自组装NiO/还原氧化石墨烯复合材料及其超级电容性能研究

通过水热法制备得到α-Ni(OH)₂,在甲酰胺溶剂中,通过机械振荡结合超声对其进行剥离,得到厚度约为1.1 nm的Ni(OH)₂纳米片,与氧化石墨烯(GO)悬浮液混合后,静电自组装得到Ni(OH)₂/GO,经高温热处理获得NiO/还原氧化石墨烯(rGO)复合材料。同时研究了NiO/rGO的结构、形貌及其用作超级电容器电极材料的电化学性能。形貌表征显示NiO/rGO呈层-层形貌,N₂吸-脱附实验表明复合材料存在介孔结构。在KOH电解液中,1 A/g电流密度下NiO/rGO的比容量为1564 F/g,远高于初始Ni(OH)₂和单纯的NiO;组装的NiO/rGO//石墨烯水凝胶(GH)非对称超级电容器(ASC)器件,充放电电位窗口为0～1.6 V,10 A/g电流密度下经1000次充放电循环的比容量保持率达84.2%。     

(CoFe)Se2@NC超级电容器电极材料的制备及其电化学性能

金属-有机框架(MOF)衍生的过渡金属硒化物和多孔碳纳米复合材料具有巨大的储能优势,是应用于电化学储能的优良电极材料。采用共沉淀法制备CoFe类普鲁士蓝(CoFe-PBA)纳米立方,并通过静电组装在CoFe-PBA上包覆聚吡咯(PPy)得到CoFe-PBA@PPy;通过在400℃氮气中退火并硒化成功制备了氮掺杂的碳(NC)包覆(CoFe)Se₂的(CoFe)Se₂@NC纳米复合材料,并对其结构和形貌进行了表征。以(CoFe)Se₂@NC为电极制备了超级电容器,测试了其电化学性能,结果表明,在电流密度1 A/g时超级电容器的比电容达到1047.9 F/g,在电流密度5 A/g下1000次循环后具有良好的循环稳定性和96.55%的比电容保持率。由于其性能优越、无毒、成本低和易于制备,未来(CoFe)Se₂@NC纳米复合材料在超级电容器中具有非常大的应用潜力。     

3DG/CoSe2@NW锂离子电池负极材料的制备和电化学性能

为开发高效储存性能的锂离子电池(LIB),利用简单的溶剂热反应合成一维Co-硝基三乙酸(NTC)前驱体,与三维石墨烯(3DG)组装并高温退火后,制备了多维度、多孔的3DG/CoSe₂@纳米线(NW)负极材料。通过一系列的表征证明在纳米结构中,CoSe₂纳米粒子嵌入一维多孔碳NW中,该一维多孔碳NW被封装在3DG中。3DG/CoSe₂@NW用作LIB负极材料时,由于其独特的纳米结构,在0.1 A·g^-1电流密度下100次循环后比容量为725.6 mA·h·g^-1,在2 A·g^-1的大电流密度下进行500次的循环后,容量保持率为92.5%。电化学测试结果表明,以3DG/CoSe₂@NW为电极的LIB具有高比容量和优异的循环稳定性。     

Co3O4@NC的制备及其电化学性能

过渡金属氧化物是一种超级电容器电极材料。采用共沉淀法制备了立方体Co类普鲁士蓝(Co-PBA)纳米材料,先将Co-PBA在氮气中进行退火,PBA衍生为掺氮的碳纳米盒,得到产物Co@NC,再在空气中250℃下退火,得到Co₃O₄@NC纳米复合材料。Co-PBA材料的微观结构为盒状并均匀分布,平均尺寸约为500 nm。在三电极体系下测试其电化学性能,循环伏安(CV)测试结果显示在不同电流密度下曲线具有相似的形状,拥有良好的对称性,说明该材料制备的电极在充放电时的可逆性较好。Co₃O₄@NC复合材料在电流密度1 A/g时的比电容为1 000.02 F/g,在电流密度5 A/g下充放电2 500次后电容保持率为97.29%,保持了良好的循环稳定性。实验结果表明,Co₃O₄@NC复合材料是一种很有前途的超级电容器电极材料。     

