In a recent study published by Nature Communications, an interdisciplinary team of researchers investigated how rechargeable battery materials respond to extreme environments. Their conclusions lay the groundwork for a better understanding of how engineers can design and select more effective materials for these types of specialized batteries going forward.

Led by Feng Lin, an assistant professor of chemistry, and Xianming (David) Bai, an assistant professor of materials science and engineering, the team believes their findings will enable further study of the potential use of rechargeable batteries in space, in nuclear reactors, and in other environments where human access may be limited – and where robotics might be used.

Major hurdles for battery performance in these extreme environments arise with exposure to wide variation in temperature (-100 °C to 400 °C) and to radiation by high-energy neutrons and gamma rays, which can lead to structural damage, explained the study’s lead author, Muhammad Mominur Rahman, a fifth-year doctoral student in Lin’s research group. How exactly battery materials respond to intense irradiation and temperature isn’t well known, he said, and in turn, there’s a lack of guiding principles for batteries designed to stand up to them.

To help fill those gaps, the researchers worked to systematically study the defect and structural evolution of battery materials in severe environments. They focused on sodium-ion and lithium-ion materials in the context of high-energy krypton irradiation at various temperatures.

The team conducted the work at Argonne National Laboratory, and using microstructural analysis, Lin’s group found that the lithium-ion battery material proved to be more resistant to radiation than that of sodium-ion based battery materials. To understand the underlying reason, Bai’s group conducted quantum-mechanics-based density functional theory modeling.

They found that the smaller ionic radius of lithium, compared to that of sodium, leads to easier accommodation of antisite defects — a type of defect produced by radiation in these materials — and results in higher radiation tolerance of lithium-ion battery materials. The researchers’ findings on the effects of ionic radius difference could provide simple but effective guidance for selecting rechargeable battery materials with good radiation tolerance, Rahman said.

“This work provides a stepping stone for promoting future studies involving electrochemical energy storage devices in extreme environments,” Rahman said. “This is one of the first systematic and fundamental studies of the defect and structural evolution of alkali ion-based battery materials under extreme environments. We believe our study will inspire the research community and promote more studies related to the effects of radiation on the performance of battery materials in the future." 

The team also emphasizes that their research effort demonstrates the positive results of interdisciplinary collaboration at Virginia Tech. Bai and Lin came to know one another through the Proposal Development Institute, sponsored by the Office of the Vice President for Research and Innovation. Since then, they have frequently pursued opportunities to collaborate.

In this collaboration, the two had complementary expertise: Lin’s group mainly conducted the experimental work, while Bai’s group conducted atomistic modeling work to explain the experimental results. “Our work is one good example of how interdisciplinary collaboration enables us to come across the boundaries of our individual research areas and get to the findings that couldn’t be reached alone,” Bai said.

Written by Lee Ann Ellis