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超电容器活性炭/炭黑复合电极电容特性研究 总被引:3,自引:0,他引:3
为制备实用化的超电容器,对活性炭材料进行了表征,详细描述了活性炭/炭黑复合电极的制备工艺。通过循环伏安法和恒电流充电法,对活性炭/炭黑复合电极在水系电解液中的电容行为进行了研究。结果表明:活性炭的BET比表面积达1 654 m2/g,具有合理的孔径分布,主要在2 nm附近。添加高比表面积、高导电性纳米级炭黑制备的活性炭/炭黑复合电极具有优良的电容行为和较好的功率特性,复合电极的比容量达到102.4 F/g。此外还对孔径分布与电容的关系进行了阐述。 相似文献
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有机双电层电容器用活性炭电极的修饰 总被引:5,自引:2,他引:3
利用石墨、炭黑、碳纳米管三种导电碳材料,对高比表面积活性炭进行掺杂修饰,制备有机电解液双电层电容器用薄膜电极。经电化学测试发现,在 1 mol/L 的 LiPF6/EC-DEC(体积比 1∶1)溶液中,经不同导电材料修饰后的活性炭电极,其单电极比容量和大电流充放电性能均有较大改善。其中,掺杂 10%(质量分数)碳纳米管的活性炭电极,在 330 mA/g 电流密度下的单电极比容量可达 81 F/g,比未掺杂活性炭电极 60 F/g 的比容量提高了 35%;电流密度从 60 mA/g 增至 330 mA/g,该电极的容量保持率为 79.4%。 相似文献
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改性活性炭双电层电容器电极材料研究 总被引:2,自引:2,他引:0
用氢氧化钾对普通活性炭活化改性,比表面积和总孔容由806m2/g和0.411cm3/g分别增加到1168m2/g和0.577cm3/g。用该材料制成硬币型双电层电容器,经测定炭材料比电容高达203.5F/g,提高了64%;等效串联内阻仅为1.94?,大电流放电时容量衰减小于10%。其突出优点是体积与面积比电容高达109.6F/cm3和17.4×10–6F/cm2。研究发现孔径分布于1.4~2.78nm的超微孔和小中孔,有利于电解质离子形成双电层而提高炭材料的电容量。 相似文献
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Next‐Generation Activated Carbon Supercapacitors: A Simple Step in Electrode Processing Leads to Remarkable Gains in Energy Density 下载免费PDF全文
Jee Y. Hwang Mengping Li Maher F. El‐Kady Richard B. Kaner 《Advanced functional materials》2017,27(15)
The global supercapacitor market has been growing rapidly during the past decade. Today, virtually all commercial devices use activated carbon. In this work, it is shown that laser treatment of activated carbon electrodes results in the formation of microchannels that can connect the internal pores of activated carbon with the surrounding electrolyte. These microchannels serve as electrolyte reservoirs that in turn shorten the ion diffusion distance and enable better interaction between the electrode surfaces and electrolyte ions. The capacitance can be further increased through fast and reversible redox reactions on the electrode surface using a redox‐active electrolyte, enabling the operation of a symmetric device at 2.0 V, much higher than the thermodynamic decompostion voltage of water. This simple approach can alleviate the low energy density of supercapacitors which has limited the widespread use of this technology. This work represents a clear advancement in the processing of activated carbon electrodes toward the next‐generation of low‐cost supercapacitors. 相似文献
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Thangavelu Palaniselvam Mustafa Goktas Bihag Anothumakkool Ya‐Nan Sun Richard Schmuch Li Zhao Bao‐Hang Han Martin Winter Philipp Adelhelm 《Advanced functional materials》2019,29(18)
Here, a Sn–C composite material prepared from bulk precursors (tin metal, graphite, and melamine) using ball milling and annealing is reported. The composite (58 wt% Sn and 42 wt% N‐doped carbon) shows a capacity up to 445 mAh gSn+C?1 and an excellent cycle life (1000 cycles). For the graphite, the ball milling leads to graphene nanoplatelets (GnP) for which the storage mechanism changes from solvent co‐intercalation to conventional intercalation. The final composite (Sn at nitrogen‐doped graphite nanoplatelets (SnNGnP)) is obtained by combining the GnPs with Sn and melamine as the nitrogen source. Rate‐dependent measurements and in situ X‐ray diffraction are used to study the asymmetric storage behavior of Sn, which shows a more sloping potential profile during sodiation and more defined steps during desodiation. The disappearance of two redox plateaus during desodiation is linked to the preceding sodiation current density (memory effect). The asymmetric behavior is also found by in situ electrochemical dilatometry. This method also shows that the effective electrode expansion during sodiation is much smaller (about +14%) compared to what is expected from Sn (+420%), which gives a reasonable explanation for the excellent cycle life for the SnNGnP (and likely other nanocomposites in general). Next to the advantages, challenges, which result from the nanocomposite approach, are also discussed. 相似文献
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Hard–Soft Composite Carbon as a Long‐Cycling and High‐Rate Anode for Potassium‐Ion Batteries 下载免费PDF全文
Zelang Jian Sooyeon Hwang Zhifei Li Alexandre S. Hernandez Xingfeng Wang Zhenyu Xing Dong Su Xiulei Ji 《Advanced functional materials》2017,27(26)
