共查询到20条相似文献,搜索用时 38 毫秒
1.
Lei Tao Yuanbo Huang Xiaoqin Yang Yunwu Zheng Can Liu Mingwei Di Zhifeng Zheng 《RSC advances》2018,8(13):7102
Carbon nanofibers (CNFs) with excellent electrochemical performance represent a novel class of carbon nanostructures for boosting electrochemical applications, especially sustainable electrochemical energy conversion and storage applications. This work builds on an earlier study where the CNFs were prepared from a waste biomass (walnut shells) using a relatively simple procedure of liquefying the biomass, and electrospinning and carbonizing the fibrils. We further improved the mass ratio of the liquefying process and investigated the effects of the high temperature carbonization process at 1000, 1500 and 2000 °C, and comprehensively characterized the morphology, structural properties, and specific surface area of walnut shell-derived CNFs; and their electrochemical performance was also investigated as electrode materials in Li-ion batteries. Results demonstrated that the CNF anode obtained at 1000 °C exhibits a high specific capacity up to 271.7 mA h g−1 at 30 mA g−1, good rate capacity (131.3 and 102.2 mA h g−1 at 1 A g−1 and 2 A g−1, respectively), and excellent cycling performance (above 200 mA h g−1 specific capacity without any capacity decay after 200 cycles at 100 mA g−1). The present work demonstrates the great potential for converting low-cost biomass to high-value carbon materials for applications in energy storage.Carbon nanofibers (CNFs) with excellent electrochemical performance represent a novel class of carbon nanostructures for boosting electrochemical applications, especially sustainable electrochemical energy conversion and storage applications. 相似文献
2.
Herein, we present a simple and rapid method to synthesize porous silicon/carbon microtube composites (PoSi/CMTs) by adopting a unique configuration of acid etching solution. The CMTs can act as both conductive agent and buffer for Si volume change during the charge and discharge process. The highly reversible capacity and excellent rate capability can be ascribed to the structure, where porous silicon powders are wrapped by a network of interwoven carbon microtubes. The composites show specific capacities of more than 1712 mA h g−1 at a current density of 100 mA g−1, 1566 mA h g−1 at 200 mA g−1, 1407 mA h g−1 at 400 mA g−1, 1177 mA h g−1 at 800 mA g−1, 1107 mA h g−1 at 1000 mA g−1, 798 mA hg−1 at 2000 mA g−1, and 581 mA h g−1 at 3000 mA g−1 and maintain a value of 1127 mA h g−1 after 100 cycles at a current density of 200 mA g−1. Electrochemical impedance spectroscopy (EIS) measurements prove that charge transfer resistance of PoSi/CMT composites is smaller than that of pure PoSi. In this study, we propose a quick, economical and feasible method to prepare silicon-based anode materials for lithium-ion batteries.We added additives to the acid etching solution and prepared the silicon/carbon microtubes composites using a simple and fast method. 相似文献
3.
Chenyang Fan Mingyang Ou Peng Wei Jia Xu Shixiong Sun Yi Liu Yue Xu Chun Fang Qing Li Jiantao Han 《RSC advances》2021,11(24):14883
The Stöber method is a highly efficient synthesis strategy for homogeneous monodisperse polymer colloidal spheres and carbon spheres. This work delivers an extended Stöber method and investigates the synthesis process. By calcining the precursor under appropriate conditions, solid secondary particles of amorphous carbon (SSAC) and hollow secondary particles of graphitized carbon (HSGC) can be directly synthesized. The two materials have a nano-primary particle structure and a closely-packed sub-micron secondary particle structure, which can be used in energy storage. We find that SSAC and HSGC have high potassium-ion storage capacity with reversible capacities of 274 mA h g−1 and 283 mA h g−1 at 20 mA g−1 respectively. Significantly, SSAC has better rate performance with a specific capacity of 107 mA h g−1 at 1 A g−1.A modified Stöber method synthesizes resorcinol-formaldehyde resin-based secondary particle hard carbon spheres as anode material for high-performance potassium-ion batteries. 相似文献
4.
