Chemical Engineering Commons^™

High Capacity Silicon Electrodes With Nafion As Binders For Lithium-Ion Batteries, Jiagang Xu, Qinglin Zhang, Yang-Tse Cheng

Chemical and Materials Engineering Faculty Publications

Silicon is capable of delivering a high theoretical specific capacity of 3579 mAh g⁻¹ which is about 10 times higher than that of the state-of-the-art graphite based negative electrodes for lithium-ion batteries. However, the poor cycle life of silicon electrodes, caused by the large volumetric strain during cycling, limits the commercialization of silicon electrodes. As one of the essential components, the polymeric binder is critical to the performance and durability of lithium-ion batteries as it keeps the integrity of electrodes, maintains conductive path and must be stable in the electrolyte. In this work, we demonstrate that electrodes consisting of …

Chemical Processing Cell With Nanostructured Membranes, Dibakar Bhattacharyya, Scott R. Lewis, Saurav Datta

Chemical and Materials Engineering Faculty Patents

A chemical processing cell includes an upstream membrane and a downstream membrane. The upstream membrane generates a first reaction product. The downstream membrane converts the first reaction product to a second reaction product.

Electrode Kinetics Of Vanadium Flow Batteries: Contrasting Responses Of VIi-VIii And VIv-VV To Electrochemical Pretreatment Of Carbon, A. Bourke, M. A. Miller, R. P. Lynch, Xin Gao, James Landon, J. S. Wainright, R. F. Savinell, D. N. Buckley

Center for Applied Energy Research Faculty and Staff Publications

Electrochemical impedance spectroscopy and cyclic voltammetry were used to investigate the electrode kinetics of V^II-V^III and V^IV-V^V in H₂SO₄ on glassy carbon, carbon paper, carbon xerogel, and carbon fibers. It was shown that, for all carbon materials investigated, the kinetics of V^II-V^III is enhanced by anodic, and inhibited by cathodic, treatment of the electrode; in contrast, the kinetics of V^IV-V^V is inhibited by anodic, and enhanced by cathodic, treatment. The potential region for each of these effects varied only slightly with carbon material. Rate constants …

Structural And Functional Characterization Of A Lytic Polysaccharide Monooxygenase With Broad Substrate Specificity, Anna S. Borisova, Trine Isaksen, Maria Dimarogona, Abhishek A. Kognole, Geir Mathiesen, Anikó Várnai, Åsmund K. Røhr, Christina M. Payne, Morten Sørlie, Mats Sandgren, Vincent G. H. Eijsink

Chemical and Materials Engineering Faculty Publications

The recently discovered lytic polysaccharide monooxygenases (LPMOs) carry out oxidative cleavage of polysaccharides and are of major importance for efficient processing of biomass. NcLPMO9C from Neurospora crassa acts both on cellulose and on non-cellulose β-glucans, including cellodextrins and xyloglucan. The crystal structure of the catalytic domain of NcLPMO9C revealed an extended, highly polar substrate-binding surface well suited to interact with a variety of sugar substrates. The ability of NcLPMO9C to act on soluble substrates was exploited to study enzyme-substrate interactions. EPR studies demonstrated that the Cu²⁺ center environment is altered upon substrate binding, whereas isothermal titration …

Electrode Side Reactions, Capacity Loss And Mechanical Degradation In Lithium-Ion Batteries, Jiagang Xu, Rutooj D. Deshpande, Jie Pan, Yang-Tse Cheng, Vincent S. Battaglia

Chemical and Materials Engineering Faculty Publications

For advancing lithium-ion battery (LIB) technologies, a detailed understanding of battery degradation mechanisms is important. In this article, experimental observations are provided to elucidate the relation between side reactions, mechanical degradation, and capacity loss in LIBs. Graphite/Li(Ni_1/3Mn_1/3Co_1/3)O₂ cells of two very different initial anode/cathode capacity ratios (R, both R > 1) are assembled to investigate the electrochemical behavior. The initial charge capacity of the cathode is observed to be affected by the anode loading, indicating that the electrolyte reactions on the anode affect the electrolyte reactions on the cathode. Additionally, the rate of “marching” …

A Quantitative Perspective On Surface Marker Selection For The Isolation Of Functional Tumor Cells, Calvin F. Cahall, Jacob L. Lilly, Edward A. Hirschowitz, Brad J. Berron