There exist tremendous needs for sustainable storage solutions for intermittent renewable energy sources, such as solar and wind energy. Thus, systems based on Earth‐abundant elements deserve much attention. Potassium‐ion batteries represent a promising candidate because of the abundance of potassium resources. As for the choices of anodes, graphite exhibits encouraging potassium‐ion storage properties; however, it suffers limited rate capability and poor cycling stability. Here, nongraphitic carbons as K‐ion anodes with sodium carboxymethyl cellulose as the binder are systematically investigated. Compared to hard carbon and soft carbon, a hard–soft composite carbon with 20 wt% soft carbon distributed in the matrix phase of hard carbon microspheres exhibits highly amenable performance: high capacity, high rate capability, and very stable long‐term cycling. In contrast, pure hard carbon suffers limited rate capability, while the capacity of pure soft carbon fades more rapidly. 相似文献
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微波加热法制备电极材料活性炭 总被引:2,自引:0,他引:2
以煤为原料,KOH为活化剂,采用微波辐射加热法和电阻炉加热法制备出双电层电容器用活性炭。对比研究了两种工艺下KOH用量、活化时间对活性炭比电容量的影响,考察了活性炭双电层电容器的充放电特性。结果显示:微波活化时,ζ(KOH∶煤)为3∶1,起电弧时间5min,比电容为283.67F/g;电阻炉活化时,ζ(KOH∶煤)为4∶1,保温时间为1h,比电容为235.55F/g。经过100次循环充放电后,微波法和电阻炉法所得的活性炭的比电容分别保持在98.10%和91.04%。 相似文献
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B‐doped Carbon Coating Improves the Electrochemical Performance of Electrode Materials for Li‐ion Batteries 下载免费PDF全文
Cong Wang Ziyang Guo Wei Shen Qunjie Xu Haimei Liu Yonggang Wang 《Advanced functional materials》2014,24(35):5511-5521
An evolutionary modification approach, boron doped carbon coating, is initially used to improve the electrochemical properties of electrode materials of lithium‐ion batteries, such as Li3V2(PO4)3, and demonstrates apparent and significant modification effects. Based on the precise analysis of X‐ray photoemission spectroscopy results, Raman spectra, and electrochemical impedance spectroscopy results for various B‐doped carbon coated Li3V2(PO4)3 samples, it is found that, among various B‐doping types (B4C, BC3, BC2O and BCO2), the graphite‐like BC3 dopant species plays a huge role on improving the electronic conductivity and electrochemical activity of the carbon coated layer on Li3V2(PO4)3 surface. As a result, when compared with the bare carbon coated Li3V2(PO4)3, the electrochemical performances of the B‐doped carbon coated Li3V2(PO4)3 electrode with a moderate doping amount are greatly improved. For example, when cycled under 1 C and 20 C in the potential range of 3.0–4.3 V, this sample shows an initial capacity of 122.5 and 118.4 mAh g?1, respectively; after 200 cycles, nearly 100% of the initial capacity is retained. Moreover, the modification effects of B‐doped carbon coating approach are further validated on Li4Ti5O12 anode material. 相似文献
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Unconventional Carbon: Alkaline Dehalogenation of Polymers Yields N‐Doped Carbon Electrode for High‐Performance Capacitive Energy Storage 下载免费PDF全文
Guoxin Zhang Lin Wang Yongchao Hao Xiuyan Jin Yuqi Xu Yun Kuang Liming Dai Xiaoming Sun 《Advanced functional materials》2016,26(19):3340-3348
Polymers are important precursors for the fabrication of carbon materials. Herein, halogenated polymers are explored as precursors for the synthesis of high‐quality carbon materials via alkaline dehalogenation. It is found that the halogen elements (F, Cl) connecting to vinylidene units are highly reactive so that dehalogenation can take place a few seconds at room temperature by simple hand grinding in the presence of strong inorganic alkaline. Furthermore, the halogen element‐leaving sites are shown to be susceptible to heteroatom doping (e.g., N doping) to become stable capacitive sites for charge storage (e.g., ions). By using a mixture of NaOEt and KOH as dehalogenation reagents, abundant hierarchical pores (macro/meso/micropores) in the resultant doped carbon matrix for fast mass transportation can be created. Very high capacitance (328 F g?1 at 0.5 A g?1) and rate capability (75.3% retention at 50 A g?1 and 62.5% retention at 100 A g?1) are observed for the newly developed halogenated polymer‐derived doped carbon materials. 相似文献
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Lead‐Carbon Batteries: Synthesis of Nanostructured PbO@C Composite Derived from Spent Lead‐Acid Battery for Next‐Generation Lead‐Carbon Battery (Adv. Funct. Mater. 9/2018) 下载免费PDF全文
Yuchen Hu Jiakuan Yang Jingping Hu Junxiong Wang Sha Liang Huijie Hou Xu Wu Bingchuan Liu Wenhao Yu Xiong He R. Vasant Kumar 《Advanced functional materials》2018,28(9)
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Synthesis of Nanostructured PbO@C Composite Derived from Spent Lead‐Acid Battery for Next‐Generation Lead‐Carbon Battery 下载免费PDF全文