Kainian Chu Mulin Hu Bo Song Senlin Chen Junyu Li Fangcai Zheng Zhiqiang Li Rui Li Jingya Zhou 《RSC advances》2023,13(9):5634
Heteroatom-doped porous carbon materials have been widely used as anode materials for Li-ion and Na-ion batteries, however, improving the specific capacity and long-term cycling stability of ion batteries remains a major challenge. Here, we report a facile based metal–organic framework (MOFs) strategy to synthesize nitrogen-doped porous carbon nanofibers (NCNFs) with a large number of interconnected channels that can increase the contact area between the material and the electrolyte, shorten the diffusion distance between Li+/Na+ and the electrolyte, and relieve the volume expansion of the electrode material during cycling; the doping of nitrogen atoms can improve the conductivity and increase the active sites of the carbon material, can also affect the microstructure and electron distribution of the electrode material, thereby improving the electrochemical performance of the material. As expected, the obtained NCNFs-800 exhibited excellent electrochemical performance with high reversible capacity (for Li+ battery anodes: 1237 mA h g−1 at 100 mA g−1 after 200 cycles, for Na+ battery anodes: 323 mA h g−1 at 100 mA g−1 after 150 cycles) and long-term cycling stability (for Li+ battery anodes: 635 mA h g−1 at 2 A g−1 after 5000 cycles, for Na+ battery anodes: 194 mA h g−1 at 2 A g−1 after 5000 cycles).Heteroatom-doped porous carbon materials have been widely used as anode materials for Li-ion and Na-ion batteries, however, improving the specific capacity and long-term cycling stability of ion batteries remains a major challenge. 相似文献
5.
Ji-Eun Lee Min-Cheol Kim Sang-Hyun Moon Eun-Soo Kim Yeon-Kyung Shin Sojeong Choi Suk-Hui Kwon Si-Jin Kim Hye-Jin Kwon Kyung-Won Park 《RSC advances》2019,9(18):10297
While Li2MnO3 as an over-lithiated layered oxide (OLO) shows a significantly high reversible capacity of 250 mA h g−1 in lithium-ion batteries (LIBs), it has critical issues of poor cycling performance and deteriorated high rate performance. In this study, modified OLO cathode materials for improved LIB performance were obtained by heating the as-prepared OLO at different temperatures (400, 500, and 600 °C) in the presence of polyvinylpyrrolidone (PVP) under an N2 atmosphere. Compared to the as-prepared OLO, the OLO sample heated at 500 °C with PVP exhibited a high initial discharge capacity of 206 mA h g−1 and high rate capability of 111 mA h g−1 at 100 mA g−1. The superior performance of the OLO sample heated at 500 °C with PVP is attributed to an improved electronic conductivity and Li+ ionic motion, resulting from the formation of the graphitic carbon structure and increased Mn3+ ratio during the decomposition of PVP.The modified OLO cathode materials for improved LIB performance were obtained by heating the as-prepared OLO in the presence of polyvinylpyrrolidone (PVP) under an N2 atmosphere. 相似文献
6.
Xin Chen Guojun Gao Zhipeng Wu Jun Xiang Xiaoqiang Li Guangguang Guan Kaiyin Zhang 《RSC advances》2019,9(64):37556
Flexible free-standing hierarchically porous carbon nanofibers embedded with ultrafine (∼3.5 nm) MoO2 nanoparticles (denoted as MoO2@HPCNFs) have been synthesized by electrospinning and subsequent heat treatment. When evaluated as a binder-free anode in Li-ion batteries, the as-obtained MoO2@HPCNFs film exhibits excellent capacity retention with high reversible capacity (≥1055 mA h g−1 at 100 mA g−1) and good rate capability (425 mA h g−1 at 2000 mA g−1), which is much superior to most of the previously reported MoO2-based materials. The synergistic effect of uniformly dispersed ultrasmall MoO2 nanoparticles and a three-dimensionally hierarchical porous conductive network constructed by HPCNFs effectively improve the utilization rate of active materials, enhance the transport of both electrons and Li+ ions, facilitate the electrolyte penetration, and promote the Li+ storage kinetics and stability, thus leading to a greatly enhanced electrochemical performance.A novel binder-free LIB anode made of ultrafine MoO2 nanoparticles encapsulated in hierarchically porous carbon nanofibers exhibits high Li-storage performance. 相似文献
7.
