Preparation and application of lignin-based hierarchical porous carbon based on direct carbonization method

A lignin-based, hierarchically porous technology, applied in carbon compounds, chemical instruments and methods, inorganic chemistry, etc., can solve the problems of increasing experimental costs, unfavorable for large-scale production, and high corrosion of equipment, achieving high specific surface area, The effect of excellent supercapacitor performance and simple preparation process

Active Publication Date: 2022-01-28
GUANGDONG UNIV OF TECH
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  • Summary
  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

This patent adopts the method of first carbonization and then activation. Although the additionally introduced activator has the effect of creating pores, it does not form a self-template agent in situ and develop pores at the same time, thereby improving the performance of the supercapacitor.
[0006] Patent application CN109516458A discloses a preparation method based on biomass-based hierarchical porous carbon, and KCl, LiCl, ZnCl 2 , ZnSO 4 , AlCl 3 、K 2 SO 4 Two of the salts are used as templates, with KOH, K 2 CO 3 、KHCO 3 、K 2 C 2 o 4 、Na 2 CO 3 One of them is used as an activator to prepare biomass-based hierarchical porous carbon with a specific surface area of ​​1000-2000 m 2 / g, a large amount of activator or templating agent is used in this patent, which is highly corrosive to the equipment, increases the cost of the experiment, and is not conducive to large-scale production
[0007] Patent application CN102633252A discloses a method of using lignosulfonate to prepare electrode materials for supercapacitors, using calcium lignosulfonate or magnesium lignosulfonate as a carbon precursor to calcinate under nitrogen or argon to prepare porous carbon materials, In a symmetric two-electrode system with 6 M KOH as the electrolyte, it shows good behavior of electric double layer capacitors, although the experimental operation is simple and green, but it fails to take full advantage of the richness of lignosulfonate functional groups

Method used

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  • Preparation and application of lignin-based hierarchical porous carbon based on direct carbonization method
  • Preparation and application of lignin-based hierarchical porous carbon based on direct carbonization method
  • Preparation and application of lignin-based hierarchical porous carbon based on direct carbonization method

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Experimental program
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Effect test

Embodiment 1

[0049] (1) 10g sodium lignosulfonate and 21.6g KOH aqueous solution with a mass fraction of 20% were added to the three-necked flask in turn and stirred until dissolved;

[0050] (2) After slowly adding 3.75 g of chloroacetic acid to the mixed solution in step (1), add 20 g of deionized water to stir the mixture until it is completely dissolved;

[0051] (3) After raising the temperature to 70 °C for 90 min, cooling to room temperature, and adjusting the pH to 10 with hydrochloric acid to obtain a mixed solution of potassium lignin, which is placed in a 70 °C oven to dry for use;

[0052] (4) The dried potassium lignin was heated at a rate of 5 °C / min, N 2 Gas, under the condition of gas flow rate of 40 mL / min, heat treatment at 900 °C for 2 h, after the reaction, take out and wash with 2 mol / L hydrochloric acid for 12 h, wash with deionized water until neutral, and drum at 80 °C. Air-dried for 12 h to obtain lignin-based hierarchical porous carbon, named LHPC-900.

[0053] ...

Embodiment 2

[0060] (1) Add 15 g of alkali lignin and 6 g of KOH aqueous solution with a mass fraction of 10% into the three-necked flask in turn, and add 20 g of deionized water and stir for 1 h until completely dissolved;

[0061] (2) After the temperature was raised to 70°C for 90min, the pH was adjusted to 9 with hydrochloric acid to obtain a mixed solution of potassium lignin, which was put into a blast oven at 70°C for drying for 24 hours before use;

[0062] (3) The dried potassium lignin was heated at a heating rate of 5 °C / min, N 2 The gas was treated at 700 °C for 2 h under the condition of a gas flow of 40 mL / min. After the reaction, it was taken out and washed with 2 mol / L hydrochloric acid for 12 h, washed with deionized water until neutral, and dried at 80 °C. Air-dried for 12 h to obtain lignin-based hierarchical porous carbon, which was named LPC-700;

[0063] Electrodes were prepared by using LPC-700: conductive carbon black: polytetrafluoroethylene (PTFE) in a mass ratio...

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Abstract

The invention discloses preparation of lignin-based hierarchical porous carbon based on a direct carbonization method and application of the lignin-based hierarchical porous carbon to an electrochemical supercapacitor. Under the condition that a small amount of KOH is introduced, lignin is subjected to carboxylation and phenolic hydroxylation modification by utilizing the advantage of rich functional groups of lignin, and potassium atoms are grafted to carboxyl or phenolic hydroxyl. According to the method, the effect of assisting chemical activation with physical activation is achieved, under the condition that no template agent is added, template salt KCl or carbonate is formed in the pyrolysis carbonization process to achieve the self-template effect, and the obtained porous carbon not only has the high specific surface area and the developed pore channel structure, but also has the excellent super-capacitor performance. The rich pore structure of the lignin-based hierarchical porous carbon can effectively improve the mass specific capacitance, coulombic efficiency and rate capability of the supercapacitor.

Description

technical field [0001] The invention belongs to the technical field of material science and energy chemical industry, and particularly relates to a preparation method of lignin-based hierarchical porous carbon based on a direct carbonization method and its application in electrochemical supercapacitors. Background technique [0002] Supercapacitors, also known as electrochemical capacitors, have the characteristics of long cycle life, high charge-discharge efficiency, high power density, and strong environmental adaptability. Supercapacitors store energy at the interface of porous carbon electrode and electrolyte through electrostatic adsorption of ions. At present, supercapacitors have broad application prospects in electronic equipment energy storage, aerospace, aviation, military and other fields. Among them, porous carbon materials are commercialized electrode materials. [0003] Lignin is a three-dimensional network high molecular aromatic polymer formed by three phen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/318C01B32/348
CPCC01B32/318C01B32/348Y02E60/13
Inventor 张文礼赵磊邱学青张晓珊简文斌温福旺秦延林林绪亮俎喜红
Owner GUANGDONG UNIV OF TECH
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