Yuefan Ji
Lithium-ion batteries are key to electrifying transportation. However, the nature of the current lithium ion battery technology is unsafe. Researchers are working on the development and improvement of battery techniques to manufacture high performance and safe batteries. Importantly, lithium ion batteries are a closed and complicated system, which makes it impossible to open and diagnose the commercialized battery without damaging it. Fortunately, electrochemical impedance spectroscopy (EIS) is available for us to diagnose the lithium ion battery non-invasively. EIS is powerful, but has not been fully understood. Thus, my works focus on the theories and applications of EIS in providing more insights on battery diagnostics and...
Mercie Hodges
Polymers are commonly used in the energy field as matrices for photovoltaics, but they also have the potential to act as electrodes. My work in Matt Golder’s lab is upcycling polyolefins via post-polymerization modification, a method of chemically transforming polymer chains to give them new properties with added value. I am using a selenium-catalyzed amination reaction developed by the Michael lab to add sulfonamides to the polymer backbone, modifying their thermal and physical properties. Recently, it has been found that conjugated sulfonamides can be used to form lithium-ion positive electrodes that are air-stable and demonstrate reversible electrochemistry, allowing for charge storage. I am attempting...
Seancarlos Gonzalez
Renewable energy technologies have gained use as a means of combating the causes of global climate change. Nevertheless, even with 100% renewable energy, chemicals manufacturing will still produce carbon dioxide emissions. Current gas separation techniques are both energy and cost intensive, meaning that we need affordable technologies that can scrub CO2 from exhaust streams. My research focuses on developing more effective gas separation membranes that can be used to separate CO2 from a mixture of other gases. Specifically, my work uses reactive vapors to grow metal organic frameworks (MOFs) in situ within polymer membranes. The incorporation of these MOFs has already been shown to...
Anthony Gironda
Once-through nuclear fuel cycles leave thousands of metric tons of spent nuclear waste to be disposed of -approximately 80,000 tons in the US alone. The enduring proposal for disposal are geological repositories, deep facilities that store waste in crystalline rock or clay where they can safely decay without escaping into the biosphere. To ensure this, engineered barrier systems encapsulate the waste container, forming an additional boundary between waste and the biosphere. The time scale for disposal is ~1M years, with the first 100,000 years being the most critical. My work uses x-ray spectroscopy to characterize different concretes proposed for use in barrier systems to...
Kristina Gill
With global temperatures rising, technologies that can improve energy efficiency of heating and cooling are more important than ever before. The energy use of buildings and transportation vehicles due to lighting, cooling and heating corresponds to about 40% of the world’s annual energy consumption. Windows are the leading source of energy loss for buildings and vehicles. One way to reduce this energy loss is to use smart windows with thermochromic coatings which can spontaneously modulate the solar energy transmission in response to the ambient temperature. Vanadium dioxide (VO2) is a promising candidate for these coatings due to a stable, rapid, reversible metal-to-insulator transition across a...
Aaron Gehrke
Thin-film photovoltaics such as Cu(In,Ga)Se2 (CIGS) and CdTe are among the most promising solar cell technologies. We study these materials using computational materials methodologies, such as density functional theory (DFT), molecular dynamics (MD), kinetic lattice Monte Carlo (KLMC), and continuum-scale models. One of my primary goals is developing atomistic models of diffusion in these materials, for both native species and extrinsic dopants. Knowledge and control of diffusion is necessary for optimizing device performance, such as In/Ga interdiffusion in CIGS, which must be understood to spatially tune the bandgap. I use DFT to predict defect formation energies, defect complex binding, and defect migration barriers. These results...
Andrei Draguicevic
I'm a second-year graduate student in the Velian lab, where I'm working on heterogenous single-site catalysts for environmentally relevant reactions. My research is focused on using black phosphorus, a 2D van der Waal material, to support single metal atoms to create distinct and tunable active sites on a heterogenous support. Currently, I am using hydroformylation as a test reaction to probe this system, where Rh atoms are supported onto the black phosphorus surface to catalytically convert olefins into aldehydes. Advisor: Alexandra Velian - Chemistry...
Jonathan DeStefano
I utilize materials synthesis and thermodynamic, magnetometric, and transport measurements to study materials with non-trivial topological band structures. These materials host surface states which hold promise for applications in a wide variety of fields including quantum computing and next-generation electronics. Of particular interest to me is the interplay of these surface states with magnetism or superconductivity. I hope to develop a deeper understanding of these materials, thus pushing them closer to being used in technical applications. Advisor: Jiun-Haw Chu - Physics...
Yuri Choe
My project is to create hybrid organic-inorganic membranes with greater stabilities at high temperatures and/or with organic solvents. To reduce the energy consumption and associated emissions from industrial thermal chemical separations, switching to membrane separations could reduce energy required by up to 90%. However, commercially available membranes are unstable in many industrial applications. To produce more resilient membranes, I am exploring the use of vapor phase infiltration (VPI) to enhance stabilities of separation membranes and enable its integration into current industrial manufacturing processes without the need for significant changes. My goal is to develop new VPI process chemistries and test properties of the synthesized...
Hannah Contreras
Highly efficient, financially feasible solar photovoltaic technology is crucial to the global transition from fossil fuels to renewable energy to mitigate climate change. Perovskite solar cells (PSCs) represent a promising next generation technology; they have already matched the efficiency of the current market-dominant silicon technology in just a decade of research. Widespread, viable commercial application of PSCs requires stable, scalable device structures to maintain efficiency over time. My goal is to enhance PSC stability and efficiency by studying charge carrier recombination and defect dynamics in the charge transport and active layers of PSCs through extensive device fabrication and subsequent spectroscopic characterization. Advisor: David Ginger -...
Matthew Chang
Information and communications technology (ICT) is predicted to comprise 30% of the world's total energy consumption by 2030. Because of the increasing demand in telecommunications and other relevant technologies, more efficient nanophotonic devices will need to be made industrially. One such device is the Faraday isolator, an optical device that allows the transmission of light in one direction while blocking it in the opposite direction. Yttrium iron garnet (YIG) is a staple ferrimagnetic Faraday isolator material. However, the processability of YIG is lacking due to it mainly being grown as a single crystal. Currently, I am in the process of perfecting a hydrothermal synthesis...
Tyson Carr
I research the fundamentals of anode-electrolyte interactions in Li-ion batteries, in order to enable use of high-capacity, next-generation alloying electrode materials. Standard graphite anodes have up to an order of magnitude lower theoretical capacity than alloying materials such as silicon. However, the volume expansion in these materials as they store lithium ions causes the capacity to fade as they are charged and discharged. My research specifically involves modifying the electrode interface to dynamically mitigate the effects of the volume expansion, while still allowing reversible lithium ion storage to proceed. While the current model system is with silicon electrodes, my research will inform adaptation of...