Mechanical Engineering Commons^™

The Effects Of Carbon Coating On The Electrochemical Performance Of Metal-Oxide Short Fiber Anodes For Lithium-Ion Batteries, David A. Sanchez

Theses and Dissertations

This thesis focuses on the process of oxidizing centrifugally spun precursor fibers and the subsequent process of carbon coating via chemical vapor deposition (CVD) for use as anode material in lithium-ion batteries (LIBs). Metal oxides have been studied as a potential replacement for graphite as they have been shown to have high theoretical capacities, good electronic conductivity, and can be synthesized using low-cost, scalable methods. However, metal oxides with high theoretical capacities also have low cycle life. To avoid this, metal oxides have been integrated with carbon to expand their life cycle. The work in this thesis shows the synthesis …

Equations Of State For Warm Dense Carbon From Quantum Espresso, Derek J. Schauss

Theses and Dissertations

Warm dense plasma is the matter that exists, roughly, in the range of 10,000 to 10,000,000 Kelvin and has solid-like densities, typically between 0.1 and 10 grams per centimeter. Warm dense fluids like hydrogen, helium, and carbon are believed to make up the interiors of many planets, white dwarfs, and other stars in our universe. The existence of warm dense matter (WDM) on Earth, however, is very rare, as it can only be created with high-energy sources like a nuclear explosion. In such an event, theoretical and computational models that accurately predict the response of certain materials are thus very …

Lead Doped Carbon Nanofibers In Li-Ion Batteries, Omar Torres

Theses and Dissertations

Lead acid batteries have been a very reliable rechargeable battery since its inception in the mid-1800s. Lithium-Ion batteries have been sought out for their light-weight and capacity of holding large amounts of energy in a small amount of space. Few studies have been conducted in the use of lead in lithium-ion batteries.

In this thesis, lead-doped carbon nanofibers were produced by using the Forcespinning® method and used as an anode on a lithium-ion battery. The morphology, material characterization and thermal properties of the anode material were analyzed using the Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Thermogravimetric Analysis …

Design Of Metal Oxides/Metal Sulfides For The Improvement Of Sodium Ion Batteries, David E. Flores

Theses and Dissertations

Herein, the improvement in performance for sodium ion batteries (NIBs) is discussed from available literature and work conducted in the laboratory setting to demonstrate the ability of sodium to perform in the world of energy storage. The reason that sodium is being explored as an alternative to Lithium in energy storage devices is because of the potential depletion of the lithium in the world causing lithium prices to surge. Researchers show that many Sn, Sb, Ge, and other composites perform well as anode materials within NIBs. The research conducted in the dissertation applies the Forcespinning method to produce fibers for …

Nanocomposite Bioelectronics For Biopotential Enabled Prosthesis, Dong Sup Lee

Theses and Dissertations

Soft material-enabled electronics can demonstrate extreme mechanical flexibility and stretchability. Such compliant, comfortable electronics allow continuous, long-term measurement of biopotentials on the skin. Manufacturing of the stretchable electronic devices is enabled by the recent development combining materials transfer printing and microfabrication. However, the existing method using inorganic materials and multi-layered polymers requires long material preparation time and expensive processing cost due to the requirement of microfabrication tools and complicated transfer printing steps. Here, this study develops a new fabrication method of soft electronics via a micro-replica-molding technique, which allows fast production, multiple use, and low cost by avoiding microfabrication and …

The Composition And Distribution Of Coal-Ash Deposits Under Reducing And Oxidizing Conditions From A Suite Of Eight Coals, David R. Brunner

Theses and Dissertations

Eighteen elements, including: carbon, oxygen, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, calcium, titanium, chromium, manganese, iron, nickel, strontium, and barium were measured using a scanning electron microscope with energy dispersive spectroscopy from deposits. The deposits were collected by burning eight different coals in a 160 kWth, staged, down-fired, swirl-stabilized combustor. Both up-stream and down-stream deposits from an oxidizing region (equivalence ratio 0.86) and reducing region (equivalence ratio 1.15) were collected. Within the deposits, the particle size and morphology were studied. The average particle cross-sectional area from the up-stream deposits ranged from 10 - 75 µm2 and had a …