Zinc-bromine flow battery integrated electrode and preparation method thereof

Abstract

The invention discloses a zinc-bromine flow battery integrated electrode and a preparation method thereof. The preparation method comprises the following steps: by taking a carbon fiber fabric as a framework material, spreading mixed powder of strong acid and alkali resistant resin and conductive carbon powder on the carbon fiber fabric through a mold, placing a PAN-based active carbon fiber fabric with high specific surface area (500-1500m < 2 > / g) on one surface, and then pressing to obtain the high-specific-surface-area high-specific-surface-area high-specific-surface-area high-specific-surface-area active carbon fiber composite material. And the carbon fiber reinforced integrated electrode with high conductivity, high specific surface area and high strength is prepared. According to the zinc-bromine flow battery integrated electrode prepared by the invention, the density is 1.0-1.9 g / cm < 3 >, the sheet resistance value is less than or equal to 800m omega, the conductivity is greater than or equal to 15S / cm, the thickness tolerance is + / -5%, the bending strength is greater than or equal to 35Mpa, the tensile strength is greater than or equal to 50Mpa, a hydrogen permeation test is carried out under the pressure of 1.5 Mpa, the hydrogen permeation rate is less than or equal to 5 * 10 <-6 > cm < 3 > / cm < 2 > * min, and the drop contact angle on one side attached to an electrode fabric is 0 degree.

Description

Technical Field

[0001] The invention relates to the field of liquid flow batteries, and in particular to an integrated electrode for a zinc-bromine liquid flow battery and a preparation method thereof. Background Art

[0002] There are two main types of integrated electrodes in zinc-bromine flow batteries currently on the market: one is to spread carbon powder with high specific surface area such as activated carbon or coconut shell carbon on a conductive plastic bipolar plate, and then make an integrated electrode by hot pressing; the other is to spread fabric electrodes such as electrode felt or electrode cloth on a conductive plastic bipolar plate, and then make an integrated electrode by hot pressing.

[0003] The prior art process has the following problems:

[0004] Carbon powder-sprinkled integrated electrode: (1) Generally, activated carbon or coconut shell carbon powder is spread, and a small amount of resin powder is added (adding more resin powder can reduce the possibility of powder shedding, but the resin will block the pores of the carbon powder and affect performance). The carbon powder is easy to fall off during use; (2) The internal resistance of activated carbon or coconut shell carbon is generally large; (3) The internal resistance of conductive plastic bipolar plates is relatively large; (4) The mechanical strength of conductive plastic bipolar plates is low, especially the shear resistance performance is poor.

[0005] Hot-pressed fabric electrode integrated electrode: (1) Since fabric electrodes are generally hydrophilicized by grafting oxygen-containing hydrophilic functional groups, oxygen-containing functional groups such as hydroxyl or carboxyl groups are prone to chemical bond breakage during high-temperature hot pressing, resulting in inactivation of the fabric electrode; (2) The specific surface area of ​​fabric electrodes commonly used in liquid flow batteries is generally 5-20㎡ / g, which is much lower than the specific surface area of ​​activated carbon or coconut shell carbon powder, and has fewer reactive sites; (3) The internal resistance of conductive plastic bipolar plates is large; (4) The mechanical strength of conductive plastics is low, especially the shear resistance is poor. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides an integrated electrode for a zinc-bromine flow battery and a preparation method thereof.

[0007] In a first aspect, the present invention provides an integrated electrode for a zinc-bromine flow battery, which is realized by the following technical solutions.

[0008] The invention discloses an integrated electrode for a zinc-bromine liquid flow battery, which is formed by laminating a carbon fiber skeleton layer, a resin carbon powder conductive layer and an activated carbon fiber fabric layer.

[0009] Specifically, an integrated electrode for a zinc-bromine flow battery includes a carbon fiber skeleton layer, resin carbon powder conductive layers are arranged on both sides of the carbon fiber skeleton layer, and an activated carbon fiber fabric layer is arranged on the outer side of one of the resin carbon powder conductive layers.

[0010] In a second aspect, the present invention provides a method for preparing an integrated electrode for a zinc-bromine flow battery, which is achieved through the following technical solution.

