Electrodeposition of adherent submicron to micron thick manganese dioxide films with optimized current collector interface for 3D Li-ion electrodes

Three-dimensional (3D) configuration of high-performance energy storage devices has been the subject of ongoing investigations targeting their integration in autonomous microelectronic systems. In this study we demonstrate a route toward the realization of high capacity cathode material for 3D thin-film lithium-ion (Li-ion) batteries. Electrolytic manganese dioxide (EMD) film can be applied as a Li-ion intercalation electrode upon its conversion to lithium manganese dioxide (LiMn2O4 or LMO) by solid-state reaction. The main challenges of depositing thicker EMD film directly on the current collector often lay in achieving a good film adhesion and preventing oxidation of non-noble current collectors such as TiN, Ni. To improve the adhesion of the EMD films we modify the surface of the current collector by means of thin-film or seed layer coatings, which also prevent the oxidation of the underlying current collector substrate during the anodic deposition process. As a result submicron to micron thick EMD films with good adhesion were deposited on various current collectors. The acidity of the electrolyte solutions was varied depending on the type of the surface coating or current collector used. The mechanism of the EMD film growth and morphology on different substrates was examined. Compatibility of the proposed current collector interface modification for the electrodeposition of conformal thick EMD films on high-aspect ratio microstructures was demonstrated. A method of EMD film conversion to LMO at low-temperature on different substrates was shown as the path toward their application in 3D Li-ion batteries

Roadmap on Li-ion battery manufacturing research

Growth in the Li-ion battery market continues to accelerate, driven primarily by the increasing need for economic energy storage for electric vehicles. Electrode manufacture by slurry casting is the first main step in cell production but much of the manufacturing optimisation is based on trial and error, know-how and individual expertise. Advancing manufacturing science that underpins Li-ion battery electrode production is critical to adding to the electrode manufacturing value chain. Overcoming the current barriers in electrode manufacturing requires advances in materials, manufacturing technology, in-line process metrology and data analytics, and can enable improvements in cell performance, quality, safety and process sustainability. In this roadmap we explore the research opportunities to improve each stage of the electrode manufacturing process, from materials synthesis through to electrode calendering. We highlight the role of new process technology, such as dry processing, and advanced electrode design supported through electrode level, physics-based modelling. Progress in data driven models of electrode manufacturing processes is also considered. We conclude there is a growing need for innovations in process metrology to aid fundamental understanding and to enable feedback control, an opportunity for electrode design to reduce trial and error, and an urgent imperative to improve the sustainability of manufacture

Roadmap on Li-ion battery manufacturing research

Growth in the Li-ion battery market continues to accelerate, driven primarily by the increasing need for economic energy storage for electric vehicles. Electrode manufacture by slurry casting is the first main step in cell production but much of the manufacturing optimisation is based on trial and error, know-how and individual expertise. Advancing manufacturing science that underpins Li-ion battery electrode production is critical to adding to the electrode manufacturing value chain. Overcoming the current barriers in electrode manufacturing requires advances in materials, manufacturing technology, in-line process metrology and data analytics, and can enable improvements in cell performance, quality, safety and process sustainability. In this roadmap we explore the research opportunities to improve each stage of the electrode manufacturing process, from materials synthesis through to electrode calendering. We highlight the role of new process technology, such as dry processing, and advanced electrode design supported through electrode level, physics-based modelling. Progress in data driven models of electrode manufacturing processes is also considered. We conclude there is a growing need for innovations in process metrology to aid fundamental understanding and to enable feedback control, an opportunity for electrode design to reduce trial and error, and an urgent imperative to improve the sustainability of manufacture

