CN-122025684-A - Recovery and regeneration method of all-vanadium redox flow battery waste electrode material

Abstract

The invention belongs to the technical field of vanadium battery production, and discloses a method for recycling and regenerating a waste electrode material of an all-vanadium redox flow battery. The regenerated electrode is obtained through the steps of (1) pretreatment, (2) carboxylation modification of the waste electrode, (3) in-situ growth of carbon nanotubes, (4) surface amination treatment and (5) grafting activation of the carbon nanotubes. The invention can lead the abandoned electrode to obtain the battery performance equivalent to or even higher than the initial electrode, can be reused as the electrode of the all-vanadium redox flow battery, and reduces the electrode material cost of the all-vanadium redox flow battery.

Inventors

• JIANG XINXI
• ZHOU LI
• LI HONGXIA
• WAN WEI
• LI XIAFENG
• NI YUNTAO
• LI XIANTAO
• Xie Hongqian
• LIU ZHIHAN
• REN CHUAN
• Hu Shidan

Assignees

• 贵州志喜科技有限公司

Dates

Publication Date

20260512

Application Date

20260202

Claims (10)

1. 1. The recovery and regeneration method of the all-vanadium redox flow battery waste electrode material is characterized by comprising the following specific steps: (1) The pretreatment comprises the steps of flushing the waste electrode material with deionized water, immersing in an acid solution, flushing the acid solution cleanly, and drying; the waste electrode material is a carbon material; (2) Waste electrode modification, namely carboxylating the pretreated waste electrode to obtain a modified waste electrode; (3) Immersing the modified waste electrode into a carbon nanotube catalyst solution for soaking, taking out, roasting under inert atmosphere, then introducing mixed gas of H 2 and C 2 H 2 , and continuously roasting to obtain the waste electrode of the in-situ grown carbon nanotube; (4) Performing surface amination treatment, namely performing plasma modification on the waste electrode with the carbon nano tube grown in situ, wherein the power of a plasma processor is 200W-260W, high-purity NH 3 with the air flow of 15ml/min-40ml/min is introduced, the air pressure is 1kPa-5kPa, and the treatment time is 1h-2h, so as to obtain the waste electrode with the surface aminated; (5) The method comprises the steps of dispersing carbon nanotubes in strong acid, oxidizing the carbon nanotubes to obtain activated carbon nanotubes, dispersing the activated carbon nanotubes in acetone solution, immersing the obtained surface aminated waste electrode in the acetone solution of the activated carbon nanotubes, immersing the waste electrode in the acetone solution of the activated carbon nanotubes at room temperature, washing the waste electrode with deionized water, and drying the waste electrode to obtain the regenerated electrode of the surface grafted carbon nanotubes.
2. 2. The method for recycling and regenerating the all-vanadium redox flow battery waste electrode material according to claim 1, wherein in the step (1), the acid solution is one or two of sulfuric acid and nitric acid solution, the concentration of the acid solution is 2mol/L, the time for immersing in the acid solution is 1-3h, and the time for immersing in the acetone is more than 10 h.
3. 3. The method for recycling and regenerating the all-vanadium redox flow battery waste electrode material according to claim 1, wherein in the step (2), the carboxylation treatment is that the pretreated waste electrode is soaked in an aqueous solution consisting of K 2 S 2 O 8 and AgNO 3 , heated for 2-3 hours at 60-80 ℃, and dried after cleaning, so as to obtain the modified waste electrode.
4. 4. The method for recycling and regenerating the waste electrode material of the all-vanadium redox flow battery according to claim 3, wherein the concentration of K 2 S 2 O 8 and AgNO 3 in the aqueous solution is 0.1mol/L.
5. 5. The method for recycling and regenerating a waste electrode material of an all-vanadium redox flow battery according to claim 1, wherein in the step (3), the carbon nanotube catalyst solution is a cobalt or nickel nitrate solution, the concentration of cobalt or nickel ions in the carbon nanotube catalyst solution is 0.01-0.05mol/L, and the soaking time is 10-30min.
6. 6. The method for recycling and regenerating the waste electrode material of the all-vanadium redox flow battery according to claim 1, wherein in the step (3), the roasting operation is that firstly, heat preservation is carried out for 10-15min at 450 ℃ under inert atmosphere, then mixed gas of H 2 and C 2 H 2 is introduced, the temperature is raised to 600-700 ℃ and the heat preservation is carried out for 5-10min; The total flow rate of H 2 and C 2 H 2 is 0.1-0.5L/min, wherein the flow rate ratio of H 2 to C 2 H 2 is 2:1.
7. 7. The method for recycling and regenerating the waste electrode material of the all-vanadium redox flow battery according to claim 1, wherein in the step (5), the strong acid is a mixed solution of concentrated sulfuric acid and concentrated nitric acid, the volume ratio of the concentrated sulfuric acid to the concentrated nitric acid is 3:1, and the oxidation treatment of the carbon nano tube is carried out at 50-80 ℃ for 2-3h.
8. 8. The method for recycling and regenerating a waste electrode material of an all-vanadium redox flow battery according to claim 1, wherein in the step (5), the solid-to-liquid ratio of the carbon nanotubes to the strong acid is 0.2-1g:50mL.
9. 9. The method for recycling and regenerating a waste electrode material of an all-vanadium redox flow battery according to claim 1, wherein in the step (5), the mass fraction of the activated carbon nanotubes in the acetone solution of the activated carbon nanotubes is 5-10%.
10. 10. The method for recycling and regenerating a waste electrode material of an all-vanadium redox flow battery according to claim 1, wherein in the step (5), the mass ratio of the surface-aminated waste electrode to the activated carbon nanotube is 1 (0.01-0.2).

