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Full-Text Articles in Engineering

Effect Of Acetylation On The Mechanical And Thermal Properties Of Soy Flour Elastomers, Kendra A. Allen, Sarah Cady, David Grewell Sep 2019

Effect Of Acetylation On The Mechanical And Thermal Properties Of Soy Flour Elastomers, Kendra A. Allen, Sarah Cady, David Grewell

Sarah Cady

Biobased fillers were utilized as components in soy-elastomer composites. Soy flour is lightweight, low cost, and high strength, which makes it an ideal alternative to petroleum-derived fillers. However, poor interfacial adhesion and low dispersion within the polymer matrix are limiting factors for composite performance. Soy flour chemically pretreated by acetylation was compounded with synthetic rubber elastomers. In general, soy flour (as received) concentration in the composite is proportional to the ultimate strength. However, soy-elastomer composites with acetylated filler performed similar to the neat elastomer. In addition, the pretreated composite's thermal stability increased and exhibited less phase seperation compared to the …


Polyurethane-Carbon Microfiber Composite Coating For Electrical Heating Of Concrete Pavement Surfaces, Alireza Sassani, Ali Arabzadeh, Halil Ceylan, Sunghwan Kim, Kasthurirangan Gopalakrishnan, Peter C. Taylor, Ali Nahvi Aug 2019

Polyurethane-Carbon Microfiber Composite Coating For Electrical Heating Of Concrete Pavement Surfaces, Alireza Sassani, Ali Arabzadeh, Halil Ceylan, Sunghwan Kim, Kasthurirangan Gopalakrishnan, Peter C. Taylor, Ali Nahvi

Ali Nahvi

Electrically-heated pavements have attracted attention as alternatives to the traditional ice/snow removal practices. Electrically conductive polymer-carbon composite coatings provide promising properties for this application. Based on the concept of joule heating, the conductive composite can be utilized as a resistor that generates heat by electric current and increases the surface temperature to melt the ice and snow on the pavement surface. This research investigates the feasibility of applying an electrically conductive composite coating made with a Polyurethane (PU) binder and micrometer-scale carbon fiber (CMF) filler as the electrical heating materials on the surface of Portland cement concrete (PCC) pavements. PU-CMF …


Open Source Multi-Head 3d Printer For Polymer-Metal Composite Component Manufacturing, J. Laureto, Joshua M. Pearce Mar 2018

Open Source Multi-Head 3d Printer For Polymer-Metal Composite Component Manufacturing, J. Laureto, Joshua M. Pearce

Joshua M. Pearce

As low-cost desktop 3D printing is now dominated by free and open source self-replicating rapid prototype (RepRap) derivatives, there is an intense interest in extending the scope of potential applications to manufacturing. This study describes a manufacturing technology that enables a constrained set of polymer-metal composite components. This paper provides (1) free and open source hardware and (2) software for printing systems that achieves metal wire embedment into a polymer matrix 3D-printed part via a novel weaving and wrapping method using (3) OpenSCAD and parametric coding for customized g-code commands. Composite parts are evaluated from the technical viability of manufacturing …


An Extended Finite Element Method (Xfem) Study On The Effect Of Reinforcing Particles On The Crack Propagation Behavior In A Metal–Matrix Composite, Chang Ye, Jay Shi, Gary J. Cheng Apr 2015

An Extended Finite Element Method (Xfem) Study On The Effect Of Reinforcing Particles On The Crack Propagation Behavior In A Metal–Matrix Composite, Chang Ye, Jay Shi, Gary J. Cheng

Dr. Chang Ye

In this paper, the eXtended Finite Element Method (XFEM) was integrated in ABAQUS to simulate crack propagation and to predict the effect of reinforcing particles to the crack propagation behavior of Al2O3/Al6061 composite materials. It has been demonstrated that, higher reinforcing particle volume fraction leads to improved fatigue resistance and smaller particles size is more effective than larger particles at the same particle volume fraction. The underlying mechanisms of these effects are systematically investigated. The stress fields captured by XFEM during the crack propagation help in understanding the crack propagation behavior during cyclic loading.


