Spring 2024 CHME Seminar Abstracts
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Friday, February 2nd, 2024
In silico Design and Optimization of Abundant Energy Materials
Dr. Pieremanuele Canepa, Department of Electrical and Computer Engineering - University of Houston
Computational material science is crucial to establishing a firm link between complex phenomena occurring at the atomic scale and macroscopic observations of functional materials, such as energy materials for solar cells, fuel cells, and rechargeable batteries. Storing and distributing green energy is central to the modernization of our society. Rechargeable batteries, including lithium (Li)-ion batteries, contribute substantially to shifting away from oil and other petrochemicals. The 2019 Nobel Prize in Chemistry awarded to John Goodenough, Stanley Whittingham, and Akira Yoshino resulted in the introduction of the Li-ion battery as a mainstream technology powering millions of portable devices, electric vehicles, and stationary applications.
Commercial Li-ion batteries suffer from stability issues. All-solid-state batteries utilizing solid-electrolyte ceramics separating the distinct chemistries of the electrode materials is a safer alternative. Stabilizing solid-solid “buried” interfaces in all-solid-state batteries remains a poorly understood aspect. In my talk, I will showcase the power of machine-learning-driven simulations to inform the complex reaction mechanisms, which take place at these complex interfaces.
Finding alternatives to the Li-ion battery appears a priority in the diversification and modernization of energy storage technologies. When the life-cycle analysis is examined in the design of batteries, sodium (Na) is attractive because it can be “harvested” directly from seawater, making Na ∼50 times lower in cost than Li. An important class of phosphate electrodes and electrolytes discovered by Hong and Goodenough is the Natrium Super Ionic CONductors (NaSICONs) with chemical formula NaxM2(XO4)3, where M is transition metal, and X = Si and/or P. NaSICON electrode and electrolyte materials display significant Na-ion mobility. In this talk, I will demonstrate that first-principles methods can guide the design of better NaSICON electrodes and electrolytes, with superior energy densities and improved ion transport. For example, our predictions indicate that suitably doped NASICON compositions, especially with high silicon content, can achieve high Na+ mobilities. These findings push the optimization of mixed polyanion solid electrolytes and electrodes, including sulfide-based polyanion frameworks, which are known for their superior ionic conductivities.
Friday, February 16th, 2024
From Aerogels to Hydrogels: Polymer-Guided Assembly of Functional MXene Materials
Dr. Nader Taheri-Qazvini, Departments of Chemical Engineering and Biomedical Engineering - University of South Carolina
Two-dimensional titanium carbide (Ti3C2Tx, MXene) nanosheets offer tantalizing properties, but effectively translating these properties into functional materials requires controlling their organization across length scales. We leverage charged polymeric species to direct the bottom-up assembly of MXene building blocks, allowing us to tailor their alignment to optimize electrical, mechanical, and electromagnetic interference shielding performance.
I will discuss our work utilizing cationic polyelectrolytes to direct organization of MXene nanosheets in macroscale constructs. By harnessing electrostatic attraction and diffusion, we generate highly aligned porous networks and films, combining high conductivity with 99.9% electromagnetic shielding. We also utilize an alternative approach with negatively charged microgels, employing them as templates to guide the assembly of MXene nanosheets. The resulting composites have exceptionally low density but retain impressive mechanical integrity and electromagnetic shielding despite ultralow loadings.
Moving beyond such preformed structures, I will present our efforts examining molecular-scale interactions between MXene, monomers, and polyelectrolytes to inform the synthesis of conductive, highly stretchable hydrogels. Nanosheet crosslinking also imparts robust mechanical properties, with improved adhesion leading to a transition from cohesive to adhesive failure modes.
In dynamically directing assembly across multiple length scales, we can balance critical properties like conductivity, permittivity, porosity, and adhesion to construct tailored MXene composites for different applications. I will highlight current gaps and opportunities in translating the promise of 2D conducting carbides into next-generation devices using this polymer-guided approach.
Friday, March 1st, 2024
Nano-enhanced bioremediation of hydrocarbons
Dr. Michael Benton, Cain Department of Chemical Engineering - Louisiana State University
Two-dimensional titanium carbide (Ti3C2Tx, MXene) nanosheets offer tantalizing properties, but effectively translating these properties into functional materials requires controlling their organization across length scales. We leverage charged polymeric species to direct the bottom-up assembly of MXene building blocks, allowing us to tailor their alignment to optimize electrical, mechanical, and electromagnetic interference shielding performance.