Anu Adamson Ronald Vli Maarja Paalo Jaan Aruvli Miriam Koppel Rasmus Palm Eneli Hrk Jaak Nerut Tavo Romann Enn Lust Alar Jnes 《RSC advances》2020,10(34):20145
Herein we demonstrate how peat, abundant and cheap biomass, can be successfully used as a precursor to synthesize peat-derived hard carbons (PDCs), applicable as electrode materials for sodium-ion batteries (SIB). The PDCs were obtained by pre-pyrolysing peat at 300–800 °C, removing impurities with base–acid solution treatment and thereafter post-pyrolysing the materials at temperatures (T) from 1000 to 1500 °C. By modification of pre- and post-pyrolysis temperatures we obtained hard carbons with low surface areas, optimal carbonization degree and high electrochemical Na+ storage capacity in SIB half-cells. The best results were obtained when pre-pyrolysing peat at 450 °C, washing out the impurities with KOH and HCl solutions and then post-pyrolysing the obtained carbon-rich material at 1400 °C. All hard carbons were electrochemically characterized in half-cells (vs. Na/Na+) and capacities as high as 350 mA h g−1 at 1.5 V and 250 mA h g−1 in the plateau region (E < 0.2 V) were achieved at charging current density of 25 mA g−1 with an initial coulombic efficiency of 80%.A synthesis method has been developed to turn peat, cheap biomass into hard carbons that demonstrate high capacity and excellent sodium storage capability as anode material in sodium-ion batteries. 相似文献
8.
Lan Zhang Lu Xu Yagang Zhang Xin Zhou Letao Zhang Akram Yasin Lulu Wang Keke Zhi 《RSC advances》2018,8(7):3869
Biomass-derived O- and N-doped porous carbon has become the most competitive supercapacitor electrode material because of its renewability and sustainability. We herein presented a facile approach to prepare O/N-doped porous carbon with cotton as the starting material. Absorbent cotton immersed in diammonium hydrogen phosphate (DAP) was activated at 800 °C (CDAP800s) and then was oxidized in a temperature range of 300–400 °C. The electrochemical capacitance of the impregnated cotton was significantly improved by doping with O and N, and the yield was improved from 13% to 38%. The sample oxidation at 350 °C (CDAP800-350) demonstrated superior electrical properties. CDAP800-350 showed the highest BET surface area (1022 m2 g−1) and a relatively high pore volume (0.53 cm3 g−1). In a three-electrode system, the CDAP800-350 electrodes had high specific capacitances of 292 F g−1 in 6 M KOH electrolyte at a current density of 0.5 A g−1. In the two-electrode system, CDAP800-350 electrode displayed a specific capacitance of 270 F g−1 at 0.5 A g−1 and 212 F g−1 at 10 A in KOH electrolyte. In addition, the CDAP800-350-based symmetric supercapacitor achieved a high stability with 87% of capacitance retained after 5000 cycles at 5 A g−1, as well as a high volumetric energy density (18 W h kg−1 at 250 W kg−1).Biomass-derived O- and N-doped porous carbon has become one of the most competitive supercapacitor electrode material because of its renewability and sustainability. 相似文献
9.
