Lithium ion batteries (LIBs) have been the most prominent electrochemical energy storage technology over the past decades and enabled the wireless evolution of portable electronic devices. Yet the expanded use of renewable but intermittent energy sources coupled with increasing demand for electric transportation vehicles put forward requirements to electrochemical energy...
Porous metal structures exhibit numerous advantages over dense materials due to their high specific stiffness, strength, damping, energy absorption, and surface areas, making them suitable for applications ranging from actuators to medical implants. However, traditional foam manufacturing methods do not provide sufficient control of the foam micro-architectures, and the creation...
Gels are three-dimensional polymer networks capable of absorbing a large amount of solvent molecules subject to various external stimuli (pH, temperature, light, etc.). They exhibit a rich mechanical behavior and prominent nonlinearity owing to their high flexibility, stimuli-responsiveness and superabsorbency. More compelling are the intriguing morphologies and novel functionalities achieved...
The limits of miniaturization of electronic device components and the steady need for faster computation power have motivated the discovery and cultivation of low-dimensional materials. Among these, two-dimensional (2D) materials have exhibited a wide range of superlative optoelectronic, thermal and mechanical properties. The interest in 2D materials took-off with the...
Electromagnetic metamaterials composed of colloidally synthesized plasmonic metal nanoparticles offer new opportunities to probe light-matter interactions. The properties of these structures largely depend on the spatial arrangement of nanoparticles within them. Therefore, new assembly strategies that afford a high level of structural control are expected to enable a broad range...
While synthesis and transformation processes to produce monodisperse nanoparticles are empirically well-developed, the pathways for these reactions as well as the exact role of synthetic agents and binding characteristics of surface moieties remain poorly understood. This lack of understanding is primarily due to the paucity of information about nanoparticle structural...
Technology has advanced rapidly, especially in the twenty-first century, influencing our day-to-day life on unprecedented levels. Most such advances in technology are closely linked to, and often driven by, the discovery and design of new materials. It follows that the discovery of new materials can not only improve existing technologies...
Microkinetic modeling is a powerful tool for creating dynamic and quantitative descriptions of complex systems. These detailed mechanistic models compliment experimental techniques and provide an ability to achieve deeper insights into chemical processes where numerous intermediates are highly reactive and difficult to quantify in the laboratory. This thesis discusses the...
Thin film oxidation is investigated using two modeling techniques in the interest of better understanding the roles of space charge and non-equilibrium effects.
An electrochemical phase-field model of an oxide-metal interface is formulated in one dimension and studied at equilibrium and during growth. An analogous sharp interface model is developed...
This work reports studies on the physical properties of collections of nanosheets. First, the configurations of graphene oxide sheets in solution are studied. Polarized optical microscopy reveals quickly and decisively that sheets remain flat and form lyotropic liquid crystals over a wide range of solvent conditions. When solvent conditions are...
Moving away from fossil fuels requires environmentally friendly and economically viable alternative energy sources. A wide adoption of new technologies for energy production and storage depends on better performing materials. Computational methods, such as electronic structure calculations and machine learning, hold the promise to work in conjunction with traditional experimentation...
There is growing interest in and demand for lightweight, age-hardenable alloys such as aluminum (Al) alloys in the transportation sector. This interest is due to the potential for reducing vehicle mass and thereby improving fuel economy. Precipitation microstructures improve the mechanical properties of materials, such as yield stress, by impeding...
Two-dimensional (2D) materials such as graphene exhibit unique, superlative electronic, optical, and mechanical properties that are dictated by the precise atomic structure within each layer. Consequently, control of this atomic-scale configuration is critical to engineering desirable characteristics. To date, however, most 2D materials have been discovered by isolating mono- or...
Supported metal catalysts find many important uses in areas including chemical production, petroleum refining and emission control. The catalytic behavior of a supported metal catalyst is influenced by size and type of reaction sites on metal nanoparticles. For many structure insensitive reactions catalyzed by the supported metal catalysts, smaller metal...
Over the last 20 years a new field of amorphous transparent conducting oxides (a-TCOs) has developed. The amorphous nature of these films makes them well suited for large area applications. In addition, a-TCOs can be made at low temperatures and through solution processing methods. These assets provide promising opportunities to...
Atom probe tomography (APT) was used to analyze doping and alloying in low-dimensional electronic materials including thin film heterostructures, van der Waals materials, and colloidal quantum dots (QDs).
Firstly, APT was used to reveal structure-property relationship for low-dimensional thin film semiconductors used in electronic and opto-electronic devices. APT was shown...
Carbonate minerals are integral to life on earth, as reservoirs for CO2 in the earth’s natural carbon cycle and as the skeletal elements of abundant organisms like corals and plankton. Because of its relevance, availability, and low toxicity, calcium carbonate is also an important model system for phase transformations in...
High performance structural materials are needed for Naval applications which require an excellent combination of yield strength, low-temperature impact toughness, ductility, ballistic-resistance, and weldability. This research investigates precipitation-strengthened HSLA-115 steels and ballistic-resistant 10 wt. % Ni steels, which have emerged as promising alternatives to the widely used HSLA-100 steels for...
The morphological evolution due to coarsening is analyzed for two distinctive types of microstructure. First, the feasibility of characterizing spatial correlations of interfacial curvature in topologically complex structures is demonstrated with the analysis of bicontinuous two-phase mixtures produced using phase field modeling. For structures produced with both conserved and nonconserved...
This thesis demonstrates the use of dual-beam focused ion beam - scanning electron microscopy (FIB-SEM) for making complete three-dimensional reconstructions of SOFC electrodes in order to better understand the links between processing and performance with respect to microstructure. Sufficient compositional contrast, with nano-scale resolution, between Ni and LSM with respect...