Post-Doctoral Fellowship Winners
CESI Post-Doctoral Fellowship Winners
The Cornell Energy System Institute (CESI) is excited to announce our two newest winners of the Post-Doctoral Fellowship Program for 2020. Regina Garcia-Mendez, who will be co-advised by Dr. Andrej Singer and Dr. Lynden Archer; and Cheol Kang, who will be co-advised by Dr. Geoffrey Coates and Dr. Héctor D. Abruña.
The CESI Post-doctoral Fellowships are high-profile fellowships designed to attract the best and brightest young researchers in energy science, engineering, and materials to Cornell. The goal is to create a cohort of independent scholars pursuing frontier research in energy. Fellows will work in partnership with Cornell faculty sponsors on projects consistent with the CESI mission. The CESI fellowships are two-year appointments and provide up to 50% of the cost associated with sponsoring a postdoctoral scientist at Cornell, with the faculty advisors providing the other 50%.
Regina Garcia-Mendez completed her Ph.D. in Materials Science and Engineering at the University of Michigan in 2020, under the supervision of Professor Jeff Sakamoto. Her graduate work focused on correlating structural and interfacial effects of ceramic solid electrolytes with cycling stability of Li metal in solid-state batteries. Even though most recent investigations have been carried out focusing on the lithium anode-electrolyte interface, including her thesis, the practical stability of solid electrolytes at high voltages still needs further investigation.
In particular, the (electro-)chemical evolution of electrode materials and interfaces that can often be linked to mechanical degradation due to the all-solid nature of these systems. Thus, as a CESI Post-Doctoral Fellow, Garcia-Mendez’ research will pursue forming anionic polymer coatings in-situ throughout the cathode to prevent exposing the solid electrolyte to oxidation and attain intimate contact between components. Furthermore, the compliant nature of the polymer may accommodate volume changes during cycling allowing capacity retention. Regina’s research project is entitled, In-situ generated cathode electrode interfaces for high voltage stabilization of a ceramic electrolyte. Advanced characterization techniques such as in-situ soft and hard X-ray scattering and imaging techniques coupled with Electrochemical Impedance Spectroscopy (EIS) measurements will be used to understand the formation process and evolution of the interfaces. In addition, mobility and structural changes under dynamic conditions will be studied.
Figure 1. Schematic of anionic polymer coatings onto cathode particles for solid electrolyte oxidative-stability enhancement
Cheol Kang is a final-year Ph.D. candidate (supervised by Prof. Tae-Lim Choi) in the Department of Chemistry at Seoul National University. He completed his Bachelor’s Degree in the same department and started his Ph.D. course in 2014. During the course, Cheol focused on developing synthetic methodologies for making conjugated polyenes and polyenynes from multi-yne monomers by using Ru-based olefin metathesis catalysts. By combining olefin metathesis and metallotropic 1,3-shift reactions (cascade M&M polymerization), he enabled the controlled synthesis of conjugated polyenynes via chain-growth mechanism. After completing his Ph.D., he will join the Coates group in the Department of Chemistry and Chemical Biology at Cornell.
As a postdoctoral researcher, Cheol aims to develop new organic cathode materials by combining redox-active side chains with conductive polymer backbone. To date, most conventional batteries include inorganic materials that are rare, expensive, and energy-consuming for recycling. In contrast, organic materials enable access to greener energy storage systems because they are based on naturally abundant elements which are easier to recycle. Cheol proposes making new polymeric cathode materials consisting of conductive backbone and redox-active side chains via living cyclopolymerization of 1,6-heptadiyne derivatives. Owing to the innate conductivity of polyacetylene backbone, this new material will not require the use of carbon additives, which were generally added to conventional organic cathodes for better electronic conductivity. Furthermore, he suggests making network polymers by using cross-linking agents (covalently linked two diyne units) to improve structural stability, thereby enhancing the charge/discharge cycling stability. Due to the living character of this polymerization system, even block copolymerization with monomers having hydrophilic groups will be possible, which will improve the ionic conductivity of the cathode material. This multi-functional material will offer a better chance for sustainable, versatile, and potentially low-cost energy storage devices.
The Cornell Energy System Institute (CESI) winners of the Post-Doctoral Fellowship Program for 2019. Shuangyan Lang, who will be co-advised by Drs. Hector Abruna, Lynden Archer and Jin Suntivich; and Alexa Schmitz, who will be co-advised by Drs. Buz Barstow and Esteban Gazel.