“Turning waste into wealth” and sustainable development are bright themes of modern society. Semi-coke is mainly made up of coal but contains around 15 wt% impurities. Nevertheless, semi-coke powders with sizes smaller than 3 mm generally cannot be used in metallurgical industries and are abandoned as solid waste, resulting in environmental contamination. Herein, boron doping followed by facile one-step heat treatment in the range of 2100 to 2700 °C has been carried out to process semi-coke powder waste. Thereby, the semi-coke powders can be graphitized to give sample carbon content values of over 95%. The best product so-prepared delivered reversible capacities of 351.5 mA h g−1 at 0.1C, and 322 mA h g−1 at 1C. Surprisingly, the capacity was maintained at 314.3 mA h g−1 after 300 cycles at 1C, giving a decline rate of only 2.4% and presenting superior rate performance.The processed SC can deliver a capacity of 314.3 mA h g−1 after 300 cycles at 1C with a decline rate of 2.4%. 相似文献
10.
We report an environmentally friendly strategy for the synthesis of Fe3C/Fe/graphitic carbon based on hydrothermal carbonization and graphitization of carbon spheres with potassium ferrate (K2FeO4) at 800 °C. The obtained sample consisting of Fe3C/Fe nanoparticles and graphitic carbon (FC-1-8) delivered an enhanced pseudocapacitance of 428.0 F g−1 at a current density of 1 A g−1. After removal of the Fe3C/Fe electroactive materials, the graphitic carbon (FC-1-8-HCl) possessed a large specific surface area (SSA) up to 2813.6 m2 g−1 with a capacity of 243.3 F g−1 at 1 A g−1, far outweighing the other amorphous carbon electrodes of FC-0-8 (carbon spheres annealed at 800 °C without the treatment of K2FeO4). The graphitic material with a porous structure could offer more electroactive sites and improved conductivity of the sample. This method provided guidelines for the synthesis of superior performance supercapacitors with synchronous graphitic carbon and electroactive species.We report an environmentally friendly strategy for the synthesis of Fe3C/Fe/graphitic carbon based on hydrothermal carbonization and graphitization of carbon spheres with potassium ferrate (K2FeO4) at 800 °C. 相似文献
11.
Beibei Ma Yewei Huang Zhenzhen Nie Xiaobin Qiu Dawei Su Guoxiu Wang Jianmin Yuan Xiuqiang Xie Zhenjun Wu 《RSC advances》2019,9(35):20424
A comparatively facile and ecofriendly process has been developed to synthesize porous carbon materials from Camellia oleifera shells. Potassium carbonate solution (K2CO3) impregnation is introduced to modify the functional groups on the surface of Camellia oleifera shells, which may play a role in promoting the development of pore structure during carbonization treatment. Moreover, a small amount of naturally embedded nitrogen and sulfur in the Camellia oleifera shells can also bring about the formation of pores. The Camellia oleifera shell-derived carbon has a large specific surface area of 1479 m2 g−1 with a total pore volume of 0.832 cm3 g−1 after being carbonized at 900 °C for 1 h. Furthermore, when used as an anode for lithium-ion batteries, the sample shows superior electrochemical performance with a specific capacity of 483 mA h g−1 after 100 cycles measured at 200 mA g−1 current density. Surprisingly, the specific capacity is even gradually increased with cycling. In addition, this sample exhibits almost 100% retention capacity after 250 cycles at a current density of 200 mA g−1.Bio-waste Camellia oleifera shells (COS) are converted into porous carbon by a two-step method. 相似文献
12.
Xi Wu Xiaohua Jie Xinghua Liang Suo Li Lingxiao Lan Dan Xie Yusi Liu 《RSC advances》2022,12(35):22996
Lithium–sulfur (Li–S) batteries are considered to be one of the candidates for high-energy density storage systems due to their ultra-high theoretical specific capacity of 1675 mA h g−1. However, problems of rapid capacity decay, sharp expansion in volume of the active material, and the shuttle effect have severely restricted their subsequent development and utilization. Herein, we design a nitrogen-doped porous carbon nanofiber (NPCNF) network as a sulfur host by the template method. The NPCNF shows a feather-like structure. After loading sulfur, the NPCNF/S composite can maintain a hierarchically porous structure. A high discharge capacity of 1301 mA h g−1 is delivered for the NPCNT/S composite at 0.1C. The reversible charge/discharge capacity at 2C is 576 mA h g−1, and 700 mA h g−1 is maintained after 500 cycles at 0.5C. The high electrochemical performance of this NPCNT/S composite is attributed to the synergy effects of abundant N active sites and high electrical conductivity of the material.The conductive network of nitrogen-doped porous carbon nanofibers was successfully prepared by the template method. The doping of nitrogen and the synergistic effect of mesopores and micropores reduce the energy barrier of Li+ migration in the material. 相似文献
13.
