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1.
通过简单的溶剂热法以及其后续热处理过程,制备了NiO纳米花和NiO/还原氧化石墨烯(rGO)复合物。在NiO/rGO复合物中,rGO作为基底生长NiO,与此同时,NiO则有效的避免了rGO的团聚。采用热重分析(TG)、场发射扫描电子显微镜(FE-SEM)和X射线衍射对样品的成分、形貌和结构进行了表征。NiO/rGO复合物(NiO和rGO的质量比为82.7∶17.3)电极呈现优异的电化学性能。在1 A/g时,初始比电容为514.9 F/g,当材料完全活化后,其比电容高达600 F/g。同时,在电流密度为10 A/g时,相比于1 A/g时的比电容保持率为83.5%。此外,该电极材料具有非常优异的循环稳定性,6000次循环后电容衰减率为7.4%。表明所制备的复合物是一种有应用价值的超级电容器电极材料。  相似文献   

2.
为克服Co_3O_4负极材料导电率低、循环稳定性差的缺点,选择Co_2(NDC)_2DMF_2(NDC=1,4-萘二甲酸根)为前驱体采用两步煅烧工艺,制备了具有高碳含量的Co_3O_4/C复合材料。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和拉曼光谱对样品进行了表征。采用热重分析法(TGA)测定了Co_3O_4/C中非晶态碳的含量。作为锂离子电池的负极材料,Co_3O_4/C具有高的可逆比容量、优异的循环性能(在200 m A·g~(-1)的电流密度下,循环200圈后放电比容量稳定保持在1 000 mAh·g~(-1))和良好的倍率性能(在100、200、500、1 000和2 000 mA·g~(-1)的电流密度下,放电比容量为分别1 076.3、976.2、872.9、783.6和670.1 mAh·g~(-1))。材料优异的电化学性能归结为有机配体衍生的高含量非晶态碳的导电和缓冲作用有利于电子的快速传递并有效减缓了金属氧化物充放电过程中的体积膨胀。  相似文献   

3.
以P123为结构导向剂,采用溶胶-凝胶法结合冷冻干燥技术制备了0/1/2维混合纳米形貌的正交相V_2O_5电极活性材料.利用XRD和SEM表征了样品的结构和形貌,通过循环伏安法、恒流充放电和交流阻抗谱测试研究了样品的储锂性能.结果显示,这种0/1/2维混合纳米形貌V_2O_5具有较高的储锂容量、优异的电化学循环稳定性和出色的大倍率充放电性能,在1 A/g电流密度下循环500次后放电比容量稳定在117.5mA·h/g,容量保持率为94.4%,在5 A/g大电流密度下,其放电比容量仍保持在88.2 mA·h/g,性能明显优于未添加P123制备的2D片状V_2O_5材料.  相似文献   

4.
采用水热和低温磷化反应两步法,在无添加沉淀剂条件下成功在泡沫镍上合成纳米花状镍钴磷化物(NiCoP/NF)。研究结果表明,镍/钴元素物质的量之比为1∶1时,在1 A·g~(-1)电流密度下,Ni_(1/2)Co_(1/2)P/NF的比容量高达1 276.36 F·g~(-1),在10 A·g~(-1)电流密度下充放电循环3 000次后,比容量保持率为78.23%。此外,以Ni_(1/2)Co_(1/2)P/NF为正极,活性炭(AC)为负极组装的非对称超级电容器(Ni_(1/2)Co_(1/2)P/NF//AC/NF)在725 W·kg~(-1)的功率密度下,能量密度高达36.25 Wh·kg~(-1)。  相似文献   

