{"title":"Effect of puffing on electrochemical properties of sorghum seed based porous carbon materials in supercapacitors","authors":"","doi":"10.1016/j.est.2024.114065","DOIUrl":null,"url":null,"abstract":"<div><div>Biomass-based carbon materials are renewable, affordable and environmentally friendly, possessing great potential in electrochemical energy storage as electrode materials in supercapacitors due to their large specific surface area and self-doped heteroatoms. However, the electrochemical properties of these carbon materials may be influenced to some extent by pretreatment procedures of carbon precursors. For this research, a range of porous carbon materials based on unpuffed and puffed sorghum seeds were synthesized under various pre‑carbonization and activation temperatures. Among them, the puffed sorghum seed-based porous carbon (PH-R6A7), prepared through pre‑carbonization at 600 °C and KOH activation at 700 °C, exhibits a higher graphitization degree, increased N and O content, as well as a greater variety of nitrogen-containing groups and significant increasing graphite nitrogen compared to unpuffed sorghum seed-based porous carbon (PC-R6A7) fabricated under similar conditions. These improvements result in enhanced conductivity and wettability of electrode materials, thereby boosting their electrochemical properties. In a three-electrode setup employing a 6 M solution of KOH, PH-R6A7 demonstrates an exceptional specific capacitance of 523.84 F g<sup>−1</sup> at 1 A g<sup>−1</sup> compared with PC-R6A7 of 366.00 F g<sup>−1</sup>; even at a high current density of 20 A g<sup>−1</sup> it maintains a high level of capacitance at 387.94 F g<sup>−1</sup>. When employed in a double-electrode configuration at the same current density (i.e., 1 A g<sup>−1</sup>), PH-R6A7 also achieves higher specific capacitance of 357.83 F g<sup>−1</sup> than PC-R6A7 (286.89 F g<sup>−1</sup>), accompanied by an increased energy density of 12.35 Wh kg<sup>−1</sup> and 8.85 Wh kg<sup>−1</sup> at a power density of 249.97 W kg<sup>−1</sup> and 4.98 kW kg<sup>−1</sup>, respectively. Furthermore, after undergoing 10,000 cycles at 2 A g<sup>−1</sup>, PH-R6A7 demonstrates a superior capacitance retention of 99.68 % and coulomb efficiency of 99.91 %. PH-R6A7 fabricated through the combination method of puffing pretreatment and carbonization activation merits acknowledgment as an electrode material of superior performance and notable practical importance.</div></div>","PeriodicalId":15942,"journal":{"name":"Journal of energy storage","volume":null,"pages":null},"PeriodicalIF":8.9000,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of energy storage","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2352152X2403651X","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
引用次数: 0
Abstract
Biomass-based carbon materials are renewable, affordable and environmentally friendly, possessing great potential in electrochemical energy storage as electrode materials in supercapacitors due to their large specific surface area and self-doped heteroatoms. However, the electrochemical properties of these carbon materials may be influenced to some extent by pretreatment procedures of carbon precursors. For this research, a range of porous carbon materials based on unpuffed and puffed sorghum seeds were synthesized under various pre‑carbonization and activation temperatures. Among them, the puffed sorghum seed-based porous carbon (PH-R6A7), prepared through pre‑carbonization at 600 °C and KOH activation at 700 °C, exhibits a higher graphitization degree, increased N and O content, as well as a greater variety of nitrogen-containing groups and significant increasing graphite nitrogen compared to unpuffed sorghum seed-based porous carbon (PC-R6A7) fabricated under similar conditions. These improvements result in enhanced conductivity and wettability of electrode materials, thereby boosting their electrochemical properties. In a three-electrode setup employing a 6 M solution of KOH, PH-R6A7 demonstrates an exceptional specific capacitance of 523.84 F g−1 at 1 A g−1 compared with PC-R6A7 of 366.00 F g−1; even at a high current density of 20 A g−1 it maintains a high level of capacitance at 387.94 F g−1. When employed in a double-electrode configuration at the same current density (i.e., 1 A g−1), PH-R6A7 also achieves higher specific capacitance of 357.83 F g−1 than PC-R6A7 (286.89 F g−1), accompanied by an increased energy density of 12.35 Wh kg−1 and 8.85 Wh kg−1 at a power density of 249.97 W kg−1 and 4.98 kW kg−1, respectively. Furthermore, after undergoing 10,000 cycles at 2 A g−1, PH-R6A7 demonstrates a superior capacitance retention of 99.68 % and coulomb efficiency of 99.91 %. PH-R6A7 fabricated through the combination method of puffing pretreatment and carbonization activation merits acknowledgment as an electrode material of superior performance and notable practical importance.
期刊介绍:
Journal of energy storage focusses on all aspects of energy storage, in particular systems integration, electric grid integration, modelling and analysis, novel energy storage technologies, sizing and management strategies, business models for operation of storage systems and energy storage developments worldwide.