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Articles 1 - 25 of 25
Full-Text Articles in Engineering
Plasma Ion Source, Nathan K. Davis
Plasma Ion Source, Nathan K. Davis
Student Research Symposium
It is well known that a plasma can be created with both high input power and ultra low pressure. The challenge is in creating these same plasma characteristics with both lower power while maintaining a higher pressure. We have developed an ion beam by careful manipulation of magnetic and electric fields. Magnetic fields are used to accelerate ambient electrons to ionize the low pressure gas into a plasma. Electric fields are used to extract the ions into a focused beam. To achieve these initial ionizations, an artificial vacuum is created to reach low enough pressures to ionize the gas. A …
Centrifugally-Spun Ceramic/Carbon Composite Fibers And Their Use As Anode Materials In Li-Ion Batteries, Gabriel Gonzalez
Centrifugally-Spun Ceramic/Carbon Composite Fibers And Their Use As Anode Materials In Li-Ion Batteries, Gabriel Gonzalez
Theses and Dissertations
The work in this thesis focuses in the study of Centrifugally Spun Short Fiber Composites and their Implementation as Alternate Anode Material in Li-Ion Batteries. Due to their high theoretical capacity, abundance, and environmental friendliness, metal oxides have been widely studied as alternate anode materials for lithium ion batteries (LIBs). In this research work, the processing of SnO2 and SnO2/TiO2 ceramic short fibers as well as flexible and porous metal oxide carbon fibers (FPMOCFs) by centrifugal spinning followed by an optimized coating technique is reported. In addition, the electrochemical performance of the composites was also investigated and is provided.
Carbon-Based Artificial Sei Layers For Aqueous Lithium-Ion Battery Anodes, Usha Subramanya, Charleston Chua, Victor Gin He Leong, Ryan Robinson, Gwenlyn Cruz Cabiltes, Prakirti Singh, Bonnie Yip, Anuja Bokare, Folarin Erogbogbo, Dahyun Oh
Carbon-Based Artificial Sei Layers For Aqueous Lithium-Ion Battery Anodes, Usha Subramanya, Charleston Chua, Victor Gin He Leong, Ryan Robinson, Gwenlyn Cruz Cabiltes, Prakirti Singh, Bonnie Yip, Anuja Bokare, Folarin Erogbogbo, Dahyun Oh
Faculty Publications
Replacing flammable organic electrolytes with aqueous electrolytes in lithium-ion batteries (LIB) can greatly enhance the safety of next-generation energy storage systems. With the extended electrochemical stability window of electrolytes, 'water-in-salt' (WIS) electrolytes containing LIB presented significant performance improvements. However, the solubility limits of lithium salts in water restrain the extent of kinetic protection offered by the high salt concentration. Here, we report design strategies of anode structure to improve the cycle life of LIB with WIS electrolytes. We introduced partially graphitic protective carbon layers on anode particles using a versatile coating method. This protective layer not only improved charge transfer …
In Situ Fabrication Of Branched Tio2/C Nanofibers As Binder‐Free And Free‐Standing Anodes For High‐Performance Sodium‐Ion Batteries, Ling Wang, Guorui Yang, Jianan Wang, Silan Wang, Caiyun Wang, Shengjie Peng, Wei Yan, Seeram Ramakrishna
In Situ Fabrication Of Branched Tio2/C Nanofibers As Binder‐Free And Free‐Standing Anodes For High‐Performance Sodium‐Ion Batteries, Ling Wang, Guorui Yang, Jianan Wang, Silan Wang, Caiyun Wang, Shengjie Peng, Wei Yan, Seeram Ramakrishna
Australian Institute for Innovative Materials - Papers
Herein, 1D free-standing and binder-free hierarchically branched TiO2/C nanofibers (denoted as BT/C NFs) based on an in situ fabrication method as an anode for sodium-ion batteries are reported. The in situ fabrication endows this material with large surface area and strong structural stability, providing this material with abundant active sites and smooth channels for fast ion transportation. As a result, BT/C NFs with the character of free-standing membranes are directly used as binder-free anode for sodium-ion batteries, delivering a capacity of 284 mA h g−1 at a current density of 200 mA g−1 after 1000 cycles. Even at a high …
Processing-Property-Structure Relationships Of Carbonaceous Materials Derived From Renewable Lignin Products, Valerie García-Negrón