The control of structure and morphology in an electrode design for the development of large-power lithium ion batteries is crucial to create efficient transport pathways for ions and electrons. Herein, we report a powerful combinational strategy to build omnibearing conductive networks composed of titanium niobium oxide nanorods and carbon nanofibers (TNO/CNFs) via an electrostatic spinning method and a hydrothermal method into free-standing arrays with a three-dimensional heterostructure core/shell structure. TNO/CNF electrode exhibits significantly superior electrochemical performance and high-rate capability (241 mA h g−1 at 10C, and 208 mA h g−1 at 20C). The capacity of the TNO/CNF electrode is 257 mA h g−1 after 2000 cycles at 20C, which is much higher than that of the TNO electrode. In particular, the TNO/CNF electrode delivers a reversible capacity of 153.6 mA h g−1 with a capacity retention of 95% after 5000 cycles at ultrahigh current density. Superior electrochemical performances of the TNO/CNF electrode are attributed to the unique composite structure.The control of structure and morphology in an electrode design for the development of large-power lithium ion batteries is crucial to create efficient transport pathways for ions and electrons. 相似文献
14.
Jun Wang Shengli Li Yi Zhao Juan Shi Lili Lv Huazhi Wang Zhiya Zhang Wangjun Feng 《RSC advances》2018,8(12):6660
With a high specific capacity (4200 mA h g−1), silicon based materials have become the most promising anode materials in lithium-ions batteries. However, the large volume expansion makes the capacity reduce rapidly. In this work, a periodic silicon/carbon (Si/C) multilayer thin film was synthesized by magnetron sputtering method on copper foil. The titanium (Ti) film (about 20 nm) as the transition layer was deposited on the copper foil prior to the deposition of the multilayer film. Superior electrochemical lithium storage performance was obtained by the multilayer thin film. The initial discharge and charge specific capacity of the Si (15 nm)/C (5 nm) multilayer film anode are 2640 mA h g−1 and 2560 mA h g−1 with an initial coulombic efficiency of ∼97%. The retention specific capacity is about 2300 mA h g−1 and there is ∼87% capacity retention after 200 cycles.With a high specific capacity (4200 mA h g−1), silicon based materials have become the most promising anode materials in lithium-ions batteries. 相似文献
15.
Hang Xu Chuanqiang Yin Xinran Hou Man Gong Changshu Yang Lexiang Xu Jinpeng Luo Lei Ma Lang Zhou Xiaomin Li 《RSC advances》2022,12(34):21904
Free-standing and flexible carbon nanofiber membranes (CNMs) with a three-dimensional network structure were fabricated based on PMDA/ODA polyimide by combining electrospinning, imidization, and carbonization strategies. The influence of carbonization temperature on the physical-chemical characteristics of CNMs was investigated in detail. The electrochemical performances of CNMs as free-standing electrodes without any binder or conducting materials for lithium-ion batteries were also discussed. Furthermore, the surface state and internal carbon structure had an important effect on the nitrogen state, electrical conductivity, and wettability of CNMs, and then further affected the electrochemical performances. The CNMs/Li metal half-cells exhibited a satisfying charge–discharge cycle performance and excellent rate performance. They showed that the reversible specific capacity of CNMs carbonized at 700 °C could reach as high as 430 mA h g−1 at 50 mA g−1, and the value of the specific capacity remained at 206 mA h g−1 after 500 cycles at a high current density of 1 A g−1. Overall, the newly developed carbon nanofiber membranes will be a promising candidate for flexible electrodes used in high-power lithium-ion batteries, supercapacitors and sodium-ion batteries.Free-standing and flexible carbon nanofiber membranes (CNMs) with a three-dimensional network structure were fabricated based on PMDA/ODA polyimide by combining electrospinning, imidization, and carbonization strategies. 相似文献
16.