[0011] A method for preparing the above-mentioned integrated electrode for zinc-bromine flow battery comprises the following steps:

[0012] Place the lower mold on the hot press, lay the carbon fiber skeleton layer, resin carbon powder conductive layer and activated carbon fiber fabric layer on the lower mold, and after placing the upper mold, press at a pressure of 400-2000 tons per square meter, and keep the temperature of the hot pressing plate at 150-350℃; put the material into the press at the beginning of heating, and heat it under pressure at 2-20℃ / min, keep the pressure for 2-8 hours, and then cool it down at 5-30℃ / min; after cooling to room temperature, remove the pressed bipolar plate and perform edge die cutting.

[0013] Furthermore, the carbon fiber skeleton layer is selected from one or more of carbon fiber mesh, carbon fiber felt, and carbon fiber cloth.

[0014] Furthermore, the preparation method of the carbon fiber mesh tire is: select carbon fiber filaments, cut them into carbon fiber staple fibers with a fiber length of 50-100 mm, air-form the chopped carbon fibers into a web, and then needle-punch them to make a carbon fiber needle-punched mesh tire; the preparation method of the carbon fiber thin mat is: select carbon fiber filaments, cut them into carbon fiber staple fibers with a fiber length of 5-100 mm, stably disperse the chopped carbon fibers in a solvent (the solvent is preferably water), and then add an adhesive resin (the adhesive resin is a polyurethane resin, and the resin accounts for 10% of the carbon fiber) The ratio is 1-3%), after being stirred and dispersed evenly, filtered and dried, and then hot-pressed to solidify to make a carbon fiber felt; the preparation method of the carbon fiber cloth is: selecting pre-oxidized filaments, curling them with a curl of 3-9 / cm, and then chopping them into 38-150mm pre-oxidized short filaments, and then spinning them, using ring spinning, Siro or airflow process to make 10-30 double-strand yarns, and then weaving them into cloth, and then carbonizing them at 1000-1500℃ and graphitizing them at 1600-2200℃ to make graphitized carbon fiber cloth.

[0015] Furthermore, the preparation method of the conductive powder in the resin carbon powder conductive layer is: mixing 200-1500 mesh strong acid and alkali resistant resin with conductive carbon powder, and obtaining the conductive powder after uniform mixing; wherein the mass proportion of the strong acid and alkali resistant resin is 20-30%, and the mass proportion of the conductive carbon powder is 70-80%.

[0016] Furthermore, the strong acid and alkali resistant resin is selected from one or more of PVDF, PTFE, PVF, PP, and PE; the conductive carbon powder is selected from one or a mixture of expanded graphite powder, graphite powder, carbon nanotube powder, graphene powder, conductive carbon black powder, and carbon fiber powder.

[0017] Furthermore, the activated carbon fiber fabric layer uses PAN-based activated carbon cloth. The preparation method of the PAN-based activated carbon cloth is as follows: select pre-oxidized filaments, curl them with a curl of 3-9 curls / cm, and then cut them into 38-150mm pre-oxidized short filaments, and then spin them using ring spinning, siro or airflow processes to make 10-30 English double-strand yarns, which are then woven into cloth, and then activated by a continuous activation furnace, and 20-60% of the effective temperature zone of the activation furnace is selected to introduce water vapor, the atmosphere introduction amount is 5-30L / min, the pressure in the furnace is slightly positive, and the pressure value is ≤0.3Mpa. At a temperature of 1000-1500°C, the carbon fiber is etched by high temperature water vapor to make an activated carbon fiber fabric with a specific surface area of ​​500-1500㎡ / g and a pore size of 5-15nm.

[0018] This application has the following beneficial effects.