Processing-Property-Structure Relationships Of Carbonaceous Materials Derived From Renewable Lignin Products, Valerie García-Negrón
Masters Theses
Efforts to effectively use lignin, a by-product of paper and biofuels production, have been carried out for several decades. This renewable resource has potential for use as a carbonaceous material due to its aromatic structure and high carbon content, reminiscent of graphite. The search for new carbon-based materials is extremely active, because they are necessary components in many applications, such as energy storage, electronics, catalysis, and lubricants. Traditional carbon-based materials are derived or mined from petroleum or coal, thus, contributing to pollution, national security risks, and anthropogenic climate change. Lignin, a carbon-rich component found in the tissues of vascular plants, …
Investigation Of Electric Field–Induced Structural Changes At Fe-Doped Srtio3 Anode Interfaces By Second Harmonic Generation, David Ascienzo, Haochen Yuan, Steven Greenbaum, Thorsten J. Bayer, Russell A. Maier, Jian-Jun Wang, Clive A. Randall, Elizabeth C. Dickey, Haibin Zhao, Yuhang Ren
Investigation Of Electric Field–Induced Structural Changes At Fe-Doped Srtio3 Anode Interfaces By Second Harmonic Generation, David Ascienzo, Haochen Yuan, Steven Greenbaum, Thorsten J. Bayer, Russell A. Maier, Jian-Jun Wang, Clive A. Randall, Elizabeth C. Dickey, Haibin Zhao, Yuhang Ren
Publications and Research
We report on the detection of electric field–induced second harmonic generation (EFISHG) from the anode interfaces of reduced and oxidized Fe-doped SrTiO3 (Fe:STO) single crystals. For the reduced crystal, we observe steady enhancements of the susceptibility components as the imposed dc-voltage increases. The enhancements are attributed to a field-stabilized electrostriction, leading to Fe:Ti-O bond stretching and bending in Fe:Ti-O6 octahedra. For the oxidized crystal, no obvious structural changes are observed below 16 kV/cm. Above 16 kV/cm, a sharp enhancement of the susceptibilities occurs due to local electrostrictive deformations in response to oxygen vacancy migrations away from the anode. Differences between …
Forcespinning: A New Method For The Mass Production Of Sn/C Composite Nanofiber Anodes For Lithium Ion Batteries, Victor Agubra, Luis Zuniga, David De La Garza, Luis Gallegos, Madhab Pokhrel, Mataz Alcoutlabi
Forcespinning: A New Method For The Mass Production Of Sn/C Composite Nanofiber Anodes For Lithium Ion Batteries, Victor Agubra, Luis Zuniga, David De La Garza, Luis Gallegos, Madhab Pokhrel, Mataz Alcoutlabi
Chemistry Faculty Publications and Presentations
The development of nanostructured anode materials for rechargeable Lithium-ion Batteries has seen a growing interest. We herein report the use of a new scalable technique, Forcespinning (FS) to produce binder-free porous Sn/C composite nanofibers with different Sn particle size loading. The preparation process involves the FS of Sn/PAN precursor nanofibers and subsequently stabilizing in air at 280 °C followed by carbonization at 800 °C under an inert atmosphere. The Sn/C composite nanofibers are highly flexible and were directly used as binder-free anodes for lithium-ion batteries. The produced Sn/C composite nanofibers showed an improved discharge capacity of about 724 mA …
Enhanced Cycle Life And Capacity Retention Of Iron Oxide Ultrathin Film Coated Sno₂ Nanoparticles At High Current Densities, Sai Abhishek Palaparty, Rajankumar L. Patel, Xinhua Liang
Enhanced Cycle Life And Capacity Retention Of Iron Oxide Ultrathin Film Coated Sno₂ Nanoparticles At High Current Densities, Sai Abhishek Palaparty, Rajankumar L. Patel, Xinhua Liang
Chemical and Biochemical Engineering Faculty Research & Creative Works
Tin oxide (SnO2) has a high theoretical capacity (∼782 mA h g-1), but it experiences large volume changes during charge and discharge cycles that cause rapid capacity fade, which limits its practical use as an anode material. In an attempt to solve this, we coated these particles with ultrathin electrochemically active iron oxide (FeOx) films that act as an artificial solid electrolyte interphase layer, thus stabilizing the SnO2 particles for better longevity of significantly improved performance at high current densities in a practical voltage window. Since there exists a tradeoff between species transport …
