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CN-121983588-A - Preparation method of bismuth-based modified composite carbon felt electrode

CN121983588ACN 121983588 ACN121983588 ACN 121983588ACN-121983588-A

Abstract

The invention discloses a preparation method of a bismuth-based modified composite carbon felt electrode, which comprises the steps of carrying out carbothermic reduction treatment on the surface of carbon fiber of an original carbon-based material in a tube furnace, forming carbon defects on the surface of the carbon fiber, and providing more and more uniform attachment points for the subsequent loading of bismuth simple substances. The air and argon alternately react to ensure uniform load and complete conversion of bismuth simple substance. Meanwhile, bismuth steam is formed at the reaction temperature by utilizing the characteristic of low melting point of the metal bismuth, and the carbon substrate exposed on the modified electrode is further uniformly loaded, so that the bismuth loading degree is more controllable.

Inventors

  • JIA CHUANKUN
  • GAO ZIJIAN
  • JI YONGHUA
  • XU JIAN
  • YAN SU
  • YAN LI
  • DING MEI

Assignees

  • 张家港德泰储能装备有限公司

Dates

Publication Date
20260505
Application Date
20251224

Claims (9)

  1. 1. The preparation method of the bismuth-based modified composite carbon felt electrode is characterized by comprising the following preparation steps: Step S1, pretreating a carbon felt material to obtain CF-1; step S2, immersing the CF-1 into the precursor solution, and stirring to obtain CF-2 loaded with Bi (OH) 3 ; S3, carrying out heat treatment on the CF-2, and decomposing Bi (OH) 3 on the surface of the carbon felt into Bi 2 O 3 to obtain CF-3; s4, performing carbothermal reduction on Bi 2 O 3 by utilizing carbon on the surface of the carbon felt, and carrying out manufacturing etching while loading Bi on the surface of the carbon felt to obtain EGF-1; S5, annealing the EGF-1, oxidizing Bi by utilizing oxygen in air, and generating Bi 2 O 3 on the surface of the carbon felt again to obtain an EGF-2 precursor; S6, placing bismuth powder near an air inlet of a tube furnace, placing an EGF-2 precursor at the downstream of the air flow, and heating under the protection of argon atmosphere to enable bismuth steam generated by sublimation of the bismuth powder to reduce Bi 2 O 3 to the downstream EGF-2 precursor through carbon on the surface of a carbon felt again to obtain EGF-2; s7, repeating the operations of the steps S5-S6 on the EGF-2 to obtain EGF-3; and S8, cooling to room temperature, taking out the carbon felt, repeatedly washing with deionized water, and drying to obtain the bismuth-based modified composite carbon felt electrode.
  2. 2. The method for preparing the bismuth-based modified composite carbon felt electrode according to claim 1, wherein in the step S1, the carbon felt is calcined for 4-8 hours under the condition of 200-600 ℃ in an air atmosphere.
  3. 3. The preparation method of the bismuth-based modified composite carbon felt electrode according to claim 1, wherein in the step S2, a precursor solution is a solution prepared by mixing a bismuth source and NaOH according to a molar ratio of 1 (15-25), and the concentration of the precursor solution is 2-3M.
  4. 4. The method for preparing the bismuth-based modified composite carbon felt electrode according to claim 3, wherein the bismuth source is one of bismuth chloride, bismuth citrate, bismuth sulfate and bismuth nitrate.
  5. 5. The method for preparing the bismuth-based modified composite carbon felt electrode according to claim 1, wherein the heat treatment in S3 is performed in an air atmosphere, and the temperature is raised to 700-900 ℃ at a speed of 5-10 ℃ per minute.
  6. 6. The method for preparing the bismuth-based modified composite carbon felt electrode according to claim 1, wherein in the step S4, the temperature of 700-900 ℃ is kept, a valve of a vacuum pump is opened, the air pressure in a tube is lower than 5Pa, argon is continuously introduced into a tube furnace at a flow rate of 5-10 sccm, and the temperature is kept for 0.5-1.5 h under the argon atmosphere.
  7. 7. The method for preparing the bismuth-based modified composite carbon felt electrode according to claim 1, wherein in the step S5, the bismuth-based modified composite carbon felt electrode is annealed to 500-700 ℃, air is introduced, and the temperature is kept for 0.5-1.5 h.
  8. 8. The method for preparing the bismuth-based modified composite carbon felt electrode according to claim 1, wherein in the step S6, 2-5 g of bismuth powder is taken, after the air in a pipe is reduced to be lower than 5Pa again, argon is continuously introduced at a flow of 5-10 sccm, the temperature is raised to 700-900 ℃ at a speed of 5-10 ℃ per minute under the protection of argon atmosphere, and the temperature is kept for 0.5-1.5 h.
  9. 9. The method for preparing the bismuth-based modified composite carbon felt electrode according to claim 1, wherein in the step S8, the drying temperature is 60-90 ℃ in vacuum, and the drying time is 5-7 h.