5.
MOFs材料作为一类新型的锂离子电池电极材料而受到广泛关注和研究.作者通过溶液扩散法将Co_3(HCOO)_6原位负载在rGO(还原氧化石墨烯)上制备出Co_3(HCOO)_6@rGO复合材料.将Co_3(HCOO)_6@rGO作为锂离子电池负极材料,以500 mA·g~(-1)的电流密度恒电流充放电循环100周后,仍然保持有926 mAh·g~(-1)的比容量,亦表现出很好的倍率性能.循环伏安和X-射线光电子能谱测试表明,Co_3(HCOO)_6@rGO材料上的Co~(2+)和甲酸根在充放电过程中均发生可逆的电化学反应.对比同样采用溶液扩散法合成的Co_3(HCOO)_6的测试结果发现,rGO起到活化甲酸根的电化学反应的作用,同时也改善了Co_3(HCOO)_6的倍率性能.将MOFs材料与rGO复合为优化MOFs材料的电池性能提供了一个新思路.  相似文献   

6.
我们合理设计和制备了一种新型的高性能析氧电催化剂——泡沫镍负载Co_3O_4@NiMn-LDH(层状双金属氢氧化物)三维异质结构阵列(Co_3O_4@NiMn-LDH/NF)。这种基于泡沫镍基底的三维异质结构催化剂经简单的两步水热反应即可制得。对比Co_3O_4、NiMn-LDH及传统RuO2催化剂,所制备的Co_3O_4@NiMn-LDH/NF催化剂展示出更优异的电催化析氧性能。在1 mol·L~(-1)KOH溶液中,电流密度为50 mA·cm~(-2)时的过电势仅为282 mV,塔菲尔斜率为64 mV·dec~(-1)。通过有效的界面工程设计,使异质结构陈列Co_3O_4@NiMn-LDH发挥出Co_3O_4和NiMn-LDH各自优异的电催化性能。其中,基于泡沫镍基底生长的活性组分Co_3O_4纳米线阵列作为中间核支撑结构,保持了良好的空隙率,不仅有利于暴露更多的活性位点,而且有利于电解液的扩散和气体产物的释放;而依附于Co_3O_4纳米线阵列上的NiMn-LDH异质结构纳米片层则富有更多的亲水性基团,使得活性位点更易与水结合,从而促进氧析出反应的进行。  相似文献   

7.
采用原位水热生长法在泡沫镍基底上制备了β-Ni(OH)2纳米盘并通过煅烧获得NiO,均可以直接作为工作电极。利用XRD和SEM对样品进行了表征,并进行了电化学性能测试,结果表明我们所制备的Ni(OH)2电极在2 M KOH溶液中2.5 A/g的放电电流密度下,比容量达1495 F/g,通过煅烧得到的NiO,同样可以作为电极材料。  相似文献   

8.
通过简易、可控的水热方法在泡沫镍基体上直接生长了核壳结构的阵列型Co_3O_4@δ-MnO_2/Pt正极。阵列电极有利于电极的润湿、氧气的传输和Li_2O_2的负载。Co_3O_4@δ-MnO_2/Pt正极对氧还原和氧析出反应具有高的催化性能,可促使Li_2O_2依附Co_3O_4@δ-MnO_2/Pt阵列生长,从而保持阵列结构。该生长行为有利于Li_2O_2在充电时分解。以Co_3O_4@δ-MnO_2/Pt为催化正极的锂氧电池显示出高的容量(在电流密度100 mA·g~(-1)时容量为2 480 m Ah·g~(-1)),以及长的循环寿命(容量限定在500 mAh·g~(-1)时,在200mA·g~(-1)电流密度下,可循环65次),该性能超过了使用Co_3O_4或Co_3O_4@δ-MnO_2催化剂的电池。  相似文献   

9.
通过简单的共沉淀反应和热处理过程在还原氧化石墨烯(rGO)表面生长鳞状锰酸钴(CoMn_2O_4)纳米片,得到了CoMn_2O_4/rGO复合材料.通过场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)、X射线衍射(XRD)以及X射线光电子能谱(XPS)对样品的结构和组成进行了表征.电化学性能测试结果表明,CoMn_2O_4/rGO具有较好的储能性能和优良的循环稳定性.当电流密度为2 A/g时,CoMn_2O_4/rGO的比电容可达1000.8 F/g.经过1000周充放电循环后比电容保持率为93.6%.  相似文献   

