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CN-121983436-A - Gradient pore porous carbon material and preparation method and application thereof

CN121983436ACN 121983436 ACN121983436 ACN 121983436ACN-121983436-A

Abstract

The invention belongs to the technical field of porous carbon materials, and particularly relates to a gradient pore porous carbon material, and a preparation method and application thereof. The preparation method comprises the steps of mixing a carbon source precursor, a soft template and a densification carbon forming component, adding a gas release regulator and a heterogeneous atom introducing agent, mixing the mixture with a solvent, granulating and forming, pre-curing, sectionally carbonizing, activating by graded gas, and finally post-treating and heat-treating to obtain the gradient pore porous carbon material. The method realizes the fine trimming and channel dredging of micropore aperture by constructing a continuous mesoporous channel network by a phase separation soft template and activating graded gas, improves compaction density and conductive continuity by introducing a char formation densification and structure shape locking strategy, and obtains the gradient pore porous carbon material which has high specific capacitance, high multiplying power performance and high volume capacitance, is suitable for thick electrodes and high surface density electrodes, and has the advantages of mild process, good repeatability, easy amplification and low post-treatment burden.

Inventors

  • ZHANG LEI
  • Chen Rucan
  • TONG HUI
  • TIAN QINGHUA

Assignees

  • 中南大学
  • 长沙新能源创新研究院

Dates

Publication Date
20260505
Application Date
20260311

Claims (10)

  1. 1. The preparation method of the gradient pore porous carbon material is characterized by comprising the following steps of: s1, mixing a carbon source precursor, a soft template and a densified carbon forming component, adding a gas release pore regulator and a heterogeneous atom introducing agent, and mixing to obtain a mixture; S2, mixing the mixture with a solvent to form a slurry material, and granulating and forming to obtain a precursor material; S3, carrying out pre-curing treatment on the precursor material, and then carrying out sectional carbonization treatment under inert atmosphere to obtain a mesoporous framework carbon material; s4, carrying out graded gas activation treatment on the mesoporous framework carbon material to obtain a coarse gradient porous material; S5, carrying out post-treatment and heat treatment on the coarse gradient porous material to obtain the gradient porous material, wherein the post-treatment is ammonia gas treatment or oxidation treatment.
  2. 2. The method for preparing a gradient pore porous carbon material according to claim 1, wherein in the step S1: The carbon source precursor is one or more of biomass powder, lignin, cellulose, saccharides, coal pitch and phenolic resin; the soft template is one or more of a block copolymer, a surfactant or a phase-separable organic template; the densification char forming component is one or more of coal pitch, phenolic resin, furfuryl alcohol resin and carbonizable binder; The air release hole regulator is one or more of ammonium bicarbonate, ammonium oxalate and urea-organic acid air release system; the heterogeneous atom introducing agent is one or more of urea, melamine, phosphate and boron-containing compound.
  3. 3. The method for preparing the gradient pore porous carbon material according to claim 1, wherein in the step S1, the mass ratio of the carbon source precursor to the soft template to the densified carbon component is 1 (0.01-0.2): (0.01-0.3), and the mass ratio of the carbon source precursor to the outgassing pore regulator to the hetero atom introducing agent is 1 (0.01-0.15): (0.01-0.1).
  4. 4. The method for preparing the gradient pore porous carbon material according to claim 1, wherein in the step S2, the solvent is one or more of deionized water, ethanol, isopropanol or N-methylpyrrolidone, and the solid-liquid ratio of the mixture to the solvent is 1:0.5-1:5.
  5. 5. The method for preparing a gradient pore porous carbon material according to claim 1, wherein in the step S2, the granulation molding is any one of spray granulation, extrusion granulation, or spheronization granulation; the grain diameter of the granules obtained by adopting spray granulation is 50-500 mu m; The particle size of the particles obtained by adopting the spheronization granulation is 0.2 mm-2 mm.
  6. 6. The method for preparing a gradient pore porous carbon material according to claim 1, wherein in the step S3: The temperature of the pre-curing treatment is 160-280 ℃ and the time is 0.5-6 h; The segmented carbonization comprises a pre-carbonization segment and a skeletonizing segment: the pre-carbonization section is heated to 350-600 ℃ and is kept for 0.5-2 hours; the skeleton forming section is heated to 700-1000 ℃ and is kept for 0.5-3 hours; the inert atmosphere is nitrogen or argon, and the gas flow is 0.1-5L/min.
  7. 7. The method for preparing a gradient pore porous carbon material according to claim 1, wherein in the step S4, the graded activation treatment includes channel activation and micropore finishing activation; The channel is activated by adopting a mixed atmosphere of water vapor or CO 2 and inert gas, the activation temperature is 700-900 ℃, and the activation time is 3-40 min; And the micropore is refined and activated by adopting CO 2 atmosphere, the activation temperature is 800-950 ℃, and the time is 3-60 min.
  8. 8. The method for preparing a gradient pore porous carbon material according to claim 1, wherein in the step S5: the ammonia gas treatment temperature is 500-850 ℃ and the ammonia gas treatment time is 5-60 min; The oxidation treatment temperature is 150-300 ℃ and the time is 10-120 min; the heat treatment is inert annealing, the annealing temperature is 900-1200 ℃ and the time is 0.5-3 h.
  9. 9. A gradient pore porous carbon material obtained by the preparation method according to any one of claims 1 to 8, wherein the pore diameter of micropores of the gradient pore porous carbon material is 0.7 to 1.5 nm, and the pore diameter of mesopores is 3 to 25nm.
  10. 10. Use of a gradient pore porous carbon material as claimed in claim 9 in a supercapacitor, wherein the gradient pore porous carbon material is slurried in admixture with a conductive agent, a binder, and coated or tableted to form an electrode, and a symmetrical or asymmetrical supercapacitor is assembled.

