Performance of polyacrylonitrile-carbon nanotubes composite on carbon cloth as electrode material for microbial fuel cells

The performance of carbon nanotubes composite-modified carbon cloth electrodes in two-chambered microbial fuel cell (MFC) was investigated. The electrode modified with polyacrylonitrile-carbon nanotubes (PAN-CNTs) composite showed better electrochemical performance than that of plain carbon cloth. The MFC with the composite-modified anode containing 5 mg/cm2 PAN-CNTs exhibited a maximum power density of 480 mW/m2.     

Three-dimensional carbon nanotube-textile anode for high-performance microbial fuel cells

Microbial fuel cells (MFCs) harness the metabolism of microorganisms, converting chemical energy into electrical energy. Anode performance is an important factor limiting the power density of MFCs for practical application. Improving the anode design is thus important for enhancing the MFC performance, but only a little development has been reported. Here, we describe a biocompatible, highly conductive, two-scale porous anode fabricated from a carbon nanotube-textile (CNT-textile) composite for high-performance MFCs. The macroscale porous structure of the intertwined CNT-textile fibers creates an open 3D space for efficient substrate transport and internal colonization by a diverse microflora, resulting in a 10-fold-larger anolyte-biofilm-anode interfacial area than the projective surface area of the CNT-textile. The conformally coated microscale porous CNT layer displays strong interaction with the microbial biofilm, facilitating electron transfer from exoelectrogens to the CNT-textile anode. An MFC equipped with a CNT-textile anode has a 10-fold-lower charge-transfer resistance and achieves considerably better performance than one equipped with a traditional carbon cloth anode: the maximum current density is 157% higher, the maximum power density is 68% higher, and the energy recovery is 141% greater.     

锂离子电池碳纳米管负极材料储锂性能研究

将碳纳米管用于锂离子电池负极材料,用循环伏安及充放电实验研究了电极的性能.结果表明,碳纳米管用作锂离子电池负极,具有较高的储锂容量,首次放电容量达560mAh/g,但首次不可逆容量损失也大,高达430mAh/g.经过第1次充放电的容量损失后,随后各次的容量损失很小,碳纳米管的循环性能趋于稳定.     

Synthesis of fuel oil and carbon nanotubes in an autoclave using plastic waste as precursor

In this study, the synthesis of fuel oil and carbon nanotubes (CNTs) using waste plastic in a batch pyrolysis reactor of 750?mL capacity was carried out. Density, calorific values and FTIR spectroscopy confirmed the formation of fuel oil. The calorific value of oil was higher than the energy needed for pyrolysis process. The same reactor was used as an autoclave for the synthesis of CNTs. SEM and TEM results showed that carbon nanotubes of 40–60?nm diameters were grown on Ni/Mo/MgO catalyst. CNT yield was around 3.2?g of CNTs per 6?g of PP. The purity of CNTs was investigated by thermogravimetric analysis (TGA). The present study proposes a feasible process to convert plastic waste into furnace oil by rapid pyrolysis and synthesis of CNTs.     

Si@环化聚丙烯腈/多壁碳纳米管负极复合材料的制备及电化学性能

通过简单高能球磨和高温热解法制备了锂离子电池Si/C电极复合材料,聚丙烯腈（PAN）包覆的纳米颗粒（Si@PAN）与多壁碳纳米管（MWCNTs）混合,制得Si@环化PAN/MWCNTs（Si@c-PAN/MWCNTs）复合材料作为锂离子电池的负极材料。包覆在纳米Si外层的高温热解后的PAN能够有效缓冲Si在充放电过程中巨大的体积变化产生的应力,同时MWCNTs作为Si@c-PAN的基体阻止Si@c-PAN颗粒的团聚,也提高了Si@c-PAN/MWCNTs复合材料电极的导电性能。电化学测试结果表明,Si@c-PAN/MWCNTs复合材料电极在电流密度为0.2 A/g时,其首次放电比容量达到2 098 mA?h/g,库伦效率达到86%;循环50次后Si@c-PAN/MWCNTs复合材料电极的可逆比容量仍能够达到1 278 mA?h/g,在2 A/g放电时其比容量为600 mA?h/g,仍保持良好的循环稳定性。      