10.
周岳珅  李梦  吴双  李照磊  高延敏 《电化学》2019,25(6):740-748
本文采用水热反应和高温将ZnCo_2O_4纳米活性材料原位生长在泡沫镍上,并通过控制前驱体溶液中NH_4F的添加量,获得了ZnCo_2O_4四种不同的形貌.以ZnCo_2O_4-2/NF为正极,AC/NF为负极,组装得到纽扣式非对称超级电容器ZnCo_2O_4-2/NF//AC/NF.通过X射线衍射(XRD)、场发射扫描电镜(FESEM)、透射电镜(TEM)等方法对四种形貌ZnCo_2O_4的组成和结构进行了分析.在三电极体系下对不同形貌的ZnCo_2O_4电极进行循环伏安、恒流充放电以及电化学阻抗测试.结果表明,当NH_4F的添加量为5 mmol时,所获得的薄纳米线团簇具有最高的面积比容量.在电流密度为5 m A·cm~(-2)下,比容量为2.77 F·cm~(-2).基于正负两个电极的总面积,纽扣式非对称超级电容器的最大能量密度达到114.49μWh·cm~(-2),相应的功率密度达到4001.59μW·cm~(-2).同时,功率密度达到24000μW·cm~(-2)时,对应的能量密度为80μWh·cm~(-2).  相似文献   

11.
The high specific capacitance along with good cycling stability are crucial for practical applications of supercapacitors,which always demands high-performance and stable electrode materials.In this work,we report a series of ternary composites of CoO-ZnO with different fractions of reduced graphene oxide(rGO) synthesized by in-situ growth on nickel foam,named as CZG-1,2 and 3,respectively.This sort of binder-free electrodes presents excellent electrochemical properties as well as large capacitance due to their low electrical resistance and high oxygen vacancies.Particularly,the sample of CZG-2(CoO-ZnO/rGO 20 mg) in a nanoreticular structure shows the best electrochemical performance with a maximum specific capacitance of 1951.8 F/g(216.9 mAh/g) at a current intensity of 1 A/g.The CZG-2-based hybrid supercapacitor delivers a high energy density up to 45.9 Wh/kg at a high power density of 800 W/kg,and kept the capacitance retention of 90.1% over 5000 charge-discharge cycles.  相似文献   

12.
To avoid an enormous energy crisis in the not-too-distant future, it be emergent to establish high-performance energy storage devices such as supercapacitors. For this purpose, a three-dimensional (3D) heterostructure of Co3O4 and Co3S4 on nickel foam (NF) that is covered by reduced graphene oxide (rGO) has been prepared by following a facile multistep method. At first, rGO nanosheets are deposited on NF under mild hydrothermal conditions to increase the surface area. Subsequently, nanowalls of cobalt oxide are electro-deposited on rGO/Ni foam by applying cyclic-voltammetry (CV) under optimized conditions. Finally, for the synthesis of Co3O4@Co3S4 nanocomposite, the nanostructure of Co3S4 was fabricated from Co3O4 nanowalls on rGO/NF by following an ordinary hydrothermal process through the sulfurization for the electrochemical application. The samples are characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The obtained sample delivers a high capacitance of 13.34 F cm−2 (5651.24 F g−1) at a current density of 6 mA cm−2 compared to the Co3O4/rGO/NF electrode with a capacitance of 3.06 F cm−2 (1230.77 F g−1) at the same current density. The proposed electrode illustrates the superior electrochemical performance such as excellent specific energy density of 85.68 W h Kg−1, specific power density of 6048.03 W kg−1 and a superior cycling performance (86% after 1000 charge/discharge cycles at a scan rate of 5 mV s−1). Finally, by using Co3O4 @Co3S4/rGO/NF and the activated carbon-based electrode as positive and negative electrodes, respectively, an asymmetric supercapacitor (ASC) device was assembled. The fabricated ASC provides an appropriate specific capacitance of 79.15 mF cm−2 at the applied current density of 1 mA cm−2, and delivered an energy density of 0.143 Wh kg−1 at the power density of 5.42 W kg−1.  相似文献   