[0019] (1) The fiber removal rate of the fabric-shaped electrode is less than 1%, and there is no possibility of falling off after long-term electrolyte circulation flushing; (2) The conductivity of the fabric electrode is above 100S / cm, and the conductivity is relatively high; (3) The specific surface area of ​​the activated carbon fiber fabric is higher than that of the conventional carbon fiber fabric electrode, and the active site is not much different from that of activated carbon or coconut shell charcoal; (4) The electrode is reinforced with carbon fiber inside and on the surface, and has high mechanical strength; (5) The hydrophilic activation of the activated carbon fiber fabric is achieved by oxidative etching of the fiber surface, etching out small pores with a pore size of 5-15nm, and physically hydrophilizing through these high-specific surface pores, without the risk of hot pressing inactivation. (6) The density of the integrated electrode for zinc-bromine flow battery prepared in this application is 1.0-1.9g / cm 3 , square resistance ≤800mΩ, conductivity ≥15S / cm, thickness tolerance ±5%, bending strength ≥35Mpa, tensile strength ≥50Mpa, hydrogen permeability test under 1.5Mpa pressure, hydrogen permeability ≤5×10 -6 cm 3 / cm 2 ·min, and the contact angle of dripping water on the side of the fabric bonded to the electrode is 0°. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the integrated electrode of the zinc-bromine flow battery of the present application.

[0021] Among them, 1. carbon fiber skeleton layer; 2. resin carbon powder conductive layer; 3. activated carbon fiber fabric layer. DETAILED DESCRIPTION

[0022] The invention is further described below with reference to the accompanying drawings and embodiments. Unless otherwise specified, the experimental method used in the present invention is a conventional method, and the experimental equipment, materials, reagents, etc. used can be purchased from relevant material sales companies.

[0023] A method for preparing an integrated electrode for a zinc-bromine flow battery comprises the following steps:

[0024] 1. Preparation of materials and auxiliary materials

[0025] 1. Preparation of carbon fiber skeleton:

[0026] With carbon fiber mesh as the skeleton:

[0027] Select carbon fiber filaments, cut them into carbon fiber staple fibers with a fiber length of 50-100 mm, air-lay the chopped carbon fibers, and then needle-punch them through a needle-punch device to make a carbon fiber needle-punched net tire with a square meter weight of 20-150 g;

[0028] With carbon fiber felt as the skeleton:

[0029] Select carbon fiber filaments, chop them into carbon fiber staple fibers with a fiber length of 5-100 mm, stably disperse the chopped carbon fibers in water, then add adhesive resin, usually polyurethane resin, the resin accounts for 1-3% of the carbon fibers, stir and disperse evenly, filter and dry, and then heat press and solidify to make a carbon fiber felt, the carbon fiber felt has a square meter weight of 20-150g;

[0030] With carbon fiber cloth as the skeleton:

[0031] Pre-oxidized filaments are selected, curled with a curl of 3-9 / cm, chopped into 38-150mm pre-oxidized short filaments, and then spun using ring spinning, siro or airflow processes to make 10-30 double-strand yarns, which are then woven into cloth using a rapier loom with a square meter weight of 100-300g. The cloth is then carbonized at 1000-1500℃ and graphitized at 1600-2200℃ to make graphitized carbon fiber cloth with a square meter weight of 20-100g.

[0032] 2. Preparation of conductive powder:

[0033] Select a strong acid and alkali resistant resin of 200-1500 mesh (if the resin is only in pellet form, the resin pellets can be placed in liquid nitrogen and cooled to below -200°C, and ground into 200-1500 mesh powder). The resin powder is one or more of PVDF, PTFE, PVF, PP or PE, accounting for 20-30% by mass. Select conductive carbon powder, such as expanded graphite powder, graphite powder, carbon nanotube powder, graphene powder, conductive carbon black powder or carbon fiber powder, one or more of these powders mixed powder, accounting for 70-80% by mass. Mix the resin and conductive carbon powder with a mechanical mixer. Additives can also be added during mixing, such as dispersant EBS, toughening agent POE, coupling agent carbonate, etc., accounting for 1-5% by mass of the additives, and finally evenly mix them into a conductive mixed powder.