Confined Sno2 Quantum-Dot Clusters In Graphene Sheets As High-Performance Anodes For Lithium-Ion Batteries, Chengling Zhu, Shenmin Zhu, Kai Zhang, Zeyu Hui, Hui Pan, Zhixin Chen, Yao Li, Di Zhang, Dawei Wang
Confined Sno2 Quantum-Dot Clusters In Graphene Sheets As High-Performance Anodes For Lithium-Ion Batteries, Chengling Zhu, Shenmin Zhu, Kai Zhang, Zeyu Hui, Hui Pan, Zhixin Chen, Yao Li, Di Zhang, Dawei Wang
Faculty of Engineering and Information Sciences - Papers: Part A
Construction of metal oxide nanoparticles as anodes is of special interest for next-generation lithium-ion batteries. The main challenge lies in their rapid capacity fading caused by the structural degradation and instability of solid-electrolyte interphase (SEI) layer during charge/discharge process. Herein, we address these problems by constructing a novel-structured SnO2-based anode. The novel structure consists of mesoporous clusters of SnO2 quantum dots (SnO2 QDs), which are wrapped with reduced graphene oxide (RGO) sheets. The mesopores inside the clusters provide enough room for the expansion and contraction of SnO2 QDs during charge/discharge process while the integral structure …
Secondary Current Distributions Using Topaz2d And Linear Kinetics, E. C. Dimpault-Darcy, Ralph E. White
Secondary Current Distributions Using Topaz2d And Linear Kinetics, E. C. Dimpault-Darcy, Ralph E. White
Ralph E. White
Secondary current density distributions are of interest
to cell designers. The purpose of this note is to illustrate
how to use an existing numerical method to determine
these distributions for cells that contain conducting and
nonconducting bodies between the main anode and cathode.
Secondary Current Distributions Using Topaz2d And Linear Kinetics, E. C. Dimpault-Darcy, Ralph E. White
Secondary Current Distributions Using Topaz2d And Linear Kinetics, E. C. Dimpault-Darcy, Ralph E. White
Ralph E. White
Secondary current density distributions are of interestto cell designers. The purpose of this note is to illustratehow to use an existing numerical method to determinethese distributions for cells that contain conducting andnonconducting bodies between the main anode and cathode.
Phase-Control Of A Rising Sun Magnetron Using A Modulated, Addressable, Current Source, Sulmer Fernandez-Gutierrez, Jim Browning, Ming-Chieh Lin, David N. Smithe, Jack Watrous
Phase-Control Of A Rising Sun Magnetron Using A Modulated, Addressable, Current Source, Sulmer Fernandez-Gutierrez, Jim Browning, Ming-Chieh Lin, David N. Smithe, Jack Watrous
Electrical and Computer Engineering Faculty Publications and Presentations
It has been proposed that the use of gated field emitters with a faceted cathode in place of the conventional thermionic cathode could be used to control the current injection in a magnetron, both temporally and spatially. In this work, this concept is studied using the particle-in-cell code VORPAL. The magnetron studied is a ten-cavity, rising sun magnetron, which can be modeled easily using a 2D simulation. The magnetron has a ten-sided faceted cathode. The electrons are injected from three emitter elements on each of the ten facets. Each emitter is turned ON and OFF in sequence at the oscillating …
Spatially-Confined Lithiation-Delithiation In Highly Dense Nanocomposite Anodes Towards Advanced Lithium-Ion Batteries, Yinzhu Jiang, Yong Li, Wenping Sun, Wei Huang, Jiabin Liu, Ben Xu, Chuanhong Jin, Tianyu Ma, Changzheng Wu, Mi Yan
Spatially-Confined Lithiation-Delithiation In Highly Dense Nanocomposite Anodes Towards Advanced Lithium-Ion Batteries, Yinzhu Jiang, Yong Li, Wenping Sun, Wei Huang, Jiabin Liu, Ben Xu, Chuanhong Jin, Tianyu Ma, Changzheng Wu, Mi Yan
Australian Institute for Innovative Materials - Papers
Spatially-confined electrochemical reactions are firstly realized in a highly dense nanocomposite anode for high performance lithium ion batteries. The spatially-confined lithiation-delithiation effectively avoids inter-cluster migration and perfectly retains full structural integrity. Large reversible capacity, high rate capability and superior cycling stability are achieved simultaneously. This spatially-confined lithiation-delithiation offers novel insight to enhance cycling performance of high capacity anode materials.
