空心六边形镍钴硫化物/RGO复合物的合成及其超级电容性能

通过两步法制备了一种空心六边形镍钴硫化物（HHNCS）与还原氧化石墨烯（RGO）的纳米复合材料HHNCS/RGO。利用XRD,SEM,TEM和Raman光谱等对复合物进行表征,发现镍钴硫化物为空心六边形结构,并且均匀地附着在RGO的表面。该纳米复合物用作超级电容器电极表现出优异的电化学性能。在电流密度为1 A·g^-1时比电容为927 F·g^-1;当电流密度增大到20 A·g^-1时,比电容仍高达724 F·g^-1,表明材料拥有较好的倍率性能。此外,在电流密度5 A·g^-1下循环2000次后比电容保留有初始值的93%,显示出优异的循环稳定性。HHNCS/RGO优异的电容性能主要是由于RGO的存在不仅增强了材料的导电性,而且作为理想的载体分散HHNCS纳米片。HHNCS/RGO纳米复合物优异的电化学性能使其在超级电容器电极材料领域具有应用前景。     

石墨烯/聚苯胺复合材料的制备及其电化学性能

以苯胺和氧化石墨烯(GO)为原料, 采用电化学方法制备了石墨烯/聚苯胺(GP)复合材料. 利用X射线衍射(XRD)、扫描电镜(SEM)、拉曼(Raman)光谱、X射线光电子能谱分析(XPS)对其结构、微观形貌进行了表征,并对复合材料电化学性能进行了测试. 结果表明, 复合材料保持了石墨烯的基本形貌, 聚苯胺颗粒均匀地分散在石墨烯表面, 复合材料在500 mA·g^-1的电流密度下比电容达到352 F·g^-1, 1000 mA·g^-1下比电容为315 F·g^-1, 经过1000 次的充放电循环后容量保持率达到90%, 远大于石墨烯和聚苯胺单体的比电容. 复合材料放电效率高, 电解质离子易于在电极中扩散和迁移.     

无模板剂合成用于超级电容器的二氧化锰/石墨烯复合材料

以尿素、四水合氯化锰和氧化石墨烯为原料,采用水热法并通过热分解制备了一种具有石墨烯包覆结构的石墨烯-二氧化锰复合材料,利用扫描电子显微镜、X射线衍射、比表面积（BET）、拉曼光谱和热失重等技术对其形貌、晶体结构及表面结构进行了表征;在三电极条件下利用循环伏安法、恒流充放电法和交流阻抗法测试了材料的电化学性能,并考察了不同石墨烯含量对材料比电容的影响. 结果表明,在不添加模板剂的条件下制备的复合材料中二氧化锰是具有介孔结构的α-MnO₂,当复合15%（质量分数）的石墨烯后材料的比表面积从109 m²·g^-1提高到168 m²·g^-1. 复合材料具有更好的电化学性能,在0.2 A·g^-1电流密度下复合材料的比电容达到最大值（454 F·g^-1）,远高于纯二氧化锰的值（294 F·g^-1）. 在2 A·g^-1的电流密度下恒流充放电2000 次后复合材料的比电容保持率为92%.     

纳米多孔结构镍基复合膜电极的电化学法制备及其电容特性

通过对电沉积法得到的Ni-Cu合金镀层进行电化学去合金化处理, 制备了纳米多孔结构金属镍膜. 采用循环伏安法对多孔金属镍膜在1 mol·L^-1 KOH溶液中进行阳极氧化处理, 获得了纳米多孔结构的镍基复合膜电极. 应用扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)和电化学技术对所制备的膜电极的物理性质及赝电容特性进行了表征. SEM、XRD和XPS的测试结果表明, 所制备的纳米多孔结构镍基复合膜由Ni、Ni(OH)₂和NiOOH组成. 电化学实验结果显示, 该复合膜在20 A·g^-1的充放电电流密度下, 给出了578 F·g^-1的初始比电容; 在1000次充放电循环后, 它的比电容值为544 F·g^-1, 电容保持率为94%. 纳米多孔结构有利于KOH电解液的渗透, 从而促进反应物种在电极内部的传输; 纳米多孔的金属镍基体可以提高Ni(OH)₂膜的电子导电性; 纳米大小的Ni(OH)₂颗粒能够缩短质子的固相扩散路径. 上述因素是所制备的纳米多孔结构镍基复合膜电极具有优异赝电容特性的主要原因.     

