Ingenious synthesis of chitosan-based porous carbon supercapacitors with large specific area by a small amount of potassium hydroxide. (July 2022)

• Record Type: Journal Article
• Authors: Meng, Deqian; Wu, Chengfeng; Hu, Yunzhi; Jing, Yidan; Zhang, Xiaomin; Mahmud, Sakil; Su, Sheng Pei; Zhu, Jin
• Is Part Of: Journal of energy storage. Volume 51(2022)
• Publication Date: 2022-07
• Subjects: Chitosan -- Supercapacitor -- Electrochemical -- Porous carbon -- Synergism; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2022.104341
• Languages: English
• ISSNs: 2352-152X

Abstract

Abstract: Chitosan has been widely studied in the preparation of carbon-based supercapacitor electrodes due to its environment-friendly characteristic and easy processing. However, most of the chitosan-based porous carbon preparation method was complicated and required some activators such as zinc chloride and potassium hydroxide (KOH), which were all not conducive to environmental and equipment protection. Herein, we have successfully used a one-step carbonization method to prepare N-doped hierarchical porous carbon by systematically combining a small amount of KOH with magnesium acetate. The phenomenon was confirmed by observing scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption/desorption isotherms. The porous carbon showed a high specific surface area of ~2737 m 2 g −1, and its nitrogen content was up to 2.39%. Electrochemical data exhibited that the chitosan-based carbon electrode could achieve an outstanding gravimetric capacitance of 300.5 F g −1 at a current density of 0.5 A g −1 . After cyclic charging and discharging 5000 times at a current density of 5 A g −1, the specific capacitance retention rate was 92.94%. As an assembled symmetrical supercapacitor, with 6 M KOH as the electrolyte, when the power density was 250–4991 W kg −1, the corresponding energy density was 7.3–6.1 Wh kg −1 . Thus, these chitosan-based porous carbon electrodes exhibited excellent electrochemical properties. Particularly, the strategy to prepare porous carbon would provide successful experiences for designing bio-polymers porous carbon. Highlights: Chitosan-based porous carbon was synthesized by synergistic effect of template and chemical activation. Maintained the low dosage of potassium hydroxide The higher specific surface area (2737 m 2 g −1 ) with a hierarchical porous structure N-doped porous carbon materials with good electrical properties prepared by one-step carbonization strategy