Pub Date : 2024-07-02DOI: 10.1007/s42823-024-00770-w
Gyumin Kim, Hong Jun Park, Sung Tae Jang, Bong Gill Choi
Despite the widespread use of polyaniline as a pseudocapacitor material, the cycling stability and rate capability of polyaniline-based electrodes are of concern because of the structural instability caused by repeated volumetric swelling and shrinking during the charge/discharge process. Herein, nanofiber-structured polyaniline was synthesized onto activated carbon textiles to ensure the long-term stability and high-rate capability of pseudocapacitors. The nanoporous structures of polyaniline nanofibers and activated textile substrate enhanced the ion and electron transfer during charge/discharge cycles. The resulting pseudocapacitor electrodes showed high gravimetric, areal, and volumetric capacitance of 769 F g−1, 2638 mF cm−2, and 845.9 F cm−3, respectively; fast charge/discharge capability of 92.6% capacitance retention at 55 mA cm−2; and good long-term stability of 97.6% capacitance retention over 2000 cycles. Moreover, a symmetric supercapacitor based on polyaniline nanofibers exhibited a high energy of 21.45 Wh cm−3 at a power density of 341.2 mW cm−3 in an aqueous electrolyte.
尽管聚苯胺作为一种伪电容器材料已被广泛使用,但由于在充放电过程中反复的体积膨胀和收缩会导致结构不稳定,因此聚苯胺基电极的循环稳定性和速率能力令人担忧。在此,我们在活性碳纺织品上合成了纳米纤维结构的聚苯胺,以确保伪电容器的长期稳定性和高速率能力。聚苯胺纳米纤维和活性纺织品基底的纳米多孔结构增强了充放电循环过程中的离子和电子转移。所制备的伪电容器电极具有较高的重力电容、面积电容和体积电容,分别为 769 F g-1、2638 mF cm-2 和 845.9 F cm-3;具有快速充放电能力,在 55 mA cm-2 时电容保持率为 92.6%;具有良好的长期稳定性,在 2000 次循环中电容保持率为 97.6%。此外,基于聚苯胺纳米纤维的对称超级电容器在水性电解液中的功率密度为 341.2 mW cm-3 时,能量高达 21.45 Wh cm-3。
{"title":"Deposition of polyaniline nanofibers on activated carbon textile for high-performance pseudocapacitors","authors":"Gyumin Kim, Hong Jun Park, Sung Tae Jang, Bong Gill Choi","doi":"10.1007/s42823-024-00770-w","DOIUrl":"https://doi.org/10.1007/s42823-024-00770-w","url":null,"abstract":"<p>Despite the widespread use of polyaniline as a pseudocapacitor material, the cycling stability and rate capability of polyaniline-based electrodes are of concern because of the structural instability caused by repeated volumetric swelling and shrinking during the charge/discharge process. Herein, nanofiber-structured polyaniline was synthesized onto activated carbon textiles to ensure the long-term stability and high-rate capability of pseudocapacitors. The nanoporous structures of polyaniline nanofibers and activated textile substrate enhanced the ion and electron transfer during charge/discharge cycles. The resulting pseudocapacitor electrodes showed high gravimetric, areal, and volumetric capacitance of 769 F g<sup>−1</sup>, 2638 mF cm<sup>−2</sup>, and 845.9 F cm<sup>−3</sup>, respectively; fast charge/discharge capability of 92.6% capacitance retention at 55 mA cm<sup>−2</sup>; and good long-term stability of 97.6% capacitance retention over 2000 cycles. Moreover, a symmetric supercapacitor based on polyaniline nanofibers exhibited a high energy of 21.45 Wh cm<sup>−3</sup> at a power density of 341.2 mW cm<sup>−3</sup> in an aqueous electrolyte.</p>","PeriodicalId":506,"journal":{"name":"Carbon Letters","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141522498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Volatile organic compounds (VOCs) are commonly produced in the combustion of fossil fuels and in chemical industries such as detergents and paints. VOCs in atmosphere cause different degrees of harm to human bodies and environments. Adsorption has become one of the most concerned methods to remove VOCs in atmosphere due to its high efficiency, simple operation and low energy consumption. Biomass-based porous carbon (BPC) has been considered as the most promising adsorption material because of the low cost and high absorption rate. In this paper, the key characteristic (e.g., specific surface area, pore structure, surface functional groups and basic composition) of BPC affecting the adsorption of VOCs in atmosphere were analyzed. The improvement of adsorption capacity of BPC by common modification methods, such as surface oxidation, surface reduction, surface loading and other modification methods, were discussed. Examples of BPC adsorption on different types of VOCs including aldehydes, ketones, aromatic VOCs, and halogenated hydrocarbons, were also reviewed. The specific adsorption mechanism was discussed. Finally, some unsolved problems and future research directions about BPC for adsorbing VOCs were propounded. This review can serve as a valuable reference for future developing effective biomass-based porous carbon VOCs adsorption technology.