Description

Gradient pore porous carbon material and preparation method and application thereof Technical Field The invention belongs to the technical field of porous carbon materials, and particularly relates to a gradient pore porous carbon material, and a preparation method and application thereof. Background The super capacitor is commonly used in the scenes of track traffic energy recovery, power grid frequency modulation, industrial pulse power supply, start-stop system and the like which need high-frequency rapid charge and discharge due to the characteristics of high power density, rapid charge and discharge, long cycle life and the like. In engineering applications, device performance depends not only on the specific capacitance of the material, but also on the internal resistance and polarization under thick electrode conditions. In the electric double layer capacitor system, electrolyte ions are reversibly adsorbed/desorbed on the pore wall surface of the carbon material to realize energy storage, so that the porous carbon is one of the most widely used electrode materials. The existing industrial active carbon has a mature route, but the specific surface area is often emphasized more and promoted, and the volume capacitance is limited due to the problems of low compaction density, limited infiltration and mass transfer of a thick electrode and the like. The performance of the porous carbon material is closely related to the pore structure, wherein micropores (< 2 nm) provide main energy storage sites, mesopores (2-50 nm) bear ion diffusion channels, and macropores (> 50 nm) can serve as electrolyte reservoirs and shorten transmission paths. The ideal electrode needs the cooperation of a mesoporous/macroporous rapid transmission channel and a microporous energy storage site, and meanwhile, the pore canal communication and lower impedance are still kept after rolling compaction. However, in the common activation process, the pore size distribution is easy to be widened, the pore wall is thinned, the structure is embrittled, the compaction density is reduced, and finally, the thick electrode multiplying power attenuation and the volume performance are not ideal. Currently porous carbon preparation is mainly chemical activation and gas activation. Chemical activation (such as KOH) can obtain very high specific surface area, but the reagent has strong corrosiveness and heavy post-washing burden, excessive development of pore structure and batch fluctuation are easy to occur, gas activation is relatively mild, and the centralized regulation and control of mesoporous communication and micropore aperture are difficult to simultaneously achieve in a single step. Besides the activation method, the method also comprises a template method, for example, znCl 2 and the like are used as templates to be matched with saccharide precursors to prepare the porous carbon electrode material, the process is relatively simple and the cost is controllable, and a soft template strategy can be used for constructing an ordered mesoporous structure and even a composite pseudo-capacitor component so as to improve the electrochemical performance. However, the template method generally has two contradictions, namely an ordered structure tends to emphasize mesoporous morphology more, microporous energy storage sites still need subsequent activation and complementation, the pore structure is easy to regulate and control chain to become long and the repeatability is easy to reduce, and when the development degree of pores is emphasized too much, the material density and the volume performance after electrode compaction are often not ideal, and the requirements of a high-volume energy density device on high tap density and high compaction density are difficult to meet. In addition, the scheme of improving the electrode density through the process or the material morphology, for example, a continuous electrode preparation route facing to a super capacitor with high energy density is provided, the contribution of the tap density of the electrode to the volume energy density is emphasized and improved, or the super capacitor electrode is realized through a carbon aerogel system and the like, has a certain pore structure and is used for the super capacitor electrode. However, the above solution is often focused on electrode forming and density improvement or high density pore structure of a single system, and there is still lack of reproducible systematic paths for the gradient synergy of the microporous pore diameter and ion size matching and mesoporous channel and microporous energy storage sites within the same particle. In summary, the existing porous carbon material preparation technology for the supercapacitor mainly surrounds the single-point optimization expansion of 'high specific surface area' or 'template construction mesoporous' or 'electrode density improvement', and generally has the problems that micropore aperture windows are diff