Synthesis And Characterization Of Nano-Composite Lead-Free Solder, D. Lin, C. Kuo, T. Srivatsan, M. Petraroli, Guo-Xiang Wang Apr 2015

Synthesis And Characterization Of Nano-Composite Lead-Free Solder, D. Lin, C. Kuo, T. Srivatsan, M. Petraroli, Guo-Xiang Wang

Dr. Guo-Xiang Wang

A series of experiments conducted on a lead-free eutectic solder (Sn-3.5%Ag) have shown that addition of trace amounts of nanometer-sized particles does have an influence on mechanical properties of materials. In this study, three different types of nanoparticles (copper, nickel and iron) were chosen as the reinforcing candidate. For each particulate reinforcement the reflow process was performed under identical cooling conditions. Addition of trace amounts of nano-particles alters the kinetics governing solidification of the composite solder paste while concurrently exerting an influence on microstructural development, particularly the formation and presence of second phases in the solidified end product. The nano-sized …


Effect Of Surface Polarity On Wettability And Friction Coefficient Of Silicone Rubber/Poly(Acrylic Acid) Hydrogel Composite, Saeid Kheirandish, Esmaiel Jabbari Jan 2015

Effect Of Surface Polarity On Wettability And Friction Coefficient Of Silicone Rubber/Poly(Acrylic Acid) Hydrogel Composite, Saeid Kheirandish, Esmaiel Jabbari

Esmaiel Jabbari

No abstract provided.


The Development Of Conductive Composite Surfaces By A Diffusion-Limited In Situ Polymerization Of Pyrrole In Sulfonated Polystyrene Ionomers, M. Cristina De Jesus, Robert Weiss, Yuping Chen Jul 2014

The Development Of Conductive Composite Surfaces By A Diffusion-Limited In Situ Polymerization Of Pyrrole In Sulfonated Polystyrene Ionomers, M. Cristina De Jesus, Robert Weiss, Yuping Chen

Robert Weiss

Electrically conductive composite surfaces were prepared by a diffusion-controlled in situ polymerization of pyrrole in the surface layer of sulfonated polystyrene ionomer films. Premolded films of the ionomer sulfonic acid derivatives were sequentially immersed in aqueous solutions of pyrrole and FeCl3, and polymerization occurred only where both the monomer and the oxidant were present. The penetration of the polypyrrole (PPy) into the film was controlled by varying the immersion time in the monomer solution. The amount of PPy produced depended on the immersion time of the film in the monomer and the degree of sulfonation of the ionomer. Surface conductivities …


In Situ Polymerization Of Aniline Within Lightly Sulfonated Polystyrene, Yueping Fu, Robert Weiss Jul 2014

In Situ Polymerization Of Aniline Within Lightly Sulfonated Polystyrene, Yueping Fu, Robert Weiss

Robert Weiss

Highly conductive polyaniline/sulfonated polystyrene (PANI/HSPS) composites were synthesized by in situ polymerization of aniline within HSPS matrixes. The amount of polyaniline, the conductivity and the morphology of the composite films depend on the sulfonation level of HSPS and the immersion time in the aniline solution. A maximum conductivity of 0.1 S/cm and high transmittance of 80% (at 460–680 nm) have been achieved.


