Journal of Physical Chemistry C
·
2014
·
IF 4.835
Yunxia Huang,Yan Wang,Zhimin Li,Zi Yang,Chunhao Shen,Chuangchuang He
The porous carbons (PCs) with tunable morphologies and pore sizes were prepared by the sol–gel process via a freeze-drying technique for microwave absorption applications. The results of Raman spectroscopy and nitrogen sorption analysis showed that the graphitization degree was barely influenced as the ratio of tert-butanol (T) to resorcinol (R) decreased, while the pore morphologies changed from the disordered slit-shaped pores to the uniform cage-like pores. Dielectric properties of the as-prepared carbon samples were determined by a vector network analyzer in the frequency range of 8.2–12.4 GHz. Results showed that the effect of pore morphology on the dielectric loss of PCs was dominant in the case of similar graphitization. When the T/R ratio was 7.5, the sample with cage-like pores revealed the maximum values in the real part ε′ and the imaginary part ε″ of complex permittivity, which were 13.2–6.5 and 15.6–10.1, respectively, suggesting a better capacity of dielectric loss in the 8.2–12.4 GHz range. The proposed mechanism for the effect of the pore morphologies on microwave absorption performance was discussed.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Jinkui Li,Jiao Li,Zhe Hu,Mingwu Xiang,Kaijiao Duan,Yi Guo,Wei Bai,Xiaofang Liu,Junming Guo
Porous carbon synchronously with high conductivity and abundant porous structure is considered to be an effective sulfur host material for boosting the lithium-storage property in battery fields. Herein, a natural silk cocoon derived in-situ N-doping porous carbon lamella with ultrahigh graphitization degree is prepared by a facile synchronous carbonization and catalysis using the bimetallic mixed salts of FeCl 3 and ZnCl 2 . The pore structure and graphitization degree are easily regulated by changing carbonization temperature to balance the synergistic adsorption and conversion actions toward the polysulfides adhered to porous carbon lamellar. When the carbon lamellar is used to design sulfur cathode, the abundant porous structure not only encapsulates active sulfur, but also facilitates electrolyte infiltration. The shuttle effect of polysulfides can be restrained by the synergistic adsorption of porous structure and N-doping. Especially, the ultrahigh graphitized carbon lamellas provide an excellent conductive network for the favorable redox conversion of polysulfide species during charge/discharge. Owing to the structure merits of the porous carbon lamella prepared at 1000 °C, the corresponding carbon/sulfur composite cathode delivers a first discharge capacity of 807.7 mAh g −1 at 0.2C. Even at a current rate of 1C, the stable long cycling performance of 1000 cycles is still maintained. This high graphitized porous carbon materials will provide potential application in other energy-storage fields.
研究领域:
材料科学
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能源存储技术
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2016
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IF 3.205
Dongrong Zeng,Xiang Yu,Yunfeng Zhan,Linmin Cao,Xiaoxian Wu,Bodong Zhang,Jilin Huang,Zhipeng Lin,Fangyan Xie,Weihong Zhang,Jian Chen,Weiguang Xie,Wenjie Mai,Hui Meng
Nitrogen doped carbon material works as non-noble-metal catalyst for the oxygen reduction reaction . In this work the doping effect on two different carbon material by two different nitrogen sources is studied. The carbon material studied is self-prepared carbon ribbon with higher graphitization degree compared with commercial Vulcan XC72 carbon powder. NH 3 and glycine are used as nitrogen sources which produce nitrogen containing functionalities after high temperature pyrolysis . NH 3 doping of carbon ribbon has no positive effect on the ORR activity, while an obvious increase in the activity is found for the glycine doped carbon ribbon. The NH 3 and glycine doped Vulcan carbon show similar activities which are better than undoped Vulcan carbon. The difference is explained by graphitization degree, nitrogen content and type of nitrogen containing functionalities.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Jin Liu,Yu Ding,Feng Wang,Jiabing Ran,Haining Zhang,Haijiao Xie,Yuqiang Pi,Liya Ma
Regarding carbon-based electrodes, simultaneously establishing a well-defined meso -porous architecture, introducing abundant hetero-atoms and improving the graphitization degree can effectively enhance their capacitive performance. However, it remains a significant challenge to achieve a good balance between defects and graphitization degree. In this study, the porous structure and composition of carbon materials are co-optimised through a ‘dual-function’ strategy. Briefly, K 3 Fe(C 2 O 4 ) 3 and H 3 BO 3 were hybridised with a gelatin aqueous solution to form a homogeneous composite hydrogel, followed by lyophilisation and carbonisation. Owing to the dual functionality of raw materials, the graphitization, activation and hetero-atom doping processes can occur simultaneously during a one-step high-temperature treatment. The resultant carbon material exhibits a high graphitization degree (I D /I G = 0.9 ± 0.1), high hetero-atom content (N: 9.0 ± 0.3 at.%, B: 6.9 ± 0.5 at.%) and a large specific area (1754 ± 58 m 2 /g). The as-prepared electrode demonstrates a superior capacitance of 383 ± 1F g −1 at 1 A/g. Interestingly, the cyclic voltammetry (CV) curves exhibit a distinctive pair of broad redox peaks, which is uncommon in KOH electrolyte. Experiment data and density functional theory (DFT) simulation verify that N-5, B co-doping enhances the activity of the faradic reaction of carbon electrodes in KOH electrolyte. Furthermore, the fabricated Zn-ion hybrid supercapacitor (ZHSC) based on this carbon electrode delivers a high-energy density of 140.7 W h kg −1 at a power density of 840 W kg −1 .
