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CN-122025691-A - Zinc-bromine flow battery carbon-plastic bipolar plate and preparation method and application thereof

CN122025691ACN 122025691 ACN122025691 ACN 122025691ACN-122025691-A

Abstract

The invention discloses a zinc-bromine flow battery carbon-plastic bipolar plate and a preparation method and application thereof, and belongs to the technical field of electrochemical energy storage. The method comprises the steps of dispersing a nitrogen-doped hollow carbon nano box, spraying the nitrogen-doped hollow carbon nano box on the positive side of a carbon-plastic bipolar plate, drying the carbon-plastic bipolar plate to obtain a nitrogen-doped hollow carbon nano box modified positive carbon-plastic bipolar plate, dispersing boron-nitrogen co-doped carbon, spraying the boron-nitrogen co-doped carbon on the negative side of a pretreated carbon-plastic bipolar plate, and drying the carbon-plastic bipolar plate again to obtain the boron-nitrogen co-doped carbon modified negative carbon-plastic bipolar plate. On the positive electrode side, the nitrogen-doped hollow carbon nano-box catalyzes a bromine reaction through nitrogen doping to reduce overpotential, and the hollow structure adsorbs bromine species and inhibits bromine permeation by utilizing the charge effect to reduce self-discharge. On the negative side, the boron-nitrogen co-doped carbon guides zinc to be deposited uniformly and densely by utilizing B-N zinc-philic sites, suppresses dendrites, and suppresses hydrogen evolution through charge regulation. The bromine resistance, the reaction kinetics and the dendrite inhibition capability of the carbon-plastic bipolar plate are cooperatively improved.

Inventors

  • WANG DEJUN
  • LIU JUNJIE
  • Tan Guangdao
  • ZHANG WEIKE
  • LI JUNWAN
  • WANG HAORAN
  • CHEN GONG
  • Hou Ruoyang
  • QI CHUNFENG

Assignees

  • 西安热工研究院有限公司
  • 华能赫章风力发电有限公司

Dates

Publication Date
20260512
Application Date
20260414

Claims (10)

  1. 1. The preparation method of the carbon-plastic bipolar plate of the zinc-bromine flow battery is characterized by comprising the following steps of: Respectively dissolving zinc nitrate hexahydrate and 2-methylimidazole in methanol and mixing, sequentially carrying out standing reaction, centrifugation, washing, drying and high-temperature pyrolysis to obtain a nitrogen-doped hollow carbon nano box, dispersing the nitrogen-doped hollow carbon nano box, spraying the dispersed nitrogen-doped hollow carbon nano box on the positive side of the carbon plastic bipolar plate, and drying again to obtain the nitrogen-doped hollow carbon nano box modified positive carbon plastic bipolar plate; Dissolving chitosan powder in dilute acetic acid, adding boric acid, stirring and mixing uniformly, drying and grinding into fine powder, performing high-temperature pyrolysis, grinding again to obtain boron-nitrogen co-doped carbon, dispersing the boron-nitrogen co-doped carbon, spraying the dispersed boron-nitrogen co-doped carbon on the negative side of the pretreated carbon-plastic bipolar plate, and drying again to obtain the boron-nitrogen co-doped carbon-modified negative carbon-plastic bipolar plate.
  2. 2. The method for preparing the zinc-bromine flow battery carbon-plastic bipolar plate according to claim 1, wherein the dosage ratio of zinc nitrate hexahydrate to 2-methylimidazole to methanol is (15-25) g (8-15) g (1.0-1.5) L.
  3. 3. The preparation method of the zinc-bromine flow battery carbon-plastic bipolar plate according to claim 1 is characterized in that in the preparation process of the nitrogen-doped hollow carbon nano box, the standing reaction time is 20-24h, the centrifugal rotating speed is 8000-10000rpm, the centrifugal time is 10-15min, the drying temperature is 50-60 ℃ and the drying time is 10-12h; The dispersing condition of the nitrogen-doped hollow carbon nano box comprises the steps of dispersing the nitrogen-doped hollow carbon nano box in deionized water to obtain nitrogen-doped hollow carbon nano box dispersion liquid with the mass concentration of 5-30mg/mL, dispersing by adopting ultrasonic, wherein the ultrasonic power is 300-400W, the ultrasonic time is 10-60min, the jet flow speed is 5-10mL/min during spraying, the spraying time is 5-10min, the drying temperature is 40-60 ℃, and the drying time is 8-10h.
  4. 4. The preparation method of the zinc-bromine flow battery carbon-plastic bipolar plate according to claim 1, wherein in the preparation process of the nitrogen-doped hollow carbon nano box, the conditions of high-temperature pyrolysis comprise a heating rate of 3-5 ℃ per minute, a pyrolysis temperature of 800-1000 ℃ and a pyrolysis time of 2-2.5h, and a nitrogen flow rate of 50-200ml/min.
  5. 5. The method for preparing the carbon-plastic bipolar plate of the zinc-bromine flow battery according to claim 1, wherein the dosage ratio of chitosan to dilute acetic acid to boric acid is (5-10) g (300-600) ml (5-10) g.
  6. 6. The preparation method of the zinc-bromine flow battery carbon-plastic bipolar plate according to claim 1, wherein in the preparation process of boron-nitrogen co-doped carbon, the stirring speed is 300-500rpm, the stirring time is 2-4 hours, the drying temperature is 60-80 ℃, and the drying time is 12-24 hours; The conditions for dispersing the boron-nitrogen co-doped carbon comprise dispersing the boron-nitrogen co-doped carbon in deionized water to obtain boron-nitrogen co-doped carbon dispersion liquid with the mass concentration of 5-25mg/mL, dispersing by adopting ultrasonic, wherein the ultrasonic power is 300-400W, the ultrasonic time is 10-60min, the jet flow speed is 5-10mL/min during spraying, the spraying time is 5-10min, the drying temperature is 40-60 ℃, and the drying time is 8-10h.
  7. 7. The preparation method of the zinc-bromine flow battery carbon-plastic bipolar plate according to claim 1, wherein in the preparation process of boron-nitrogen co-doped carbon, the conditions of high-temperature pyrolysis comprise a heating rate of 2-5 ℃ per minute, a pyrolysis temperature of 800-1000 ℃, a heat preservation time of 1-3h and a nitrogen flow rate of 50-200ml per minute.
  8. 8. The preparation method of the zinc-bromine flow battery carbon-plastic bipolar plate according to claim 1 is characterized in that the carbon-plastic bipolar plates are pretreated carbon-plastic bipolar plates, and the pretreatment conditions comprise ultrasonic cleaning of the carbon-plastic bipolar plates by adopting ethanol or deionized water for 15-30min, and drying in a vacuum drying oven at 40-60 ℃ for 12-24h after cleaning.
  9. 9. A zinc-bromine flow battery carbon-plastic bipolar plate, which is characterized in that the zinc-bromine flow battery carbon-plastic bipolar plate is prepared by adopting the preparation method of the zinc-bromine flow battery carbon-plastic bipolar plate as claimed in any one of claims 1 to 8.
  10. 10. The application of the carbon-plastic bipolar plate of the zinc-bromine flow battery in preparing the zinc-bromine flow battery, which is characterized in that the coulombic efficiency of the zinc-bromine flow battery is 94.3% -96.1%, the voltage efficiency is 85.3% -86.1%, and the energy efficiency is 80.44% -83.03%.