Wet-Spinning Of Pedot:Pss/Functionalized-Swnts Composite: A Facile Route Toward Production Of Strong And Highly Conducting Multifunctional Fibers, Rouhollah Jalili, Joselito M. Razal, Gordon G. Wallace Mar 2014

Wet-Spinning Of Pedot:Pss/Functionalized-Swnts Composite: A Facile Route Toward Production Of Strong And Highly Conducting Multifunctional Fibers, Rouhollah Jalili, Joselito M. Razal, Gordon G. Wallace

Gordon Wallace

With the aim of fabricating multifunctional fibers with enhanced mechanical properties, electrical conductivity and electrochemical performance, we develop wet-spinning of composite formulation based on functionalized PEG-SWNT and PEDOT:PSS. The method of addition and loading are directly correlated to the quality and the ease of spinnability of the formulation and to the mechanical and electrical properties of the resultant fibers. Both the fiber modulus (Y) and strength (σ) scaled linearly with PEG-SWNT volume fraction (Vf). A remarkable reinforcement rate of dY/dVf = 417 GPa and dσ/dVf = 4 GPa were obtained when PEG-SWNTs at Vf ≤ 0.02. Further increase of PEG-SWNTs …


Exploiting High Quality Pedot:Pss-Swnt Composite Formulations For Wet-Spinning Multifunctional Fibers, Rouhollah Jalili, Joselito M. Razal, Gordon G. Wallace Mar 2014

Exploiting High Quality Pedot:Pss-Swnt Composite Formulations For Wet-Spinning Multifunctional Fibers, Rouhollah Jalili, Joselito M. Razal, Gordon G. Wallace

Gordon Wallace

In order to exploit the inherent properties of carbon nanotubes (CNT) in any polymer composite, systematic control of carbon nanotube loading and protocols that mitigate against CNT bundling are required. If such composites are to be rendered in fiber form via wet-spinning, then CNT bundling during the coagulation process must also be avoided. Here we have achieved this by utilizing highly exfoliated single walled carbon nanotubes (SWNT) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonicacid) (PEDOT:PSS) to obtain wet-spinnable composite formulations at various nanotube volume fractions (Vf). The addition of only 0.02 Vf of aggregate-free and individually dispersed SWNT resulted in a significant enhancement of modulus, …


Direct Synthesis Of Rgo/Cu2o Composite Films On Cu Foil For Supercapacitors, Xiangmao Dong, Kun Wang, Chongjun Zhao, Xiuzhen Qian, Shi Chen, Zhen Li, Hua-Kun Liu, S X. Dou Mar 2014

Direct Synthesis Of Rgo/Cu2o Composite Films On Cu Foil For Supercapacitors, Xiangmao Dong, Kun Wang, Chongjun Zhao, Xiuzhen Qian, Shi Chen, Zhen Li, Hua-Kun Liu, S X. Dou

Shi Xue Dou

Reduced graphene oxide/cuprous oxide (RGO/Cu2O) composite films were directly synthesized on the surface of copper foil substrates through a straight redox reaction between GO and Cu foil via a hydrothermal approach. Characterization of the resultant composites with X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and field emission scanning electron microscope (FESEM) confirms the formation of Cu2O and reduction of GO, in which Cu2O nanoparticles were well covered by RGO. The resultant composites (referred to as RGO/Cu2O/Cu) were directly used as electrodes for supercapacitors, and their electrochemical performance was assessed by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectrometry …


Three-Dimensional-Network Li3v2(Po4) 3/C Composite As High Rate Lithium Ion Battery Cathode Material And Its Compatibility With Ionic Liquid Electrolytes, Jiantie Xu, Shulei Chou, Cuifeng Zhou, Qinfen Gu, Hua-Kun Liu, S X. Dou Mar 2014

Three-Dimensional-Network Li3v2(Po4) 3/C Composite As High Rate Lithium Ion Battery Cathode Material And Its Compatibility With Ionic Liquid Electrolytes, Jiantie Xu, Shulei Chou, Cuifeng Zhou, Qinfen Gu, Hua-Kun Liu, S X. Dou

