Four MSE-affiliated students win NSF Fellowships

Recent MSE graduates Dylan Edelman and Malini Mukherji, incoming Ph.D. candidate Kelotchi Figueroa Nieves, and macro student Diana Kim all received NSF Graduate Research Fellowships.
Four MSE-affiliated students win NSF Fellowships

Dylan Edelman, Malini Mukherji, Kelotchi Figueroa Nieves, and Diana Kim

Four students affiliated with MSE recently received NSF Graduate Research Fellowships: Recent graduates Dylan Edelman and Malini Mukherji, incoming Ph.D. candidate Kelotchi Figueroa Nieves, and macro student Diana Kim (who is a member of the Li group).

The NSF GRFP is a five-year fellowship meant to assist graduate students in STEM at accredited universities. The fellowship includes a three-year stipend and access to NSF-supported professional development opportunities.

For the past two years, Dylan Edelman, who plans to pursue a Ph.D. at Stanford next year, has been working toward creating an all-solid-state sodium metal battery. Such a battery has the potential to be safe and have high energy density while avoiding some of the low abundance materials that are necessary for Li-ion batteries (Co, Li). Edelman's research focuses on the synthesis and properties of a ceramic electrolyte called the sodium superionic conductor (NASICON) synthesized through liquid-feed flame spray pyrolysis (LF-FSP).

LF-FSP is an aerosol combustion synthesis method that creates ceramic nanoparticles with high specific surface areas (~20 m2/g). The fine particles obtained through this method enable sintering at much lower temperatures than those reported for other synthesis routes. As for my project, the first step was to synthesize electrolytes from the NASICON family using nanopowders derived from LF-FSP and compare their electrochemical and mechanical properties. Within the NASICON family, he studied the effects of dopants (La, Mg) on ionic conductivity. Once he discovered that La doped NASICON (NZLSP = Na3.3Zr1.7La0.3Si2PO12) provided the best room temperature ionic conductivity (~0.1 mS/cm), the focus of the project shifted toward generating symmetric- and half-cell data using this electrolyte.

Creating a robust interface in solid-state batteries is a challenge. On the anode side, Na metal can be uniformly melted onto the solid electrolyte in a process called wetting, which occurs at a temperature slightly above the melting point of Na (98 ºC). The data from Na/NZLSP/Na symmetric cell studies, what Edelman considers the greatest achievement from his undergraduate research efforts, showed good stability between the NZLSP electrolyte and Na metal anode at room temperature and high current densities (up to 1 mA cm-2). This indicates that the Na/NZLSP interface can allow for fast charge/discharge rates in an all-solid-state battery. On the cathode side, he has been studying co-sintering between a sodium cobalt oxide cathode (Na0.7CoO2) and NZLSP. He is currently working toward generating NCO/NZLSP/NCO symmetric cell data to complement the work done with Na wetting.

"This work could not have been done without contributions from Eleni Temeche, Taylor Brandt, and Professor Richard Laine," Edelman said. "I would like to thank each of them for their countless ideas and help over the past two years."

Malini Mukherji, who be attending Harvard University to pursue a Ph.D. in Bioengineering this fall, has been working in Professor Joerg Lahann's lab for the past three and a half years, focusing on tissue engineering. Through this, she has worked on projects to help advance 3D jet writing to create unique polymer scaffold geometries that control deposition of extracellular matrices with precisely controlled compositions of key extracellular matrix proteins. As a result, they have created a technology that has great promise for tissue engineering applications, with a specific focus on the replication of the extracellular matrix to study and improve the treatment of breast cancer, cardiovascular disease and brain cancer. More recently, she has studied tumor associated collagen signatures (TACS) as a platform for high throughput expansion of patient cells for personalized drug screening and precision medicine. Lastly, she has helped in loading our scaffolds with various antioxidants - showing the potential for the use of polymeric scaffolds as drug delivery systems. As drug delivery vehicles, our scaffolds can help in the creation of personalized medicine through customizable medication pills and chemotherapy drug loaded grafts implanted after surgical removal of tumors during cancer treatment, for example.

"This project is what inspired my NSF-GRFP proposal and my interest in the combination of drug delivery and tissue engineering—the research I will be focusing on in my doctoral studies," Mukherji remarked. 

Kelotchi S. Figueroa Nieves, who was just accepted into the 2022 Ph.D. cohort, is an undergraduate student from the Bachelor of Physics Applied to Electronic at the University of Puerto Rico at Humacao. As a sophomore, he got accepted in the UPRH-UPenn Partnership of Research and Education in Materials (PREM) program that provided research opportunities. At the UPRH, he focused on the development and electrical characterization of nano-devices based on 2D materials under the mentoring Ph.D. Nicholas Pinto. He has also participated in 3 internships in 2D materials which have helped him build the base to develop a research project for the NSF-GRFP fellowship. For the fellowship, he proposed to study interlayer excitons (IXs) of TMDs sandwiching an insulator. By adding an insulator, the possibility of introducing defects such as vacancies can bring an intriguing system to study IXs. The purpose of this study is to understand better IXs and give rise to the era of excitonic devices which overcomes the limitations of electronic devices.

Macro Ph.D. student Diana Kim is conducting research with the Li group: The ability to process massive quantities of data in the 21st century through technologies such as machine learning and artificial intelligence have been key to technological and economic advancements; however, they consume extraordinary amounts of energy and will be major contributors to climate change. An alternative is neuromorphic computing, where the key is the analog resistive memory component. Kim's research focuses on Electrochemical Random Access Memory cells (ECRAM) in which analog information states are stored in the bulk concentration of oxygen vacancies and are switched by electrochemically increasing or decreasing the oxygen vacancy concentration. She is investigating how the defect chemical properties of transition metals affect the switching and retention behavior of ECRAM cells and aim to advance the understanding of how future electronic materials can operate using both redox chemical as well as electrostatic stimuli.

Congratulations to Dylan, Malini, Kelotchi and Diana!