Description

Zinc-bromine flow battery carbon-plastic bipolar plate and preparation method and application thereof Technical Field The invention belongs to the technical field of electrochemical energy storage, and particularly relates to a zinc-bromine flow battery carbon-plastic bipolar plate and a preparation method and application thereof. Background As an important electrochemical energy storage technology, the zinc-bromine flow battery has the advantages of high energy density, low cost, long cycle life and the like, and has wide application prospect in the field of large-scale energy storage, but industrialization is limited by the core bottleneck that the cathode active bromine species (Br 3-/Br2) penetrates through a diaphragm to cause self-discharge, so that coulomb efficiency suddenly drops and capacity continuously decays. The conversion reaction rate of the bromine/bromide (Br 2/Br-) of the anode is slow, the multi-step reaction is involved, high activation energy is needed, a complexing agent is usually added into the anode, the Br 2 is complexed to improve the solubility, but the reaction path of the Br 2 becomes more complex, the reaction delay of the Br 2 becomes a short plate with the whole battery performance, high polarization voltage is generated, the voltage efficiency and the power density are obviously reduced, the energy efficiency is lower, the power density is limited, and the coulomb efficiency is low. The negative electrode electric field is unevenly distributed, dendrites are easy to form during zinc deposition, a membrane is easy to puncture to cause short circuit of the battery, safety is threatened, and the cycle life is limited (< 500 times), and the zinc-bromine flow battery is directly caused to fall into an industrialized dilemma due to the bottleneck. The traditional zinc-bromine flow battery bipolar plate is insufficient in bromine corrosion resistance, bromine and polybromide in electrolyte can erode a graphite matrix to cause material pulverization and resistance increase, so that the service life of the battery is shortened, interface resistance is high, contact resistance between the bipolar plate and electrodes can cause large internal resistance of the battery to reduce voltage and energy efficiency, and finally, the traditional bipolar plate is inert to bromine reaction, lacks catalytic activity, cannot promote bromine/bromide conversion reaction, limits the power density of the battery and possibly aggravates bromine side reaction. These drawbacks together limit the long-term cycling stability and power performance of the battery. The Chinese patent application with publication number of CN120978108A discloses a composite bipolar plate for a zinc-bromine flow battery and a preparation method thereof, wherein a 'point-line-surface' interpenetrating conductive network is constructed by compositing carbon fiber, ketjen black and graphene, so that the overall conductivity of the bipolar plate is remarkably improved, and meanwhile, a nitrogen-doped porous carbon material is sprayed on the surface of a substrate, and a Br 2 adsorption site is provided by utilizing the large specific surface area and a mesoporous structure of the nitrogen-doped porous carbon material, so that bromine reaction kinetics is improved and bromine shuttling is inhibited. However, the modified layer of the scheme has single function, the same nitrogen doped porous carbon material is used on the positive and negative sides, and no special solution is provided for special problems such as zinc dendrite growth and hydrogen evolution side reaction on the negative side. The Chinese patent application with publication number of CN121307076A further provides a technical idea of anode and cathode partition modification, and discloses a multifunctional bipolar plate of a zinc-bromine flow battery and a preparation method thereof. The scheme loads polyaniline on the positive electrode side, utilizes physical coverage of a benzene ring structure and reversible adsorption of a matched structure to realize combination of bromine blocking and catalytic functions, loads a cyclodextrin polymer/Nafion composite coating on the negative electrode side, limits Zn 2+ diffusion direction and Nafion sulfonic acid groups to form a directional ion channel through a nano channel of cyclodextrin, and cooperatively regulates and controls uniform deposition of zinc and stabilizes an interface pH value to inhibit hydrogen evolution. Although the scheme realizes the functional partition of the anode and the cathode, the anode modified material is an organic polymer system, the electron conductivity is limited, the regulation and control of zinc deposition mainly depend on physical limit and ion conduction, and an active site with strong chemical adsorption effect on Zn 2+ is lacking, so that the improvement space is still provided in the aspects of guiding zinc to uniformly nucleate and fundamentally inhibiting dendrite growth. Theref