Physical Sciences and Mathematics Commons^™

Contribution Of Radicals And Ions In Catalyzed Growth Of Single-Walled Carbon Nanotubes From Low-Temperature Plasmas, Z Marvi, S Xu, G Foroutan, Kostya Ostrikov

Australian Institute for Innovative Materials - Papers

The growth kinetics of single-walled carbon nanotubes (SWCNTs) in a low-temperature, low-pressure reactive plasma is investigated using a multiscale numerical simulation, including the plasma sheath and surface diffusion modules. The plasma-related effects on the characteristics of SWCNT growth are studied. It is found that in the presence of reactive radicals in addition to energetic ions inside the plasma sheath area, the effective carbon flux, and the growth rate of SWCNT increase. It is shown that the concentration of atomic hydrogen and hydrocarbon radicals in the plasma plays an important role in the SWCNT growth. The effect of the effective carbon …

One Dimensional Graphitic Carbon Nitrides As Effective Metal-Free Oxygen Reduction Catalysts, Muhammad Nawaz Tahir, Nasir Mahmood, Jinghan Zhu, Asif Mahmood, Faheem K. Butt, Syed Rizwan, Imran Aslam, M Tanveer, Faryal Idrees, Imran Shakir, Chuanbao Cao, Yanglong Hou

Australian Institute for Innovative Materials - Papers

To explore the effect of morphology on catalytic properties of graphitic carbon nitride (GCN), we have studied oxygen reduction reaction (ORR) performance of two different morphologies of GCN in alkaline media. Among both, tubular GCN react with dissolved oxygen in the ORR with an onset potential close to commercial Pt/C. Furthermore, the higher stability and excellent methanol tolerance of tubular GCN compared to Pt/C emphasizes its suitability for fuel cells.

Significantly Enhanced Critical Current Density In Nano-Mgb2 Grains Rapidly Formed At Low Temperature With Homogeneous Carbon Doping, Yongchang Liu, Feng Lan, Zongqing Ma, Ning Chen, Huijun Li, Shaon Barua, Dipakkumar Patel, Md S. Hossain, S Acar, Jung Ho Kim, S X. Dou

Australian Institute for Innovative Materials - Papers

High performance MgB₂ bulks using carbon-coated amorphous boron as a boron precursor were fabricated by Cu-activated sintering at low temperature (600 °C, below the Mg melting point). Dense nano-MgB₂ grains with a high level of homogeneous carbon doping were formed in these MgB₂ samples. This type of microstructure can provide a stronger flux pinning force, together with depressed volatility and oxidation of Mg owing to the low-temperature Cu-activated sintering, leading to a significant improvement of critical current density (J_c) in the as-prepared samples. In particular, the value of J_c for the carbon-coated (Mg …

Efficient, Absorption-Powered Artificial Muscles Based On Carbon Nanotube Hybrid Yarns, Marcio D. Lima, Mohammad W. Hussain, Geoffrey M. Spinks, Sina Naficy, Daniela Hagenasr, Julia S. Bykova, Derrick Tolly, Ray H. Baughman

Australian Institute for Innovative Materials - Papers

A new type of absorption-powered artificial muscle provides high performance without needing a temperature change. These muscles, comprising coiled carbon nanotube fibers infiltrated with silicone rubber, can contract up to 50% to generate up to 1.2 kJ kg⁻¹. The drive mechanism for actuation is the rubber swelling during exposure to a nonpolar solvent. Theoretical energy efficiency conversion can be as high as 16%.

Dual Yolk-Shell Structure Of Carbon And Silica-Coated Silicon For High-Performance Lithium-Ion Batteries, L Y. Yang, H Z. Li, Jun Liu, Ziqi Sun, S S. Tang, M Lei

Australian Institute for Innovative Materials - Papers

Silicon batteries have attracted much attention in recent years due to their high theoretical capacity, although a rapid capacity fade is normally observed, attributed mainly to volume expansion during lithiation. Here, we report for the first time successful synthesis of Si/void/SiO₂/void/C nanostructures. The synthesis strategy only involves selective etching of SiO₂ in Si/SiO₂/C structures with hydrofluoric acid solution. Compared with reported results, such novel structures include a hard SiO₂-coated layer, a conductive carbon-coated layer, and two internal void spaces. In the structures, the carbon can enhance conductivity, the SiO₂ layer has mechanically …

High Acetic Acid Production Rate Obtained By Microbial Electrosynthesis From Carbon Dioxide, Ludovic Jourdin, Timothy Grieger, Juliette Monetti, Victoria Flexer, Stefano Freguia, Yang Lu, Jun Chen, Mark S. Romano, Gordon G. Wallace, Jurg Keller

