Apr 25, 2024
4:45pm - 5:00pm
Room 424, Level 4, Summit
Xueli Zheng1
Stanford University1
Operando sulfur K-edge X-ray Absorption Spectroscopy (XAS) has emerged as a powerful tool to unravel the complex sulfur redox chemistry in lithium-sulfur (Li-S) batteries. Li-S batteries are promosing as a compelling alternative to conventional lithium-ion batteries due to their exceptional theoretical energy density. However, their practical implementation faces challenges related to capacity fading, limited cycle life, and complex sulfur redox chemistry.
Operando XAS plays a crucial role in understanding and addressing the above-mentioned challenges.
In this abstract, we first explore the application of
operando sulfur K-edge XAS to gain real-time insights into the sulfur redox chemistry occurring at the sulfur cathode during Li-S battery operation. Using
operando sulfur K-edge XAS, we revealed the dynamics of intermediate polysulfide species and the sulfur electrochemical conversion. Furthermore, the result guides us to design the multi-metal interaction with polysulfides. Li-S battery performance significantly enhanced by incorporating multi-metal to accelerate the Li-S reaction kinetics.
Then, we designed the cross-sectional Li-S battery cell to quantify polysulfide diffusion rate using sulfur K-edge X-ray spectromicroscopy. We found that elemental sulfur discharged to higher-order polysulfide species (Li
2S
8 and Li
2S
6) on the cathode and quickly diffused to the entire separator. This polysulfide diffusion resulted in the majority capacity decay in Li-S batteries.
In summary, we highlight the crucial role of
operando XAS and X-ray spectromicroscopy as a transformative tool to overcome the fundamental challenges in Li-S batteries. Our study offers the potential for high-energy-density and sustainable energy storage solutions.