Roadmap on Li-ion battery manufacturing research

Growth in the Li-ion battery market continues to accelerate, driven by increasing need for economic energy storage in the electric vehicle market. Electrode manufacture is the first main step in production and in an industry dominated by slurry casting, much of the manufacturing process is based on trial and error, know-how and individual expertise. Advancing manufacturing science that underpins Li-ion battery electrode production is critical to adding value to the electrode manufacturing value chain. Overcome the current barriers in the electrode manufacturing requires advances in material innovation, manufacturing technology, in-line process metrology and data analytics to improve cell performance, quality, safety and process sustainability. In this roadmap we present where fundamental research can impact advances in each stage of the electrode manufacturing process from materials synthesis to electrode calendering. We also highlight the role of new process technology such as dry processing and advanced electrode design supported through electrode level, physics-based modelling. To compliment this, the progresses in data driven models of full manufacturing processes is reviewed. For all the processes we describe, there is a growing need process metrology, not only to aid fundamental understanding but also to enable true feedback control of the manufacturing process. It is our hope this roadmap will contribute to this rapidly growing space and provide guidance and inspiration to academia and industry

Roadmap on Li-ion battery manufacturing research

Growth in the Li-ion battery market continues to accelerate, driven by increasing need for economic energy storage in the electric vehicle market. Electrode manufacture is the first main step in production and in an industry dominated by slurry casting, much of the manufacturing process is based on trial and error, know-how and individual expertise. Advancing manufacturing science that underpins Li-ion battery electrode production is critical to adding value to the electrode manufacturing value chain. Overcome the current barriers in the electrode manufacturing requires advances in material innovation, manufacturing technology, in-line process metrology and data analytics to improve cell performance, quality, safety and process sustainability. In this roadmap we present where fundamental research can impact advances in each stage of the electrode manufacturing process from materials synthesis to electrode calendering. We also highlight the role of new process technology such as dry processing and advanced electrode design supported through electrode level, physics-based modelling. To compliment this, the progresses in data driven models of full manufacturing processes is reviewed. For all the processes we describe, there is a growing need process metrology, not only to aid fundamental understanding but also to enable true feedback control of the manufacturing process. It is our hope this roadmap will contribute to this rapidly growing space and provide guidance and inspiration to academia and industry

Constructing the Home Space: Reclaiming the Orientalist Image in Contemporary Mena Art

This project will investigate how home and identity is constructed in the works of artists who operate from within and outside of the MENA world in various states of exile. By looking at the tropes established in Orientalist photography, this project seeks to examine a connective thread between nineteenth-century Orientalist photography of the Middle East and North Africa and the works by contemporary photographic and video artists from the MENA world within the past ten years. The master narrative created in these nineteenth-century photographs, implying that the Middle East and North Africa is a homogenous location marked by ruined vacant cities and sexual abundance continues to impact the global perception of this diverse area in mainstream media. By investigating the many ways that contemporary artists turn the tropes established in early photography on their head, this thesis explores how contemporary MENA artists reclaim and rewrite their narratives of home

Nanostructured electrodes with high surface area and porosity for energy storage applications

Although the highest combined energy and power density of rechargeable lithium-ion (Li-ion) batteries should make them an optimal energy storage solution for miniaturized devices, small Li-ion batteries exhibit only a fraction of the energy density of their bigger counterparts. To increase the energy density of small batteries, the superficial loading of energy-storing components needs to be increased by, for example, coating active materials on three-dimensional (3D) nanostructured substrates. Using the advantages of fast electronic and ionic transport in nanofilms, the energy and power density of the 3D electrodes could be maximized if they utilized high loadings of sub-50 nm thick active material coatings. To realize such electrodes, they must be based on nanostructured 3D current collectors that combine high porosity, large internal surface area, sufficiently large pores and mechanical stability - the target combination for not only the batteries, but virtually any electrochemical device. Besides using adequate substrates, harnessing the potential of nanofilm-based battery electrodes requires finding new methods for conformal coating of functional materials within the inherently small pores of nanostructured current collectors. Importantly, the entire fabrication process needs to be cheap and fast to bring the new batteries from the laboratory to the market. In this work, nanostructuring has been exploited to introduce high energy and power density to the electrodes for small Li-ion batteries. First, new 3D-intreconnected nanowire meshes (nanomeshes) were developed to act as free-standing structural current collectors. To assess the potential of the material for various electrochemical applications, its surface area and porosity were accurately determined using three newly-established electrochemical methodologies. Based on the results, the unique combination of high surface area and porosity in the nanomesh was revealed with respect to the properties of over 70 porous metals reported in the literature. The electrochemical performance of the thin nanomesh was demonstrated during electrolytic hydrogen generation and compared to that of 300-times thicker commercial electrodes. To functionalize the nanomesh with a Li-ion cathode precursor, a new method was developed for fast coating complex 3D nanostructures with thin layers of MnO2. Through a combination of the new method and electrodeposition, the nanomeshes were conformally coated with nanofilms of MnO2 using industrially-relevant processes. With the help of thermodynamic simulations, a low temperature conversion was developed to transform the MnO2-coated nanomeshes into electroactive Li-ion cathodes. Finally, the energy and power density of the new nanomesh-base Li-ion electrodes were assessed and compared to these of the known 3D Li-ion cathodes.status: publishe