Integration Of Mno@Graphene With Graphene Networks Towards Li-Ion Battery Anodes, Wei Guo, Xiu Li, Dickon Ng, Jianmin Ma
Integration Of Mno@Graphene With Graphene Networks Towards Li-Ion Battery Anodes, Wei Guo, Xiu Li, Dickon Ng, Jianmin Ma
Australian Institute for Innovative Materials - Papers
In this work, we have directly integrated MnO@graphene with graphene networks through the thermal decomposition of a Mn-oleate complex in an Ar atmosphere at high temperatures. By introducing dual protective graphene shells and networks, the as-synthesized MnO/graphene composites exhibited superior cycling performance.
One-Pot Synthesis Of Ultra-Small Magnetite Nanoparticles On The Surface Of Reduced Graphene Oxide Nanosheets As Anodes For Sodium-Ion Batteries, Shaohua Zhang, Weijie Li, Bien Tan, Shulei Chou, Zhen Li, S X. Dou
One-Pot Synthesis Of Ultra-Small Magnetite Nanoparticles On The Surface Of Reduced Graphene Oxide Nanosheets As Anodes For Sodium-Ion Batteries, Shaohua Zhang, Weijie Li, Bien Tan, Shulei Chou, Zhen Li, S X. Dou
Australian Institute for Innovative Materials - Papers
Nanocomposites with ultra-small magnetite (Fe3O4) nanoparticles (approx. 3 nm) uniformly anchored on the surfaces of reduced graphene oxide (RGO) nanosheets were successfully synthesized for anodes in sodium-ion batteries by a novel single-step high-temperature coprecipitation approach. The best electrode delivers a reversible Na+ storage capacity of 204 mA h g-1 with excellent capacity retention, i.e., 98% of the second-cycle value was retained after 200 cycles.
Simulation Of A Rising Sun Magnetron Employing A Faceted Cathode With A Continuous Current Source, Sulmer Fernandez-Gutierrez, Jim Browning, Ming-Chieh Lin, David N. Smithe, Jack Watrous
Simulation Of A Rising Sun Magnetron Employing A Faceted Cathode With A Continuous Current Source, Sulmer Fernandez-Gutierrez, Jim Browning, Ming-Chieh Lin, David N. Smithe, Jack Watrous
Electrical and Computer Engineering Faculty Publications and Presentations
It has been proposed that gated field emitters could be used in place of conventional thermionic cathodes to control the current injection in a magnetron, both temporally and spatially. Since gated field emitters have to be fabricated on flat surfaces, a faceted cathode would be used to implement this approach. A 2D ten cavity, rising sun magnetron has been modeled using the particle-in-cell code VORPAL. Cylindrical, five-sided, and ten-sided faceted cathodes were modeled to study the variation of magnetron operation due to the cathode shape. This work shows the results of the device performance employing three different cathode geometries with …
Microwave Autoclave Synthesized Multi-Layer Graphene/Single-Walled Carbon Nanotube Composites For Free-Standing Lithium-Ion Battery Anodes, Chao Zhong, Jia-Zhao Wang, David Wexler, Hua-Kun Liu
Microwave Autoclave Synthesized Multi-Layer Graphene/Single-Walled Carbon Nanotube Composites For Free-Standing Lithium-Ion Battery Anodes, Chao Zhong, Jia-Zhao Wang, David Wexler, Hua-Kun Liu
Australian Institute for Innovative Materials - Papers
Multi-layer graphene sheets have been synthesized by a time-efficient microwave autoclave method and used to form composites in situ with single-walled carbon nanotubes. The application of these composites as flexible free-standing film electrodes was then investigated. According to the transmission electron microscopy and X-ray diffraction characterizations, the average d-spacing of the graphene-single-walled carbon nanotube composites was 0.41 nm, which was obviously larger than that of the as-prepared pure graphene (0.36 nm). The reversible Li-cycling properties of the free-standing films have been evaluated by galvanostatic discharge-charge cycling and electrochemical impedance spectroscopy. Results showed that the free-standing composite film with 70 wt% …
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
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
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 …
Quantifying Individual Potential Contributions Of The Hybrid Sulfur Electrolyzer, John A. Staser, Maximilian B. Gorensek, John W. Weidner
Quantifying Individual Potential Contributions Of The Hybrid Sulfur Electrolyzer, John A. Staser, Maximilian B. Gorensek, John W. Weidner
Faculty Publications