The CESI Post-doctoral Fellowships are high-profile postdoctoral fellowships designed to attract the best and brightest young researchers in energy science, engineering, and materials to Cornell. The goal is to create a cohort of independent scholars pursuing frontier research in energy. Fellows will work in partnership with Cornell faculty sponsors on projects consistent with the CESI mission. The CESI Fellowships are two-year appointments and provide up to 50% of the cost associated with sponsoring a postdoctoral scientist at Cornell, with the faculty advisors providing the other 50%.
Shuangyan Lang is a final-year doctoral candidate (supervised by Profs. Li-Jun Wan and Rui Wen) in Physical Chemistry at the Institute of Chemistry, Chinese Academy of Sciences (ICCAS) in Beijing, China. She earned a Bachelor’s Degree in 2014 in the department of Chemistry, Jilin University. Her Ph.D research has focused on the in-situ investigation of interfacial processes and kinetics of Li-S batteries via EC-AFM (electrochemistry-atomic force microscopy).
The research project that she will be working on is entitled, In Operando Fundamental Studies of Li/S Cells as Next-Generation Electrical Energy Storage Technologies.
Her research will focus on the operando observation and characterization of the interfacial processes and an in-depth investigation of the reaction mechanism of Li-S batteries. Through the use of advanced operando techniques (Scheme 1) such as X-ray based methods, in-situ TEM and cryo-STEM, she intends to achieve the direct visualization of the morphological and structural evolution at both CEI (cathode electrolyte interface) and SEI (solid electrolyte interface), providing a detailed mechanistic understanding/picture of the delicate interplay of interfacial processes in Li-S batteries and insightful clues for novel design criteria for advanced, next-generation electrical energy storage technologies.
Alexa Schmitz is currently a postdoc in the Barstow Lab in Biological and Environmental Engineering at Cornell. Originally from southeastern PA, Alexa completed her bachelor’s degrees in biochemistry and violin performance at Oberlin College and Conservatory in Oberlin, OH. She then interned at the Smithsonian Tropical Research Institute in Panama studying competitive interactions between microbial tree-root endosymbionts on an island in the middle of the Panama Canal. With a desire to gain competence in microbiology and molecular biology, Alexa joined the lab of Dr. Cammie Lesser at Harvard Medical School where she developed a microscopic assay for visualizing protein-protein interactions in yeast, which she used to investigate how Shigella flexneri, a causal agent of dysentery, secretes type III effector proteins. Alexa first came to Cornell University for her PhD in Plant Pathology and Plant-Microbe Biology, which she completed in the lab of Dr. Maria Harrison at Boyce Thompson Institute studying molecular mechanisms underlying the interaction between beneficial arbuscular mycorrhizal fungi and plant roots. Now in the Barstow Lab, she is excited to biologically engineer solutions to problems in sustainable energy using microorganisms. When not in the lab, Alexa continues to pursue her passion for music as a violinist with Ithaca’s Cayuga Chamber Orchestra.
As a CESI postdoctoral fellow, Alexa Schmitz will be working towards the development of an efficient, sustainable, environmentally responsible, and commercially viable system for extraction of rare earth elements (REE). The global demand for these critical metals is rising rapidly due to their use in many important technologies, especially renewable energy systems. Typically, extraction of REE requires harsh chemicals and high temperature and pressure. A promising alternative is to use the bacterium, Gluconobacter oxydans to bioleach REE from end-of-life waste via its production of strong, but biodegradable, organic acids. Furthermore, the costly sugars used by the bacteria to produce the acid can be obtained by enzymatically breaking down agricultural waste, like corn stover, using the fungus, Trichoderma reesei. Although such a combined biological system can work in the lab, scaling up for commercial application will require much improvement of both microorganisms. With her co-advisors, Buz Barstow and Esteban Gazel, and in collaboration with researchers at the Idaho National Lab, Alexa will comprehensively identify genes underlying REE bioleaching and corn stover digestion by G. oxydans and T. reesei, respectively, and then target those genes for improvement through bioengineering. A bioleaching system combining both improved G. oxydans and improved T. reesei could provide a game-changing solution for environmentally responsible and sustainable REE recovery from end-of-life waste.