共查询到18条相似文献,搜索用时 234 毫秒
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采用改进Hummers法,在不同KMnO4用量下制得了不同氧化程度的系列氧化石墨,并以其为前驱体在N2中经400℃热还原制备了石墨烯。利用XRD、FT-IR、Raman光谱与SEM表征了所得石墨烯的结构、官能团及表面形貌,通过循环伏安和恒流充放电测试研究了氧化石墨的氧化程度对石墨烯电化学性能的影响。结果表明,当KMnO4用量较低(1.0 g)时,前驱体氧化程度较低,不能被剥离;当KMnO4用量较高(≥1.0 g)时,前驱体氧化程度增高,可实现剥离制备石墨烯。随着前驱体氧化程度增加,所制石墨烯堆叠层数与sp2平均尺寸逐渐减小,含氧官能团与缺陷逐渐增多,比容量逐渐增大。 相似文献
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《微纳电子技术》2020,(2):119-124
以柠檬酸为原料,通过碳化制备石墨烯量子点(GQD)溶液,对制备的石墨烯量子点溶液进行超声使石墨烯量子点吸附在石墨毡表面。采用场发射扫描电子显微镜(FE-SEM)、X射线光电子能谱(XPS)和喇曼光谱对石墨烯量子点修饰的石墨毡进行表征。通过循环伏安(CV)曲线、电化学阻抗谱(EIS)和计时电位法研究其电化学性能。测试发现,该石墨毡电极在电流密度1 mA·cm-2下比电容高达2 394 F/g,在电流密度4 mA·cm-2下经过5 000次循环后稳定性达到95%。结果表明石墨烯量子点修饰的石墨毡电极具有优异的电化学性能,可以成为极具应用前景的超级电容器的电极材料。 相似文献
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《电子元件与材料》2019,(9):22-27
以氧化石墨烯为原料,通过水热处理得到石墨烯水凝胶,浸渍KOH溶液后进一步高温活化制备了高比表面积的三维多孔石墨烯,系统地研究了KOH活化剂用量对石墨烯多孔结构和电容性能的影响规律。研究结果表明,随KOH用量增加,三维多孔石墨烯的比表面积增加,多孔结构更加发达,比容量增大。所制备的三维多孔石墨烯的比表面积最高可达2133 m~2·g~(-1),在1 mol·L~(-1) Et_4NBF_4/AN的有机电解液中于0.2 A·g~(-1)电流密度下的比容量高达108 F·g~(-1),循环和倍率性能优异。优异的电化学性能,结合简单的制备工艺,使得这种方法制备的三维多孔石墨烯成为极具应用前景的超级电容器电极材料。 相似文献
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使用氧化石墨烯量子点(GQD)嵌入氧化石墨烯(GO)层间,在NH3氛围下采用光照辐射进行还原和氮掺杂,制备一种类“三明治”结构的超级电容器电极材料。光化学还原法可以在短时间内实现材料的还原和掺氮。氧化石墨烯量子点丰富的边缘活性位点使氮的原子数分数高达18.19%,大幅提高了材料的湿润性和电导率。同时量子点嵌入氧化石墨烯层间,可以有效防止氧化石墨烯片的堆叠,增加材料中离子通道数量。制备的两电极超级电容器在0.3 A/g电流密度下的比容量高达380 F/g,电极充放电循环2 000次以后,电容量仍然保持初始电容量的86%。这种富氮石墨烯在新型储能系统中具有潜在的应用前景。 相似文献
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通过湿法纺丝工艺成功制备了纳米硅/还原氧化石墨烯复合纤维材料,并对其进行形貌表征与电化学性能测试。纳米硅颗粒嵌入石墨烯层间褶皱的结构具有限制硅材料在储锂过程中体积膨胀的作用,适于作为锂离子电容器负极。同时,研究了锂离子电容器多孔活性炭正极材料的双电层电容特性,通过组装成对称超级电容器,对其电化学性能进行测试,并结合材料的形貌,分析其作为锂离子电容器正极的合理性。为使正负极电荷匹配,分别对负极硅碳纤维和正极活性炭材料组装的锂离子半电池的倍率、循环稳定性、电化学阻抗等电化学性能进行了测试。结果表明,纳米硅/还原氧化石墨烯复合纤维材料的比容量最高可达826.2 mA·h/g(在电流密度为0.2 A/g时),活性炭比容量可达39.9 mA·h/g。组装成的锂离子电容器在合理的匹配条件下,充放电首圈循环比容量可达58.2 mA·h/g (在电流密度为0.2 A/g时),能量密度为26.8 W·h/kg,循环100圈后,比容量保持率降至41.7%。 相似文献
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Jun Yan Zhuangjun Fan Wei Sun Guoqing Ning Tong Wei Qiang Zhang Rufan Zhang Linjie Zhi Fei Wei 《Advanced functional materials》2012,22(12):2632-2641
Hierarchical flowerlike nickel hydroxide decorated on graphene sheets has been prepared by a facile and cost‐effective microwave‐assisted method. In order to achieve high energy and power densities, a high‐voltage asymmetric supercapacitor is successfully fabricated using Ni(OH)2/graphene and porous graphene as the positive and negative electrodes, respectively. Because of their unique structure, both of these materials exhibit excellent electrochemical performances. The optimized asymmetric supercapacitor could be cycled reversibly in the high‐voltage region of 0–1.6 V and displays intriguing performances with a maximum specific capacitance of 218.4 F g?1 and high energy density of 77.8 Wh kg?1. Furthermore, the Ni(OH)2/graphene//porous graphene supercapacitor device exhibits an excellent long cycle life along with 94.3% specific capacitance retained after 3000 cycles. These fascinating performances can be attributed to the high capacitance and the positive synergistic effects of the two electrodes. The impressive results presented here may pave the way for promising applications in high energy density storage systems. 相似文献
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Mianqi Xue Fengwang Li Juan Zhu Hang Song Meining Zhang Tingbing Cao 《Advanced functional materials》2012,22(6):1284-1290
