Physical Sciences and Mathematics Commons^™

A Conductive Polypyrrole-Coated, Sulfur-Carbon Nanotube Composite For Use In Lithium-Sulfur Batteries, Jianli Wang, Lin Lu, Dongqi Shi, Richard Tandiono, Zhaoxiang Wang, Konstantin Konstantinov, Hua Liu

Jianli Wang

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A novel ternary composite, polypyrrole (PPy)-coated sulphur-carbon nanotube (S-CNT), is synthesised by using an in situ, one-pot method. Firstly, elemental sulfur is loaded into the CNT network by a solution-based processing technique. Then conducting PPy is coated on the surface of the S-CNT composite to form the S-CNT-PPy ternary composite by carrying out polymerization of the pyrrole monomer in situ. The ternary composite is tested as a cathode for lithium-sulfur batteries. The results show that PPy coating improves significantly the performance of the binary composites (S-CNT and S-PPy). The conducting PPy is believed to serve multiple functions in the composite: …

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Microscopic Role Of Carbon On Mgb2 Wire For Critical Current Density Comparable To Nbti, Jung Ho Kim, Sangjun Oh, Yoon-Uk Heo, Satoshi Hata, Hiroaki Kumakura, Akiyoshi Matsumoto, Masatoshi Mitsuhara, Seyong Choi, Yusuke Shimada, Minoru Maeda, Judith Macmanus-Driscoll, S X. Dou

Shi Xue Dou

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Increasing dissipation-free supercurrent has been the primary issue for practical application of superconducting wires. For magnesium diboride, MgB2, carbon is known to be the most effective dopant to enhance high-field properties. However, the critical role of carbon remains elusive, and also low-field critical current density has not been improved. Here, we have undertaken malic acid doping of MgB2 and find that the microscopic origin for the enhancement of high-field properties is due to boron vacancies and associated stacking faults, as observed by high-resolution transmission electron microscopy and electron energy loss spectroscopy. The carbon from the malic acid almost uniformly encapsulates …

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Nano-Structured Sno2-Carbon Composites Obtained By In Situ Spray Pyrolysis Method As Anodes In Lithium Batteries, Ling Yuan, Konstantin Konstantinov, Guoxiu Wang, Hua-Kun Liu, S X. Dou

Shi Xue Dou

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In this paper, we report on a series of SnO2-carbon nano-composites synthesized by in situ spray pyrolysis of a solution of SnCl2·2H2O and sucrose at 700 °C. The process results in super fine nanocrystalline SnO2, which is homogeneously distributed inside the amorphous carbon matrix. The SnO2 was revealed as a structure of broken hollow spheres with porosity on both the inside and outside particle surfaces. This structure promises a highly developed specific surface area. X-ray diffraction (XRD) patterns and transmission electron microscope (TEM) images revealed the SnO2 crystal size is about 5–15 nm. These composites show a reversible lithium storage …

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Strong Competition Between The Delta L And Delta T-C Flux Pinning Mechanisms In Mgb2 Doped With Carbon Containing Compounds, Shaban R. Ghorbani, Xiaolin Wang, Md S. Hossain, Qiwen Yao, S X. Dou, Sung-Ik Lee, K C. Chung, Y K. Kim

Shi Xue Dou

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The transport and magnetic properties of 10 wt % malic acid and 5 wt % nanocarbon doped MgB2 have been studied by measuring the resistivity (p), critical current density (jc), connectivity factor (AF), irreversibility field (Hirr), and upper critical field (Hc2). The pinning mechanisms are studied in terms of the collective pinning model. It was found that both mean free path (δl) and critical temperature (δTc) pinning mechanisms coexist in both doped MgB2. For both the malic acid and nanocarbon doped samples, the temperature dependence of the crossover field, which separates the single vortex and the small bundle pinning regime, …

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Free-Standing Single-Walled Carbon Nanotube/Sno2 Anode Paper For Flexible Lithium-Ion Batteries, Lukman Noerochim, Jia-Zhao Wang, Shulei Chou, David Wexler

Shulei Chou

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Free-standingsingle-walledcarbonnanotube/SnO₂ (SWCNT/SnO₂) anodepaper was prepared by vacuum filtration of SWCNT/SnO₂ hybrid material which was synthesized by the polyol method. From field emission scanning electron microscopy and transmission electron microscopy, the CNTs form a three-dimensional nanoporous network, in which ultra-fine SnO₂ nanoparticles, which had crystallite sizes of less than 5 nm, were distributed, predominately as groups of nanoparticles on the surfaces of singlewalled CNT bundles. Electrochemical measurements demonstrated that the anodepaper with 34 wt.% SnO₂ had excellent cyclic retention, with the high specific capacity of 454 mAh g⁻¹ beyond 100 cycles at a current …

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Irradiation Si On Carbon Nanotube Paper As A Flexible Anode Material For Lithium-Ion Batteries, Shulei Chou, Mihail Ionescu, Jia-Zhao Wang, Brad Winton, Hua Liu

Shulei Chou

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Silicon single walled carbon nanotube composite paper was modified by low energy ion implantation using 5i to obtain a flexible composite paper. Raman and FE-SEM results show that structure of SWCNT could be destroyed by the implantation. Electrochemical measurements display that the implanted SI can improve the specific capacity and the reversible capacity of CNT paper. After 50 cycles, the specific capacity of 5Hmplanted CNT paper is 30 per cent higher than the pristine CNT.