新型锂电池负极复合材料硅/无定形碳/碳纳米管的制备及性能研究

通过高温裂解蔗糖混合纳米硅和碳纳米管,得到硅/无定形碳/碳纳米管复合材料.实验结果表明,复合材料的首次放电容量高达1315.4mAh/g,首次充放电效率为72.4%,经过20次充放电循环后可逆容量仍高达830.5mAh/g.具有良好弹性的碳纳米管组成的网状结构使复合材料能保持较好的形貌,而碳纳米管优良的导电性可以使更多...     

Spherical hard carbon prepared from potato starch using as anode material for Li-ion batteries

Spherical hard carbon (SHC) was easily prepared by one-step programmed heating of potato starch under inert atmosphere. The as-prepared hard carbon spherules preserved original spherical shapes of natural potato starch granules and had widely dispersed diameters which were smaller than those of potato starch granules. The surfaces of the hard carbon spherules were very smooth, which differed from rough undulating appearances of potato starch granules. In terms of microstructure, SHC was typical of disordered carbon with micropores throughout it. In addition, SHC was evaluated as an anodic material for Li-ion batteries. The reversible capacity of SHC was about 531 mAhg^? 1 with a first-cycle coulombic efficiency of 73.1%. Besides, SHC showed stable cycling performances and good rate capability.     

Performance improvement of fuel cells using platinum-functionalised aligned carbon nanotubes

The focus of this research was towards the improvement of the performance of proton exchange membrane fuel cells. The overarching goals were: (1) providing guidelines for design of new catalysts; (2) promoting nanocatalyst applications towards alternative energy applications; and (3) integrating advanced instrumentation into nanocharacterisation and fuel cell (FC) electrochemical behaviour. In tandem with these goals, the cathode catalysts were extensively refined to improve FC performance and minimise noble metal usage. In this study, the major accomplishment was producing aligned carbon nanotubes (ACNT), which were then modified by platinum (Pt) nanoparticles via a post-synthesis colloidal chemistry approach. The Pt-ACNTs demonstrated improved cathodic catalytic activity, as a result of incorporation of the nanotubes with the additional advantage of decreased Pt loading. It was also determined that surface mechanical properties, such as elastic modulus and hardness were increased. Collectively, these enhancements provided an improved FC performance.     

Preparation of porous chromium oxide nanotubes using carbon nanotubes as templates and their application as an ethanol sensor

Chromium oxide nanotubes were successfully prepared using multi-walled carbon nanotubes (MWCNTs) as a template via a supercritical fluid-mediated route. In this method, with chromium (III) nitrate nonahydrate as precursor, chromium oxide was first deposited on MWCNTs in supercritical ethanol in the presence of NH(4)HCO(3). The as-prepared chromium oxide/MWCNT nanocomposites were characterized by transmission electron microscopy, x-ray diffraction, infrared spectroscopy and thermogravimetric analysis. It was demonstrated that the MWCNTs were coated with a layer of amorphous Cr(2)O(3)·xH(2)O. The thickness of the Cr(2)O(3)·xH(2)O sheath on MWCNTs could be tuned by manipulating the ratio of precursor to MWCNTs. Calcining the composites at 550?°C, the MWCNTs were removed, producing polycrystalline α-Cr(2)O(3) nanotubes. The as-prepared α-Cr(2)O(3) sample was used as a sensor material to detect ethanol vapor, and it was demonstrated that the α-Cr(2)O(3) nanotubes exhibited good performance even at 400?°C.     