Shi Xue Dou

A high performance Li3V2(PO4)3 cathode material for lithium ion batteries was synthesized by the microwave-assisted hydrothermal method followed by a post annealing process. The synchrotron X-ray diffraction analysis results confirmed that single-phase Li3V2(PO4)3 with monoclinic structure was obtained. Scanning electron microscope and transmission electron microscope images revealed that the as-prepared Li3V 2(PO4)3 was composed of nanowires and microsized particles. Electrochemical results demonstrated that the Li 3V2(PO4)3 electrode measured at 10 C after 500 cycles can deliver discharge capacities of 85.4 mAh g-1 and 103.4 mAh g-1, with a capacity retention of 99.3% and 95.9%, in the voltage ranges of 3.0-4.3 …


Fusion Of Nacre, Mussel, And Lotus Leaf: Bio-Inspired Graphene Composite Paper With Multifunctional Integration, Da Zhong, Qinglin Yang, Lin Guo, S X. Dou, Kesong Liu, Lei Jiang Mar 2014

Fusion Of Nacre, Mussel, And Lotus Leaf: Bio-Inspired Graphene Composite Paper With Multifunctional Integration, Da Zhong, Qinglin Yang, Lin Guo, S X. Dou, Kesong Liu, Lei Jiang

Shi Xue Dou

Multifunctional integration is an inherent characteristic for biological materials with multiscale structures. Learning from nature is an effective approach for scientists and engineers to construct multifunctional materials. In nature, mollusks (abalone), mussels, and the lotus have evolved different and optimized solutions to survive. Here, bio-inspired multifunctional graphene composite paper was fabricated in situ through the fusion of the different biological solutions from nacre (brick-and-mortar structure), mussel adhesive protein (adhesive property and reducing character), and the lotus leaf (self-cleaning effect). Owing to the special properties (self-polymerization, reduction, and adhesion), dopamine could be simultaneously used as a reducing agent for graphene oxide …


Microstructure And Metal-Dielectric Transition Behaviour In A Percolative Al2o3-Fe Composite Via Selective Reduction, Zidong Zhang, Runhua Fan, Zhicheng Shi, Kelan Yan, Zhijia Zhang, Xiaolin Wang, S X. Dou Mar 2014

Microstructure And Metal-Dielectric Transition Behaviour In A Percolative Al2o3-Fe Composite Via Selective Reduction, Zidong Zhang, Runhua Fan, Zhicheng Shi, Kelan Yan, Zhijia Zhang, Xiaolin Wang, S X. Dou

Shi Xue Dou

The electromagnetic (EM) medium plays a key role in many areas, such as communications, stealth technology, etc. Different EM properties are required for different applications. In this paper, we have obtained tunable EM properties in an Al2O3-Fe composite via selective reduction. By adjusting the content of one functional component, the composite shows totally different EM properties, in accordance with the predictions of effective medium theory. Hybrid EM behaviour is obtained near the percolation threshold, which has a close relationship with its microstructure.


Utilising Non-Composite Steel-Concrete-Steel Panels For Protective Structures, A M. Remennikov, S Y. Kong, Brian Uy Oct 2013

Utilising Non-Composite Steel-Concrete-Steel Panels For Protective Structures, A M. Remennikov, S Y. Kong, Brian Uy

Alex Remennikov

A high-performance protective structure utilising non-composite steel-concrete-steel (SCS) sandwich panels for protecting buildings and facilities against close-range detonation of VBIEDs and heavy ve-hicle impacts has been developed. Unlike other existing composite sandwich panels, no shear connec-tors between the steel faceplates are utilised to construct protective panels in order to simplify the con-struction process. The concrete core of the panel is included to provide the mass for increased inertia effects, and the steel faceplates are designed to develop tensile membrane resistance at large displace-ment to dissipate impulsive energy. The energy dissipation capability and high ductility of the axially-restrained non-composite SCS panels …


The Response Of Axially Restrained Non-Composite Steel-Concrete-Steel Sandwich Panels Due To Large Impact Loading, Alex M. Remennikov, Sih Ying Kong, Brian Uy Oct 2013

