The COVID-19 pandemic may have prevented Naiara Munich ’23 from participating in hands-on experiments during the summer of 2020, but she has more than made up for lost time: Being in the Science Pathways Scholars Program (SP)2 and part of Barnard’s Summer Research Institute (SRI) has allowed her to explore her love of science and grow as a researcher.
Munich earned a spot in the Marbella Lab, where she received mentorship and training that has given her deeper insights into how to perform bench science.
“Working in the Marbella Lab has taught me that the key to solid research and a positive research experience is to work as one team, especially when you’re approaching a project from different angles,” Munich said.
Throughout the duration of her SRI program, Munich has conducted research in the Marbella Lab alongside two Ph.D. mentors, Julia C. Hestenes and Richard May, as well as with Professor Lauren E. Marbella and Jerzy Sadowski of Brookhaven National Laboratory. The lab is focused on improving lithium-ion batteries in order to create a more sustainable future.
Collaborating with her mentors and graduate students, Munich prepares battery cells and samples for experiments. This lab work has given her the opportunity to learn different characterization techniques, which further piqued her interest in chemistry and allowed her to explore the field of chemical engineering. It has also enhanced her collaboration and teamwork skills.
“Whether I was working on their project or not, my lab mates would answer my questions, guide me through data analysis, or re-teach me experiment techniques when I forgot to write them in my lab notebooks,” said Munich.
In the future, she hopes to use the skills she gained in SRI and the Marbella Lab to continue pursuing a chemical engineering 4+1 combined master’s degree program through Barnard College and SEAS.
To learn more about Munich’s research in the Marbella Lab and her SRI experience, read her “Research Reflections” in the Q&A below.
How would you describe this research and what you discovered to a lay audience?
Our lab focuses on improving lithium-ion batteries (LIBs) for a more sustainable future. Our goal is to make LIB-powered electric vehicles superior to gas-fueled vehicles so that our cities can start to fully transition from relying on fossil fuels to running on renewable energy sources. The amount of energy — or the “energy density” — that can be stored within an LIB is directly dependent on the electrochemical materials (“electrodes”) used in the battery, which store lithium ions for reversible charge/discharge of the battery. Though lithium cobalt oxide (LiCoO2) has been used as the positive electrode (“cathode”) in the industry for more than 20 years, battery scientists have long been interested in finding alternative materials with greater energy densities.
My two Ph.D. mentors, Julia C. Hestenes and Richard May; my PI, Professor Lauren E. Marbella; Jerzy Sadowski of Brookhaven National Laboratory; and I conducted research on a promising nickel-rich transition metal oxide cathode material (LiNi0.8Mn0.1Co0.1O2, commonly abbreviated “NMC811”) that has a higher energy density than the industry standard.
The major obstacle has been that the interface of Ni-rich cathodes is not stable during battery charging, which causes poor retention of the battery’s energy density over time. During charging, the cathode undergoes many side reactions with the battery’s liquid electrolyte and forms a nanometers-thick layer on its surface, called the cathode electrolyte interphase (CEI). By studying the chemical composition of the CEI, we can pinpoint the specific parasitic reactions occurring at this interface that eventually lead to battery failure.
It is incredibly difficult to characterize the CEI of Ni-rich cathodes due to the nanoscale size of the layer as well as its sensitivity to air. In our study that the journal Chemistry of Materials published late last year, we combined several cutting-edge surface characterization techniques to gain a better understanding of the CEI that forms on cathode films. Using nuclear magnetic resonance (NMR) spectroscopy and X-ray photoemission electron microscopy (XPEEM) at Brookhaven Lab, we discovered that battery charge/discharge causes lithium fluoride, lithium carbonate, and some carboxy-containing structures to bind directly to the NMC811 particle surface. We were also able to find several soluble products that either react with the CEI or deposit randomly on the CEI surface.
So, in very simple terms, we were able to identify the chemical compounds that form due to the surface instability of this promising battery component! Very cool. We hope this work will be useful to researchers working to optimize these cathodes for commercial use by mitigating side reactions.