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Parametric Study Of Reaxff Simulation Parameters For Molecular Dynamics Modeling Of Reactive Carbon Gases, Benjamin David Jensen

Dissertations, Master's Theses and Master's Reports - Open

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Abstract

The development of innovative carbon-based materials can be greatly facilitated by molecular modeling techniques. Although the Reax Force Field (ReaxFF) can be used to simulate the chemical behavior of carbon-based systems, the simulation settings required for accurate predictions have not been fully explored. Using the ReaxFF, molecular dynamics (MD) simulations are used to simulate the chemical behavior of pure carbon and hydrocarbon reactive gases that are involved in the formation of carbon structures such as graphite, buckyballs, amorphous carbon, and carbon nanotubes. It is determined that the maximum simulation time step that can be used in MD simulations with …

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A Highly Efficient Tio2-Xcx Nano-Heterojunction Photocatalyst For Visible-Light Induced Antibacterial Applications, Vinodkumar Etacheri, Michael Seery, Stephen Hinder, Georg Michlits, Suresh Pillai

Articles

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Visible-light-induced antibacterial activity of carbon-doped anatase-brookite titania nano-heterojunction photocatalysts are reported for the first time. These heterostructures were prepared using a novel low temperature (100 °C) non-hydrothermal low power microwave (300 W) assisted method. Formation of interband C 2p states was found to be responsible for the band gap narrowing of the carbon doped heterojunctions. The most active photocatalyst obtained after 60 minutes of microwave irradiation exhibits a 2-fold higher visible-light induced photocatalytic activity in contrast to the standard commercial photocatalyst Evonik-Degussa P-25. Staphylococcus aureus inactivation rate constant for carbon-doped nano-heterojunctions and the standard photocatalyst was 0.0023 and -0.0081 min …

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Microwave Characterization Of Carbon Nanotube Yarns For Uwb Medical Wireless Body Area Networks, Syed Muzahir Abbas, Oya Sevimli, Michael C. Heimlich, Karu P. Esselle, B Kimiaghalam, Javad Foroughi, Farzad Safaei

Australian Institute for Innovative Materials - Papers

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Carbon nanotube (CNT) yarns are novel CNT-based materials that extend the advantages of CNT from the nanoscale to macroscale applications. In this study, we have modeled CNT yarns as potential data transmission lines. Test structures have been designed to measure electrical properties of CNT yarns, which are attached to these test structures using gold paste. DC testing and microwave S-parameter measurements have been conducted for characterization. The observed frequency independent resistive behavior of the CNT yarn is a very promising indicator that this material, with its added values of mechanical resilience and thermal conductivity, could be invaluable for a range …

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Polyamide 6/Multiwalled Carbon Nanotubes Nanocomposites With Modified Morphology And Thermal Properties, Nasir Mahmood, Mohammad Islam, Asad Hameed, Shaukat Saeed

Australian Institute for Innovative Materials - Papers

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Pure polyamide 6 (PA6) and polyamide 6/carbon nanotube (PA6/CNT) composite samples with 0.5 weight percent loading of pristine or functionalized CNTs were made using a solution mixing technique. Modification of nanotube surface as a result of chemical functionalization was confirmed through the presence of lattice defects as examined under high-resolution transmission electron microscope and absorption bands characteristic of carboxylic, sulfonic and amine chemical groups. Microstructural examination of the cryogenically fractured surfaces revealed qualitative information regarding CNT dispersion within PA6 matrix and interfacial strength. X-ray diffraction studies indicated formation of thermodynamically more stable α-phase crystals. Thermogravimetric analysis revealed that CNT incorporation …

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'Laser Chemistry' Synthesis, Physicochemical Properties, And Chemical Processing Of Nanostructured Carbon Foams, Andres Seral-Ascaso, Rosa Garriga, Maria Luisa Sanjuan, Joselito M. Razal, Ruth Lahoz, Mariano Laguna, German F. De La Fuente, Edgar Munoz

