(3jd) Cryogenic Spectroscopy for Preserved Interface Characterization

For transitioning into a fossil-fuel-free world, there is an urgency to create more efficient next-generation energy technologies. Li-metal battery (LMB) is considered a key technology to overcome the current limitations of conventional lithium-ion batteries due to their high energy density. My current Ph.D. research focuses on improving and understanding next-generation Lithium metal batteries (LMBs) using interface engineering principles advised by Prof. Stacey F. Bent and Prof. Yi Cui. My core synthesis expertise for battery surface modification is atomic layer deposition (ALD). Leveraging ALD, I can control thickness and chemistry of nanofilms with angstrom scale precision. Moreover, I am highly interested in developing new characterization tools to understand critical interfaces in their pristine form in a non-destructive manner. My few major research accomplishments are as follows.

• Cryo-XPS: I have developed and demonstrated a cryogenic X-ray photoelectronic spectroscopy protocol for Li metal anodes. My developed technique allows for sensitive and reactive battery interface characterization with preservation at their pristine state. This is achieved because very low cryogenic temperatures halt chemical reactions and freeze volatile interfacial species. Thus, we can describe the detailed chemical environment of pristine battery interfaces.
• EASE: Electrolyte additives for surface engineering (EASE) inspired by atomic layer deposition. I have demonstrated a new class of electrolyte toward in-situ interface engineering of lithium metal batteries that use unconventional precursor materials as electrolyte additives. This new electrolyte class not only becomes fundamentally interesting due to its distinct properties but also introduces a highly scalable and easy route toward interface engineering for Li metal stability while showing significant performance benefits.

Notably, both cryo-XPS and EASE are independent research directions that I initiated in Bent and Cui groups and in my research field.

• I have developed the interface engineering frameworks for decoupling Li-metal battery performance parameters in their kinetically convoluted regime. This is achieved by correlating thin film properties with performance metrics.

In my Meet the Faculty Candidates poster I will present my work on a new cryogenic spectroscopic tool for battery characterization. Important understanding of the major battery interface, solid electrolyte interphase (SEI) in lithium battery anodes, originates from X-ray photoelectron spectroscopy (XPS). However, room temperature (RT) and ultra-high vacuum (UHV) conditions used during XPS measurement can induce major SEI evolution from reactions and volatilization during XPS. To address this issue, I have developed and demonstrated the cryogenic XPS for SEI characterization. We show that cryogenic conditions can halt chemical reactions and freeze UHV-volatile species due to slow reaction and desorption kinetics at these temperatures We hypothesize that the true SEI thickness can also be retained, benefiting from the lower vapor pressure of different frozen SEI species at cryoT. Indeed, we discover significantly different SEI speciation and a thicker pristine SEI with cryo-XPS. While cryo-XPS ensures SEI preservation over an extended period under UHV, compositions derived from RT-XPS are dominated by stable species only. We confirm the SEI thickness preservation from Li 1s high-resolution spectra of the underlying metal substrate. We carefully analyze and decouple three major effects during SEI analysis: UHV effect, reaction effect, and X-ray beam effect. UHV and reaction are found to be the major drivers for SEI compositional changes. Whereas RT-XPS-based chemical descriptions fail to provide performance correlations, pristine SEI composition achieved by cryo-XPS enables performance correlations across diverse electrolyte chemistries. We expect our research to inspire future studies of sensitive and reactive interface characterization under cryogenic conditions to ensure pristine state preservation.

Overall, I think that I am highly equipped to address the energy generation challenges in the world based on my Ph.D. experience in next-generation lithium metal batteries. I envision a world where energy crisis is a thing of the past. Ultimately, in my independent research career as a principal investigator, I will continue working on solving grand energy challenges and accelerating industrial scaleup of next-generation energy-efficient technologies. To improve the fundamental understanding of the systems which is crucial for technological scaleup, I will also develop new characterization tools for characterizing pristine interfaces in non-destructive manners.

