Title: High-Energy-Density Solid-State Lithium-Sulfur Battery Design
Speaker: Dr. Changmin Shi, Postdoctoral Research Associate, School of Engineering, Brown University
Abstract: Solid-State Lithium-Sulfur (Li-S) batteries are a very promising candidate to achieve safe battery design with high energy density. Among all solid-state electrolyte separators, cubic-structural garnet electrolyte (Li7La3Zr2O12, LLZO) is highly desired due to its relatively high ionic conductivity and air stability. However, the unstable Li-metal-anode/LLZO and sulfur-cathode/LLZO interface hindered development of garnet solid-state Li-S batteries. The Li-metal-anode/LLZO interface challenge has been well-resolved by us through a porous-dense(-porous) 3D architecture with evidence of achieving a critical current density of 100 mA/cm2 at room temperature. Nevertheless, the instability between sulfur cathode and LLZO has not been explored and systematically studied in battery field.
I will first discuss about the charge failure mechanism in solid-state Li-S batteries using LLZO solid electrolyte. I will show how the surface element segregation of LLZO on the sulfur cathode side impacts the charge voltage profile. I will also discuss about different strategies on how to overcome the surface element segregation problems that led to a cell failure. With our designed catholyte chemistry, the highest energy density of 223 Wh/kg and 769 Wh/L was obtained.
Given the fact that a small amount of catholyte is normally required for batteries using LLZO as a solid electrolyte, it compromises the safety of the solid-state batteries. In the second part of my talk, I will introduce the first up-to-date all-solid-state Li-S batteries using LLZO solid electrolyte that eliminate the need for any liquid components. This work pioneers a design by using Li salt as both an ionic conductive medium and as an adhesive agent. Overall, these works establish new aspects and new approaches towards the design of high-energy-density solid-state Li-S batteries and other battery systems.
Dr. Changmin Shi is a Postdoctoral Research Associate at the School of Engineering at Brown University, working with Prof. Brian Sheldon. He obtained his Ph.D. in 2023 at the department of Materials Science and Engineering from the University of Maryland, College Park, supervised by Prof. Eric Wachsman, and his Master’s degree from Columbia University in 2019 and B.Eng from the University of Science and Technology Beijing in 2017. Since 2023, he has been appointed as Youth Editorial Board Member of Nano Research Energy, a sister-journal of Nano Research. His research aims to tackle pressing challenges at the energy-environment nexus by tuning electrode/electrolyte interface in batteries, thermal energy management for radiation cooling and solar energy collection, as well as characterizing the properties of energy storage and harvesting materials and establishing correlations between their structure and properties.
Zoom link:
https://iastate.zoom.us/j/98391312464?pwd=SjBncGRMQjZ1bUJQaElaZ3d1SHlsZz09
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