13.
《Electroanalysis》2017,29(11):2591-2601
In present work, reduced graphene oxide nanosheets (rGO) decorated with trimetallic three‐dimensional (3D) Pt−Pd−Co porous nanostructures was fabricated on glassy carbon electrode (Pt−Pd−Co/rGO/GCE). First, GO suspension was drop‐casted on the electrode surface, then GO film reduction was carried out by cycling the potential in negative direction to form the rGO film modified GCE (rGO/GCE). Then, electrodeposition of the cobalt nanoparticles (CoNPs) as sacrificial seeds was performed onto the rGO/GCE by using cyclic voltammetry. Afterward, Pt−Pd−Co 3D porous nanostructures fabrication occurs through galvanic replacement (GR) method based on a spontaneous redox process between PtCl2, PdCl2, and CoNPs. The morphology and structure of the Pt−Pd−Co/rGO porous nanostructure film was characterized by scanning electron microscopy, energy dispersive spectroscopy and X‐ray diffraction method. The performance of the prepared electrode was investigated by various electrochemical methods including, cyclic voltammetry and electrochemical impedance spectroscopy. The electrocatalytic activity of the as‐prepared modified electrode with high surface areas was evaluated in anodic oxidation of ethylene glycol. The study on electrocatalytic performances revealed that, in comparison to various metal combinations in modified electrodes, trimetallic Pt−Pd−Co/rGO/GCE exhibit a lower onset potential, significantly higher peak current density, high durability and stability for the anodic oxidation of ethylene glycol. The excellent performances are attributed to the rGO as catalysts support and resulting synergistic effects of the trimetallic and appropriate characteristics of the resulted 3D porous nanostructures. Moreover, the influence of various concentrations of ethylene glycol, the potential scan rate and switching potential on the electrode reaction, in addition, long‐term stability have been studied by chronoamperometric and cyclic voltammetric methods.  相似文献   

14.
A novel supercapacitor based on ultralight and elastic three-dimensional porous melamine foam-derived macroporous carbon/reduced graphene oxide/polyaniline nanocomposites were fabricated, which showed great electrical performance and cycle performance.  相似文献   

15.
以氧化石墨烯(GO)为前驱体,Ni(NO_3)_2·6H_2O为镍源,甲酸为配体,N,N-二甲基甲酰胺为溶剂,通过一步溶剂热法制备了Ni_3(HCOO)_6/rGO复合电极材料.研究结果表明,通过金属镍离子和配体在氧化石墨烯表面超分子自组装成核,形成了"三明治"式的夹心复合结构;不同的GO浓度对复合材料的物相结构、晶体尺寸大小、形貌及电化学性能有很大的影响;当GO的浓度为8 mg/m L时,在100℃下反应24 h得到的Ni_3(HCOO)_6/rGO复合材料在电解液为1 mol/L KOH,5 m V/s下比电容高达940 F/g,经过500次充放电循环后电容的保持率为96.28%.  相似文献   

16.
为了开发较高能量密度的超级电容器,我们通过简单的溶剂热反应合成了一种三维的钴基金属有机框架(MOF)化合物([KCo7(OH)3(ip)6(H2O)4]·12H2O,Co?ip;ip=间苯二甲酸根),并考察了其作为超级电容器电极材料的性能。Co?ip电极显示出高比电容、良好的循环稳定性和优良的倍率性能。在1 mol·L^-1 KOH溶液中,电流密度为1 A·g^-1时,其最大比电容为1660 F·g^-1。在电流密度为2 A·g^-1条件下,循环3000次后,其比电容的保持率为82.7%。优异的超级电容性能可归因于Co?ip具有纳米尺寸颗粒和三维的多孔结构。  相似文献   

17.
Sub-micron-scaled sodium cobalt oxide (NaCo2O4) powders are prepared by a solid-state reaction method. Characterization using X-ray diffraction indicates that the synthesized NaCo2O4 has a hexagonal layered structure. The electrochemical performance of the NaCo2O4 electrodes is investigated using cyclic voltarnmetry and galvanostatic charge/discharge in NaOH solution. The results show that the specific capacitance of the NaCo2O4 electrode reaches 337 F/g over the potential range of 0.15-0.65 V at a mass normalized current of 50 mA/g. Moreover, NaCo2O4 exhibits very good stability and cycling performance as a supercapacitor material.  相似文献   

