PNNL

PNNL and Oklahoma State University (OSU) are joining forces to understand the chemistry that causes mechanical stress and strain in sodium-ion and potassium-ion batteries. This work is possible thanks to an award from the U.S. Department of Energy’s (DOE’s) Established Program to Stimulate Competitive Research (EPSCoR). 

Led by OSU’s Ömer Özgür Çapraz, the project brings together the university’s mechanical studies on the properties of sodium-ion and potassium-ion batteries and PNNL’s quantitative measurements of the batteries’ chemical surfaces and structures. PNNL physicist Vijay Murugesan’s spectroscopy imaging expertise can capture the inner working of ions as they flow through these materials, elucidating challenges and considerations necessary to lengthen the life cycle of sodium-ion and potassium-ion batteries.

Potassium-ion and sodium-ion batteries are promising alternatives to lithium-ion batteries because sodium and potassium are readily available, less expensive, and have competitive performance for electric grid storage. However, because these elements are much heavier and larger than lithium, they react differently and require different chemical hosts. Linking the physical changes sodium and potassium experience in working batteries with their respective chemical changes gives researchers a better idea of the technical challenges to developing sodium-ion and potassium-ion batteries with longer life cycles.

“In our lab, we are capable of detecting potential-dependent dynamic physical responses of the battery electrodes associated with nanoscale changes in the surface or structure of these materials during the cycling condition, but our instruments cannot identify chemistry responsible for stress and strain evolutions in these materials,” said Çapraz. “Combining our work with Vijay’s techniques will be very useful to identify the chemistry behind the surface and structural changes in these cathode materials.”

As a focus lead for the Joint Center for Energy Storage Research (JCESR), Murugesan typically works with other national laboratories to study magnesium and zinc batteries. However, he was interested in the blend of mechanical, physical, and electrochemistry in Çapraz’s project. After Çapraz reached out, Murugesan was intrigued by the initial measurements and eager use PNNL’s capabilities to reveal the surface chemistries.

“I normally collaborate with other electrochemistry researchers,” said Murugesan. “It’s been interesting to return to some of my roots as a physicist to examine these mechanical phenomena and explore these battery challenges.”

DOE’s EPSCoR connects research laboratories like PNNL with universities and institutions in underserved regions of the country for energy research projects. The projects improve research capabilities in the host institutions as top scientists and engineers work together with graduate students and postdoctoral fellows on common research topics.