Australian Institute for Innovative Materials - Papers

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Laser ablation of selected coordination complexes can lead to the production of metal-carbon hybrid materials, whose composition and structure can be tailored by suitably choosing the chemical composition of the irradiated targets. This 'laser chemistry' approach, initially applied by our group to the synthesis of P-containing nanostructured carbon foams (NCFs) from triphenylphosphine-based Au and Cu compounds, is broadened in this study to the production of other metal-NCFs and P-free NCFs. Thus, our results show that P-free coordination compounds and commercial organic precursors can act as efficient carbon source for the growth of NCFs. Physicochemical characterization reveals that NCFs are low-density …

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Aqueous Dispersions Of Reduced Graphene Oxide And Multi Wall Carbon Nanotubes For Enhanced Glucose Oxidase Bioelectrode Performance, Willo Grosse, Joffrey Champavert, Sanjeev Gambhir, Gordon G. Wallace, Simon E. Moulton

Australian Institute for Innovative Materials - Papers

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Aqueous dispersions of reduced graphene oxide (rGO) and multi walled carbon nanotubes (MWCNT) were fabricated through a modified chemical reduction method. The significant advantage of the method developed here is the omission of any stabilising compound or organic solvent to obtain stable rGO-MWCNT dispersions. Significantly biological entities, in this case the enzyme glucose oxidase (GOx), can be successfully incorporated into the dispersion. These dispersions were characterised using XPS, SEM, zeta potential and particle size measurements which showed that the dispersion stability is not sacrificed with the addition of GOx, and significantly, the electrical properties of the rGO and MWCNTs are …

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Platinum Electrodeposition On Unsupported Single Wall Carbon Nanotubes And Its Application As Methane Sensing Material, Enid Contes-De Jesus, Diana Santiago, Gilberto Casillas, Alvaro Mayoral, Cesar Magen, Miguel Jose-Yacaman, Jing Li, Carlos R. Cabrera

Australian Institute for Innovative Materials - Papers

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This paper reports the decoration of single wall carbon nanotubes (SWCNTs) with platinum (Pt) nanoparticles using an electrochemical technique, rotating disk slurry electrode (RoDSE). Pt/SWCNTs were electrochemically characterized by cyclic voltammetry technique (CV) and physically characterized through the use of transmission electron microscopy (TEM), energy dispersive spectroscopy - X-ray florescence (EDS-XRF) and X-ray diffraction (XRD). After characterization it was found that electrodeposited nanoparticles had an average particle size of 4.1 ± 0.8 nm. Pt/SWCNTs were used as sensing material for methane (CH4) detection and showed improved sensing properties in a range of concentration from 50 ppm to 200 ppm parts …

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Facile Synthesis Of Reduced Graphene Oxide/Mwnts Nanocomposite Supercapacitor Materials Tested As Electrophoretically Deposited Films On Glassy Carbon Electrodes, Widsanusan Chartarrayawadee, Simon E. Moulton, Chee O. Too, Byung C. Kim, Rao Yepuri, Anthony C. Romeo, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

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This paper reports on a facile synthesis method for reduced graphene oxide (rGO)/multi-walled carbon nanotubes (MWNTs) nanocomposites. The initial step involves the use of graphene oxide to disperse the MWNTs, with subsequent reduction of the resultant graphene oxide/MWNTs composites using l-ascorbic acid (LAA) as a mild reductant. Reduction by LAA preserves the interaction between the rGO sheets and MWNTs. The dispersion-containing rGO/MWNTs composites was characterized and electrophoretically deposited anodically onto glassy carbon electrodes to form high surface area films for capacitance testing. Pseudo capacitance peaks were observed in the rGO/MWNTs composite electrodes, resulting in superior performance with capacitance values up …

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Flexible Supercapacitors - Development Of Bendable Carbon Architectures, Zhiqiang Niu, Lili Liu, Peter C. Sherrell, Jun Chen, Xiaodong Chen

Australian Institute for Innovative Materials - Papers

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As energy storage devices, Supercapacitors (SCs), also known as electrochemical capacitors, possess high power densities, excellent reversibility and long cycle life. SCs could be applied to diverse fields including electric vehicles, pulse power applications and portable devices. Flexible SCs have attracted significant attention for powering recently developed portable, flexible and wearable electronics. During the past several years, a variety of bendable carbon-based electrode architechtures and flexible SC devices with different designs have been successfully prepared. In this review, we will describe recent developments in the preparation of such bendable carbon-based electrode architechtures and the subsequent design of flexible SC devices. …

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Flexible Cellulose Based Polypyrrole-Multiwalled Carbon Nanotube Films For Bio-Compatible Zinc Batteries Activated By Simulated Body Fluids, Sha Li, Zai Ping Guo, Cai Yun Wang, Gordon G. Wallace, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