Rahmat Agung Susantyoko Tawaddod Saif Alkindi Amarsingh Bhabu Kanagaraj Boohyun An Hamda Alshibli Daniel Choi Sultan AlDahmani Hamed Fadaq Saif Almheiri 《RSC advances》2018,8(30):16566
The typical lithium-ion-battery positive electrode of “lithium-iron phosphate (LiFePO4) on aluminum foil” contains a relatively large amount of inactive materials of 29 wt% (22 wt% aluminum foil + 7 wt% polymeric binder and graphitic conductor) which limits its maximum specific capacity to 120.7 mA h g−1 (71 wt% LiFePO4) instead of 170 mA h g−1 (100 wt% LiFePO4). We replaced the aluminum current-collector with a multi-walled carbon nanotube (MWCNT) network. We optimized the specific capacity of the “freestanding MWCNT-LiFePO4” positive electrode. Through the optimization of our unique surface-engineered tape-cast fabrication method, we demonstrated the amount of LiFePO4 active materials can be as high as 90 wt% with a small amount of inactive material of 10 wt% MWCNTs. This translated to a maximum specific capacity of 153 mA h g−1 instead of 120.7 mA h g−1, which is a significant 26.7% gain in specific capacity compared to conventional cathode design. Experimental data of the freestanding MWCNT-LiFePO4 at a low discharge rate of 17 mA g−1 show an excellent specific capacity of 144.9 mA h g−1 which is close to its maximum specific capacity of 153 mA h g−1. Furthermore, the freestanding MWCNT-LiFePO4 has an excellent specific capacity of 126.7 mA h g−1 after 100 cycles at a relatively high discharge rate of 170 mA g−1 rate.We optimized the specific capacity of freestanding MWCNT-LiFePO4 positive electrode. We demonstrated as high (low) as 90 wt% LiFePO4 active material (10 wt% MWCNTs inactive material). This corresponded to a maximum specific capacity of 153 mA h g−1. 相似文献
17.
Wenjie Fan Hao Zhang Huanlei Wang Xiaochen Zhao Shijiao Sun Jing Shi Minghua Huang Wei Liu Yulong Zheng Ping Li 《RSC advances》2019,9(56):32382
Nowadays, designing heteroatom-doped porous carbons from inexpensive biomass raw materials is a very attractive topic. Herein, we propose a simple approach to prepare heteroatom-doped porous carbons by using nettle leaves as the precursor and KOH as the activating agent. The nettle leaf derived porous carbons possess high specific surface area (up to 1951 m2 g−1), large total pore volume (up to 1.374 cm3 g−1), and high content of nitrogen and oxygen heteroatom doping (up to 17.85 at% combined). The obtained carbon as an electrode for symmetric supercapacitors with an ionic liquid electrolyte can offer a superior specific capacitance of 163 F g−1 at 0.5 A g−1 with a capacitance retention ratio as high as 67.5% at 100 A g−1, and a low capacitance loss of 8% after 10 000 cycles. Besides, the as-built supercapacitor demonstrates a high specific energy of 50 W h kg−1 at a specific power of 372 W kg−1, and maintains 21 W h kg−1 at the high power of 40 kW kg−1. Moreover, the resultant carbon as a Li-ion battery anode delivers a high reversible capacity of 1262 mA h g−1 at 0.1 A g−1 and 730 mA h g−1 at 0.5 A g−1, and maintains a high capacity of 439 mA h g−1 after 500 cycles at 1 A g−1. These results demonstrate that the nettle leaf derived porous carbons offer great potential as electrodes for advanced supercapacitors and lithium ion batteries.Nettle leaf derived nitrogen and oxygen dual-doped porous carbons exhibit great potential as anodes for high performance supercapacitors and lithium ion batteries. 相似文献
18.