三氧化钼纳米带/石墨烯纳米复合材料的简单制备及其在超级电容器中的应用

采用简单的超声自组装法制备了石墨烯/三氧化钼纳米带复合材料。最终产物的组成和结构采用多种不同的手段进行了表征,包括扫描电镜、透射电镜、X射线衍射、拉曼光谱以及热分析等。该复合材料可以用作超级电容器电极材料。电化学实验结果表明石墨烯/三氧化钼纳米带复合材料比电容可达到285.5 F·g^-1,且在电流密度为1 A·g^-1时经过1 000次循环后其电容值能保持初始值的99.5%.     

三氧化钼纳米带/石墨烯纳米复合材料的简单制备及其在超级电容器中的应用

采用简单的超声自组装法制备了石墨烯/三氧化钼纳米带复合材料。最终产物的组成和结构采用多种不同的手段进行了表征,包括扫描电镜、透射电镜、X射线衍射、拉曼光谱以及热分析等。该复合材料可以用作超级电容器电极材料。电化学实验结果表明石墨烯/三氧化钼纳米带复合材料比电容可达到285.5 F·g^-1,且在电流密度为1 A·g^-1时经过1 000次循环后其电容值能保持初始值的99.5%.     

碳和石墨烯对磷酸锰锂材料性能的影响

在采用溶剂热法制备磷酸锰锂的基础上,以蔗糖和石墨烯为碳源,制备了裂解碳和石墨烯含量不同的磷酸锰锂/碳/石墨烯复合材料,研究了裂解碳和石墨烯对材料性能的影响。采用扫描电镜（SEM）和透射电镜（TEM）对材料的形貌进行了表征。裂解碳包覆可以提高LiMnPO₄纳米片表面的电子导电性,对于材料性能的改善起到主要的作用;石墨烯可以提高纳米片之间的电子和离子导电性,改善材料的电化学性能。电化学测试表明,当裂解碳含量为4%、石墨烯含量为2%时,LiMnPO₄电极具有较好的电化学性能,在0.5C下的放电比容量为139.1 mAh·g^-1,循环100次后,容量保持率为93.6%。与添加单一碳和单一石墨烯的LiMnPO₄电极相比,该电极在0.5C下的放电比容量分别提高了35.0%和48.6%。     

应用多中心分区方法构建H3分子反应势能面

以氧化石墨凝胶制备的氧化石墨烯溶胶为前驱体, 在120-220 ℃条件下, 采用水热法制备了系列不同还原程度的三维还原氧化石墨烯, 采用扫描电镜(SEM), X射线衍射(XRD), 傅里叶变换红外(FTIR)光谱, X射线光电子能谱(XPS)和电化学测试等手段研究了水热反应温度对材料形貌、结构和超级电容性能的影响. 结果表明: 采用水热法制备的三维还原氧化石墨烯呈多孔网状结构, 材料的体积和内部网状孔径随着水热反应温度的升高而减小; 同时, 氧化石墨烯的还原程度随反应温度的升高而增加, 有序度提高, 其结构逐渐向着类石墨结构转化; 而材料的比电容和能量密度则随反应温度的升高呈现出先增大后减小的趋势, 且均以双电层电容为主;相比之下, 当水热反应温度为180 ℃时, 制备的三维还原氧化石墨烯具有最佳的超级电容性能, 在电解液为6mol·L^-1的KOH溶液中, 0.5 A·g^-1电流密度下其比电容达到315 F·g^-1, 10 A·g^-1时仍能保持212 F·g^-1的高比容量, 能量密度为40.5 Wh·kg^-1, 5000次循环后比电容保持率为86%, 表现出了良好的电化学性能.     