聚吡咯包覆的硒化铁复合材料电极的制备及其电化学性能

以普鲁士蓝(PB)作为前驱体,通过固相烧结法在氮气环境中制备FeSe₂材料,结合聚吡咯(PPy)优良的导电性能,利用原位氧化聚合法包覆聚吡咯,设计出了FeSe₂@PPy复合材料。在三电极体系中,以2 mol/L KOH溶液为电解液、FeSe₂@PPy复合材料为工作电极、Hg/HgO电极为参比电极,FeSe₂@PPy复合材料表现出了优良的电化学性能：在0.5 A·g^-1电流密度下的比电容高达1 177 F·g^-1。同时也测量了FeSe₂@PPy复合材料电极的循环性能：在0.5 A·g^-1电流密度下,经过3 000次充放电测试后比电容保持率为90.5%。电化学测试结果表明该复合材料在超级电容器应用方面具有一定的优势。     

基于2,6NDC的二维纳米阵列MOF材料的制备及其在超级电容器中的应用

金属有机框架(MOF)具有比表面积较大、形貌多样和金属中心丰富等优点。然而传统的以对苯二甲酸(BDC)为配体的MOF直接用作超级电容器电极材料时其比电容低、稳定性差。为此以双苯环有机配体2,6萘二羧酸(2,6NDC)为链接剂,采用简单高效的一步溶剂热法成功合成了超薄片状2D纳米阵列2,6NDC MOF材料,对其物相结构和表面形貌进行了表征分析,并探究了其电化学性能。结果表明,在电流密度为1 A·g^-1下,基于2,6NDC的超薄片状2D纳米阵列MOF具有较高的比电容,为136.2 F·g^-1,而以BDC为配体的MOF比电容只有53.9 F·g^-1。以2,6NDC MOF构筑的超级电容器在电流密度0.5 A·g^-1下的能量密度为28.2 W·h·kg^-1,功率密度为1 650.7 W·kg^-1,且在15 000次循环后依然有约125%的初始放电比容量,显示出优异的循环稳定性。     

基于SWCNT复合硫化镍/氮化镍电极材料的制备及其电化学性能

以单壁碳纳米管(SWCNT)为碳源,氯化镍为金属源,硫脲为氮源和硫源,通过水热和高温热解方法制备N,S-Ni@S@C复合材料,并对复合材料进行物理表征和电化学性能测试。结果表明,SWCNT与硫化镍、氮化镍复合的结构不仅能提高电极材料的电导率,还能提供更多的活性位点供电解质离子插入或脱出,从而显著提高电化学性能。在三电极体系下,N,S-Ni@S@C复合材料具有较高的电压窗口(1.5 V)和优异的充放电能力,在电流密度为1 A·g^-1下,N,S-Ni@S@C的比电容可达162.45 F·g^-1。其比电容与SWCNT相比提高了2.61倍,与SWCNT和氯化镍复合材料(C@Ni)相比提高了19倍,与SWCNT和硫脲复合材料(C@S@N)相比提高了16倍。此外,以N,S-Ni@S@C复合材料为正极,商业活性炭(YP50F)为负极,组装得到非对称型超级电容器(N,S-Ni@S@C//AC)。该非对称型超级电容器在功率密度为818.78 W·kg^-1时,其能量密度可达41.03 W·h·kg^-1,在电流密度为1....     

纳米硅/还原氧化石墨烯复合纤维材料及其负极结构锂离子超级电容器

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%。     

FeCo2S4/Ni(OH)2的合成及超电容性能研究

将多组分活性材料组合成新的结构用作电极材料是提高超级电容器性能的一种有效措施。采用典型的两步水热法与电沉积法制备了FeCo2S4/Ni(OH)2复合纳米材料,并表征其物理及电化学性能。结果表明,FeCo2S4纳米花被电沉积上的Ni(OH)2纳米片包围,形成三维互连网状结构,有利于电极材料与电解液的充分接触。所得的FeCo2S4/Ni(OH)2复合电极材料显示出极高的比电容(当电流密度为1 A·g^-1时,比电容达1588.2 F·g^-1)、优异的倍率性能及循环稳定性。此外,以FeCo2S4/Ni(OH)2为正极、活性炭为负极组装了非对称超级电容器。结果显示,非对称超级电容器具有高能量密度及良好的循环稳定性。     

