Preparation method of polyacrylamide hydrogel-based nitrogen-doped porous carbon

Abstract

The invention relates to a preparation method of a nitrogen-doped porous carbon material, in particular to a method for preparing a nitrogen-doped porous carbon material by taking cross-linked polyacrylamide gel as a carbon source and a nitrogen source through the processes of vacuum freeze drying, carbonization and activation, and further relates to application and electrochemical performance ofthe nitrogen-doped porous carbon material in super capacitors. The preparation method is convenient in raw material source, mild in reaction condition and easy to operate and control; the specific capacitance of a super capacitor electrode material prepared under better conditions reaches 302.1 F / g in a 6M KOH solution when the current density is 1A / g, reaches 217.0 F / g under the current density of 20A / g, and the capacitance retention rate is 71.83%; after 8000 times of charge-discharge cycles under the current density condition of 10A / g, the specific capacitance is maintained to be 96% of theinitial capacitance and relatively high specific capacitance and good cycle stability are achieved.

Description

technical field [0001] The invention relates to a method for preparing a nitrogen-doped porous carbon material, in particular to a method for preparing a nitrogen-doped porous carbon material by using polyacrylamide gel as a raw material, and also relates to its application and electrochemical performance in supercapacitors. Background technique [0002] As a new type of energy storage device, supercapacitors have gradually attracted people's attention due to their high power density, long cycle life and high safety. Supercapacitors can be divided into two types: one is pseudocapacitors, which store and release charges through reversible redox reactions, but the slow ion transport rate leads to low conductivity and poor cycle stability. The other is an electric double layer capacitor (EDLC), which stores charges by ion adsorption. This type of capacitor usually requires electrode materials to have a high specific surface area, because this can accumulate a large amount of ch...

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Problems solved by technology

[Anhui Chemical Industry, 2016, 42(6): 24-28.] used natural products as carbon sources, and produced carbonized residues through high-temperature pyrolysis. These residues were sieved, mixed with potassium hydroxide and melamine, Grinding, then high-temperature roasting, washing, and drying to obtain N-doped porous carbon, the nitrogen content is 6.45wt%, and when the current density is 0.1A / g, the specific capacitance of the assembled supercapacitor reaches 145F / g, and Exhibiting excellent cycle stability; Guo Kunkun et al. [Journal of Hunan University (Natural Science Edition), 2018, 45(6): 78-84.] using dicyandiamide, phenol, and formaldehyde as the main raw materials, using solvent volatilization combined with high-temperature heat Nitrogen-doped porous carbon materials were prepared by polymerization, and the specific capacitance reached 192.8F / g at a current density of 0.5A / g, and had good rate performance and cycle stability; but the specific capacitance value reported in the above literature was still low , to this end, we propose a nitrogen-doped porous carbon prepared by vacuum freeze-drying, carbonization, and activation processes using cross-linked polyacrylamide gel as a carbon and nitrogen source, which can be used as an electrode material for a supercapacitor to improve the electrode material specific capacitance and exhibit good energy storage performance

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