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POWER SOURCES
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2024
·
IF 8.1
Zhenxing Jin,Qiping Cao,Hui Gong,Bo Chen,Yuewei Jiang,Yingying Su,Jinghui Zhou,Yao Li
Developing a simple and effective method for optimizing lignin structure is a key challenge for the application of biomass-based carbon nanofibers in energy storage and moisture-enabled electricity generation fields. In this work, an effective strategy is designed to prepare novel biomass-based carbon nanofibers . Carbon quantum dots (CQDs) are introduced as functional components into biomass-based carbon nanofibers to optimize the inherent structural defects of lignin. The introduction of CQDs effectively reduces the interaction between lignin macromolecules , thereby increasing the flexibility of lignin macromolecule chain segments. The obtained biomass-based carbon nanofibers exhibit excellent microfiber morphologies and a high degree of graphitization . The specific capacitance and energy density for biomass-based carbon nanofibers as the energy storage device reach 294.4 F/g and 28.3 W h/kg, respectively. Furthermore, the biomass-based moist-electric generator shows high power generation efficiency , the output voltage and output current of a single device reach 0.75 V and 1.8 μA, respectively. Notably, as the number of biomass-based moist-electric generators in series or parallel increases, the overall output efficiency of the device system has a linear relationship, which means that a sufficient number of biomass-based moist-electric generator devices can meet the power supply requirements of larger power systems . This work puts forward a promising strategy to prepare low-consumption, high-performance, and environmentally friendly biomass-based carbon nanofibers for the supercapacitors and moist-electric generators.
研究领域:
材料科学
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能源技术
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2018
·Vol. 24
·期 41
·10460-10467
·
IF 5.16
Ruiying Shi,Cuiping Han,Xiaofu Xu,Xianying Qin,Lei Xu,Hongfei Li,Junqin Li,Ching-Ping Wong,Baohua Li
Graphical Highly graphitized : A highly graphitized activated carbon nanofiber (a-PANF) has been obtained by a bottom-up synthesis involving electrospinning of polyacrylonitrile followed by calcination and chemical activation (see figure). The product has a hierarchical porous structure and abundant N-heteroatom doping. The lithium-ion capacitor (LIC) has been regarded as a promising device that combines the merits of lithium-ion batteries and supercapacitors, and that meets the requirements for both high energy and high power density. The development of advanced electrode materials is the key requirement. Herein, we report the bottom-up synthesis of activated carbon nanofiber (a-PANF) with a hierarchical porous structure and a high degree of graphitization. Electrospinning has been employed to prepare an interconnected fiber network with macropores, and ferric acetylacetonate has been introduced as both a mesopore-creating agent and a graphitic catalyst to increase the degree of graphitization. Furthermore, chemical activation enlarges the specific surface area by producing abundant micropores. Half-cell evaluation of the as-prepared a-PANF gave a discharge capacity of 80 mA h g −1 at 0.1 A g −1 within 2–4.5 V and no capacity fading after 1000 cycles at 2 A g −1 , which represents a significant improvement compared to conventional activated carbon (AC). Furthermore, an as-assembled LIC with a-PANF cathode and Fe 3 O 4 anode showed a superior energy density of 124.6 W h kg −1 at a specific power of 93.8 W kg −1 , which remained at 103.7 W h kg −1 at 4687.5 W kg −1 . This indicates promising application potential of a-PANF as an electrode material for efficient energy storage systems.
研究领域:
材料科学
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电化学
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能源存储
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纳米技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）