Yuchen Hu Jiakuan Yang Jingping Hu Junxiong Wang Sha Liang Huijie Hou Xu Wu Bingchuan Liu Wenhao Yu Xiong He R. Vasant Kumar 《Advanced functional materials》2018,28(9)
Lead‐carbon batteries could provide better performance on high‐rate partial‐state‐of‐charge (HRPSoC) cycles than lead‐acid batteries (LABs), making them promising for the new‐generation of hybrid electric vehicles. The addition of carbon allotropes to the negative active material (NAM) could induce a significant improvement to the battery performance. Herein, an environmentally friendly strategy is demonstrated to prepare lead oxide and carbon (PbO@C) composite by pyrolyzing the lead citrate precursor derived from the spent lead paste of LABs. When the PbO@C composite is used as an additive to the NAM of lead‐carbon batteries, the utilization efficiency of the NAM is improved from 56.9% to 72.5%, and the cycle life of the cell in HRPSoC is tremendously extended by four times compared with the control one. The enhancement in battery performance is attributed to the hydrophilic carbon in the composite, which acts as a 3D electroosmotic pump facilitating electrolyte diffusion, and hindering the tendency to excess sulfation during the HRPSoC operation. This proposed research provides a sustainable and scalable strategy to recycle the discarded/spent LABs into high‐performance lead‐carbon batteries. 相似文献
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Denisa Hulicova‐Jurcakova Mykola Seredych Gao Qing Lu Teresa J. Bandosz 《Advanced functional materials》2009,19(3):438-447
Microporous activated carbon originating from coconut shell, as received or oxidized with nitric acid, is treated with melamine and urea and heated to 950 °C in an inert atmosphere to modify the carbon surface with nitrogen‐ and oxygen‐containing groups for a systematic investigation of their combined effect on electrochemical performance in 1 M H2SO4 supercapacitors. The chemistry of the samples is characterized using elemental analysis, Boehm titration, potentiometric titration, and X‐ray photoelectron spectroscopy. Sorption of nitrogen and carbon dioxide is used to determine the textural properties. The results show that the surface chemistry is affected by the type of nitrogen precursor and the specific groups present on the surface before the treatment leading to the incorporation of nitrogen. Analysis of the electrochemical behavior of urea‐ and melamine‐treated samples reveal pseudocapacitance from both the oxygen and the nitrogen containing functional groups located in the pores larger than 10 Å. On the other hand, pores between 5 Å and 6 Å are most effective in a double‐layer formation, which correlates well with the size of hydrated ions. Although the quaternary and pyridinic‐N‐oxides nitrogen groups have enhancing effects on capacitance due to the positive charge, and thus an improved electron transfer at high current loads, the most important functional groups affecting energy storage performance are pyrrolic and pyridinic nitrogen along with quinone oxygen. 相似文献
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The demand for advanced energy storage devices such as supercapacitors and lithium‐ion batteries has been increasing to meet the application requirements of hybrid vehicles and renewable energy systems. A major limitation of state‐of‐art supercapacitors lies in their relatively low energy density compared with lithium batteries although they have superior power density and cycle life. Here, we report an additive‐free, nano‐architectured nickel hydroxide/carbon nanotube (Ni(OH)2/CNT) electrode for high energy density supercapacitors prepared by a facile two‐step fabrication method. This Ni(OH)2/CNT electrode consists of a thick layer of conformable Ni(OH)2 nano‐flakes on CNT bundles directly grown on Ni foams (NFs) with a very high areal mass loading of 4.85 mg cm?2 for Ni(OH)2. Our Ni(OH)2/CNT/NF electrode demonstrates the highest specific capacitance of 3300 F g?1 and highest areal capacitance of 16 F cm?2, to the best of our knowledge. An asymmetric supercapacitor using the Ni(OH)2/CNT/NF electrode as the anode assembled with an activated carbon (AC) cathode can achieve a high cell voltage of 1.8 V and an energy density up to 50.6 Wh/kg, over 10 times higher than that of traditional electrochemical double‐layer capacitors (EDLCs). 相似文献
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Shibo Jiao Yi Liao Xinjun Xu Liping Wang Gui Yu Limin Wang Zhongmin Su Shanghui Ye Yunqi Liu 《Advanced functional materials》2008,18(16):2335-2347