What was your role?
The data that I helped produce appears in Figure 1 of the paper. This image demonstrates the electron paramagnetic resonance (EPR) spectra for NMC811 cathodes after the first charge and discharge. This experimental data, when combined with the SSNMR data, gives us a better understanding of paramagnetic interactions within the cathode film. In order to produce this data, I prepared NMC811 battery cells and learned how to get the samples ready for EPR experimentation (something that is quite nerve-wracking since the tools used for this experiment are very expensive!).
I also attempted to create NMC811 cathode films that lacked binder because it was causing some issues for us. Binder, however, turned out to be essential, as it literally binds the composite film together. It was not all that shocking that those experiments failed.
Throughout my time working on this project, I had the opportunity to learn several different characterization techniques, such as how to prepare an SSNMR rotor and how to run solution NMR. This further piqued my interest in chemistry and opened my eyes to the field of chemical engineering.
Why is it important to study this topic?
Lithium battery research is an important step towards combating the climate crisis. The impact of burning fossil fuels for energy has left humanity in a precarious situation in which Earth’s temperature has begun to increase at an alarming rate each year. Lithium-ion batteries are a renewable source of energy storage that are currently being used in a variety of products ranging from small electronic devices to electric vehicles. Although LIBs are already being utilized, studying how to improve lithium battery performance is essential if we want to move our cities towards a more sustainable future, and quickly, as the climate crisis is already a very pressing issue. Researching the spatial arrangement and composition of the CEI in the nickel-rich transition metal oxides is one step towards a better understanding of how this compound can help improve the performance of lithium-ion batteries, pushing the cathode closer to someday being used commercially.
Who has influenced your thinking most in this area?
I started off my summer ’21 at the Marbella Lab knowing almost nothing about lithium metal and very little about batteries. I remember trying to read a paper to familiarize myself with the research, but it was not until the end of the 10-week program, when I was preparing for the Summer Research Institute (SRI) poster session, that I really understood what I was reading. That level of understanding was something that I gained by constantly being mentored by Prof. Marbella and the graduate students in my lab: Richard May, Julia C. Hestenes, Andrew Ells, and Bret Schumacher. Whether I was working on their project or not, my lab mates would answer my questions, guide me through data analysis, or re-teach me experiment techniques when I forgot to write them in my lab notebooks (or when I sadly lost my lab notebook — such a tragedy). Their mentorship was instrumental in my growth and proved especially useful during the fall semester, when we gained three new graduate students — Eric Kwon, Emily Barragan, and Susie Park — who would sometimes look to me for guidance. Working in the Marbella Lab has taught me that the key to solid research and a positive research experience comes from working as one team, regardless of the difference between our research projects.
What has your experience been like as an (SP)2 scholar, and how has this program helped support your research?
Being part of the (SP)2 program, which provides funding for underrepresented students in STEM, enabled me to find summer research right after my freshman year, which can sometimes be difficult for incoming sophomores due to their lack of experience. While I was unable to participate in research during summer 2020 because of the COVID-19 pandemic, (SP)2 set up a program that exposed me to the research of professors who worked in different fields, which kept me engaged because I got to learn about more than just chemistry. While receiving funding for research has been incredible, the best part of being a scholar has been befriending my cohort. I was lucky enough to have two other students in my cohort, Maria Blankemeyer ’23 and Maria Elizarraga Hernandez ’23, who are also pursuing a chemistry degree, in addition to the chemical engineering 4+1 combined master’s degree program Barnard offers in partnership with SEAS. The program provided me with built-in study buddies and friends that I get to grow with as we all work together towards our degrees.
Where do you see this research going in the future?
The surface characterizations and research techniques used in this paper open up the possibility for future research of other electrochemical interfaces that may have applications for energy storage. We hope that the results found from our work will allow other researchers to optimize nickel-rich transition metal oxide cathodes so that they can be used commercially in Li-ion batteries!
