Promotive effect of multi-walled carbon nanotubes on Co3O4 nanosheets and their application in lithium-ion battery

Co3O4/MWCNTs composites have been synthesized by a simple hydrothermal method using a surfactant(CTAB) and a precipitation agent(urea). The samples were characterized by XRD, SEM and BET methods. The electrochemical properties of the samples as anode materials for lithium batteries were studied by EIS and Galvanostatic measurements. The Co3O4/MWCNTs composites displayed higher capacity and better cycle performance in comparison with the Co3O4 nanosheets. The remarkable improvement of electrochemical performance within the hybrid composites is probably related to the addition of MWCNTs that possesses improved properties such as excellent electric conductivity and large surface area, which helps to alleviate the effect of volume change, shorten the distance of lithium ion diffusion, facilitate the transmission of electron and keep the structure stable.     

Understanding supercapacitors based on nano-hybrid materials with interfacial conjugation

The recent fast development of supercapacitors,also known scientifically as electrochemical capacitors,has benefited significantly from synthesis,characterisations and electrochemistry of nanomaterials.Herein,the principle of supercapacitors is explained in terms of performance characteristics and charge storage mechanisms,i.e.double layer(or interfacial) capacitance and pseudo-capacitance.The semiconductor band model is applied to qualitatively account for the pseudo-capacitance in association with rectangular cyclic voltammograms(CVs) and linear galvanostatic charging and discharging plots(GCDs),aiming to differentiate supercapacitors from rechargeable batteries.The invalidity of using peak shaped CVs and non-linear GCDs for capacitance measurement is highlighted.A selective review is given to the nano-hybrid materials between carbon nanotubes and redox active materials such as electronically conducting polymers and transition metal oxides.A new concept,"interfacial conjugation",is introduced to reflect the capacitance enhancement resulting from π-π stacking interactions at the interface between two materials with highly conjugated chemical bonds.The prospects of carbon nanotubes and graphenes for supercapacitor applications are briefly compared and discussed.Hopefully,this article can help readers to understand supercapacitors and nano-hybrid materials so that further developments in materials design and synthesis,and device engineering can be more efficient and objective.     

Effect of TiO_2 Addition to the Microwave Absortion Property of Polyaniline Micro/Nanocomposites

1 Results Recently,conducting polymers as molecular wires have attracted considerable attention because of their long conjugated length,metal conductivity and promising potential application in nanodevices.It is important to manipulate the synthesis parameters or additives used in order to produce conducting polymer showing moderate conductivity,magnetic and dielectric properties that could enhance its microwave absorbing and shielding properties.As nano-material possessing moderate conductivity,dielectric and magnetic property,novel hexanoic acid (HA) doped PAni micro/nanocomposites containing TiO2 (30 nm) and Fe3O4 (1 μm) were prepared by template free method.The composites were then characterized by FTIR,X-ray diffraction,TGA and SEM analysis.The conductivity,dielectric,magnetic and microwave absorption properties of the composites were also investigated.The resulted nanorods/tubes shown in the SEM images indicate that PAni micro/nanocomposites exhibited polymerization through elongation.     

Carbon Nanotube-Conducting Polymer Composites Based Solar Cells

1 Results Combination of carbon nanotubes (CN) with polymers is important for application towards value added composites,solar cells,fuel cells etc.Especially interesting is the combination of CN with π-conjugated polymers because of the potential interaction between the highly delocalized π-electrons of the CN and the π-electrons correlated with the lattice of polymer skeleton.Efficient exciton dissociation due to electron transfer from the photoexcited polymer to CN is of interest for photovoltaic app...     

Carbon Nanotube-Conducting Polymer Composites Based Solar Cells

1 Results Combination of carbon nanotubes (CN) with polymers is important for application towards value added composites,solar cells,fuel cells etc.Especially interesting is the combination of CN with π-conjugated polymers because of the potential interaction between the highly delocalized π-electrons of the CN and the π-electrons correlated with the lattice of polymer skeleton.Efficient exciton dissociation due to electron transfer from the photoexcited polymer to CN is of interest for photovoltaic applications.In the present work,solar cells are fabricated using CN-conjugated polymer composite films.     