I will discuss our work utilizing cationic polyelectrolytes to direct organization of MXene nanosheets in macroscale constructs. By harnessing electrostatic attraction and diffusion, we generate highly aligned porous networks and films, combining high conductivity with 99.9% electromagnetic shielding. We also utilize an alternative approach with negatively charged microgels, employing them as templates to guide the assembly of MXene nanosheets. The resulting composites have exceptionally low density but retain impressive mechanical integrity and electromagnetic shielding despite ultralow loadings.
Moving beyond such preformed structures, I will present our efforts examining molecular-scale interactions between MXene, monomers, and polyelectrolytes to inform the synthesis of conductive, highly stretchable hydrogels. Nanosheet crosslinking also imparts robust mechanical properties, with improved adhesion leading to a transition from cohesive to adhesive failure modes.
In dynamically directing assembly across multiple length scales, we can balance critical properties like conductivity, permittivity, porosity, and adhesion to construct tailored MXene composites for different applications. I will highlight current gaps and opportunities in translating the promise of 2D conducting carbides into next-generation devices using this polymer-guided approach.
Friday, March 29th, 2024
When fluid mechanics meets rheology and electrokinetics
Dr. Jae Sung Park, Department of Mechanical and Materials Engineering - University of Nebraska-Lincoln
This talk will start by introducing diverse fluid-mechanics projects conducted in Park research group at Nebraska, including complex fluids, laminar-to-turbulent transition, and turbulent drag reduction. I will then focus on complex fluids, where a concentrated suspension of highly conductive particles in an electric field is studied. The dynamics and rheology of such suspension become more complex as fluid mechanics is coupled with nonlinear electrokinetics. In particular, I will present our intriguing findings at high concentrations, which could be useful for many applications, especially suspension-based flow batteries. In general, particle motions tend to get hindered as a concentration is further increased. Surprisingly, the nonlinear electrokinetics makes it get enhanced at a concentration of 35% until 50%. This non-trivial dynamics also gives rise to unique suspension rheology – negative particle pressure. This negative pressure could be considered first-of-its-kind in such suspension systems. I conclude by discussing the applications of these intriguing findings, such as water purification and desalination processes.
Friday, April 12th, 2024
From Green to Red: Quantifying Metabolism Across the Kingdoms
Dr. Nanette Boyle, Department of Chemical & Biomolecular Engineering - Colorado School of Mines
Metabolism powers all life on Earth and even the simplest organisms have complex and interwoven metabolic pathways. The Boyle Laboratory combines chemical engineering principles such as mass and energy balances with experimental systems biology to simulate and quantify in vivo metabolic fluxes across a wide array of species. The metabolic flux maps that result from this can be used to develop a better understanding of cellular physiology, identify engineering targets to manipulate carbon flux or to optimize growth conditions. In this talk, I will highlight two ongoing projects in the lab: (i) metabolic modeling of diurnal growth in algae to aide in metabolic engineering for biofuels production and (ii) experimental approaches to quantify changes in metabolism that occur in platelets upon clotting and the impact of oral contraceptives on activation.
Friday, April 26th, 2024
Integrating Hydrothermal Liquefaction into a Wastewater Treatment Plant
Dr. Susan Stagg-Williams, Chemical & Petroleum Engineering Department - University of Kansas
The desire to produce energy and commodities using more sustainable processes has increased significantly over the past few decades, and the need for decarbonization has led researchers to explore converting renewable or waste biomass feedstocks to higher value products. One thermochemical conversion technique that has gained attention for wet feedstocks is hydrothermal liquefaction (HTL). The HTL process requires subcritical temperatures and pressures (250-350°C; 5-22 MPa) and operates at 10-30 wt% solids. Since the HTL process utilizes water as a reaction media, extensive drying of wet feedstocks is not necessary which reduces the feedstock pretreatment costs. Thus, HTL is an ideal conversion technique for wet waste biomass such as algae and municipal sludge. This seminar will highlight work of at the University of Kansas on the valorization of waste biomass to produce a high quality biocrude and a biochar rich in nutrients. Studies will be presented on HTL of municipal sludge and the impact of the wastewater treatment processes on the product quality and yield. The feasibility of implementing HTL for municipal sludge processing at wastewater treatment plants will be discussed.