The Response Of Axially Restrained Non-Composite Steel-Concrete-Steel Sandwich Panels Due To Large Impact Loading, Alex M. Remennikov, Sih Ying Kong, Brian Uy

Alex Remennikov

In conventional steel-concrete-steel (SCS) construction, the external steel plates are connected to the concrete infill by welded shear stud connectors. This paper describes a programme of experimental and numerical investigations on reduced-scale non-composite SCS panels with axially restrained connections. The experimental results have demonstrated that the non-composite SCS panels are capable of developing enhanced load-carrying capacity through the tensile membrane resistance of the steel faceplates. This type of construction was found to exhibit highly ductile response and be able to sustain large end rotations of up to 18° without collapse. High fidelity finite element models for SCS panels under impact …


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 Jul 2013

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

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: …


Silicon/Single-Walled Carbon Nanotube Composite Paper As A Flexible Anode Material For Lithium Ion Batteries, Shulei Chou, Yue Zhao, Jiazhao Wang, Zhixin Chen, Hua-Kun Liu, S. X. Dou Jun 2013

Silicon/Single-Walled Carbon Nanotube Composite Paper As A Flexible Anode Material For Lithium Ion Batteries, Shulei Chou, Yue Zhao, Jiazhao Wang, Zhixin Chen, Hua-Kun Liu, S. X. Dou

Shi Xue Dou

Flexible silicon/single-walled carbon nanotube (Si/SWCNT) composite paper was prepared using the pulsed laser deposition (PLD) method to deposit Si onto SWCNT paper. In the composite, Si mainly shows nanoworm-like morphology. Increasing deposition time results in an increased amount of Si microspheres. Electrochemical measurements show that the capacity of the composite paper is improved by the presence of Si. The Si/SWCNT composite with only 2.2% Si shows a capacity of 163 mA h g−1 at a current density of 25 mA g−1 up to 50 cycles, which is more than 60% improvement of the capacity of pristine CNT paper. The Si …


Ybco Coated Conductor Using Biaxially Textured Clad Composite Ni-Mn/Ni-Cr Substrate, D Q. Shi, S X. Dou, R. K. Ko, J K. Chung, H S. Kim, H S. Ha, K J. Song, C. Park Jun 2013

Ybco Coated Conductor Using Biaxially Textured Clad Composite Ni-Mn/Ni-Cr Substrate, D Q. Shi, S X. Dou, R. K. Ko, J K. Chung, H S. Kim, H S. Ha, K J. Song, C. Park

Shi Xue Dou

A new biaxially textured composite tape of Ni–4.5% Mn/Ni–1.5% Cr was used as a substrate for a YBCO coated conductor through the RABiTS approach. Multi-layer CeO2/YSZ/Y2O3 buffer layers and YBCO film were deposited on the substrate by pulsed laser deposition. The deposition conditions of the buffer layers and the YBCO were studied and compared. Good biaxial textures have been obtained for buffer layers on composite Ni–4.5% Mn/Ni–1.5% Cr substrates. Scanning electron microscopy on sample cross-sections was used to examine the interface and diffusion of oxygen. The uniform formation of an Ni–Mn–O layer between NiO and the Ni–4.5% Mn layer was …


Preparation And Characterisation Of Graphene Composite Hydrogels, Nicholas J. Whiteside, Gordon G. Wallace, Marc In Het Panhuis May 2013

Preparation And Characterisation Of Graphene Composite Hydrogels, Nicholas J. Whiteside, Gordon G. Wallace, Marc In Het Panhuis

Gordon Wallace

Stable dispersions containing graphene and gellan gum are used to form composite films. Incorporation of graphene into the gellan gum matrix results in mechanical reinforcement and electrical conductivity at low and high graphene loading fractions, respectively. Graphene-containing gellan gum hydrogel films are prepared by immersion of composite films in Ca2+ cross-linking solutions. The resulting hydrogels are electrically conducting and exhibit reinforcement compared to the corresponding gellan gum hydrogels. 2013 Elsevier B.V.