纳米纤维素/还原氧化石墨烯复合材料用于高性能超级电容器

以高浓度氧化石墨烯(GO)溶液作为反应前驱体,纳米纤维素(NC)作为物理间隔物和电解液储存器,通过简单的一步水热法制备了纳米纤维素/还原氧化石墨烯(NC/rGO)复合材料,并探究了其作为超级电容器电极材料的潜力。结果如下：NC添加量为1 mL所制备的NC/rGO-1具有最佳电化学性能。基于NC/rGO-1的无黏合剂对称型超级电容器在0.3 A·g^-1的电流密度下显示出了 269.33 F·g^-1和 350.13 F·cm^-3的高质量和体积比电容,并在 10.0 A·g^-1时仍能达到 215.88 F·g^-1和 280.62 F·cm^-3(其初始值的 80.15%)。组装器件还显示出了较高的质量和体积能量密度(9.3 Wh·kg^-1和 12.13 Wh·L^-1)和出色的循环性能(10 A·g^-1下10 000次循环后其初始比电容仅减少6.02%)。     

惰性盐辅助合成介孔石墨化碳片及其电容性能

以惰性盐KCl为模板、硝酸镍为金属催化剂镍源、葡萄糖为碳源,通过碳化处理制备了介孔石墨化碳片。利用扫描电子显微镜、透射电子显微镜、X-射线衍射仪和比表面测试仪对介孔石墨化碳片进行了表征。探讨了碳片形成的机理,采用三电极测试体系研究了介孔石墨化碳片电极材料的电化学性能。结果表明,10gKCl制备的碳片比表面积最大（989m²·g^-1）,在6mol·L^-1KOH电解液中,当电流密度为0.5A·g^-1时,比电容达到180F·g^-1;当电流密度达到10A·g^-1时,比电容维持在148F·g^-1,显示了电极具有较好的倍率性能;在10A·g^-1条件下,2000次循环充放电测试后电容没有发生衰减,展示了在超级电容器方面的应用潜力。     

Ni-based nanocomposites supported on graphene nano sheet (GNS) for supercapacitor applications

The Ni-based/graphene nano sheet (GNS) materials have been prepared by using the polyol reduction process and the NiO dispersed layer was fabricated on Ni metal to form the core/shell nanocomposites. These Ni-based/GNS composite materials possess excellent electrochemical properties, and have been investigated by thermal gravimetric analysis, X-ray diffraction, transmission electron microscopy and field emission scanning electron microscopy techniques. The electrochemical performance was measured by cyclic voltammograms and galvanostatic charge/discharge tests in 1 M KOH electrolyte solution. The results show that the 60Ni-250 sample has the potential application in supercapacitors because of its good electrochemical properties.     

石墨烯/钴镍双氢氧化物复合材料的制备及其超电容特性

采用氧化石墨(GO)还原法制备石墨烯(GNS),以氨水为沉淀剂,在石墨烯存在的情况下,通过Co²⁺和Ni²⁺化学共沉积的方法合成了石墨烯/钴镍双氢氧化物复合电极材料,采用红外光谱(FT-IR)、X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)、比表面积测试(BET)等技术手段表征了产物的组成、结构和形貌,用循环伏安、恒电流充放电等测试方法对复合材料的电化学性能进行了研究。 研究发现,石墨烯纳米片均匀分散在钴镍双氢氧化物中,改善了钴镍双氢氧化物的传导性和结构稳定性。 电化学测试表明,在1 A/g的电流密度下,复合材料比电容高达2770 F/g,且循环500次后,比电容仍能保持93.4%,呈示该复合材料具有优异的电化学性能。     

Green synthesis of graphene nanosheets/ZnO composites and electrochemical properties