Chemical and Materials Engineering Faculty Publications

Much effort has gone into developing fluid biopsies of patient peripheral blood for the monitoring of metastatic cancers. One common approach is to isolate and analyze tumor cells in the peripheral blood. Widespread clinical implementation of this approach has been hindered by the current choice of targeting epithelial markers known to be highly variable in primary tumor sites. Here, we review current antigen-based tumor cell isolation strategies and offer biological context for commonly studied cancer surface markers. Expression levels of the most common markers are quantitated for three breast cancer and two non-small cell lung cancer (NSCLC) lineage models. These …

Secondary Organic Aerosol Formation From The Β-Pinene+No3 System: Effect Of Humidity And Peroxy Radical Fate, C. M. Boyd, J. Sanchez, L. Xu, Alexis J. Eugene, T. Nah, W. Y. Tuet, Marcelo I. Guzman, N. L. Ng

Chemistry Faculty Publications

The formation of secondary organic aerosol (SOA) from the oxidation of β-pinene via nitrate radicals is investigated in the Georgia Tech Environmental Chamber (GTEC) facility. Aerosol yields are determined for experiments performed under both dry (relative humidity (RH) < 2 %) and humid (RH = 50 % and RH = 70 %) conditions. To probe the effects of peroxy radical (RO₂) fate on aerosol formation, "RO₂ + NO₃ dominant" and "RO₂ + HO₂ dominant" experiments are performed. Gas-phase organic nitrate species (with molecular weights of 215, 229, 231, and 245 amu, which likely correspond to molecular formulas of C₁₀H₁₇NO₄, C₁₀H₁₅NO₅, C₁₀H₁₇NO …

General Method To Predict Voltage-Dependent Ionic Conduction In A Solid Electrolyte Coating On Electrodes, Jie Pan, Yang-Tse Cheng, Yue Qi

Chemical and Materials Engineering Faculty Publications

Understanding the ionic conduction in solid electrolytes in contact with electrodes is vitally important to many applications, such as lithium ion batteries. The problem is complex because both the internal properties of the materials (e.g., electronic structure) and the characteristics of the externally contacting phases (e.g., voltage of the electrode) affect defect formation and transport. In this paper, we developed a method based on density functional theory to study the physics of defects in a solid electrolyte in equilibrium with an external environment. This method was then applied to predict the ionic conduction in lithium fluoride (LiF), in contact with …

Composition And Work Function Relationship In Os–Ru–W Ternary Alloys, Phillip D. Swartzentruber, Michael J. Detisch, Thomas John Balk

Chemical and Materials Engineering Faculty Publications

Os–Ru thin films with varying concentrations of W were sputter deposited in order to investigate their structure–property relationships. The films were analyzed with x-ray diffraction to investigate their crystal structures, and a Kelvin probe to investigate their work functions. An Os–Ru–W film with ∼30 at. % W yielded a work function maximum of approximately 5.38 eV. These results align well with other studies that found work function minima from thermionic emission data on M-type cathodes with varying amounts of W in the coatings. Furthermore, the results are consistent with other work explaining energy-level alignment and charge transfer of molecules on …

Cytotoxic Activity Of Triazole-Containing Alkyl Ss-D-Glucopyranosides On A Human T-Cell Leukemia Cell Line, Edward Davis Oldham, Larissa M. Nunes, Armando Varela-Ramirez, Stephen E. Rankin, Barbara L. Knutson, Renato J. Aguilera, Hans-Joachim Lehmler

Chemical and Materials Engineering Faculty Publications

BACKGROUND: Simple glycoside surfactants represent a class of chemicals that are produced from renewable raw materials. They are considered to be environmentally safe and, therefore, are increasingly used as pharmaceuticals, detergents, and personal care products. Although they display low to moderate toxicity in cells in culture, the underlying mechanisms of surfactant-mediated cytotoxicity are poorly investigated.

RESULTS: We synthesized a series of triazole-linked (fluoro)alkyl β-glucopyranosides using the copper-catalyzed azide-alkyne reaction, one of many popular "click" reactions that enable efficient preparation of structurally diverse compounds, and investigate the toxicity of this novel class of surfactant in the Jurkat cell line. Similar to …