Selected Publications

1. Shuchi, S. B., D’Acunto, G., Sayavong, P., Oyakhire, S. T., Sanroman Gutierrez, K. M., Risner-Jamtgaard, J., Cui, Y., Bent, S. F. Cryogenic X-ray photoelectron spectroscopy for battery interfaces. (In revision) Preprint:https://chemrxiv.org/engage/chemrxiv/article-details/67c210216dde43c908e52d44
2. Shuchi, S. B.†, Oyakhire, S. T.†, Zhang, W., Sayavong, P., Ye, Y., Chen, Y., Yu, Z., Cui, Y., Bent, S. F., 2024. Deconvoluting Effects of Lithium Morphology and SEI Stability at Moderate Current Density Using Interface Engineering. Advanced Materials Interfaces, 11(36), 2400693. Cover article (back), Editor’s choice, Wiley Hot Topic: Surfaces and Interfaces
3. Shuchi, S. B.†, Sanroman Gutierrez, K. M.†, Shearer, A. B., Oyakhire, S. T., Cui, Y., Bent, S. F. Equal resistance single and bilayer films decouple role of solid electrolyte interphase from lithium morphology in batteries. Energy & Environmental Science Batteries (EES Batteries), RSC. 2025, DOI: 10.1039/D5EB00004A.
4. Oyakhire, S.T.†, Kim, S.C.†, Zhang, W.†, Shuchi, S.B.†, Cui, Y. and Bent, S.F., 2024. Galvanic Corrosion Underlies Coulombic Efficiency Differences in High-Performing Lithium Metal Battery Electrolytes. Energy & Environmental Science (EES), RSC. Preprint: https://chemrxiv.org/engage/chemrxiv/article-details/672668e25a82cea2fad470ad

Patent and Disclosure

1. Shuchi, S.B., Cui, Y., Bent, S.F. Electrolyte additives for alkali metal batteries. US Provisional patent application number 63/836942 (2025).

Teaching Interests

Throughout my academic and research career, I have been committed to advance and encourage teaching, research mentorship, and organizational mentorship efforts. My teaching and mentoring philosophy is to make sure that the students and mentees can achieve their specific goals from the mentorship, and I play the role of a facilitator to make the path easier for them. I have taught the Microkinetics class with Prof. Matteo Cargnello at Stanford for two consecutive years. I have led many discussion sessions to deeply explain how the theories in the class can be used to solve problems. I think that patience and encouragement are very important qualities for teachers, and I always practice that during my roles as a teacher or, mentor. Oftentimes, this helps the students to become more confident. For my role as a teaching assistant, I have received excellent evaluations from my students. For any course, it is very important to understand the basics and to be able to apply the learnings. In my future teaching roles, I aim to design interactive course-works, highlight real world applications, and introduce industrial visit or laboratory experience opportunities.

In research mentorship, I try to find suitable projects for my mentees that are not only impactful but also the mentees will enjoy working on those. Two of my Ph.D. research rotation mentees ended up joining the lab, which was a very fulfilling experience. A co-first authored article with one my Ph.D. mentees is also published. Moreover, my undergraduate student have successfully completed undergraduate research thesis under my mentorship. I am very proud of everything my mentees have achieved and are achieving. Apart from formal mentorships, I also try to provide research and career guidance to multiple junior students in the lab through spontaneous conversations.

Beyond research and teaching, I have been engaged in multiple outreach efforts throughout my career. One of my major non-research outputs at Stanford is serving as organizer for graduate application mentorship program (GradAMP) at Stanford University where I recently led efforts to initiate mentorship for undergraduate students at and outside of Stanford to encourage equity and inclusion in graduate school admission. Altogether, we have matched and provided mentorship to a cohort of ~180 Stanford Ph.D. student mentors and undergraduate student mentees from different universities. Besides, I have served as organizer for Engineering students for DEI (ES4DEI), served as mentor and lab representative at multiple programs, led Ph.D. recruitment event mentorship initiatives. Moreover, during my undergraduate, I served as the vice-president of Environment Watch club where I organized multiple programs including national level environmental olympiads for high school students to encourage them for future environmental works. I have also spoken at multiple public seminars, served as a panelist in high-school STEM workshops and fellowship info sessions to encourage education and research. In future, I plan to continue fostering mentorship activities across different departments in my institution and multiple institutions around the world in my independent career as a faculty member.