A green and facile approach was demonstrated to prepare graphene nanosheets/ZnO (GNS/ZnO) composites for supercapacitor materials. Glucose, as a reducing agent, and exfoliated graphite oxide (GO), as precursor, were used to synthesize GNS, then ZnO directly grew onto conducting graphene nanosheets as electrode materials. The small ZnO particles successfully anchored onto graphene sheets as spacers to keep the neighboring sheets separate. The electrochemical performances of these electrodes were analyzed by cyclic voltammetry, electrochemical impedance spectrometry and chronopotentiometry. Results showed that the GNS/ZnO composites displayed superior capacitive performance with large capacitance (62.2 F/g), excellent cyclic performance, and maximum power density (8.1 kW/kg) as compared with pure graphene electrodes. Our investigation highlight the importance of anchoring of small ZnO particles on graphene sheets for maximum utilization of electrochemically active ZnO and graphene for energy storage application in supercapacitors.     

石墨烯负载新型π-共轭聚合物纳米复合电极材料的合成及其超级电容特性

采用γ射线辐照还原技术获得易分散石墨烯(GNS),并以其为载体,以樟脑磺酸为掺杂剂和软模板,借助化学氧化聚合方法制备出分级孔结构的石墨烯负载聚(1, 5-二氨基蒽醌)(GNS@PDAA)纳米复合材料。运用傅里叶变换红外(FTIR)光谱、拉曼光谱(Raman)、原子力显微镜(AFM)、能谱仪(EDS)、场发射扫描电镜(FE-SEM)和电化学测试等手段研究了不同GNS/DAA质量比对GNS@PDAA复合材料的形貌、结构及超级电容特性的影响。研究表明,当DAA/GNS质量比为6/1时,借助π-π堆叠和网络限域作用, PDAA以20-40 nm纳米颗粒的形式牢固沉积于石墨烯表面,材料内部存在大量10-30 nm尺寸的介孔。该GNS@PDAA复合材料在0.5 A·g^-1时呈现最高的比电容(398.7 F·g^-1),优异的倍率特性(在50 A·g^-1下比电容保持率为71%)和非常好的循环性能(20000次循环后比电容损失仅为8.3%)。进而证实了GNS@PDAA复合材料所组装的超级电容器具有优异的串并联特性。     

高功率超级电容器用介孔炭电极材料

以纳米CaCO3为模板、蔗糖为前躯体制备超级电容器用介孔炭电极材料.材料的结构由氮吸附、TEM表征,借助恒流充放电、循环伏安和交流阻抗评价了其在6 mol.L-1KOH电解液中的电化学电容性能.结果表明,蔗糖基介孔炭的比表面积606 m2/g,富含10~30 nm的介孔.恒流放电法测得介孔炭在电流密度50 mA/g下的比电容为125 F/g,大电流倍率性能特别突出.电流密度增大到20 000 mA/g,比电容还保持有88F/g,远高于进口电容炭,该介孔炭是一种很有前景的高功率超级电容器炭电极材料.     

Synthesis and Electrochemical Performance of Co3O4/Graphene

Co3O4/reduced graphene oxide composites were synthesized via a simple electrochemical method from graphene oxide and Co（NO3）2·6H2O as raw materials.Co3O4 nanoparticles with sizes of around 30-50 nm were distributed on the surface of graphene nanosheets confirmed by scanning electron microscopy and transmission electron microscopy.Electrochemical properties of Co3O4/graphene composite were tested by cyclic voltammetry,galvanostatic charge-discharge,and electrochemical impedance spectroscopy.The Co3O4/reduced graphene oxide composite was used as the pseudocapacitor electrode in the 2 mol/L NaOH aqueous electrolyte solution.The Co3O4/reduced graphene oxide composite electrode exhibited a specific capacitance of 357 F/g at a current density of 0.5 A/g in a three-electrode system.72％ of capacitance was retained when the current density increased to 3 A/g.The Co3O4/reduced graphene oxide composite prepared electrodes show a high rate capability and excellent long-term stability.After 1000 cycles of charge and discharge,the capacitance is still maintained 87％ at a current density of 1 A/g,indicating that the composite is a oromising alternative electrode material used for supercapacitors.     