[0034] 3. Preparation of PAN (polyacrylonitrile) based activated carbon cloth material:

[0035] Select the pre-oxidized filament, curl it, the curl degree is 3-9 curls / cm, then cut it into 38-150mm pre-oxidized filaments, and then spin it, use a process such as ring spinning, siro or air flow to make 10-30 English count double-strand yarn, and then use a rapier loom to weave it into cloth, the warp density is 20-50 strands / inch, the weft density is 30-60 strands / inch, and the square meter weight is 100-500g, and then it is activated by a continuous activation furnace. The continuous activation furnace is activated according to the needs. In order to control the etching intensity of water vapor on the fabric, it is necessary to select a temperature zone to introduce water vapor. Conventionally, 20-60% of the effective temperature zone of the activation furnace is selected to introduce water vapor. The atmosphere introduction rate is 5-30L / min, and the pressure in the furnace is slightly positive, with a pressure value of ≤0.3Mpa. At a temperature of 1000-1500°C, water vapor etches the carbon fiber at a high temperature to produce an activated carbon fiber fabric with a specific surface area of ​​500-1500㎡ / g and a pore size of 5-15nm.

[0036] 4. Preparation of hot pressing mold

[0037] According to the product size, a stainless steel mold is made. A set of molds consists of two steel plates. The lower steel plate is generally 1.5-4mm thick, and the upper mold is 1-3mm thick. The lower mold generally needs to be milled with a groove. The groove depth is determined according to the actual finished thickness of the integrated electrode. The groove depth is consistent with the finished thickness. The upper mold is a flat mirror state.

[0038] 2. Paving materials:

[0039] 1. Laying the base material:

[0040] Place the hot pressing mold on the hot pressing machine, first place the lower mold. Spray the release agent or lay the release film on the lower mold, and then lay the material;

[0041] 2. Laying conductive powder material:

[0042] Laying conductive powder material on the lower mold;

[0043] 3. Laying carbon fiber skeleton:

[0044] Laying a carbon fiber skeleton on the upper layer of the conductive powder material;

[0045] 4. Laying conductive powder material:

[0046] Conductive powder material is laid on the upper layer of the carbon fiber skeleton;

[0047] 5. Laying activated carbon fiber fabric:

[0048] Activated carbon fiber fabric is laid on the upper layer of the conductive powder material.

[0049] The order and number of layers of material laying can be adjusted according to specific needs and are not limited to the above structure.

[0050] 6. Place the upper mold

[0051] After accurate alignment, place the upper mold on top. Spray a release agent on the upper mold or lay a release film underneath it.

[0052] 3. Pressing

[0053] The press is a multi-layer press. A mold loaded with materials is placed on each layer, and then pressed at a pressure of 400-2000 tons per square meter. The temperature of each layer of the hot pressing plate of the press is maintained at 150-350℃. The material is placed in the press at the beginning of the heating, and the temperature is raised under pressure at 2-20℃ / min. The pressure is maintained for 2-8 hours, and then the temperature is lowered at 5-30℃ / min.

[0054] 4. Cutting

[0055] After the laminating machine cools down to room temperature, remove the mold, then remove the pressed bipolar plate, and use a die-cutting machine to cut the edges (see Figure 1 ).

[0056] The thickness of the integrated electrode prepared in the following embodiments of the present application is tested by a thickness tester of Shanghai Kaifa JD400 So model; the bending resistance test detection standard refers to GB / T 40398.2-2021 Carbon-Carbon Composite Carbon Material Test Method; the square resistance and conductivity are tested by using a four-probe square resistance tester and an RTS-9 dual-electric 4-probe resistance tester; the airtightness of the bipolar plate is tested by using a commercially available hydrogen permeation tester to detect the hydrogen permeation amount.

[0057] Embodiment 1:

[0058] A method for preparing an integrated electrode for a zinc-bromine flow battery comprises the following steps:

[0059] 1. Preparation of carbon fiber skeleton:

[0060] Sinopec 2.2Dtex, 48K pre-oxidized filament with a limiting oxygen index of 48% was used, and after curling and chopped, 6 curls / cm, 53mm length of pre-oxidized chopped filaments were made, and then 30s double-strand yarns were made through a ring spinning process, and then through a rapier loom, a plain fabric with a warp and weft density ratio of 1:1.5 and a fabric weight of 160gsm per square meter was made; then the fabric was carbonized and graphitized, and a carbonization and graphitization integrated continuous furnace was selected for carbonization and graphitization. The speed of the pre-oxidized silk cloth in the continuous carbonization and graphitization furnace was 300mm / min, and there were 20 temperature zones for continuous carbonization and graphitization, each temperature zone was 3 meters, and nitrogen was introduced into the furnace to maintain a slight positive pressure, and the entire carbonization process was protected by a nitrogen atmosphere. The temperatures of temperature zones 1-4 are 400°C, 800°C, 100°C and 1100°C respectively; the carbonization temperature of temperature zones 5-10 is 1200°C; the temperature zone 11-12 is 1300°C and 1600°C; the temperature zone 14-18 is 1800°C, and the temperature zone 19-20 is 1600°C and 1400°C.