Polyaniline And Polyaniline-Carbon Nanotube Composite Fibres As Battery Materials In Ionic Liquid Electrolyte, Caiyun Y. Wang, Vahid Mottaghitalab, Chee O. Too, Geoffrey M. Spinks, G G. Wallace Mar 2013

Polyaniline And Polyaniline-Carbon Nanotube Composite Fibres As Battery Materials In Ionic Liquid Electrolyte, Caiyun Y. Wang, Vahid Mottaghitalab, Chee O. Too, Geoffrey M. Spinks, G G. Wallace

Gordon Wallace

New battery materials are presented that consist of either a solid polyaniline (PANi) fibre or the same fibre containing carbon nanotubes (CNTs). An ionic liquid ethylmethyl imidazolium bis(trifluoromethanesulfonyl) amide (EMI.TFSA) is used as electrolyte. The electrochemical properties of PANi and PANi/CNT fibres are investigated by means of cyclic voltammetry, a.c. impedance and galvanostatic charge–discharge techniques. A PANi fibre with a CNT content of 0.25 wt.% exhibits a discharge capacity of 12.1 mAh g−1.


Flexible Free-Standing Graphene-Silicon Composite Film For Lithium-Ion Batteries, Jiazhao Wang, Chao Zhong, Shulei Chou, Hua Liu Feb 2013

Flexible Free-Standing Graphene-Silicon Composite Film For Lithium-Ion Batteries, Jiazhao Wang, Chao Zhong, Shulei Chou, Hua Liu

Shulei Chou

Flexible, free-standing, paper-like, graphene-silicon composite materials have been synthesized by a simple, one-step, in-situ filtration method. The Si nanoparticles are highly encapsulated in a graphene nanosheet matrix. The electrochemical results show that graphene-Si composite film has much higher discharge capacity beyond 100 cycles (708 mAh g− 1) than that of the cell with pure graphene (304 mAh g− 1). The graphene functions as a flexible mechanical support for strain release, offering an efficient electrically conducting channel, while the nanosized silicon provides the high capacity.


Silicon/Single-Walled Carbon Nanotube Composite Paper As A Flexible Anode Material For Lithium Ion Batteries, Shulei Chou, Yue Zhao, Jiazhao Wang, Zhixin Chen, Hua-Kun Liu, S. X. Dou Nov 2012

Silicon/Single-Walled Carbon Nanotube Composite Paper As A Flexible Anode Material For Lithium Ion Batteries, Shulei Chou, Yue Zhao, Jiazhao Wang, Zhixin Chen, Hua-Kun Liu, S. X. Dou

Shulei Chou

Flexible silicon/single-walled carbon nanotube (Si/SWCNT) composite paper was prepared using the pulsed laser deposition (PLD) method to deposit Si onto SWCNT paper. In the composite, Si mainly shows nanoworm-like morphology. Increasing deposition time results in an increased amount of Si microspheres. Electrochemical measurements show that the capacity of the composite paper is improved by the presence of Si. The Si/SWCNT composite with only 2.2% Si shows a capacity of 163 mA h g−1 at a current density of 25 mA g−1 up to 50 cycles, which is more than 60% improvement of the capacity of pristine CNT paper. The Si …


Nanocrystalline Porous A-Life02-C Composite-An Environmentally Friendly Cathode For The Lithium-Ion Battery, Md Mokhlesur Rahman, Jiazhao Wang, Mohd Faiz Hassan, Shulei Chou, Zhixin Chen, Hua Liu Nov 2012

Nanocrystalline Porous A-Life02-C Composite-An Environmentally Friendly Cathode For The Lithium-Ion Battery, Md Mokhlesur Rahman, Jiazhao Wang, Mohd Faiz Hassan, Shulei Chou, Zhixin Chen, Hua Liu