{"title":"A review on the adsorption of volatile organic compounds by biomass-based porous carbon (BPC) and its mechanism","authors":"Haifan Yang, Guannan Liang, Xinyang Sun, Simiao Wu","doi":"10.1007/s42823-024-00766-6","DOIUrl":"https://doi.org/10.1007/s42823-024-00766-6","url":null,"abstract":"<p>Volatile organic compounds (VOCs) are commonly produced in the combustion of fossil fuels and in chemical industries such as detergents and paints. VOCs in atmosphere cause different degrees of harm to human bodies and environments. Adsorption has become one of the most concerned methods to remove VOCs in atmosphere due to its high efficiency, simple operation and low energy consumption. Biomass-based porous carbon (BPC) has been considered as the most promising adsorption material because of the low cost and high absorption rate. In this paper, the key characteristic (e.g., specific surface area, pore structure, surface functional groups and basic composition) of BPC affecting the adsorption of VOCs in atmosphere were analyzed. The improvement of adsorption capacity of BPC by common modification methods, such as surface oxidation, surface reduction, surface loading and other modification methods, were discussed. Examples of BPC adsorption on different types of VOCs including aldehydes, ketones, aromatic VOCs, and halogenated hydrocarbons, were also reviewed. The specific adsorption mechanism was discussed. Finally, some unsolved problems and future research directions about BPC for adsorbing VOCs were propounded. This review can serve as a valuable reference for future developing effective biomass-based porous carbon VOCs adsorption technology.</p>","PeriodicalId":506,"journal":{"name":"Carbon Letters","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141509305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Diamond/SiC composites were prepared by vacuum silica vapor-phase infiltration of in situ silicon–carbon reaction, and the thermophysical properties of the composites were modulated by controlling diamond graphitizing. The effects of diamond surface state and vacuum silicon infiltration temperature on diamond graphitization were investigated, and the micro-morphology, phase composition, and properties of the composites were observed and characterized. The results show that diamond pretreatment can reduce the probability of graphitizing; when the penetration temperature is greater than 1600 °C, the diamond undergoes a graphitizing phase transition and the micro-morphology presents a lamellar shape. The thermal conductivity, density, and flexural strength of the composites increased and then decreased with the increase of penetration temperature in the experimentally designed range of penetration temperature. The variation of thermal expansion coefficients of composites prepared with different penetration temperatures ranged from 0.8 to 3.0 ppm/K when the temperature was between 50 and 400 °C.
{"title":"Modulating the thermophysical properties of diamond/SiC composites via controlling the diamond graphitization","authors":"Xulei Wang, Yikang Li, Yabo Huang, Yalong Zhang, Pei Wang, Li Guan, Xinbo He, Rongjun Liu, Xuanhui Qu, Xiaoge Wu","doi":"10.1007/s42823-024-00767-5","DOIUrl":"https://doi.org/10.1007/s42823-024-00767-5","url":null,"abstract":"<p>Diamond/SiC composites were prepared by vacuum silica vapor-phase infiltration of in situ silicon–carbon reaction, and the thermophysical properties of the composites were modulated by controlling diamond graphitizing. The effects of diamond surface state and vacuum silicon infiltration temperature on diamond graphitization were investigated, and the micro-morphology, phase composition, and properties of the composites were observed and characterized. The results show that diamond pretreatment can reduce the probability of graphitizing; when the penetration temperature is greater than 1600 °C, the diamond undergoes a graphitizing phase transition and the micro-morphology presents a lamellar shape. The thermal conductivity, density, and flexural strength of the composites increased and then decreased with the increase of penetration temperature in the experimentally designed range of penetration temperature. The variation of thermal expansion coefficients of composites prepared with different penetration temperatures ranged from 0.8 to 3.0 ppm/K when the temperature was between 50 and 400 °C.</p>","PeriodicalId":506,"journal":{"name":"Carbon Letters","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141509307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nitrogen-doped carbon nanomaterials (N-CNMs) were prepared using Ni(NO3)2 as a catalyst in the laminar diffusion flame. Doping the structure of carbon nanomaterials (CNMs) with nitrogen can significantly change the characteristics of CNMs. The purpose of this research is to study the effect of adding ammonia (NH3) on the evolution of CNMs structure in the laminar flame of ethylene. Raman analysis shows that the intensity ratio (ID/IG) of the D-band and G-band of N-CNMs increases and then decreases after the addition of NH3. The intensity ratio is a maximum of 0.99, which has a good degree of disorder and defect density. The binding distribution of nitrogen was analyzed by X-ray photoelectron spectroscopy (XPS), and a correlation was found between the amount of nitrogen and the morphology of N-CNMs. Nitrogen atoms predominantly present in the forms of pyrrolic-N, pyridinic-N, graphitized-N and oxidized-N, with a doping ratio of nitrogen atoms reaching up to 2.44 at.%. This study found that smaller nickel (Ni) nanoparticles were the main catalysts for carbon nanotubes (CNTs), and their synthesis followed the ‘hollow growth mechanism’ and carbon nanofibers (CNFs) were synthesized from larger Ni nanoparticles according to the ‘solid growth mechanism’. Furthermore, a growth mechanism for the synthesis of bamboo-like CNTs using a specific particle size of the Ni catalyst is proposed. It is noteworthy that the synthesis and modulation of high-performance N-CNMs by flame method represents a simple and efficient approach.