[0061] 2. Preparation of conductive powder material:

[0062] Select expandable graphite with 60 mesh and 120 expansion ratio to make vermicular graphite at 850℃, and then crush it into 400 mesh powder. Select Solvay 5130 brand PVDF powder, add it to 400 mesh vermicular graphite powder, the addition amount is 20%, and the rest is vermicular graphite powder, and then use a mixer to stir and mix the powder at 200 rpm.

[0063] 3. Preparation of PAN-based activated carbon cloth material:

[0064] A large tow of 48K pre-oxidized yarn with a 1.7Dtex and a limiting oxygen index of 48 from Jinshan Petrochemical was selected and curled with a curl of 6 curls / cm. The yarn was then chopped into 60mm pre-oxidized short yarns and spun using a ring spinning process to make 10-count double-strand yarns. The yarn was then woven into cloth using a rapier loom to make a 3 / 2 twill fabric with a warp and weft density ratio of 1.5:1 and a fabric weight of 350gsm per square meter. The fabric was then activated using a continuous activation furnace, which had a total of 11 temperature zones, each with a length of 3 meters. Water vapor was introduced into the last 5 temperature zones, with an atmosphere intake of 15L / min, a slightly positive pressure in the furnace, a pressure value of 0.2Mpa, all temperature zones at 1200°C, a vehicle speed of 300mm / min, and high-temperature water vapor etching of the carbon fiber to make an activated carbon fiber fabric with a specific surface area of ​​900㎡ / g and a pore size of 8-15nm.

[0065] 4. Preparation of hot pressing mold:

[0066] A stainless steel mold is made. The mold consists of two steel plates. The lower steel plate is 4mm thick, 1250mm*650mm long and wide. The center position of 1100mm*500mm is finely milled, and the milling depth is 1.2mm. The upper mold is 3mm thick and is a mirror-finished flat plate. All flatness of the mold is guaranteed to be within 0.05mm.

[0067] 6. Paving materials:

[0068] Spray the release agent evenly on the loading surface of the bottom mold. In the lower mold groove, spread the conductive powder material at 700g / ㎡; lay the carbon fiber fabric skeleton on it; spread the conductive powder material at 700g / ㎡ on the carbon fiber fabric skeleton; and then place the activated carbon fiber cloth on the top layer. Align and place the upper mold plate, and spray the release agent evenly on the surface of the upper mold plate that contacts the material. The hot press has multiple layers of hot pressing platforms, and each layer is laid with materials in the above-mentioned laying method.

[0069] 7. Hot pressing:

[0070] After putting the materials into the hot press, the pressurization starts, the pressure is 1200 tons / ㎡; the hot press temperature is 190℃, and the temperature is kept for 2 hours; the temperature is increased at 10℃ / min and the temperature is decreased at 20℃ / min.

[0071] 8. Die cutting:

[0072] Use stamping die-cutting to cut the pressed bipolar plates flush with the edges to complete the production of finished products.

[0073] 9. Detection:

[0074] Density test: density 1.38-1.45g / cm3; square resistance test: square resistance of fabric electrode surface 0.3-0.35Ω; conductivity test: use four probes to contact the non-fabric conductive surface, and the conductivity is 210-250S / cm; thickness uniformity test: overall thickness 1.16-1.22mm; bending strength 46-48Mpa, tensile strength 80-90Mpa; air tightness test, hydrogen permeation test under 1.5Mpa pressure, hydrogen permeability 1.89×10 -6 cm 3 / cm 2 ·min; the contact angle of dripping water on the side of the fabric bonded to the electrode is 0°.