Shulei Chou

A novel nanocrystalline porous α-LiFeO2–C composite with a high surface area of around 115 m2 g−1 has been synthesized by a simple molten salt method, followed by a carbon coating process. The structure and morphology were confirmed by X-ray diffraction, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). FE-SEM observations demonstrated that the morphology consists of α-LiFeO2–C nanoclusters composed of very tiny nanoparticles joined together by a porous architecture. TEM investigations revealed that amorphous carbon was incorporated into the pores among the nanoparticles and that some nanoparticles were covered by a thin layer of carbon as well. …


Enhanced Reversible Lithium Storage In A Nanosize Silicon/Graphene Composite, Shulei Chou, Jiazhao Wang, Mohammad Choucair, Hua Liu, John Stride, S Dou Nov 2012

Enhanced Reversible Lithium Storage In A Nanosize Silicon/Graphene Composite, Shulei Chou, Jiazhao Wang, Mohammad Choucair, Hua Liu, John Stride, S Dou

Shulei Chou

Si/graphene composite was prepared by simply mixing of commercially available nanosize Si and graphene. Electrochemical tests show that the Si/graphene composite maintains a capacity of 1168 mAh g-1 and an average coulombic efficiency of 93% up to 30 cycles. EIS indicates that the Si/graphene composite electrode has less than 50% of the charge-transfer resistance compared with nanosize Si electrode, evidencing the enhanced ionic conductivity of Si/graphene composite. The enhanced cycling stability is attributed to the fact that the Si/graphene composite can accommodate large volume charge of Si and maintain good electronic contact.


The Compatibility Of Transition Metal Oxide/Carbon Composite Anode And Ionic Liquid Electrolyte For The Lithium-Ion Battery, Shulei Chou, Lin Lu, Jiazhao Wang, Md Mokhlesur Rahman, Chao Zhong, Hua Liu Nov 2012

The Compatibility Of Transition Metal Oxide/Carbon Composite Anode And Ionic Liquid Electrolyte For The Lithium-Ion Battery, Shulei Chou, Lin Lu, Jiazhao Wang, Md Mokhlesur Rahman, Chao Zhong, Hua Liu

Shulei Chou

Three types of transition metal oxide/carbon composites including Fe2O3/C, NiO/C and CuO/Cu2O/C synthesized via spray pyrolysis were used as anode for lithium ion battery application in conjunction with two types of ionic liquid: 1 M LiN(SO2CF3)2 (LiTFSI) in 1-ethyl-3-methyl-imidazolium bis(fluorosulfonlyl)imide (EMI-FSI) or 1-methyl-1-propylpyrrolidinium bis(fluorosulfonyl)imide (Py13-FSI). From the electrochemical measurements, the composite electrodes using Py13-FSI as electrolyte show much better electrochemical performance than those using EMI-FSI as electrolyte in terms of reversibility. The Fe2O3/C composite shows the highest specific capacity and the best capacity retention (425 mAh g−1) under a current density of 50 mA g−1 for up to 50 cycles, …


Sno2-Coated Multiwall Carbon Nanotube Composite Anode Materials For Rechargeable Lithium-Ion Batteries, Lukman Noerochim, Jiazhao Wang, Shulei Chou, Huijun Li, Hua Liu Nov 2012

Sno2-Coated Multiwall Carbon Nanotube Composite Anode Materials For Rechargeable Lithium-Ion Batteries, Lukman Noerochim, Jiazhao Wang, Shulei Chou, Huijun Li, Hua Liu

Shulei Chou

SnO2-coated multiwall carbon nanotube (MWCNT) nanocomposites were synthesized by a facile hydrothermal method. The as-prepared nanocomposites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The SnO2/MWCNT composites, when combined with carboxymethyl cellulose (CMC) as a binder, show excellent cyclic retention, with the high specific capacity of 473 mAh g−1 beyond 100 cycles, much greater than that of the bare SnO2 which was also prepared by the hydrothermal method in the absence of MWCNTs. The enhanced capacity retention could be mainly attributed to …


