Description:

Trienens Institute Seminar Series

Join the Paula M. Trienens Insitute for Sustainability and Energy for an event supported by the Generate Pillar, one of Six Pillars of Decarbonization. Ph.D Candidate Katherine Steinberg from Massachusetts Institute of Technology will give a presentation "Unveiling composition-functionality relationships at lithium metal solid electrolyte interphases".

What: "Unveiling composition-functionality relationships at lithium metal solid electrolyte interphases"
Who: Katherine Steinberg, Massachusetts Institute of Technology
When: Thursday, May 1, 11 am - 12 pm 
Where: Technological Institute, Room C211

Abstract:

Lithium (Li) has the lowest electrochemical reduction potential and density of any metal, making it an exceptionally desirable anode material for batteries and a powerful chemical reductant. However, the reducing nature which makes Li so useful brings challenges: it is thermodynamically unstable in practical liquid electrolytes, driving the formation of a nanoscale passivation film called the solid electrolyte interphase (SEI). The SEI mediates transport and reactivity at Li surfaces, and its composition and structure arise spontaneously from the chemistry of the electrolyte, so it is both critically important to electrode functionality and challenging to study.

In this talk, Steinberg will share three projects that advance understanding of composition-functionality relationships for Li SEI, leveraging the use of informative model systems, multimodal characterization, and quantitative analysis of key phases. To begin, Steinberg will share a project investigating the role of lithium carbonate (Li 2 CO 3), which has long been considered a beneficial phase at Li metal battery anodes, yet without a clear mechanistic explanation. Here, through the use of two model systems, Steinberg and team found that Li 2 CO 3 exhibits an elevated ionic conductivity compared to other previously-measured inorganic SEI materials, and its enrichment in native SEI correlates with decreased inactive Li 0 formation upon cycling. Next, Steinberg will share a deep dive into the titration methods used in the previous project, in which they quantitatively inventoried Li-containing residual materials recovered from cycled electrodes across multiple electrolytes, deciphering previously unresolved capacity losses and probing their impact on observed inter-electrolyte trends. Finally, Steinberg will shift focus from batteries to electrosynthesis, investigating the role of Li surface chemistry in determining reactivity in Li-mediated electrochemical ammonia synthesis (LiMEAS). Here, Steinberg and team combined quantification of key products with multiscale imaging approaches to understand how the SEI in this system differs from those in Li metal batteries, finding that the proton donor is essential to disrupt passivation against Li-N 2 reactivity. Together, these studies illustrate how the quantification of interphase components and side products applied in tandem with characterization and imaging tools can unveil important relationships between SEI chemistry and Li electrode performance.