Novel blue‐light‐emitting fluorene derivatives 5a–c and 7a–c containing bulky and highly emissive groups, namely pyrene, 10‐phenylanthracene‐9‐yl and 10‐(4′‐diphenylaminophenyl)anthracene‐9‐yl groups, as well as hole‐injecting/transporting triarylamines were synthesized. Single crystals of compounds 5a , 5c , 7a , and 7c were grown and their crystal structures were determined by X‐ray diffraction. The four fluorene derivatives have nonplanar molecular structures, which reduce the intermolecular interaction and the likelihood of molecular aggregation or excimer formation. No unwanted long‐wavelength emission was observed in the photoluminescence (PL) spectra of the 5a–c and 7a–c thin films. Their PL spectra reveal excellent thermal stability after annealing treatment under air and ambient light. All of the six compounds show high fluorescence quantum yields and outstanding thermal stabilities. The 2‐aryl and 2,7‐diaryl substituents at the fluorene molecule have a significant effect on the photophysical properties and the thermal characteristics. The six compounds show almost the same energy levels for the highest occupied molecular orbitals (HOMOs) of about ?5.20 eV, which allows effective hole injection. The C2‐ and C7‐aryl substituents play a relatively less‐important role in the HOMO energy levels, which depend mainly on the triphenylamino groups at the C9 position. The molecular orbitals, excitation energy, and emission energy were calculated to explain the real origin of their photophysical characteristics. The HOMOs are mainly localized on the triphenylamino groups at the C9 position, while the lowest unoccupied molecular orbitals (LUMOs) have a significant orbital density at the C2‐ and/or C7‐aryl substituents. Pure‐blue‐light‐emitting diodes based on 2,7‐diaryl‐9,9‐di(triarylamino)fluorenes were fabricated. 相似文献
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Yaling Wang Yan Zhang Guolong Wang Xiaowei Shi Yide Qiao Jiamei Liu Heguang Liu Anandha Ganesh Lei Li 《Advanced functional materials》2020,30(16)
The advancement of miniaturized electronic devices requires the development of high‐performance microsupercapacitors. The low areal energy density of microsupercapacitors with the interdigitated architecture is the major challenge hindering the application. Here, a simple method for the scalable fabrication of all‐solid‐state, flexible microsupercapacitors is demonstrated by direct graphene‐carbon nanotube composite ink writing technology. The microsupercapacitors demonstrate good electrochemical performance with a high areal energy density of 1.36 µWh cm–2 and power density of 0.25 mW cm–2, good cycling stability, and excellent mechanical flexibility. The method developed here sheds light on the simple method of preparing high‐performance, all‐solid‐state, flexible microsupercapacitors in a straightforward and scalable process. 相似文献
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Ultrahigh‐Strength Ultrahigh Molecular Weight Polyethylene (UHMWPE)‐Based Fiber Electrode for High Performance Flexible Supercapacitors 下载免费PDF全文
Jianguo Du Zhe Wang Jiali Yu Shahid Ullah Bo Yang Cuihua Li Ning Zhao Bin Fei Caizhen Zhu Jian Xu 《Advanced functional materials》2018,28(20)
Flexible fiber‐based supercapacitor (FSC) with excellent electrochemical performance and high tensile strength and modulus is strongly desired for some special circumstances, such as load‐bearing, abrasion resistant, and anticutting fabrics. Here, a series of ultrahigh‐strength fiber electrodes are prepared for flexible FSCs based on ultrahigh molecular weight polyethylene fibers, on which the polydopamine, Ag, and poly (3,4‐ethylene dioxythiophene): poly(styrenesulfonate) are deposited in sequence. The modified fiber‐based electrode exhibits superhigh strength up to 3.72 GPa, which is the highest among fiber‐based electrodes reported to date. In addition, FSCs fabricated with the optimized fiber electrode shows a specific areal capacity as high as 563 mF cm?2 at 0.17 mA cm?2, which corresponds to a high areal energy density of ≈50.1 µWh cm?2 at a power density of ≈124 µW cm?2. The specific areal capacity only decrease 8% after 1000 times bending test, indicating the outstanding bending performance of this composite fiber electrode. Furthermore, several FSCs can be connected in series or in parallel to get higher working voltage or higher capacity respectively, which demonstrates its potential for broad applications in flexible devices. 相似文献