α-Ni(OH)2/石墨烯纳米复合材料的制备及其电容性能研究

近年来,石墨烯复合材料作为理想基底用于电极材料的生长,在电化学的许多领域都得到了广泛的应用。以石墨烯和六水合硝酸镍为原料,用NaBH_4作为还原剂,在90℃低温条件下制备合成了具有纳米尺寸的α-Ni(OH)_2/石墨烯复合材料。研究了石墨烯与α-Ni(OH)_2的质量比不同时复合材料的电化学性能。结果表明:当质量比为5∶5时,复合材料显示了最佳的电化学性能:在0～0.47 V的电位窗口,0.2 A/g的电流密度下,比容量高达1280 F/g;2 A/g的电流密度下循环充放电测试2000次后,比容量仍然保持88%。因此,该复合材料作为一种理想的复合电极材料,可被应用到能量转化/储存系统中。     

基于石墨毡生长的镍钴基化合物电极的双功能电催化性能

以先水热后硫化的方法制备出基于石墨毡基底的镍钴基化合物(NiCo2O4/GF和NiCo2 S4/GF)电极,探究不同水热温度对电极的催化特性的影响.通过扫描电子显微镜(SEM)、能量色散X射线光谱仪(EDS)、X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)对样品表面形貌、结构、晶向及元素分布进行分析.通过循环伏安...     

Ni-MOF衍生的NiMoO4材料的超电容性能

开发可控的NiMoO4纳米结构合成方法是获得高性能赝电容器电极材料的关键.以Ni-MOF为前驱体,采用模板转化法合成NiMoO4纳米球,以改善其结构并提升电化学性能.采用XRD、FTIR和SEM对所制备的NiMoO4样品的结构和形貌进行表征,并通过氮气吸脱附表征了其孔径和比表面积.MOF衍生的NiMoO4纳米球由超薄的...     

冷冻煅烧法制备NiO/Ni复合材料及电容性能研究

首次采用冷冻煅烧法制备NiO/Ni纳米复合材料,重点考察不同冷冻温度对该复合材料的结构形貌及电容性能的影响。结果表明:随着冷冻温度的降低,结晶过冷度增大,材料的粒径不断减小并且趋于均匀化,比表面积单调增大。当冷冻温度为-20℃时,材料平均粒径为20~50 nm,比表面积达到337.6 m^2/g。同时,纳米Ni单质的引入也增强了材料的导电性能,当电流密度为1 A/g时,其比电容达到820 F/g,所制得NiO/Ni纳米复合材料具有优异的电化学性能。该方法大大降低了材料制备的能耗,为NiO/Ni纳米复合材料的制备方法提供新的思路。     

用于重金属离子电化学传感器的TiO2NT/AuNP纳米复合材料

采用水热合成法将金纳米颗粒(AuNP)修饰到TiO₂纳米管(TiO₂NT)表面。用X射线衍射仪(XRD)和场发射扫描电子显微镜(FESEM)对制备的纳米复合材料进行表征。采用电化学阻抗谱(EIS)和循环伏安法分析了TiO₂NT/AuNP纳米复合材料修饰的玻碳电极(GCE)。通过方波阳极溶出伏安法(SWASV)分析了纳米复合材料检测重金属离子的可行性。纳米复合材料对Pb(Ⅱ)、Cd(Ⅱ)、Hg(Ⅱ)和Cu(Ⅱ)具有较高的电分析活性和灵敏度,对Pb(Ⅱ)、Cd(Ⅱ)、Hg(Ⅱ)和Cu(Ⅱ)的灵敏度分别为15.63、213.19、287.86和72.75μA·μM^-1(1 M=1 mol/L),检出限分别为0.052、0.004、0.003和0.011μmol/L。采用TiO₂NT/AuNP纳米复合材料对多种重金属离子进行了检测。此外,TiO₂NT/AuNP/GCE具有抗干扰性能和稳定性。因此,TiO₂NT/AuNP纳米复合材料可适用于电化学传感器来检测多种重金属离子。     

Development of Graphene Oxide/Polyaniline Inks for High Performance Flexible Microsupercapacitors via Extrusion Printing

Extrusion printing of interdigitated electrodes for flexible microsupercapacitors (fMSCs) offers an attractive route to the fabrication of flexible devices where cost, scalability, and processability of ink formulations are critical. In this work, highly concentrated, viscous, and water‐dispersible inks are developed based on graphene oxide (GO)/polyaniline (PANi) composite for extrusion printing. The optimized GO/PANi‐based all‐solid‐state symmetric fMSCs obtained by extrusion printing interdigitated microelectrodes can deliver outstanding areal capacitance of 153.6 mF cm^?2 and volumetric capacitance of 19.2 F cm^?3 at 5 mV s^?1. It is shown that by fabricating asymmetric fMSCs using the GO/PANi as positive electrode and a graphene‐based negative electrode, the voltage window can be widened from 0.8 to 1.2 V and improvements can be achieved in energy density (from 3.36 to 4.83 mWh cm^?3), power density (from 9.82 to 25.3 W cm^?3), and cycling stability (from 75% to 100% capacitance retention over 5000 cycles) compared with the symmetric counterpart. The simple ink preparation and facile device fabrication protocols reported here make the scalable fabrication of extrusion printed fMSCs a promising technology.     