NaFeTiO4 nanorod/multi-walled carbon nanotubes composite as an anode material for sodium-ion batteries with high performances in both half and full cells

NaFeTiO4 nanorods of high yields (with diameters in the range of 30-50 nm and lengths of up to 1-5 μm) were synthesized by a facile sol-gel method and were utilized as an anode material for sodium-ion batteries for the first time.The obtained NaFeTiO4 nanorods exhibit a high initial discharge capacity of 294 mA·h·g-1 at 0.2 C (1 C =177 mA·g-1),and remain at 115 mA·h·g-1 after 50 cycles.Furthermore,multi-walled carbon nanotubes (MWCNTs) were mechanically milled with the pristine material to obtain NaFeTiO4/MWCNTs.The NaFeTiO4/MWCNTs electrode exhibits a significantly improved electrochemical performance with a stable discharge capacity of 150 mA·h·g-1 at 0.2 C after 50 cycles,and remains at 125 mA·h·g-1 at 0.5 C after 420 cycles.The NaFeTiO4/MWCNTs//Na3V2(PO4)3/C full cell was assembled for the first time;it displays a discharge capacity of 70 mA·h·g-1 after 50 cycles at 0.05 C,indicating its excellent performances.X-ray photoelectron spectroscopy,ex situ X-ray diffraction,and Raman measurements were performed to investigate the initial electrochemical mechanisms of the obtained NaFeTiO4/MWCNTs.     

炭纳米纤维-天然石墨复合材料的制备及其作为锂离子电池阳极材料的电化学性能(英文)

制备一种炭纳米纤维-天然石墨复合材料,以改善作为锂离子电池阳极材料的天然石墨的倍率性能。通过优化控制天然石墨上炭纳米纤维的生长量及其形状提高了天然石墨的循环性能和倍率性能。与天然石墨原料相比,炭纳米纤维-天然石墨复合材料第一次放电容量达到了95%。炭纳米纤维的生长量被严格地控制在天然石墨质量的15%以下。研究发现:由于炭纳米纤维对充放电过程中阳极的体积膨胀和收缩程度的控制作用,天然石墨表面边位上生长的类似常青藤形的炭纳米纤维对倍率性能的提高最为有效。提出采用炭纳米纤维-天然石墨复合材料的原理结构模型解释重复充放电过程中电极的体积稳定性。通过在石墨表面上生长类常青藤形炭纳米纤维而使得SEI(固体电解质界面)变薄并减少了充放电过程中阳极的体积变化,因而提高了倍率性能。     

Graphene and cobalt phosphide nanowire composite as an anode material for high performance lithium-ion batteries

The synthesis of a composite of cobalt phosphide nanowires and reduced graphene oxide (denoted CoP/RGO) via a facile hydrothermal method combined with a subsequent annealing step is reported. The resulting composite presents large specific surface area and enhanced conductivity, which can effectively facilitate charge transport and accommodates variations in volume during the lithiation/de-lithiation processes. As a result, the CoP/RGO nanocomposite manifests a high reversible specific capacity of 960 mA·h·g^–1 over 200 cycles at a current density of 0.2 A·g^–1 (297 mA·h·g^–1 over 10,000 cycles at a current density of 20 A·g^–1) and excellent rate capability (424 mA·h·g^–1 at a current density of 10 A·g^–1).

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Low-temperature synthesis of nanosized disordered carbon spheres as an anode material for lithium ion batteries

Disordered carbons in the order of nanometers were prepared by a hydrothermal reaction route. X-ray diffraction studies indicated a highly disordered carbon structure. SEM and TEM results revealed that these disordered carbons have a perfect spherical morphology, smooth surface and uniform particle size of about 100 nm. The lithium intercalation property of the products was also investigated. The results showed that the products delivered lithium insertion and deinsertion capacities of 1233 and 491 mA h g^− 1 respectively during the first cycle. Subsequent cycles showed a remarkable improvement in cycling efficiency with a 10th cycle efficiency of 98%. The correlation between microstructure, morphology and electrochemical behavior of such carbons was discussed.     