One-Step Spray Pyrolysis Synthesized Cuo-Carbon Composite Combined With Carboxymethyl Cellulose Binder As Anode For Lithium-Ion Batteries, Chao Zhong, Jia-Zhao Wang, Xuan-Wen Gao, Shulei Chou, Konstantin Konstantinov, Hua Liu Nov 2012

One-Step Spray Pyrolysis Synthesized Cuo-Carbon Composite Combined With Carboxymethyl Cellulose Binder As Anode For Lithium-Ion Batteries, Chao Zhong, Jia-Zhao Wang, Xuan-Wen Gao, Shulei Chou, Konstantin Konstantinov, Hua Liu

Shulei Chou

Copper oxide-carbon composite with hollow sphere structure has been synthesized by a one-step spray pyrolysis method and tested as anode material for lithium-ion batteries. Different analytical methods, including X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray spectrometry, thermogravimetric analysis, and systematic electrochemical tests were performed. The results demonstrate that the CuO-carbon composite in conjunction with carboxymethyl cellulose (CMC) binder has an excellent electrochemical performance, with a capacity of 577 mAh g-1 up to 100 cycles. The usage of the water soluble binder, CMC, not only obviously improves the electrochemical performance, but also makes the electrode fabrication process much easier and …


Graphene V2o5 Nh2o Xerogel Composite Cathodes For Lithium Ion Batteries, Guodong Du, Kuok Hau Seng, Zaiping Guo, Jun Liu, Wenxian Li, D Z. Jia, Christopher D. Cook, Z Liu, Hua-Kun Liu Aug 2012

Graphene V2o5 Nh2o Xerogel Composite Cathodes For Lithium Ion Batteries, Guodong Du, Kuok Hau Seng, Zaiping Guo, Jun Liu, Wenxian Li, D Z. Jia, Christopher D. Cook, Z Liu, Hua-Kun Liu

Christopher Cook

A layer structured V2O5·nH2O xerogel was synthesized via a simple green hydrothermal technique by dissolving commercial V2O5 powder in de-ionized water and hydrogen peroxide. Graphene–V2O5·nH2O xerogel composites were then prepared by mixing and filtration of as-prepared V2O5·nH2O xerogel and graphene in the desired ratio. The method is a cost effective and energy saving way to prepare nanostructured composites. Structure and morphology were investigated by X-ray diffraction, thermogravimetric analysis, field emission scanning electron microscopy, and transmission electron microscopy. Heat treatment at different temperatures could yield V2O5·nH2O xerogels with different amounts of crystal water, and the presence of graphene in the composites …


Hollow Hematite Nanosphere/Carbon Nanotube Composite: Mass Production And Its High-Rate Lithium Storage Properties, Shulei Chou, Jiazhao Wang, Zhixin Chen, Hua Liu, S. Dou May 2012

Hollow Hematite Nanosphere/Carbon Nanotube Composite: Mass Production And Its High-Rate Lithium Storage Properties, Shulei Chou, Jiazhao Wang, Zhixin Chen, Hua Liu, S. Dou

Shulei Chou

Spray pyrolysis was used to produce hollow hematite (α-Fe(2)O(3)) nanosphere (HHNS)/carbon nanotube (CNT) composite on a large scale. The method offers simplicity, high productivity, versatility, low cost, and suitability for industry. The structure is composed of hollow nanospheres in a network of CNTs. The possible formation mechanism of hollow α-Fe(2)O(3) nanospheres is due to the rapid evaporation of water and the super-hydrophobicity of the CNT surface. The electrochemical tests show that the HHNS/CNT composite is a promising lithium storage material in terms of high capacity (∼700 mAh g(-1)), good high-rate capability, and good cycle life (up to 150 cycles). The …