[0075] Embodiment 2:

[0076] A method for preparing an integrated electrode for a zinc-bromine flow battery comprises the following steps:

[0077] 1. Preparation of carbon fiber skeleton:

[0078] Sinopec’s 48K carbon fiber filaments were selected and chopped into carbon fiber staple fibers with a fiber length of 90 mm. The chopped carbon fibers were air-laid and then needle-punched through a needle-punching device to produce a carbon fiber needle-punched mesh with a gram per square meter weight of 80 g.

[0079] 2. Preparation of conductive powder material:

[0080] Select expandable graphite with 100 mesh and 180 expansion ratio to make worm graphite at 950℃, and then crush it into 200 mesh powder. Select Arkema HSV900 brand PVDF powder, add it to 200 mesh worm graphite powder, the addition amount is 25%, and the rest is worm graphite powder, and then use a mixer to stir and mix the powder at 100 rpm.

[0081] 3. Preparation of PAN-based activated carbon cloth material:

[0082] Select SGL's 1.7Dtex, 43 limiting oxygen index, 6 curls / cm curl, 60mm fiber length pre-oxidized short yarn, and then use the ring spinning process to spin it into 20-nein double-strand yarn, and then use a rapier loom to weave it into cloth to make a double plain fabric with a warp and weft density ratio of 1:1. The fabric has a square meter weight of 340gsm, and then it is activated by a continuous activation furnace. The continuous activation furnace has a total of 11 temperature zones, each temperature zone is 3 meters, and water vapor is introduced into the last 5 temperature zones. The atmosphere is introduced at a rate of 5L / min, the pressure in the furnace is slightly positive, the pressure value is 0.1Mpa, all temperature zones are 1500℃, the vehicle speed is 700mm / min, and the carbon fiber is etched at high temperature by water vapor to make an activated carbon fiber fabric with a specific surface area of ​​600-800㎡ / g and a pore size of 8-15nm.

[0083] 4. Preparation of hot pressing mold:

[0084] A stainless steel mold is made. The mold consists of two steel plates. The lower steel plate is 4mm thick, 1200mm*600mm long and wide. The center position of 1000mm*450mm is milled to a depth of 0.8mm. The upper mold is 3mm thick and is a mirror-finished flat plate. The flatness of the mold is guaranteed to be within 0.05mm.

[0085] 6. Paving materials:

[0086] Evenly spread silicone oil release paper on the bottom mold loading surface. In the lower mold groove, spread the conductive powder material at 400g / ㎡; lay the carbon fiber fabric skeleton on it; spread the conductive powder material at 400g / ㎡ on the carbon fiber fabric skeleton; and then place the activated carbon fiber cloth on the top layer. Align the upper mold plate and lay the silicone oil release paper on the surface of the upper mold plate that contacts the material. The hot press has multiple layers of hot press platforms, and each layer is laid with materials in the above-mentioned laying method.

[0087] 7. Hot pressing:

[0088] After putting the materials into the hot press, the pressurization starts, the pressure is 1000 tons / ㎡; the hot press temperature is 190℃, and the temperature is kept for 5 hours; the temperature is increased at 10℃ / min and the temperature is decreased at 20℃ / min.

[0089] 8. Die cutting:

[0090] Use stamping die-cutting to cut the pressed bipolar plates flush with the edges to complete the production of finished products.

[0091] 9. Detection:

[0092] Density test: density 1.4-1.5g / cm3; square resistance test: square resistance of fabric electrode surface 0.4-0.5Ω; conductivity test: use four probes to contact the non-fabric conductive surface, and the conductivity is 190-230S / cm; thickness uniformity test: overall thickness 0.76-0.84mm; bending strength 35-45Mpa, tensile strength 75-110Mpa; air tightness test, hydrogen permeation test under 1.5Mpa pressure, hydrogen permeability 1.78×10 -6 cm 3 / cm 2 ·min; the contact angle of dripping water on the side of the fabric bonded to the electrode is 0°.

[0093] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A zinc-bromine flow battery integrated electrode, characterized in that: It is formed by laminating a carbon fiber skeleton layer (1), a resin carbon powder conductive layer (2) and an activated carbon fiber fabric layer (3).

2. The integrated electrode for zinc-bromine flow battery according to claim 1, characterized in that: It comprises a carbon fiber skeleton layer (1), resin carbon powder conductive layers (2) are provided on both sides of the carbon fiber skeleton layer (1), and an activated carbon fiber fabric layer (3) is provided on the outer side of one of the resin carbon powder conductive layers (2).