Description

Recovery and regeneration method of all-vanadium redox flow battery waste electrode material Technical Field The invention relates to the technical field of vanadium redox battery production, in particular to a method for recycling and regenerating waste electrode materials of an all-vanadium redox flow battery. Background As an energy source with high efficiency, cleanliness and large capacity, the vanadium battery has the advantages of high charge and discharge efficiency, high power density and the like, and currently attracts attention of a plurality of scholars, and the vanadium battery can be used as an important support for reform of the energy field in the future. However, after the all-vanadium redox flow battery is operated for a long time, the voltage efficiency of the all-vanadium redox flow battery is reduced, so that the energy efficiency is reduced, and the actual discharge power of the battery is affected. The main reason for this phenomenon is that in the long-term charge and discharge process, pentavalent vanadium in the positive electrode and divalent vanadium in the negative electrode are precipitated on the surface of the electrode material to cover the reactive sites, and thus the electrocatalytic activity of the electrode is reduced and the electrochemical polarization of the battery is increased. As an important component of the vanadium battery system, the electrode material with higher conductivity and longer service life has important significance for guaranteeing the performance of the vanadium battery. The carbon material is widely used in electrode materials of flow batteries due to the characteristics of wide sources, low cost and good conductivity, but has a plurality of problems such as higher overpotential, poor wettability with electrolyte, few active sites and the like when being used for a long time, and the carbon material can not meet the requirements of the current vanadium battery. Therefore, the material needs to be modified, and the common modification methods in the industry at present comprise intrinsic treatment, metallization treatment, heteroatom doping and the like. However, these modification methods have certain problems, for example, doping of hetero atoms can introduce some elements which are unfavorable for the performance of the vanadium battery, the intrinsic processing of materials has large pollution to the environment, the operation is not easy, the heat treatment energy consumption is high, and the conductivity of the electrode is often reduced. The carbon nanotube is used for modifying the carbon fiber felt, and the main method is to introduce a carbon source on the surface of the carbon fiber and then generate the carbon nanotube under a certain condition. There is also a method of introducing a layer of intermediate material on the carbon fiber mat to connect the carbon nanotubes to the carbon fiber mat, which reduces the conductivity of the carbon fiber mat, although the carbon nanotubes can be more tightly bonded to the carbon fiber mat than the method of adsorbing the carbon nanotubes to the carbon fiber mat. Therefore, the provision of a method for recycling the electrode material of the discarded all-vanadium redox flow battery is a problem to be solved by those skilled in the art. Disclosure of Invention In view of the above, the invention provides a method for recycling and regenerating the waste electrode material of the all-vanadium redox flow battery, which aims to ensure that the waste electrode has the battery performance equivalent to or even higher than that of the initial electrode, can be reused as the electrode of the all-vanadium redox flow battery, and reduces the electrode material cost of the all-vanadium redox flow battery. In order to achieve the above purpose, the invention provides a method for recycling and regenerating the waste electrode material of an all-vanadium redox flow battery, which comprises the following specific steps: (1) The pretreatment comprises the steps of flushing the waste electrode material with deionized water, immersing in an acid solution, flushing the acid solution cleanly, and drying; the waste electrode material is a carbon material; (2) Waste electrode modification, namely carboxylating the pretreated waste electrode to obtain a modified waste electrode; (3) Immersing the modified waste electrode into a carbon nanotube catalyst solution for a certain time, taking out, roasting under inert atmosphere, then introducing mixed gas of H 2 and C 2H2, and continuously roasting to obtain the waste electrode of the in-situ grown carbon nanotube; (4) Performing surface amination treatment, namely performing plasma modification on the waste electrode with the carbon nano tube grown in situ, wherein the power of a plasma processor is 200W-260W, high-purity NH 3 with the air flow of 15ml/min-40ml/min is introduced, the air pressure is 1kPa-5kPa, and the treatment time is 1h-2h, so as to obtain the waste