPAN KANIGEN K.K.) containing a small amount of an ion into a vapor deposition furnace or a plating bath. The sputtering treatment of bismuth, manganese can be carried out, for example, by: the resin foam is supported by a substrate holder, and then an inert gas is introduced while applying a direct current voltage between the holder and a target (bismuth, manganese) so that inert gas ions collide with titanium, copper, bismuth, manganese and cause sputtered bismuth, manganese particles to deposit on the surface of the resin foam.

The coating weight (adhering amount) of the conductive coating layer is preferably adjusted so that the final carbon-based material composition contains greater than or equal to 60 mass% and less than or equal to 95 mass% of titanium, copper, bismuth, manganese, and greater than or equal to 5 mass% and less than or equal to 40 mass% with respect to the total weight of the coating weight and the coating weight formed in the subsequent step.

Description of the specific embodiments

A preferred embodiment of the present invention describes the preparation of carbon-based nanofibers, the method comprising the steps of:

1. a precursor solution is prepared that contains a polymer that will form the final carbon-based electrode carbon source precursor.

a. According to the requirement of the application field on the content of impurities, the carbon nano tube or other conductive additives are dispersed into the precursor solution of the carbon source by adopting related melting and mixing technical measures to form uniform dispersion.

b. Sol-gel parameters can be used to increase the viscosity of the solution, but sol-gel is not entirely necessary as the viscosity can also be varied by using additives.

c. The composite desired fiber diameter can be achieved by increasing the polymer content and/or precursor content. This must be adjusted to achieve the desired fiber diameter.

d. The viscosity of the material must be preferably 0.1s ^-1 Is maintained at a shear rate of between 0.01 and 1000 pascal seconds (Pa-s) to spin the usable fibers.

e. The solids content (polymer plus precursor) must be greater than 5% by weight in order to obtain the desired deposit.

f. The solvent utilized must be carefully selected to provide a sufficiently high evaporation rate. This can be done by, but is not limited to, mixing water with alcohol (as alcohol increases the evaporation rate).

2. The foam film electrode-based film is promoted by using a pressure spinning or casting precursor solution.

a. The spinning parameters have little or no effect on the flexibility of the resulting polymer fibers.

b. Rather, the spinning parameters can be adjusted such that the spinning step can result in a continuous film or polymer fiber. This must be adapted to the various solutions required for the shaping.

3. Fibers or films obtained by the consolidation spinning or casting process, which are not carbon-based after spinning, but rather the spun fibers are polymer fibers comprising carbon nanotubes, metal ion carbon-based or inorganic polymers.

a. The fiber is cured until all of the organic content is burned and the carbon-based ions oxidize to form carbon groups.

b. Typical thermal profiles were generated as shown in the relevant experiments, with the preferred trapezoidal shape thermal profile exhibiting annealing process parameters including heating/cooling rates, annealing temperatures and residence times. Care must be taken to adjust this distribution as necessary to obtain the desired crystallinity presented above.

c. The parameters of the annealing process are different for each material composition. E.g., as low as 0.5 deg.c/min, preferably as low as 1 deg.c/min, and as high as the thermal shock (from room temperature to the annealing temperature).

d. The annealing temperature has to be greater than the crystallization point, thus allowing the formation of a carbon-based material.

e. Residence times range from 0 to 5 hours and even higher.

4. Surface coating treatment

a. And (3) placing the graphitized porous foam film into a vapor deposition furnace or an electroplating bath, and depositing a bismuth or manganese compound according to related measures, wherein the thickness of a plating layer is about 1 um.

b. And (4) performing microwave plasma nitrogen treatment for 15 minutes, so that the metal coating enters the deeper porous inner wall and simultaneously.

C. And (5) etching and activating treatment. The surface is further roughened.

Claims

1. A foam carbon electrode with high conductivity applied to a liquid flow energy storage battery electrode is characterized in that: the material is porous foam, and the conductive agent or the catalyst is deposited and dispersed in the carbon material or on the surface of the carbon material.

2. The preparation method of the carbon electrode with high conductivity applied to the electrode of the liquid flow energy storage battery, which is characterized by comprising the following steps:

step 1: mixing a conductive additive or a catalyst with a carbon material precursor or dissolving the mixture in a solvent to obtain a foam electrode precursor stock solution, wherein the conductive doped mixed substance is a carbon nano tube, graphene and an organic metal compound of metal elements such as titanium, copper, bismuth, manganese, lead, bismuth, zinc, molybdenum or tungsten;

step 2: spinning or casting the electrode precursor stock solution into required fibers or foam films, wherein the diameters of the fibers are

Or the thickness of the foamed film is

Curing at a temperature of below 150 ℃ under normal pressure to form pre-cured fiber or a foam film;

and step 3: the precursor nanofiber foam film is placed in a blast air box for non-melting treatment, and the treatment temperature is

The heat preservation time is

And 4, step 4: placing the precursor fiber or the foam film which is solidified and formed in a corundum crucible, and then sending the corundum crucible into a resistance furnace for high-temperature heat treatment, wherein the heat treatment temperature is

Time of heat preservation

Ar gas or N2 gas as protective gas to prepare the finished composite nano-fiber foam film, wherein the heating rate during high-temperature heat treatment is

The rate of temperature decrease is

3. The method for preparing the flow battery electrode material flexible carbon/carbon composite foam film with high conductivity according to claim 1, wherein the method comprises the following steps: the high molecular polymer easy to spin or tape-cast is used as a spinning or tape-casting auxiliary agent, is a polymer which can be cracked at low temperature and quickly, does not leave any residual harmful substances after cracking, and is selected from asphalt, polyacrylamide, furan resin, plant starch cellulose or other carbides.

