Chemical Engineering Commons^™

Ac Conductivity Studies Of Polyethylene-Oxide-Garnet Type Li7la3zr2o12 Hybrid Composite Solid Polymer Electrolyte For Li-Ion Battery, Parisa Bashiri

Wayne State University Dissertations

Solid electrolytes including ceramics and polymers are considered to be the ultimate substitute for organic liquid electrolytes currently used in commercialized lithium ion batteries to address the safety concerns due to Li dendrite growth and internal short circuiting. However, low ionic conductivity due to high grain boundary resistance in ceramics and semi-crystalline nature of polymers has held back the solid electrolytes from being used in Li-ion batteries. Polyethylene oxide (PEO), complexed with a Li-salt, is a well-studied polymer electrolyte showing ionic conductivity properties at room temperature. However, the coexistence of amorphous and crystalline regions at room temperature (< Tm, the melting temperature) has

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Advanced Electrodes And Electrolytes For Long-Lived And High-Performance Lithium-Sulfur Batteries, Deepesh Gopalakrishnan

Wayne State University Dissertations

ABSTRACT

ADVANCED ELECTRODES AND ELECTROLYTES FOR LONG-LIVED AND HIGH-PERFORMANCE LITHIUM-SULFUR BATTERIES

by

DEEPESH GOPALAKRISHNAN

August 2020

Advisor: Dr. Leela Mohana Reddy Arava

Major: Mechanical Engineering

Degree: Doctor of Philosophy

Lithium – Sulfur (Li-S) batteries have received much attention and considered as a promising candidate for next generation energy storage devices because of their high theoretical energy density (≈2600 Wh kg‒1) and environmental friendliness. However, the uncontrollable growth of lithium dendrites in the lithium metal anode and the fatal effect of polysulfide shuttle hinder their practical applications. The formation of dendrites during repeated Li plating/stripping processes results in: reduced Li availability …

Engineering Of Gold Nanoparticles For Drug Delivery, Fangchao Liu

Wayne State University Dissertations

Due to their ease of synthesis, versatile surface chemistry, ease of imaging, and biocompatibility, gold nanoparticles (AuNPs) are employed as drug delivery devices in the treatment of respiratory problems associated with spinal cord injury (SCI). We have developed a method for the synthesis of a tripartite nanoconjugate comprised of an AuNP drug carrier chemically conjugated to a transporter protein (wheat germ agglutinin coupled to horseradish peroxidase or WGA-HRP) and to potent SCI drugs. The therapeutic efficacy and biodistribution were studied in a validated animal model. Our results show that a single administration of the nanoconjugate improved diaphragmatic activity at a …

Bio-Inspired Synthesis Of Nanostructured Materials On Substrates For Environmental And Energy Applications, Xinghua Meng Meng

Wayne State University Dissertations

It is still a challenging task to develop simple methods for facile synthesis of functional nanostructures on substrates under mild conditions without using expensive instruments. We have successfully developed a bio-inspired method using simple diaphragm-assisted system to synthesize functional nanostructures on various substrates under mild conditions. We have systematically studied the effects of experimental parameters on the formation of nanostructures under controlled conditions. The fundamental mechanism involved has been systematically studied and revealed. By growing the unique networks of nanostructures on a piece of substrate, a double-rough surface, with structures at both nanoscale and microscale, has been achieved, showing interesting …

New Chemistry For The Growth Of First-Row Transition Metal Films By Atomic Layer Deposition, Joseph Peter Klesko

Wayne State University Dissertations

Thin films containing first-row transition metals are widely used in microelectronic, photovoltaic, catalytic, and surface-coating applications. In particular, metallic films are essential for interconnects and seed, barrier, and capping layers in integrated circuitry. Traditional vapor deposition methods for film growth include PVD, CVD, or the use of plasma. However, these techniques lack the requisite precision for film growth at the nanoscale, and thus, are increasingly inadequate for many current and future applications. By contrast, ALD is the favored approach for depositing films with absolute surface conformality and thickness control on 3D architectures and in high aspect ratio features. However, the …

Engineering Gold Nanoparticles And Their Use To Control Nucleation, Pedram Jahanian