Description

Preparation method of bismuth-based modified composite carbon felt electrode Technical Field The invention belongs to the technical field of electrode materials of flow batteries, and particularly relates to a preparation method of a bismuth-based modified composite carbon felt electrode. Background With the rapid development of renewable energy sources, a large-scale energy storage technology becomes a key for balancing energy supply and demand and improving the stability of a power grid. Flow batteries are considered as one of the most potential energy storage technologies due to the advantages of strong expandability, long cycle life, high safety and the like. Wherein, the electrode is used as a core component of the flow battery, and directly influences electrochemical reaction kinetics and battery energy efficiency. However, the conventional carbon-based electrode (such as carbon felt and graphite felt) has the problems of insufficient active sites, slow interface reaction kinetics and the like, so that the conventional carbon-based electrode can generate larger polarization under the condition of high current density, and the battery efficiency is affected. In the prior art, bismuth-based catalysts have the comprehensive advantages of high electrocatalytic activity, strong hydrogen evolution capability and low cost, are paid attention to in the research of modifying the cathode of vanadium batteries, and a great deal of research is carried out on bismuth-based materials through different strategies, such as a dipping method, an electrodeposition method and the like, but the electrodeposition method has high energy consumption, needs continuous stable electric energy supply, has higher long-term running cost and can cause poor metal loading uniformity due to uneven distribution of active sites of a carbon felt substrate, and the dip coating method can help to improve the distribution uniformity of nano particles in a porous electrode, but the combination between the nano particles and the carbon surface depends on weak Van der Waals force, which can cause serious mechanical stability problems under fast flowing electrolyte, and a plurality of relatively complex multi-step methods, but the operation steps of the methods are numerous and the cost is high. The Chinese patent with publication number CN 119133479A discloses an electrode material for a flow battery and a preparation method thereof, wherein the surface of a graphite felt is etched to load metal oxide, but the mixed liquid is dripped on the carbon felt, so that uneven load of a catalyst and agglomeration of large particles are caused, active sites are uneven, the increase of polarization under high current density is aggravated, and the service life of the battery is poor. Disclosure of Invention The embodiment of the invention aims to provide a preparation method of a bismuth-based modified composite carbon felt electrode, which utilizes carbon on the surface of a carbon felt to reduce metal oxide so that metal atoms loaded on the surface of the carbon felt are uniformly deposited and firmly combined. In order to solve the technical problems, the technical scheme adopted by the invention is a preparation method of the bismuth-based modified composite carbon felt electrode, which is characterized by comprising the following preparation steps: Step S1, pretreating a carbon felt material to obtain CF-1; step S2, immersing the CF-1 into the precursor solution, and stirring to obtain CF-2 loaded with Bi (OH) 3; S3, carrying out heat treatment on the CF-2, and decomposing Bi (OH) 3 on the surface of the carbon felt into Bi 2O3 to obtain CF-3; s4, performing carbothermal reduction on Bi 2O3 by utilizing carbon on the surface of the carbon felt, and carrying out manufacturing etching while loading Bi on the surface of the carbon felt to obtain EGF-1; S5, annealing the EGF-1, oxidizing Bi by utilizing oxygen in air, and generating Bi 2O3 on the surface of the carbon felt again to obtain an EGF-2 precursor; S6, placing bismuth powder near an air inlet of a tube furnace, placing an EGF-2 precursor at the downstream of the air flow, and heating under the protection of argon atmosphere to enable bismuth steam generated by sublimation of the bismuth powder to reduce Bi 2O3 to the downstream EGF-2 precursor through carbon on the surface of a carbon felt again to obtain EGF-2; s7, repeating the operations of the steps S5-S6 on the EGF-2 to obtain EGF-3; And S8, cooling to room temperature, taking out the carbon felt, repeatedly washing with deionized water, and drying to obtain the bismuth-based modified composite carbon felt electrode (Bi-CF). Further, in the step S1, the carbon felt is calcined for 4-8 hours under the condition of 200-600 ℃ in an air atmosphere. In the step S2, the precursor solution is a solution prepared by mixing a bismuth source and NaOH according to a molar ratio of 1 (15-25), and the concentration of the precursor solution is 2-3M. F