The hybrid sulfur cycle has been investigated as a means to produce clean hydrogen efficiently on a large scale by first decomposing H2SO4 to SO2, O2, and H2O and then electrochemically oxidizing SO2 back to H2SO4 with the cogeneration of H2. Thus far, it has been determined that the total cell potential for the hybrid sulfur electrolyzer is controlled mainly by water transport in the cell. Water is required at the anode to participate in the oxidation of SO2 to H2SO4 …
Amorphous Carbon-Coated Silicon Nanocomposites: A Low-Temperature Synthesis Via Spray Pyrolysis And Their Application As High-Capacity Anodes For Lithium-Ion Batteries, See How Ng, Jiazhao Wang, David Wexler, Sau Yen Chew, Hua-Kun Liu
Amorphous Carbon-Coated Silicon Nanocomposites: A Low-Temperature Synthesis Via Spray Pyrolysis And Their Application As High-Capacity Anodes For Lithium-Ion Batteries, See How Ng, Jiazhao Wang, David Wexler, Sau Yen Chew, Hua-Kun Liu
Faculty of Engineering - Papers (Archive)
This article introduces an effective, inexpensive, and industrially oriented approach to produce carbon-coated Si nanocomposites as high-capacity anode materials for use in rechargeable lithium-ion batteries. Initially, nanosized Si particles (nm) were mixed in a citric acid/ethanol solution via ultrasonication. This mixture was further spray-pyrolyzed in air at low processing temperature (300-500 C), resulting in a homogeneous layer of carbon coating on the surface of the spheroidal Si nanoparticles. The effects of the processing temperature on the amorphous carbon content, the thickness of the carbon-coating layer, and the homogeneity of the carbon coating were studied in detail. These parameters strongly influenced …
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
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
Australian Institute for Innovative Materials - Papers
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 …
Anodic Oxidation Of Ethylenediaminetetraacetic Acid On Platinum Electrode In Alkaline Medium, S. N. R. Pakalapati, Branko N. Popov, Ralph E. White
Anodic Oxidation Of Ethylenediaminetetraacetic Acid On Platinum Electrode In Alkaline Medium, S. N. R. Pakalapati, Branko N. Popov, Ralph E. White
Faculty Publications
The anodic oxidation of ethylenediaminetetraacetic acid (EDTA) was studied in alkaline medium on a smooth platinum electrode. Bulk electrolysis indicated that stable organic intermediates (formaldehyde and glyoxal) are formed during the oxidation of EDTA and that complete oxidation to CO2 can be achieved. The proposed pathway suggests that the acetate groups in EDTA are initially oxidized, generating formaldehyde and ethylenediamine. The rest potential of EDTA (0.066 to 0.164 V vs. Hg/HgO) was observed to be higher than for other organic species. In alkaline medium, very little EDTA oxidation was found to occur on bare platinum. Limiting-current behavior due to …
Use Of A Hydrogen Anode For Nitrate Waste Destruction, E. E. Kalu, Ralph E. White, D. T. Hobbs
Use Of A Hydrogen Anode For Nitrate Waste Destruction, E. E. Kalu, Ralph E. White, D. T. Hobbs
Faculty Publications
No abstract provided.
A Modified Electrochemical Process For The Decomposition Of Hydrogen Sulfide In An Aqueous Alkaline Solution, Z. Mao, A. Anani, Ralph E. White, S. Srinivasan, A. J. Appleby
A Modified Electrochemical Process For The Decomposition Of Hydrogen Sulfide In An Aqueous Alkaline Solution, Z. Mao, A. Anani, Ralph E. White, S. Srinivasan, A. J. Appleby
Faculty Publications
An electrochemical process for the decomposition of hydrogen sulfide into its constituents in an aqueous alkaline solution is presented. It essentially consists of presaturation of an alkaline scrubber solution with H2S. Thereafter, partial neutralization of the presaturated solution provides not only the necessary mass balance for electrolysis, but also creates the optimum conditions under which passivation of the anode, as well as side chemical and electrochemical reactions, are minimized. Finally, the electrolysis stage of the process leads to precipitation of crystalline sulfur at the anode and evolution of hydrogen at the cathode. Regeneration of the alkaline solution via …
Secondary Current Distributions Using Topaz2d And Linear Kinetics, E. C. Dimpault-Darcy, Ralph E. White
Secondary Current Distributions Using Topaz2d And Linear Kinetics, E. C. Dimpault-Darcy, Ralph E. White
Faculty Publications
Secondary current density distributions are of interest
to cell designers. The purpose of this note is to illustrate
how to use an existing numerical method to determine
these distributions for cells that contain conducting and
nonconducting bodies between the main anode and cathode.