Electrochemical properties of Super P carbon black as an anode active material for lithium-ion batteries

A new approach to investigate upon the electrochemical properties of Super P carbon black anode material is attempted and compared with conventional mesophase pitch-based carbon fibers (MPCFs) anode material for lithium-ion batteries. The prepared Super P carbon black electrodes are characterized using transmission electron microscope (TEM). The assembled 2032-type coin cells are electrochemically characterized by ac impedance spectroscopic and cyclic voltammetric methods. The electrochemical performance of charge and discharge was analyzed using a battery cycler at 0.1 C rate and cut-off potentials of 1.20 and 0.01 V vs. Li/Li⁺. The electrochemical test illustrates that the discharge capacity corresponding to Li intercalation into the Super P carbon black electrode is higher and coulombic efficiency is maintained approximately 84% at the end of the 20th cycling at room temperature.     

Large-scale synthesis of BN nanotubes using carbon nanotubes as template

Boron nitride nanotubes (BN-NTs) were synthesized in large scale by the reaction of NaBH₄ and NH₄Cl in the temperature range of 500-600 °C for 10-18 h, where carbon nanotubes (CNTs) were mixed together with the reactants to serve as template. Pure BN-NTs were obtained by oxidizing the product at about 800 °C in air atmosphere. The structure and morphology of the product with a surface area of 106.635 m²/g were characterized by X-ray diffraction, transmission electron microscopy, Fourier transformation infrared spectroscopy, and thermogravimetric analysis. Large scale preparation of BN-NTs could be realized by this simple and effective route.     

碳包覆空心Fe3O4纳米粒子作为锂离子电池负极材料的电化学性能研究

以二茂铁为铁源,石油渣油为碳源,通过加压热解和空气氧化制备了碳包覆空心Fe3O4纳米粒子。采用X射线衍射(XRD)、透射电镜(TEM)以及高倍透射电镜(HRTEM)等测试方法对样品的形貌和结构进行表征。采用恒流充放电和交流阻抗方法测试碳包覆空心Fe3O4纳米粒子作为锂离子电池负极材料的电化学性能。在电流密度为0.2mA/cm2时,首次放电比容量高达1294.7mAh/g,30次循环之后其放电比容量为392.1mAh/g;电流密度为1mA/cm2时,首次放电比容量为216.3mAh/g,30次循环之后其放电比容量为113mAh/g。     

Purification of catalytically produced carbon nanotubes for use as support for fuel cell cathode Pt catalyst

A purification method based on HCl treatment under reflux was employed for purification of carbon nanotube (CNT) samples, obtained by the electric discharge method utilizing Zr(Co_0.5Ni_0.5)₂, Ce₃(Co_0.5Ni_0.5)₂ and Ce(Co_0.5Ni_0.5)₅ as catalysts. Raman Spectroscopy provided information on the SWCNT presence in the untreated samples. Scanning Electron Microscopy (SEM) showed CNT with different diameters and lengths. Different acid treatment conditions were employed and the best results were achieved for HCl 3 mol/L aqueous solution during 24 h reflux. Transmission Electron Microscopy (TEM) images, associated with EDS, revealed the catalyst removal from the original sample and the presence of other carbon structures near the CNT formation. CNT acid functionalization for Pt nanoparticles dispersion was successful, resulting in a homogeneously dispersed system, as seen in TEM images. Temperature Programmed Oxidation (TPO) analysis of the raw and purified samples indicated that after purification there are three different carbon species present on the purified material, each one showing a different behavior towards O₂ oxidation.     

Novel fabrication of silica nanotubes using multi-walled carbon nanotubes as template

Silica nanotubes were synthesized using multi-walled carbon nanotubes (MWCNTs) as template. The as-obtained samples were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscope (FE-SEM) and photoluminescent (PL) spectroscopy. The results indicate that the thickness of the outer walls is about 10 nm and the inner diameter is completely dependent on the size of MWCNTs. The as-fabricated silica nanotubes emit a strong violet light under excitation of 250 nm.