18.
谢超  洪国辉  赵丽娜  杨伟强  王继库 《应用化学》2019,36(12):1422-1429
超级电容器因其具有较高的循环稳定性和较好的能量密度而成为储能器件中的研究热点,其电极材料及制备方法是决定超级电容器电化学性能的关键因素。 本文以聚环氧乙烷-聚环氧丙烷-聚环氧乙烷三嵌段共聚物(P123)为软模板,通过一步原位聚合法成功地制备了石墨烯/聚吡咯纳米纤维(GR/PPy NF)复合超级电容器电极材料。 通过X射线衍射(XRD),X射线光电子能谱(XPS)、透射电子显微镜(TEM)和傅里叶变换红外光谱仪(FT-IR)等对复合材料的结构和形态进行了系统的表征。 利用电化学方法对GR/PPy NF复合电极材料的电化学性能进行了系统的分析。 结果表明,在电流密度0.5 A/g下,纳米复合材料的比电容量高达969.5 F/g,在充放电600圈之后,仍可保留初始比电容的88%,展示了良好的电容性能及循环稳定性。 GR/PPy NF制备简单,性能优异,是一种很有前途的能量转换/存储材料。  相似文献   

19.
In this paper, we report the green synthesis of 1-(4-ferrocenylbutyl)piperazine chemically grafted rGO (P.Fc/rGO) as a battery-type supercapacitor electrode material. For this purpose, initially, the ability of the aqueous Damson fruit extract is investigated in the reduction reaction of graphene oxide (GO). 1-(4-ferrocenylbutyl)piperazine (P.Fc) is synthesized via nucleophilic substitution reaction of piperazine with as-synthesized 4-chlorobutylferrocene. In continue, P. Fc is incorporated to GO by ring-opening reaction of epoxide groups on the GO surface. In the next step, the modified reduction method by aqueous Damson fruit extract was used to prepare the P.Fc/rGO from P.Fc/GO. The prepared materials were characterized by various techniques including FT-IR, Uv–vis, XRD, SEM, EDX, and BET. N2 adsorption–desorption data of P.Fc/rGO nanocomposite shows that the surface area is 37.746 m2 g−1. The capability of P.Fc/rGO nanocomposite for using as an energy storage electrode material in battery-type supercapacitor was examined by investigation of its electrochemical behavior by CV, EIS, and GCD measurements. The charge storage capacity of 1,102 mAh g−1 is achieved at 2.5 A g−1. This nanocomposite shows 89% retention of charge storage capacity after 2000 CV cycles.  相似文献   

20.
Fe3O4 is considered as a promising electrode material for lithium-ion batteries(LIBs) due to its low cost and high theoretical capacity(928 mAh/g).Nevertheless,the huge volume expansion and poor conductivity seriously hamper its practical applications.In this study,we use a facile hydrothermal reaction together with a post heat treatment to construct the three-dimensional heterostructured composite(Fe3O4/rGO) inwhich reduced graphene oxide sheets wraped the Fe3O4 submicron cubes as the conductive network.The electric conduction and electrode kinetics of lithium ion insertion/extraction reaction of the composite is enhanced due to the assist of conductive rGO,and thus the Listorage performance is obviously improved.The composite exhibits a reversible charge capacity of772.1 mAh/g at the current density of 0.1 A/g,and the capacity retention reaches 70.3% after400 cycles at0.5 A/g,demonstrating obviously higher specific capacity and rate capability over the Fe3O4 submicron cubes without rGO,and much superior cycling stability to the parent Fe_2 O_3 submicron cubes without rGO.On the other hand,as a synergic conductive carbon support,the flexible rGO plays an important role in buffering the large volume change during the repeated discharge/charge cycling.  相似文献   

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