Australian Institute for Innovative Materials - Papers

High product specificity and production rate are regarded as key success parameters for large-scale applicability of a (bio)chemical reaction technology. Here, we report a significant performance enhancement in acetate formation from CO2, reaching comparable productivity levels as in industrial fermentation processes (volumetric production rate and product yield). A biocathode current density of -102 ± 1 A m-2 and an acetic acid production rate of 685 ± 30 (g m-2 day-1) have been achieved in this study. High recoveries of 94 ± 2% of the CO2 supplied as the sole carbon source and 100 ± 4% of electrons into the final …

Uniform Yolk-Shell Iron Sulfide-Carbon Nanospheres For Superior Sodium-Iron Sulfide Batteries, Yunxiao Wang, Jianping Yang, Shulei Chou, Hua-Kun Liu, Weixian Zhang, Dongyuan Zhao, S X. Dou

Australian Institute for Innovative Materials - Papers

Sodium-metal sulfide battery holds great promise for sustainable and cost-effective applications. Nevertheless, achieving high capacity and cycling stability remains a great challenge. Here, uniform yolk-shell iron sulfide-carbon nanospheres have been synthesized as cathode materials for the emerging sodium sulfide battery to achieve remarkable capacity of ∼545 mA h g-1 over 100 cycles at 0.2 C (100 mA g-1), delivering ultrahigh energy density of ∼438 Wh kg-1. The proven conversion reaction between sodium and iron sulfide results in high capacity but severe volume changes. Nanostructural design, including of nanosized iron sulfide yolks (∼170 nm) with porous carbon shells (∼30 nm) and …

Carbon Fibre Microelectrodes For Neuroscience Applications, Jian Fang, Zhigang Xie, Gordon G. Wallace, Xungai Wang

Australian Institute for Innovative Materials - Papers

Microelectrodes have shown outstanding performance in neural signal recording, neural stimulation and electrochemical sensing1,2. Compared with their micro-sized counterparts, microelectrodes normally exhibit improved signal-to-noise ratio, fast response time and can work with limited sample volumes. Microelectrodes are required to have good biocompatibility, low electrical impedance and long-term stability in many biomedical applications. Carbon fibres are manufactured from polymeric precursor fibres through carbonization, and high carbon content makes carbon fibres electrically conductive, corrosion resistant, biologically safe and inert3. Therefore, carbon fibre has been considered as an ideal candidate for making microelectrodes.

In this work, single carbon fibres were loaded into capillary …

Yolk-Shell Silicon-Mesoporous Carbon Anode With Compact Solid Electrolyte Interphase Film For Superior Lithium-Ion Batteries, Jianping Yang, Yunxiao Wang, Shulei Chou, Renyuan Zhang, Yanfei Xu, Jianwei Fan, Weixian Zhang, Hua-Kun Liu, Dongyuan Zhao, S X. Dou

Australian Institute for Innovative Materials - Papers

Silicon as an electrode suffers from short cycling life, as well as unsatisfactory rate-capability caused by the large volume expansion (~400%) and the consequent structural degradation during lithiation/delithiation processes. Here, we have engineered unique void-containing mesoporous carbon-encapsulated commercial silicon nanoparticles (NPs) in yolk-shell structures. In this design, the silicon NPs yolk are wrapped into open and accessible mesoporous carbon shells, the void space between yolk and shell provides enough room for Si expansion, meanwhile, the porosity of carbon shell enables fast transport of Li+ ions between electrolyte and silicon. Our ex-situ characterization clearly reveals for the first time that a …

A New Strategy For Achieving A High Performance Anode For Lithium Ion Batteries-Encapsulating Germanium Nanoparticles In Carbon Nanoboxes, Dan Li, Hongqiang Wang, Hua-Kun Liu, Zaiping Guo

Australian Institute for Innovative Materials - Papers

A novel strategy to improve the electrochemical performance of a germanium anode is proposed via encapsulating germanium nanoparticles in carbon nanoboxes by carbon coating the precursor, germanium dioxide cubes, and then subjecting them to a reduction treatment. The complete and robust carbon boxes are shown to not only provide extra void space for the expansion of germanium nanoparticles after lithium insertion but also offer a large reactive area and reduced distance for the lithium diffusion. Furthermore, the thus-obtained composite, composed of densely stacked carbon nanoboxes encapsulating germanium nanoparticles (germanium at carbon cubes (Ge at CC)), exhibits a high tap density …