In Situ Characterization of Polymer Matrices for Bio-electrode Applications

1 Results Electropolymerized azines are considered an important group of mediators for NAD / NADH-based biocatalytic applications[1].Characterizing these electroactive polymers in situ on electrode surface is vital to understand their behavior and properties.We recently studied the polymer deposition on electrodes using imaging ellipsometry (IE) as an in situ technique[2].The observation of surface morphology development can be conducted in cyclic voltammetric cycles in a nanometer scale.We then combined with quartz crystal microbalance (QCM) to monitor layer-by-layer polymer growth in terms of morphology,mass,charge,and film thickness progression,which allows a more mechanistic understanding of the steps involved in the electrochemical polymerization process.This electrochemical microgravimetric imaging ellipsometry (EmIE) technique enables us to distinguish mass change due to adsorption against redox reactions during cyclic voltammetry,offering a direct observation of electrode process in a non-invasive,in-situ manner.Such a capability promises nano-scale observations of electrode surface with direct correlation of mass,charge,and film property changes,with broad implications for kinematic studies of redox systems at interfaces.     

Study on the Mechanical Properties of Carbon Nanotube/Polyacrylonitrile Composite Fibers

The method of preparing the multi-walled carbon nanotubes (MWNTs)-polyacrylonitriIe (PAN) composite fibers is described and the effects of draw ratio on the mechanical properties of CNT/PAN fibers have also been discussed. The results show that the degrees of MWNTs dispersion in the polymer matrix have much effect on the mechanical properties.     

Grafting of thermoresponsive polymer from the surfaceof functionalized multiwalled carbon nanotubes via atom transfer radical polymerization

Multiwalled carbon nanotubes were oxidized with concentrated HNO3 and H2SO4 to introduce carboxylic groups onto carbon nanotubes surfaces. The oxidized carbon nanotubes were reacted subsequently with thionyl chloride and 2-Hydroxylethyl-2＇-bromoisobutyrate, producing MWNT-based macroinitiators, MWNT-Br, for the atom transfer radical polymerization of （N-isopropylacrylamide）. FTIR, XPS, ^1H NMR, Raman and TGA were used to characterize the resulting products and to determine the content of the water-soluble poly （N-isopropylacrylamide） chains in the product. The MWNTs grafted with PNIPAM chains have good solubility in distilled water; THF and CHCl3. TEM images of the samples provide direct evidence for the formation of a nanostructure that MWNTs coated with polymer layer. The produced MWNT-g-PNIPAM has a PNIPAM shell, which is very sensitive to the change of temperature. This method would open a door for the fabrication of novel functional carbon nanotube-based nanomaterials or nanodevices with designable structure and tailor-made properties.     

Surface Grafting of Polymers onto Nano-Sized Particles in Solvent-Free Dry-System and in Ionic Liquid

1 Introduction We have reported the grafting of various polymers onto the surface of inorganic nano-sized particles, such as silica, titanium oxide, and carbon black~([1]). The polymer-grafted nano-sized particles are known to have excellent properties, such as a good dispersibility in solvents and polymer matrices~([1, 2]). However, scale-up production of polymer-grafted nano-sized particles was hardly achieved, because complicated procedures, such as centrifugation, filtration, and solvent e…     

A review on hybridization modification of graphene and its polymer nanocomposites

Recently,graphene has attracted numerous interests from both fundamental and applied fields due to its excellent mechanical,thermal,electrical conductivity and other novel properties.This review gives an overview of recent progress on hybridization modifications of graphene with carbon nanomaterials.Some example applications of graphene-based nanohybrids in polymer composites,optical and conducting materials,high performance electrolyte materials and as well as other functional materials are summarized and discussed.     

Synthesis and supercapacitor characteristics of PANI/CNTs composites

The polyaniline coated multi-walled carbon nanotubes (PANI/CNTs) composites were synthesized by in situ polymerization. The microstructure and component of the composites were characterized by scanning electron microscope (SEM), Fourier transfer infrared spectroscopy (FTIR), X-ray diffraction (XRD), and N2 adsorption BET. The electrochemical performances of the samples were tested by cyclic voltammogram (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge. The results showed...     

