New microscope helps with design of high-performance batteries

A research team from the University of Houston, in collaboration with researchers from the Pacific Northwest National Laboratory and the U.S. Army Research Laboratory, has developed a cutting-edge microscope that offers a deep understanding of the functioning of batteries by unveiling their inner workings.

By providing real-time visualization of the solid electrolyte interphase (SEI) dynamics, the innovative operando reflection interference microscope (RIM) sheds light on a previously elusive component of batteries. This breakthrough has significant implications for the development of next-generation high-performance batteries, addressing the growing demand for safer, more efficient, and affordable energy storage solutions, the university said in a release about the research. 

The world is increasingly powered by batteries, as smartphones, electric cars and other devices that rely on lithium-ion batteries proliferate society. In response to this trend, and the increasing demand for reliable energy storage, the research team undertook their work that centers around the development of the RIM, which they assert will pave the way for the next generation of high-performance batteries. 

The key focus of the research was the SEI layer, an ultra-thin and delicate layer on the surface of battery electrodes that plays a crucial role in determining battery performance. The chemical composition and structure of the SEI layer undergo continuous changes during battery operation, making it a challenge to study. 

Xiaonan Shan, assistant professor of electrical and computer engineering at the University of Houston's Cullen College of Engineering and the corresponding author of the study published in the journal Nature Nanotechnology, explained the significance of their achievement. "We have achieved real-time visualization of solid electrolyte interphase (SEI) dynamics for the first time," Shan said. "This provides key insight into the rational design of interphases, a battery component that has been the least understood and most challenging barrier to developing electrolytes for future batteries."

The RIM developed by the research team offers an unprecedented level of sensitivity, allowing for the study of the SEI layer. By applying the principles of interference reflection microscopy, the microscope directs a beam of light toward the battery electrodes and SEI layers, capturing reflected light that contains crucial information about the SEI's evolution process. This technique enables researchers to observe the entire reaction process with high spatial and temporal resolution, providing valuable insights into the working mechanism of the SEI layer and facilitating the design of high-performance batteries. Guangxia Feng, a graduate student at the University of Houston who conducted a significant portion of the experimental work, highlighted the advantages of the RIM. "The RIM is very sensitive to surface variations, which enables us to monitor the same location with large-scale high spatial and temporal resolution," Feng said.

In contrast to conventional cryo-electron microscopes that capture a single image at a specific time, the RIM allows continuous tracking of changes at the same location. This breakthrough offers battery researchers a new tool to deepen their understanding of battery reactions and materials. 

The research team emphasized the collaborative nature of their work. Wu Xu from the Pacific Northwest National Lab, an expert in electrolyte design, provided critical insights and guidance on the project. Kang Xu, a specialist in SEI research at the Army Research Lab, contributed significant expertise to help interpret the observed phenomenon. 

Lead authors of the study were Feng and Yaping Shi, engineering students from the University of Houston, along with Hao Jia from the Pacific Northwest National Laboratory. Additional contributors to the research are Xu Yan, Yanliang Liang, Chaojie Yang, and Ye Zhang from the University of Houston, as well as Mark Engelhard from the Pacific Northwest National Laboratory. 

This breakthrough in microscopy technology holds promise for the development of next-generation batteries with improved performance and safety. As the demand for advanced energy storage solutions continues to grow, this research will play a vital role in enabling the design of batteries that meet the evolving needs of modern society.