A novel method is described for fabricating an all‐solid‐state flexible micro‐supercapacitor. The microelectrodes of the supercapacitor are prepared by in situ electrodeposition of polyaniline (PANI) nanorods on the surface of reduced graphene oxide (rGO) patterns that are fabricated by micromolding in capillaries. The morphologies of PANI nanorods could be controlled by the concentration of aniline and the growth time in the electrodeposition process. The micro‐supercapacitor possesses electrochemical capacitance as high as 970 F g?1 at a discharge current density of 2.5 A g?1, as well as good stability, retaining 90% of its initial capacitance after 1700 consecutive cycles for the synergistic effect of these new rGO/PANI nanostructures. The results show that the method could represent a route for translating the interesting fundamental properties of rGO and conducting polymers into technologically viable energy devices. Furthermore, this study might further guide the preparation of functional graphene‐based materials. 相似文献
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Xiao‐Miao Feng Rui‐Mei Li Yan‐Wen Ma Run‐Feng Chen Nai‐En Shi Qu‐Li Fan Wei Huang 《Advanced functional materials》2011,21(15):2989-2996
This work describes a new one‐step large‐scale electrochemical synthesis of graphene/polyaniline (PANI) composite films using graphite oxide (GO) and aniline as the starting materials. The size of the film could be controlled by the area of indium tin oxide (ITO). Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and ultraviolet–visible absorption spectrum (UV–vis) results demonstrated that the graphene/PANI composite film was successfully synthesized. The obtained graphene/PANI composite film showed large specific area, high conductivity, good biocompatibility, and fast redox properties and had perfect layered and encapsulated structures. Electrochemical experiments indicated that the composite film had high performances and could be widely used in applied electrochemical fields. As a model, horseradish peroxidase (HRP) was entrapped onto the film‐modi?ed glassy carbon electrode (GCE) and used to construct a biosensor. The immobilized HRP showed a pair of well‐de?ned redox peaks and high catalytic activity for the reduction of H2O2. Furthermore, the graphene/PANI composite film could be directly used as the supercapacitor electrode. The supercapacitor showed a high specific capacitance of 640 F g?1 with a retention life of 90% after 1000 charge/discharge cycles. 相似文献
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Flexible electrodes of ternary composites, in which highly conductive carbon nanotube films (CNFs) are coated with carbon nanotube-doped graphene oxide/polypyrrole (CNT-GO/PPy), have been fabricated via facile electrochemical synthesis. Long and short CNTs are separately doped into the composites (lCNT-GO/PPy and sCNT-GO/PPy) and their electrochemical performances are compared. Electrochemical measurements indicate that the doping of CNTs in the composites significantly improves the electrochemical behaviors of the GO/PPy electrodes. Notably, the lCNT-GO/PPy electrodes show superior electrochemical properties with respect to the sCNT-GO/PPy electrodes, which is related to the introduction of abundant CNTs in the former electrodes and their special microstructures. Two symmetric electrodes with the lCNT-GO/PPy composites coated on CNFs are assembled to fabricate a solid-state supercapacitor device, which features lightweight, ultrathinness, and high flexibility. The device achieves a high areal and volumetric specific capacitance of 70.0 mF cm−2 at 10 mV s−1 and 6.3 F cm−3 at 0.043 A cm−3, respectively. It also shows superior rate performance and cycle stability, with a capacitance retention rate of 87.7% for 10,000 cycles. The supercapacitor device fabricated is promising for the use in lightweight and flexible integrated electronics. 相似文献