Enhancing the Capacitive Storage Performance of Carbon Fiber Textile by Surface and Structural Modulation for Advanced Flexible Asymmetric Supercapacitors

The exploration of high‐energy anodes with good mechanical properties is highly attractive for flexible asymmetric supercapacitors (ASCs) but challenging. Owing to the excellent conductivity and superior mechanical flexibility, carbon fiber textile (CFT) holds great promise as a substrate/current‐collector for fabricating flexible electrodes. Yet, it is rarely used as a flexible active electrode in terms of its low electrochemical reactivity and small accessible area. In this work, an effective surface and structural modulation strategy is developed to directly tune CFT into a highly active anode for flexible ASCs by creating hierarchical pores and numerous pseudocapacitive oxygenic groups. Arising from large surface and increased active sites, the as‐prepared activated porous CFT (APCFT) electrode not only achieves a large capacitance (1.2 F cm^?2 at 4 mA cm^?2) and fast kinetics but also shows satisfying cycling durability (no capacitance decay after 25 000 cycles). More importantly, an advanced flexible ASC device with an impressive energy density of 4.70 mWh cm^?3 is successfully assembled by employing this APCFT as an anode, outperforming most recently reported ASC devices. This dual modification strategy may throw light on the rational design of new generation advanced carbon electrodes for high‐performance flexible supercapacitors.     

Studies on Conducting Polypyrrole/Graphene Oxide Composites as Supercapacitor Electrode

An electrode material based on polypyrrole (PPy) doped with graphene oxide (GO) sheets was synthesized via in situ polymerization of pyrrole in the presence of GO in various proportions (5% and 10%). The synthesized samples were characterized by Fourier-transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–vis) absorption spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), x-ray diffraction (XRD) analysis, and electrical conductivity measurements. FTIR spectroscopy and XRD revealed the interaction between GO and PPy. The direct-current (DC) electrical conductivity (75.8 S/cm) of the prepared composites was dramatically enhanced compared with pure PPy (1.18 S/cm). High specific capacitance of PPy/GO composite of 421.4 F/g was obtained in the potential range from 0 V to 0.50 V at 2 mA compared with 237.2 F/g for pure PPy by galvanostatic charge–discharge analysis. Incorporation of GO into the PPy matrix has a pronounced effect on the electrical conductivity and electrochemical capacitance performance of PPy/GO nanocomposites.     

Flexible Solid‐State Supercapacitors with Enhanced Performance from Hierarchically Graphene Nanocomposite Electrodes and Ionic Liquid Incorporated Gel Polymer Electrolyte

High energy density, durability, and flexibility of supercapacitors are required urgently for the next generation of wearable and portable electronic devices. Herein, a novel strategy is introduced to boost the energy density of flexible soild‐state supercapacitors via rational design of hierarchically graphene nanocomposite (GNC) electrode material and employing an ionic liquid gel polymer electrolyte. The hierarchical graphene nanocomposite consisting of graphene and polyaniline‐derived carbon is synthesized as an electrode material via a scalable process. The meso/microporous graphene nanocomposites exhibit a high specific capacitance of 176 F g^?1 at 0.5 A g^?1 in the ionic liquid 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIBF₄) with a wide voltage window of 3.5 V, good rate capability of 80.7% in the range of 0.5–10 A g^?1 and excellent stability over 10 000 cycles, which is attributed to the superior conductivity (7246 S m^?1), and quite large specific surface area (2416 m² g^?1) as well as hierarchical meso/micropores distribution of the electrode materials. Furthermore, flexible solid‐state supercapacitor devices based on the GNC electrodes and gel polymer electrolyte film are assembled, which offer high specific capacitance of 180 F g^?1 at 1 A g^?1, large energy density of 75 Wh Kg^?1, and remarkable flexible performance under consecutive bending conditions.