碳气凝胶的孔结构及其对电化学超级电容器性能的影响

通过改变碳气凝胶的溶胶-凝胶制备条件和炭化活化工艺,实现了对碳气凝胶纳米孔洞结构的控制.采用扫描电子显微镜(SEM)和氮气等温气体吸附法对碳气凝胶和KOH活化碳气凝胶的形貌和孔结构进行了表征和分析,并且使用循环伏安法(CV),恒流充放电,电化学阻抗谱(EIS)等检测技术评价了电化学性能.结果表明:发达的三维纳米网络结构与合理的孔径分布是影响碳气凝胶电化学超级电容器性能的关键因素.经适度活化后的碳气凝胶材料含有丰富的介孔,比表面积可达1480m2·g-1.在6mo·lL-1的KOH溶液中,在100mV·s-1的扫描速率下其比电容量高达216F·g-1.通过拟合发现,碳气凝胶类材料的大孔和介孔拥有更高的单位面积比电容量.     

In‐situ thermal reduction and effective reinforcement of graphene nanosheet/poly (ethylene glycol)/poly (lactic acid) nanocomposites

This study aims to achieve a molecule‐level dispersion of graphene nanosheets (GNSs) and a maximum interfacial interaction between GNSs and a polymer matrix. GNS‐reinforced poly (ethylene glycol) (PEG)/poly (lactic acid) (PLA) nanocomposites are obtained by a facile and environment‐friendly preparation method. Graphite oxide and GNSs are characterized by atomic force microscopy, Raman spectroscopy, and X‐ray diffraction. Scanning electron microscopy shows that the state of dispersion of the GNS in the PEG/PLA matrix is distribution. The tensile strength and Young's modulus increases by 45% and 188%, respectively, with the addition of 4.0 wt% GNSs. The thermal stability of the GNS‐based nanocomposites also improves. Differential scanning calorimetry indicates that GNSs have no remarkable effect on the crystallinity of the nanocomposites. The effective reinforcement of the nanocomposites is mainly attributed to the highly strong molecular‐level dispersion of the GNSs in the polymer matrix. Copyright © 2014 John Wiley & Sons, Ltd.     

Preparation and electrochemical analysis of graphene/polyaniline composites prepared by aniline polymerization

Polyaniline (PANI)/graphene nanosheet (GNS) composites were prepared by a chemical oxidation polymerization. The morphology, structure, and crystallinity of the composites were examined by scanning electron microscopy, transition electron microscopy, and X-ray diffraction. Electrochemical properties were characterized by cyclic voltammetry in 1 M H₂SO₄ electrolyte. GNS are considered as supporting materials which can provide a large number of active sites. The PANI nanofibers with diameter of 50 nm were homogeneously coated on the surface of GNS. The PANI/GNS composites exhibited a better electrochemical performance than the pure individual components. The PANI/GNS composites showed the highest specific capacitance 923 Fg^?1 at 10 mVs^?1 compared to 465 Fg^?1 for pure PANI and 99 Fg^?1 for GNS.     

Crystallization behavior, thermal and mechanical properties of PHBV/graphene nanosheet composites

Biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/graphene nanosheet (GNS) composites were prepared via a solution-casting method at low GNS loadings in this work. Transmission electron microscopy revealed that a fine dispersion of GNSs was achieved in the PHBV matrix. The thermal properties of the nanocomposites were investigated by thermogravimetric analysis, and the results showed that the thermal stability of PHBV was significantly improved with a very low loading of GNSs. Nonisothermal melts crystallization behavior, spherulitic morphology and crystal structure of neat PHBV and the PHBV/GNSs nanocomposites were investigated, and the experimental results indicated that crystallization behavior of PHBV was enhanced by the presence of GNSs due to the heterogeneous nucleation effect; however, the two-dimensional (2D) GNSs might restrict the mobility of the PHBV chains in the process of crystal growing. Dynamic mechanical analysis studies showed that the storage modulus of the PHBV/GNSs nanocomposites was greatly improved.