不同锂源和碳源对RAPET法合成LiFePO_4/C的影响

以自制的磷酸铁作为铁源和磷源,用高温自生压力法（即RAPET法）合成了LiFe-PO4/C复合材料,分别比较了以葡萄糖、蔗糖或柠檬酸为碳源和以碳酸锂或氢氧化锂为锂源所得LiFePO4/C复合材料电化学性能的影响。利用X射线衍射（XRD）、循环伏安（CV）、交流阻抗（EIS）和充放电测试等方法,分别对样品的晶型和电化学性能等进行了表征和分析。结果表明：以柠檬酸为碳源、碳酸锂为锂源制备的LiFePO4/C复合材料电化学性能更优异,首次放电比容量达到166.1mAh/g。     

聚苯乙烯/碳纳米管复合材料的力学性能与结构

研究了聚苯乙烯／碳纳米管复合材料的力学性能，探讨了该材料的微观结构与性能之间的关系，结果表明，在碳纳米管加入量为1.0%时，复合材料的拉伸强度和冲击韧性较高，综合性能达到最佳，此时，碳纳米管在基体中呈纳米级分布，而且碳纳米管对苯乙烯的聚合过程没有阻碍作用。     

导电聚合物的电化学性质

综述了几种有代表性的导电聚合物——聚吡咯、聚苯胺、聚噻吩等的电化学特性及其电化学掺杂／脱掺杂反应的机理,介绍了聚对苯撑乙烯(PPV)等光电活性共轭聚合物的循环伏安特性及其HOMO和LUMO能级的电化学表征方法;还对导电聚合物的电化学稳定性以及取代基对共轭聚合物电子结构的影响进行了讨论．     

聚噻吩(PT)、聚-3-甲基-噻吩(PMT)和聚-3,4-亚乙二氧基-噻吩(PEDT)作为超电容器电极材料的研究

通过线性扫描伏安法分别测试了电解质0．2MEt4NBF4的碳酸丙稀酯溶液在铂电极和玻璃碳电极上的电化学稳定窗口，结果表明，试电解质在玻璃碳电极上更稳定。通过电化学聚合在玻璃碳电极上分别合成了聚噻吩、聚-3-甲基-噻吩和聚-3，4-亚乙二氧基-噻吩，并通过循环伏安对三种导电高分子的掺杂特性进行了表征，分析比较三种导电高分子在电化学掺杂／去掺杂过程中的掺杂电位、可传递电荷、掺杂度和电荷捕获度可知，对于其掺杂电位，PT〉PMT〉PEDT；而对于去掺杂电荷和掺杂度，PEDT〉PMT〉PT，这表明PEDT是更有应用前景的超电客器电极材料。     

碳纳米管的表面修饰及性能研究

通过原子转移自由基聚合法(ATRP)在碳纳米管表面接枝聚甲基丙烯酸二甲氨基乙酯(PDMAEMA),得到 表面修饰的碳纳米管(MWNT-g-PDMAEMA),进一步与二茂铁甲酸反应,成功制备了碳纳米管复合材料(MWNT g-PDMAEMA/C11H10O2Fe).详细研究了碳纳米管复合材料(MWNT-g-PDMAEMA/...     

碳纳米管复合材料的研究应用现状与展望

综述了碳纳米管复合材料的制备基础及制备方法，碳纳米管复合材料物理、力学性能及其应用，并对碳纳米管复合材料未来的进行了展望。     

不同载硅量对Li2FeSiO4/C材料电性能的影响

以多壁纳米碳管和Si(OC2H5)4为原料,采用液相法合成包覆了SiO2的多壁碳纳米管(MWCNTs@SiO2),通过调节Si(OC2H5)4的加入量,制备出不同载硅量的前驱体MWCNTs@SiO2,并以此种前驱物合成硅酸铁锂Li2FeSiO4/C材料.采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、恒流充放电对Li2FeSiO4/C材料进行了表征及电化学性能测试,实验结果表明载硅量为35.72%的MWCNTs@SiO2前驱体合成的Li2FeSiO4/C材料颗粒大小一致,在0.1C电流密度下循环50圈后获得180 mAh·g－1的稳定放电比容量,具有优良的电化学性能.     

碳纳米管/炭黑并用导电橡胶的制备与性能研究

文章基于溶液共混法,制成了一种新型的碳纳米管/炭黑/硅胶多相复合材料.实验利用TEM、压阻测试平台等手段表征和分析了碳纳米管的功能化、添加比例对复合材料性能的影响.实验结果表明:功能化可以有效改善碳纳米管的表面特性,进而改善其在聚合物中的分散性;不同维度纳米材料(碳纳米管/炭黑)的并用会在橡胶体系中形成“葡萄串”结构,...