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This work aims to develop biocompatible non-toxic materials for implantable bio-electronic cells. Polypyrrole (PPy)–carbon nanotube (CNT) composites with varied ratios of PPy to CNTs were chemically synthesized and used as cathodes with the support of cellulose paper. Zinc foil was used as the anode material due to its non-toxicity and moderate dissolution rate in aqueous solutions. Simulated body fluids (SBFs) with various protein concentrations were applied as electrolytes in this battery system. The PPy–CNT|Zn cell is capable of being discharged up to 24.5 hours at a current density of 60 μA cm⁻² in a protein free SBF. The batteries …

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Simply Mixed Commercial Red Phosphorus And Carbon Nanotube Composite With Exceptionally Reversible Sodium-Ion Storage, Wei-Jie Li, Shulei Chou, Jia-Zhao Wang, Hua-Kun Liu, S X. Dou

Australian Institute for Innovative Materials - Papers

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Recently, sodium ion batteries (SIBs) have been given intense attention because they are the most promising alternative to lithium ion batteries for application in renewable power stations and smart grid, owing to their low cost, their abundant natural resources, and the similar chemistry of sodium and lithium. Elemental phosphorus (P) is the most promising anode materials for SIBs with the highest theoretical capacity of 2596 mA h g-1, but the commercially available red phosphorus cannot react with Na reversibly. Here, we report that simply hand-grinding commercial microsized red phosphorus and carbon nanotubes (CNTs) can deliver a reversible capacity of 1675 …

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Carbon Nanotube-Reduced Graphene Oxide Composites For Thermal Energy Harvesting Applications, Mark S. Romano, Na Li, Dennis Antiohos, Joselito M. Razal, Andrew Nattestad, Stephen Beirne, Shaoli Fang, Yongsheng Chen, Rouhollah Jalili, Gordon G. Wallace, Ray Baughman, Jun Chen

Australian Institute for Innovative Materials - Papers

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By controlling the SWNT-rGO electrode composition and thickness to attain the appropriate porosity and tortuosity, the electroactive surface area is maximized while rapid diffusion of the electrolyte through the electrode is maintained. This leads to an increase in exchange current density between the electrode and electrolyte which results in enhanced thermocell performance.

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Nanocomposites Of Silicon And Carbon Derived From Coal Tar Pitch: Cheap Anode Materials For Lithium-Ion Batteries With Long Cycle Life And Enhanced Capacity, Yun-Xiao Wang, Shulei Chou, Hua-Kun Liu, S X. Dou

Australian Institute for Innovative Materials - Papers

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From energy and environmental consideration, an industrial waste product, coal tar pitch (CTP), is used as the carbon source for Si/AC composite. We exploited a facile sintering method to largely scale up Si/amorphous carbon nanocomposite. The composites with 20 wt.% silicon with PVdF binder exhibited stable lithium storage ability for prolonged cycling. The composite anode delivered a capacity of 400.3 mAh g−1 with a high capacity retention of 71.3% after 1000 cycles. Various methods are used to investigate the reason for the outstanding cyclability. The results indicate that the silicon nanoparticles are wrapped by amorphous SiOx and AC in Si/AC …

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Co2 Capture And Gas Separation On Boron Carbon Nanotubes, Qiao Sun, Meng Wang, Zhen Li, Yingying Ma, Aijun Du

Australian Institute for Innovative Materials - Papers

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Concern about the increasing atmospheric CO2 concentration and its impact on the environment has led to increasing attention directed toward finding advanced materials and technologies suited for efficient CO2 capture, storage and purification of clean-burning natural gas. In this letter, we have performed comprehensive theoretical investigation of CO2, N2, CH4 and H2 adsorption on B2CNTs. Our study shows that CO2 molecules can form strong interactions with B2CNTs with different charge states. However, N2, CH 4 and H2 can only form very weak interactions with B 2CNTs. Therefore, the study demonstrates B2CNTs could sever as promising materials for CO2 capture and …

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Highly Uniform Tio2/Sno2/Carbon Hybrid Nanofibers With Greatly Enhanced Lithium Storage Performance, Zunxian Yang, Qing Meng, Zaiping Guo, Xuebin Yu, Tailiang Guo, Rong Zeng

Australian Institute for Innovative Materials - Papers

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Highly uniform, relatively large area TiO2/SnO 2/carbon hybrid nanofibers were synthesized by a simple method based on thermal pyrolysis and oxidation of an as-spun titanium-tin/polyacrylonitrile nanoweb composite in an argon atmosphere. This novel composite features the uniform dispersion and encapsulation of highly uniform nanoscale TiO 2/SnO2 crystals in a porous carbon matrix. The high porosity of the nanofiber composite material, together with the conductive carbon matrix, enhanced the electrochemical performance of the TiO 2/SnO2/carbon nanofiber electrode. The TiO 2/SnO2/carbon nanofiber electrode displays a reversible capacity of 442.8 mA h g-1 for up to 100 cycles, and exhibits excellent rate capability. …

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