Wayne State University Dissertations

This study focuses on fabrication of hybrid nanostructures using gold nanoparticles (AuNP) as seeds and partially oxidized potassium tetracyanoplatinate, known as Krogmann’s salt (KCP), and later this method will be employed to manufacture a prototype sensor for detecting different vapors. Nanocrystals are synthesized using electrochemical method with the aim to have more control over the size and shape of the charge transfer salt based on the seed mediated nucleation method. AuNP seeds are prepared on highly ordered pyrolytic graphite (HOPG) substrate by the electrocrystallization method. An aqueous solution of 0.05 to 1 mM Hydrogen tetrachloroaurate (HAuCl4) with 0.1 mM (Potassium …

Green Diesel Production Via Catalytic Hydrogenation/Decarboxylation Of Triglycerides And Fatty Acids Of Vegetable Oil And Brown Grease, Elvan Sari

Wayne State University Dissertations

Increase in the petroleum prices, projected increases in the world’s energy demand and environmental awareness have shifted the research interest to the alternative fuel technologies. In particular, green diesel, vegetable oil/animal fat/waste oil and grease derived hydrocarbons in diesel boiling range, has become an attractive alternative to biodiesel— a mixture of fatty acid methyl esters, particularly due to its superior fuel properties that are similar to petroleum diesel. Hence, green diesel can be used as a drop-in fuel in the current diesel engines. The current technology for production of green diesel– hydrodeoxygenation of triglycerides and fatty acids over conventional hydrotreating …

Engineering Nanoparticle And Nanoring Patterns For The Study Of Molecular Crystallization Under Nanoconfinement, Sunxi Wang

Wayne State University Dissertations

This dissertation focuses on generating the inorganic nanoparticle/organic nanorod hybrid nanostructures by the strategy of nanoparticle induced molecular crystallization developed by us and the new electrochemical method. We synthesize the gold nanoparticles with different sizes and functional groups and then fabricate the nanohybrids with fatty acid nanorods by spin coating method. Atomic force microscope monitors the topography of the hybrid nanostructures to help understand the underlying mechanism of the crystallization process. This successful self-assembled method could be used to fabricate nanohybrids based on seed-mediated nucleation. Also the novel "nano-flasks" have been generated by particle lithography method, which could be served …

Bioreducible Polymer Nanosystems For Gene Delivery, Yi Zou

Wayne State University Dissertations

This dissertation describes the research of bioreducible polymers for gene delivery. A series of bioreducible poly(amido amine)s (PAAs) were synthesized. They complex with DNA forming polyplex nanoparticles and layer-by-layer (LbL) thin films as gene delivery vectors. Atomic force microscope (AFM), especially in situ real time AFM, provides a microscopic view of DNA release dynamics. It is shown that the depolymerization of bioreducible polymer triggers DNA release via disulfide-thiol exchange reaction. The AFM images revealed a three-stage pathway beginning with a morphological change from metastable nanostructures into the more favorable toroid structure. Then toroids interact with each other by aggregation and …

New Precursors And Chemistry For The Growth Of Transition Metal Films By Atomic Layer Deposition, Thomas Joseph Knisley

Wayne State University Dissertations

The advancing complexity of advanced microelectronic devices is placing rigorous demands on currently used PVD and CVD deposition techniques. The ALD deposition method is proposed to meet the film thickness and conformality constraints needed by the semiconductor industry in future manufacturing processes. Unfortunately, there is a limited number of chemical precursors available that have high thermal stability, reactivity, and vapor pressure suitable for ALD film growth to occur. These properties collectively contribute to the lack of suitable transition metal precursors available for use in ALD. In this thesis, we report the discovery of a series of novel transition metal diazadienate …

Reinforced Chitosan-Based Heart Valve Scaffold And Utility Of Bone Marrow-Derived Mesenchymal Stem Cells For Cardiovascular Tissue Engineering, Mohammad Z. Albanna

Wayne State University Dissertations

Recent research has demonstrated a strong correlation between the differentiation profile of mesenchymal stem cells (MSCs) and scaffold stiffness. Chitosan is being widely studied for tissue engineering applications due to its biocompatibility and biodegradability. However, its use in load-bearing applications is limited due to moderate to low mechanical properties. In this study, we investigated the effectiveness of a fiber reinforcement method for enhancing the mechanical properties of chitosan scaffolds. Chitosan fibers were fabricated using a solution extrusion and neutralization method and incorporated into porous chitosan scaffolds. The effects of different fiber/scaffold mass ratios, fiber mechanical properties and fiber lengths on …