Thermal batteries with molten salt electrolytes are used for many military applications, primarily as power sources for guided missiles. The Li–B/CoS2 couple is designed for high-power, high-voltage thermal batteries. However, their capacity and safe properties are influenced by acute self-discharge that results from the dissolved lithium anode in molten salt electrolytes. To solve those problems, in this paper, carbon coated CoS2 was prepared by pyrolysis reaction of sucrose at 400 °C. The carbon coating as a physical barrier can protect CoS2 particles from damage by dissolved lithium and reduce the self-discharge reaction. Therefore, both the discharge efficiency and safety of Li–B/CoS2 thermal batteries are increased remarkably. Discharge results show that the specific capacity of the first discharge plateau of carbon-coated CoS2 is 243 mA h g−1 which is 50 mA h g−1 higher than that of pristine CoS2 at a current density of 100 mA cm−2. The specific capacity of the first discharge plateau at 500 mA cm−2 for carbon-coated CoS2 and pristine CoS2 are 283 mA h g−1 and 258 mA h g−1 respectively. The characterizations by XRD and DSC indicate that the carbonization process has no noticeable influence on the intrinsic crystal structure and thermal stability of pristine CoS2.Suppressing self-discharge of Li–B/CoS2 thermal batteries through modifying the CoS2 cathode with a protective carbon coating layer. 相似文献
19.
Milad Vafaeinia Mobin Safarzadeh Khosrowshahi Hossein Mashhadimoslem Hosein Banna Motejadded Emrooz Ahad Ghaemi 《RSC advances》2021,12(1):546
Oxygen and nitrogen enriched micro–meso porous carbon powders have been prepared from pectin and melamine as oxygen and nitrogen containing organic precursors, respectively. The synthesis process has been performed following a solvothermal approach in an alkaline solution during which Pluronic F127 was added to the solution as the soft template. Following the solvothermal treatment, the carbonization process has been performed at 700, 850 and 950 °C. The synthesized porous carbons have been characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption isotherms and Fourier transform infrared spectroscopy (FTIR). The surface area of 499.5 m2 g−1, total pore volume of 0.35 cm3 g−1, and a high nitrogen and oxygen content of 9.3 and 29.1 wt% are displayed for the fine sample. The optimal porous carbon had CO2 adsorption of up to 3.1 mmol g−1 at 273 K at 1 bar owing to abundant basic nitrogen-containing functionalities and the valuable micro–meso porous structure. Despite the absence of any reagent and also having a relatively moderate specific surface area, compared to similar materials, a very high ratio of adsorption capacity to specific surface area (6.2 μmol m−2) was observed. The Elovich kinetic model was found to be the best and the physisorption process was reported.Oxygen and nitrogen enriched micro–meso porous carbon powders have been prepared from pectin and melamine as oxygen and nitrogen containing organic precursors, respectively. 相似文献
20.
Carbon nanofibrous mats (CNFMs) are prepared by electrospinning of blended precursor of polyacrylonitrile and polysulfone (PSF) followed by pre-oxidation stabilization and carbonization. Addition of PSF as a sacrificial polymer leads to CNFMs with high surface area, large numbers of micropores and mesopores, good degree of carbonization, and interconnected fibrous network, due to the high decomposition temperature, release of SO2 during decomposition, and large amount of carbon residue of PSF during carbonization. The electrochemical characterization shows that the CNFM electrode has a specific capacitance of 272 F g−1 at a current density of 1 A g−1 with 74% of the specific capacitance retained at 50 A g−1 in 2.0 M KOH electrolyte. The CNFM electrodes have excellent cycling durability with 100% capacitance retention after 10 000 cycles.Carbon nanofibrous mats (CNFMs) are prepared by electrospinning of blended precursor of polyacrylonitrile and polysulfone (PSF) followed by pre-oxidation stabilization and carbonization. 相似文献