Safety at highway-railroad crossings : a case study of the Austin-San Antonio corridor

textFor over a decade proposals for connecting the metropolitan areas of Austin and San Antonio, Texas via passenger rail have been studied. In the Texas Department of Transportation’s 2010 Rail Plan several ideas, including high-speed rail, regional Amtrak service, and a new passenger rail service have been proposed as a means to provide an alternate mode of transportation along the I-35 corridor. Union Pacific Railroad currently owns and operations a rail line that connects the Austin and San Antonio metropolitan areas; each of the passenger rail projects proposes sharing this corridor with Union Pacific. A literature review reveals that a key factor in negotiating with a freight railroad for shared use of a corridor is safety. One element of the safety risk analysis is the evaluation of at-grade highway-railroad crossing. This study discusses the Austin-San Antonio corridor, its current mobility challenges and the proposed passenger rail projects. It then discusses rail safety as expressed in the literature and provides background about safety at highway-railroad crossings. Crossing inventory and accident data, as maintained by the Federal Railroad Administration (FRA), is then analyzed using regression modeling in an attempt to better understand the relationship between the physical and operational characteristics of highway-railroad crossings and accidents on corridors shared by freight and passenger rail. It analyzes a five-year accident history (2005 to 2009) from of a sample of shared use highway-rail crossings throughout the US. The findings are then used to analyze the at-grade highway-railroad crossings along the Austin-San Antonio corridor. And finally, the implications of the findings are discussed. The findings of this report recommend that characteristics of the built environment such as land use, number of traffic lanes, and function classification of the roadway should be considered when assessing accident risk at highway-railroad crossings. In addition, this analysis reveals the need for a way to better measure safety risks at private highway-railroad crossings.Community and Regional Plannin

Monte Carlo analysis of the 10 MV x-ray beam from a Clinac-18 linear accelerator

The treatment head of the Clinac-18 medical linear accelerator was modelled using-the EGS4 Monte Carlo simulation package. Photon-energy spectra for fields ranging from 2 x 2 cm$sp2$ to 20 x 20 cm$sp2$ in size were generated and the primary and scatter spectra were analyzed separately. The generated x-ray spectra were used in the calculation of the percent depth dose (PDD) distributions for flattened and unflattened 10 MV x-ray beams in a water phantom at a source-surface distance of 100 cm for the various field sizes. The agreement between calculated and measured depth doses is excellent.Measurements of the dose in the build-up region show that the depth of dose maximum (d$sb{max}$) increases with increasing field size for fields up to 5 x 5 cm$sp2$ for both the flattened and unflattened beams. As the field size is increased beyond 5 x 5 cm$sp2,$ d$sb{max}$ decreases with increasing field size for the flattened x-ray beam while remaining nearly constant for the unflattened beam. Additionally, the surface dose of the flattened beam is found to approach that of the unflattened beam for large field sizes. Calculations show that the decrease in d$sb{max}$ as the field size is increased above 5 x 5 cm$sp2,$ and the rapid increase in the surface dose for the flattened x-ray beam with increasing field size, are due to the degradation of the flattened-beam parameters caused by low-energy photons produced in the flattening filter