3. A method for preparing the integrated electrode of zinc-bromine flow battery according to claim 1 or 2, characterized in that: The following steps are involved: A lower mold is placed on a hot press, and a carbon fiber skeleton layer (1), a resin carbon powder conductive layer (2) and an activated carbon fiber fabric layer (3) are laid on the lower mold. After placing an upper mold, the materials are pressed at a pressure of 400-2000 tons per square meter, and the temperature of the hot pressing plate is maintained at 150-350°C; the materials are placed in the press at the beginning of heating, and heated under pressure at a rate of 2-20°C / min, and the pressure is maintained for 2-8 hours, and then cooled at a rate of 5-30°C / min; after cooling to room temperature, the pressed bipolar plates are removed and die-cut to flush the edges.

4. The method for preparing an integrated electrode for a zinc-bromine flow battery according to claim 3, characterized in that: The carbon fiber skeleton layer (1) is selected from one or more of carbon fiber mesh, carbon fiber felt, and carbon fiber cloth.

5. The method for preparing an integrated electrode for a zinc-bromine flow battery according to claim 4, characterized in that: The preparation method of the carbon fiber mesh tire is as follows: selecting carbon fiber filaments, chopping them into carbon fiber staple fibers with a fiber length of 50-100 mm, air-forming the chopped carbon fibers into a web, and then needle-punching them to form a carbon fiber needle-punched mesh tire; The preparation method of the carbon fiber felt is as follows: selecting carbon fiber filaments, chopping them into carbon fiber staple fibers with a fiber length of 5-100 mm, stably dispersing the chopped carbon fibers in a solvent, then adding an adhesive resin, stirring and dispersing them evenly, filtering and drying them, and then hot pressing and curing them to make a carbon fiber felt; the preparation method of the carbon fiber cloth is as follows: selecting pre-oxidized filaments, curling them with a curl of 3-9 / cm, chopping them into pre-oxidized staple fibers with a length of 38-150 mm, spinning them, using a ring spindle, siro or airflow process to make 10-30 English count double-strand yarns, then weaving them into cloth, and then carbonizing them at 1000-1500° C. and graphitizing them at 1600-2200° C. to make graphitized carbon fiber cloth.

6. The method for preparing an integrated electrode for a zinc-bromine flow battery according to claim 3, characterized in that: The preparation method of the conductive powder in the resin carbon powder conductive layer (2) is as follows: 200-1500 mesh strong acid and alkali resistant resin is mixed with conductive carbon powder, and the conductive powder is obtained after uniform mixing; wherein the mass proportion of the strong acid and alkali resistant resin is 20-30%, and the mass proportion of the conductive carbon powder is 70-80%.

7. The method for preparing an integrated electrode for a zinc-bromine flow battery according to claim 6, characterized in that: The strong acid and strong alkali resistant resin is selected from one or more of PVDF, PTFE, PVF, PP, and PE; the conductive carbon powder is selected from one or a mixture of expanded graphite powder, graphite powder, carbon nanotube powder, graphene powder, conductive carbon black powder, and carbon fiber powder.

8. The method for preparing an integrated electrode for a zinc-bromine flow battery according to claim 3, characterized in that: The activated carbon fiber fabric layer (3) is a PAN-based activated carbon cloth. The preparation method of the PAN-based activated carbon cloth is as follows: pre-oxidized filaments are selected, curled, and the curling degree is 3-9 curls / cm, and then they are cut into 38-150mm pre-oxidized short filaments, and then they are spun, using ring spinning, Siro or airflow process to make 10-30 Ne double-strand yarns, and then they are woven into cloth, and then activated by a continuous activation furnace, selecting 20-60% of the effective temperature zone of the activation furnace to introduce water vapor, the atmosphere introduction amount is 5-30L / min, the pressure in the furnace is slightly positive, and the pressure value is ≤0.3Mpa, at a temperature of 1000-1500°C, the water vapor high temperature etches the carbon fiber to make an activated carbon fiber fabric with a specific surface area of ​​500-1500㎡ / g and a pore size of 5-15nm.

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