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Growth of Vertically Aligned Tunable Polyaniline on Graphene/ZrO2 Nanocomposites for Supercapacitor Energy‐Storage Application
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In‐situ hydrothermal method is employed to synthesize graphene/zirconium oxide composite from respective precursors graphene oxide and zirconium oxy‐nitrate. In this method, the graphene oxide is reduced itself to graphene and simultaneously metal oxide gets anchor on the graphene sheets. A novel method is also developed for the preparation of vertically aligned tunable polyaniline on the graphene/zirconium oxide nanocomposite, which leads to achieve high surface area (207.1 m2 g?1), high electrical conductivity (70.8 S cm?1), high specific capacitance (1359.99 Fg?1 at 1 mV s?1), and high electrochemical performances as supercapacitor electrode materials. This vertically aligned conducting polymer gets easy contact with electrolyte ions and provides numerous redox active sites during charging and discharging. Moreover, such a simple and low cost assembly approach can be a pioneer for the large‐scale production of various functional architectures for energy storage and conversions. 相似文献
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以氧化石墨烯修饰的功能复合纸为吸附材料,研究其对水中重金属Pb(Ⅱ)离子的吸附能力,探讨了吸附剂的用量和初始浓度等净化条件对吸附效果的影响。结果表明:氧化石墨烯修饰的功能复合纸的结构平整、化学性质稳定,易分离;功能复合纸对Pb(Ⅱ)离子有良好的吸附能力,且吸附效果全部归功于氧化石墨烯的作用;功能复合纸上负载的氧化石墨烯用量增加反而降低单位质量氧化石墨烯对Pb(Ⅱ)的吸附量,在所研究的净化条件中,吸附量跨度为90 mg/g^500 mg/g;随着Pb(Ⅱ)初始浓度的增加,功能复合纸对Pb(Ⅱ)的吸附效果明显提升,当Pb(Ⅱ)离子溶液的初始浓度为350 mg/L时,吸附效果最佳。吸附反应动力学较好的符合伪二阶动力学模型,即吸附过程受化学作用主导,氧化石墨烯表面的含氧官能团在吸附过程中起到重要作用。功能复合纸在吸附饱和后,易于与水体分离,避免二次污染现象。 相似文献
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High‐Performance Polypyrrole/Graphene/SnCl2 Modified Polyester Textile Electrodes and Yarn Electrodes for Wearable Energy Storage
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Xiaolong Li Rong Liu Chunyang Xu Yang Bai Xiaoming Zhou Yongji Wang Guohui Yuan 《Advanced functional materials》2018,28(22)
Flexible supercapacitors have potential for wearable energy storage due to their high energy/power densities and long operating lifetimes. High electrochemical performance with robust mechanical properties is highly desired for flexible supercapacitor electrodes. Usually, the mechanical properties are improved by choosing high flexible textile substrates but at the much expense of electrochemical performance due to the nonideal contact between conductive materials and textile substrates. Herein, the authors present an efficient, scalable, and general strategy for the simultaneous fabrication of high‐performance textile electrodes and yarn electrodes. It is interesting to find that the conformal reduced graphene oxide (RGO) layer is uniformly and successively painted on the surface of SnCl2 modified polyester fibers (M‐PEF) via a repeated “dyeing and drying” strategy. The large‐area textile electrodes and ultralong yarn electrodes are fabricated by using RGO/M‐PEF as substrate with subsequent deposition of polypyrrole. This work provides new opportunities for developing high flexible textile electrodes and yarn electrodes with further increased electrochemical performance and scalable production. 相似文献
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以Mn(NO3)2、活性中间相碳微球(活性MCMB)为原料,采用KBrO3氧化法,成功制备了MnO2/活性MCMB新型复合电极材料;以该材料制成电极,并以质量分数为30%的KOH溶液为电解液,组装成扣式电容器。通过XRD和SEM分析了MCMB,活性MCMB及MnO2/活性MCMB的晶相结构和表面形态;采用循环伏安、交流阻抗和恒流充放电法研究了电容器的电容性能。结果表明:以MnO2/活性MCMB复合电极制成的电容器电容性能优良。在0.5A/g电流密度下,其充放电曲线表现出典型的电容行为,初始比容量高达403.5F/g,相应能量密度为12.5Wh/kg;其循环伏安曲线关于零电流线对称,呈现为较规则的矩形;其等效串联电阻约为0.7Ω。 相似文献