Materials Horizons Emerging Investigator Series: Dr Guang Yang, Oak Ridge National Laboratory (ORNL), USA
Abstract
Our Emerging Investigator Series features exceptional work by early-career researchers working in the field of materials science.
Dr Guang Yang is an Energy Storage Material Scientist in the Energy Storage & Conversion Group within the Chemical Sciences Division at Oak Ridge National Laboratory (ORNL). Yang completed his BS in Biological Sciences and Medical Engineering at Southeast University, China, in 2009, followed by an MS in Advanced Materials from Ulm University, Germany, in 2012, and a PhD in Chemical Engineering from Florida State University in 2017. He began his career as an ASTRO Fellow and subsequently underwent 2 years of postdoctoral training at ORNL. Dr Yang currently spearheads several U.S. Department of Energy (DOE)-funded programs focused on next-generation batteries and sustainable energy conversion technologies. These initiatives include the development of high-energy solid-state batteries, redox flow batteries for grid-scale energy storage, and electrochemical CO2 conversion technologies. Dr Yang has been recognized with several prestigious awards, such as the ARPA-E IGNIITE Early Career Award and the UT-Battelle Outstanding Scholarly Output Award. He has authored over 80 peer-reviewed publications, two book chapters, and has filed six patents and invention disclosures.
Read Guang Yang's Emerging Investigator Series article ‘Effects of catholyte aging on high-nickel NMC cathodes in sulfide all-solid-state batteries’ ( https://doi.org/10.1039/D4MH01211A ) and read more about him in the interview below:
MH: Your recent Materials Horizons Communication demonstrates catholyte aging on high-nickel NMC cathodes in sulfide all-solid-state batteries. How has your research evolved from your first article to this most recent article and where do you see your research going in future?
GY: From the inception of our research into solid-state batteries, we've taken significant strides in understanding and mitigating challenges associated with high-nickel NMC cathodes in sulfide all-solid-state batteries. Initially, our studies focused on the capacity loss observed when using the cold-press thick pellet with Generation 1 sulfide solid-state electrolyte (SSE), specifically β-Li3PS4. Utilizing operando neutron and Raman imaging technologies, we discovered significant lithium losses at the cathode SSE interface (cathode electrolyte interface or CEI) with high-voltage cathode LiNi0.8Mn0.1Co0.1O2 (NMC811).
Our subsequent research aimed to stabilize this cathode/sulfide SSE interface more effectively. We ventured into developing thin, flexible sulfide SSEs using Generation 2 materials, such as argyrodites Li6PS5Cl. Here, we explored how tailoring the molecular weight of a rubbery binder could stabilize the cathode/SSE interfaces, addressing the unstable CEI from the electrolyte side.
More recently, our efforts have shifted toward selecting optimal materials as catholytes, including various sulfides (Li6PS5Cl, Li10GeP2S12, Li10SnP2S12, etc.) and halide SSEs (Li3InCl6 and Li3YCl6) working collaboratively with other colleagues at ORNL, and collaborators from SLAC and ANL. The next phase involved developing a reliable method to evaluate which catholyte effectively reduces the parasitic current resulting from side reactions between the cathode and SSE. This led to the development of a new methodology, detailed in our latest Materials Horizons Communication, to more efficiently evaluate these interactions.
Looking ahead, our research will continue to evolve in several exciting directions:
Development of new methodologies: we aim to refine methods that better correlate the cycle life and calendar life of sulfide solid-state batteries (SSBs).
Material evaluation: we plan to utilize our newly developed evaluation methodology to more effectively screen materials that stabilize the cathode/SSE interface.
These steps are part of our broader goal to advance the practical application of solid-state battery technology, making it a more viable and sustainable option for energy storage.
MH: What aspect of your work are you most excited about at the moment?
GY: The most exciting aspect of my work is the transformative research our team is doing to enhance lab-scale solid-state battery (SSB) performance. We're leveraging a comprehensive understanding of materials and processes to innovate in cell fabrication and design. For example, the most recent key breakthrough, informed by polymer physics, was discovering that increasing the binder molecular weight in sulfide sheet-type electrolytes leads to a strain-hardening effect that improves the electrolyte/cathode contact during SSB cycling. These advancements not only bridge the gap between theory and practical application but also expand the possibilities within this field.
MH: In your opinion, what are the most important questions to be asked/answered in this field of research?
GY: In the evolving field of sulfide solid-state batteries (SSBs), there are pivotal questions that must be tackled to push the technology forward. For example, reducing the costs associated with SSE precursors, boosting the air stability of SSEs, and improving the interfacial stability between the anodes (such as Li metal) and cathodes with SSEs are areas that demand attention. These challenges can be structured into two main categories:
At the laboratory scale, a fundamental question is how to accelerate the discovery of new materials and chemistries and develop an effective evaluation matrix to fulfill the needs of next-generation all-solid-state batteries. This requires advancing our current capabilities in chemistry and materials science to discover solutions that not only enhance the performance, safety, and durability of SSBs but also streamline their evaluation.
On the manufacturing and processing level, the challenge lies in scaling these technologies efficiently. A key question here is identifying what new equipment and methods are necessary for scaling up production and material processing that diverge from traditional lithium-ion battery infrastructures. This involves innovating manufacturing techniques suited to the unique properties of sulfide solid-state electrolytes and integrating these methods into existing battery production frameworks.
MH: What do you find most challenging about your research?
GY: The most challenging aspects of my research on solid-state batteries include: (1) the lack of effective tools to thoroughly explore embedded solid/solid interfaces, and (2) the difficulty in unveiling the failure mechanisms due to the heavily coupled mechano-chemical and electrochemical responses during cell operation. To address these challenges, our team is actively developing tools for operando Raman, neutron (with Dr Yuxuan Zhang and Hassina Bilheux at ORNL), and synchrotron spectroscopy (with Dr Jagjit Nanda and Xueli Zheng at Stanford, SLAC), as well as imaging techniques. These advancements are crucial for deepening our understanding and improving the performance of solid-state batteries.
MH: In which upcoming conferences or events may our readers meet you?
GY: You can meet me at several notable events in the coming months. I am co-organizing the High-Energy Battery Frontiers symposium at ACS Spring 2025 in San Diego, CA, and will be giving invited talks on our latest research progress in sulfide solid-state batteries at the 247th ECS Meeting from May 18–22, 2025, in Montréal, Canada. Additionally, I will be attending the ARPA-E Energy Innovation Summit in March and the DOE VTO Annual Merit Review (AMR) meeting in June, both in Washington, DC.
MH: How do you spend your spare time?
GY: In my spare time, I cherish every moment with my 4-year-old, ensuring I'm there to accompany her and my wife through her daily adventures. As a family, we love unwinding together by watching cartoons, which adds a touch of fun and laughter to our day. Additionally, I have a keen interest in house improvement and repair projects, whether it's building decks, painting walls, or fixing things around the house, I find it both challenging and rewarding. We also embrace the outdoors during the summer, taking full advantage of East Tennessee's beautiful mountains and waters by swimming, kayaking, boating, and hiking.
MH: Can you share one piece of career-related advice or wisdom with other early career scientists?
GY: To excel in your scientific career, focus on becoming highly skilled in the topics you know best, and creatively explore related yet distinct areas where your passion can truly flourish.
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