4. The method for preparing the flexible carbon/carbon composite nanofiber or the foam film with the high-conductivity liquid flow energy storage battery electrode according to claim 1, wherein the flexible carbon/carbon composite nanofiber or the foam film is prepared by the following steps: the organic solvent is toluene, xylene, a tetrahydroceratose or chloroform.

5. The method for preparing the flexible carbon/carbon composite nanofiber foam film with the high-conductivity liquid flow energy storage battery electrode according to claim 1, is characterized in that: the precursor solutions are prepared by using a process selected from e.g. pressure spinning, electro spinning or casting, wherein the spinning or casting parameters are adjustable such that the spinning or casting step results in a polymer fiber and the spinning or casting parameters are adaptable to each precursor solution.

6. The method for preparing the flexible carbon/carbon composite nanofiber or the foam film with the high-conductivity liquid flow energy storage battery electrode according to claim 1, is characterized in that: the flexible carbon is composed of fibers with the diameter of 20-10000 nanometers, the aperture and the porosity of the carbon ultrathin foam are adjusted by a pore-forming agent according to the needs, and the pore-forming agent is a sacrificial material which can disappear or a material which can generate phase transfer, such as micromolecular water, a volatile solvent and a phase-insoluble polymer; carbon foam has its fibers free to move and is extremely flexible on a macroscopic scale.

7. The method for preparing the flexible carbon/carbon composite nanofiber or the foam film with the high-conductivity liquid flow energy storage battery electrode according to claim 1, wherein the flexible carbon/carbon composite nanofiber or the foam film is prepared by the following steps: the carbon fiber or the foam film has certain porosity, and the pore size can be adjusted according to the pore size.

8. The method of making a flexible composite comprising flexible carbon nanofibers and a polymer of claims 1 to 7, further comprising the steps of:

a. a sample of flexible carbon nanoporous foam was soaked by: applying a catalyst solution onto the sample that has been previously extended, preferably on a flat and rigid surface, wherein the catalyst is carbon nanotubes, graphene, an organometallic compound of a metal element such as titanium, copper, bismuth, manganese, lead, bismuth, zinc, molybdenum or tungsten;

b. completely soaking the carbon nano porous foam sample by the catalyst solution through capillary action and gravity;

c. the thermal curing of the catalyst solution spread over the carbon nanofiber sample by placing the sample in an oven at a temperature ranging between 20 ℃ and preferably between 60 ℃ up to 300 ℃, noting that this curing step can be achieved at temperatures as low as 20 ℃ with the only effect being a longer curing time;

d. the resulting cured sample is able to maintain the desired specific electrode structure by applying a catalyst as a thin coating on the surface of each individual carbon nanofiber foam membrane electrode, with the coating being in the preferred range of tens to hundreds of nanometers;

e. the catalyst thickness is adjusted by adjusting the viscosity of the catalyst solution used to embed the carbon nanofibers.

9. The method of making a flexible composite of claims 1 to 8, further comprising:

a. depositing a layer of catalyst material on the porous surface using a high temperature chemical or physical deposition process on an undiluted or minimally diluted catalyst precursor, having a preferred thickness of between 0.0001 to 0.0005um millimeters;

b. preferably in a high temperature vapor deposition furnace, by catalyst precursor molecules gasification on the foam film, thus by capillary force make the catalyst solution permeate the whole sample, wherein the catalyst is carbon nanotube, graphene, metal elements such as titanium, copper, bismuth, manganese, lead, bismuth, zinc, molybdenum or tungsten organometallic compound precursor material;

c. infiltrating the sample by placing the sample in a vapor deposition furnace at a temperature between 20 ℃ and 800 ℃, preferably between 20 ℃ and 600 ℃ for a predetermined cure time, and depositing a catalyst on the sample in a thickness range from 0.0001 μm to 0.005um, with a typical thickness at all void material surfaces of the composite;

d. the active catalyst compact composite material is arranged on all pore surfaces.

10. A method according to claim 8 or 9, having the following steps for the deposition of catalyst coated fiber foam film surface alone:

a. etching the activated foam film material in a special solution to roughen the surface of the activated foam film material so as to improve the active area of the surface of the electrode;

b. etching the flexible foam carbon film without the deposited catalyst to improve the binding force of the catalyst layer;

c. raising the temperature to promote the etching activation efficiency and leaving etching points as the electrochemical active points of the foam carbon film;

or carrying out porous treatment on the surface layer of the compact catalyst;

d. adopting a pulse plasma technology to perform functional treatment on the element N, O of the carbon porous foam film;

e. some pressure and/or temperature is preferably applied for better impregnation of the polymer into the carbon fiber porous membrane matrix.

11. The method for preparing the carbon electrode with high conductivity applied to the electrode of the liquid flow energy storage battery according to claim 1 or 9, wherein the method comprises the following steps: the porous foam membrane electrode is manufactured by a spinning or casting method.