Large-Scale Synthesis Of Ordered Mesoporous Carbon Fiber And Its Application As Cathode Material For Lithium-Sulfur Batteries, Hongqiang Wang, Chaofeng Zhang, Zhixin Chen, Hua-Kun Liu, Zaiping Guo

Australian Institute for Innovative Materials - Papers

A novel type of one-dimensional ordered mesoporous carbon fiber has been prepared via the electrospinning technique by using resol as the carbon source and triblock copolymer Pluronic F127 as the template. Sulfur is then encapsulated in this ordered mesoporous carbon fibers by a simple thermal treatment. The interwoven fibrous nanostructure has favorably mechanical stability and can provide an effective conductive network for sulfur and polysulfides during cycling. The ordered mesopores can also restrain the diffusion of long-chain polysulfides. The resulting ordered mesoporous carbon fiber sulfur (OMCF-S) composite with 63% S exhibits high reversible capacity, good capacity retention and enhanced rate …

Stretchable, Weavable Coiled Carbon Nanotube/Mno2/Polymer Fiber Solid-State Supercapacitors, Changsoon Choi, Shi Hyeong Kim, Hyeon Jun Sim, Jae Ah Lee, A Young Choi, Youn Tae Kim, Xavier Lepro, Geoffrey M. Spinks, Ray H. Baughman, Seon Jeong Kim

Australian Institute for Innovative Materials - Papers

Fiber and yarn supercapacitors that are elastomerically deformable without performance loss are sought for such applications as power sources for wearable electronics, micro-devices, and implantable medical devices. Previously reported yarn and fiber supercapacitors are expensive to fabricate, difficult to upscale, or non-stretchable, which limits possible use. The elastomeric electrodes of the present solid-state supercapacitors are made by using giant inserted twist to coil a nylon sewing thread that is helically wrapped with a carbon nanotube sheet, and then electrochemically depositing pseudocapacitive MnO₂ nanofibers. These solid-state supercapacitors decrease capacitance by less than 15% when reversibly stretched by 150% in the …

Nano-Carbon Electrodes For Thermal Energy Harvesting, Mark S. Romano, Joselito M. Razal, Dennis Antiohos, Gordon G. Wallace, Jun Chen

Australian Institute for Innovative Materials - Papers

Thermogalvanic cells are capable of converting waste heat (generated as a by-product of almost all human activity) to electricity. These devices may alleviate the problems associated with the use of fossil fuels to meet the world's current demand for energy. This review discusses the developments in thermogalvanic systems attained through the use of nano-carbons as the electrode materials. Advances in cell design and electrode configuration that improve performance of these thermo converters and make them applicable in a variety of environments are also summarized. It is the aim of this review to act as a channel for further developments in …

Hierarchically Porous Carbon-Zirconium Carbide Spheres As Potentially Reusable Transmutation Targets, Nicholas Scales, Jun Chen, Tracey L. Hanley, Daniel P. Riley, Gregory R. Lumpkin, Vittorio Luca

Australian Institute for Innovative Materials - Papers

The preparation of hierarchically porous phase-pure carbon-zirconium carbide spheres with surface areas upwards of 70 m²/g and diameters in the 1-2 mm range has been achieved. The zirconium carbide beads were prepared through carbothermal reduction of polyacrylonitrile-zirconium composites prepared via three different routes including infiltration of a zirconium precursor into preformed polyacrylonitrile (PAN) beads and two one-pot co-precipitation methods. Depending on the route used to prepare the composites, relatively high surface area phase-pure zirconium carbides with the radial macroporous internal structure of the PAN template could be prepared. The adsorption of the elements U, Mo, Cs and Sr …

Hollow Carbon Spheres With Encapsulated Germanium As An Anode Material For Lithium Ion Batteries, Dan Li, Chuanqi Feng, Hua-Kun Liu, Zaiping Guo

Australian Institute for Innovative Materials - Papers

A novel composite consisting of hollow carbon spheres with encapsulated germanium (Ge@HCS) was synthesized by introducing a germanium precursor into the porous-structured hollow carbon spheres. The carbon spheres not only function as a scaffold to hold the germanium and thus maintain the structural integrity of the composite, but also increase the electrical conductivity. The voids and vacancies that are formed after the reduction of germanium dioxide to germanium provide free space for accommodating the volume changes during discharging-charging processes, thus preventing pulverization. The obtained Ge@HCS composite exhibits excellent lithium storage performance, as revealed by electrochemical evaluation.