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Navigating the crossroads: Mali Balasubramanian takes a new path for battery research

Mali Balasubramanian made a rewarding mid-career shift to focus on studying new battery materials and systems using X-ray spectroscopy and other methods. Credit: Carlos Jones/ORNL, U.S. Dept. of Energy

Having passed the midpoint of his career, physicist Mali Balasubramanian was part of a tight-knit team at a premier research facility for X-ray spectroscopy. But then another position opened, at the Department of Energy’s Oak Ridge National Laboratory — one that would take him in a new direction.

“I was really at a crossroads,” said Balasubramanian, who was enjoying his research and colleagues at the DOE’s Argonne National Laboratory. “I loved the work there. But I also liked battery science and wanted to explore something different: being involved directly in programmatic science.”

So after 18 years on one path, he took a left turn to become leader of ORNL’s Emerging and Solid State Batteries Group in the Energy Science and Technology Directorate. He guides his team in exploring potential new materials and systems for electric vehicle and other batteries.

Batteries operate by the movement of ions between positively and negatively charged electrodes separated by an electrolyte. Balasubramanian and his group work on problems such as finding effective, earth-abundant materials for the positive electrode and methods for manufacturing solid electrolytes, which could enhance battery safety while reducing their size.

Balasubramanian chose his new direction partly because his professional experiences had demonstrated how refreshing new viewpoints could be. Collaborating across scientific fields was a hallmark of his job at a DOE circular particle accelerator, the Advanced Photon Source, or APS. Balasubramanian helped visitors from around the globe study how the X-rays interact with matter. His collaborations fed each other, with prolific results: He has authored more than 275 publications, which other scientists have cited more than 16,000 times.

“I’ve always done my best work with others,” he said. “I was excited by the people here at ORNL. It’s always the people that are important.”

Shining a light on materials

Balasubramanian’s father, a chemist at an ordnance factory in the south of India, sparked his son’s interest in science. Balasubramanian recalls being around age 8 when his dad explained heavy water and the structure of glucose, conveying obvious excitement about what chemistry could do and reveal. “Dad was an inspiration for me and my sister,” Balasubramanian said. “We both became scientists.”

Later Balasubramanian was drawn to spectroscopy, the branch of science concerned with measuring how matter absorbs or emits light and other radiation. The results reveal details about material structure and properties.

After studying physics in India, Balasubramanian attended graduate school at the University of Connecticut, where his doctoral advisor opened the door to using the synchrotron light source at Brookhaven National Laboratory. Although he went on to work at Brookhaven, Balasubramanian soon accepted a position at the APS, a DOE Office of Science user facility, where intense X-ray light is channeled to experiments at various beamlines.

Balasubramanian supported beamlines directed by Edward Stern, known as the father of the field of X-ray absorption fine structure spectroscopy, while at Argonne. During the limited time set aside for his own research, Balasubramanian focused on new ways to use X-ray spectroscopy to probe the characteristics of energy materials in fuel cells, batteries and biofuels.

For example, he developed and applied a technique for studying operating lithium-ion batteries in the beamline. The materials in these batteries, which power everything from cell phones to electric vehicles, change atomically and chemically during cycling. Balasubramanian used his new spectroscopy method to understand the real-time correlation between the materials’ structures and properties at various stages.

While assisting APS users, Balasubramanian discovered a passion for mentoring, which led him to collaborate with students and postdoctoral researchers on fundamental studies related to energy storage. Over time, he also became a senior investigator in Argonne’s battery group, pursuing advances for electric grid storage as well as electric vehicles. All facets of his work involved partnering with researchers from different scientific fields, backgrounds and experience levels.

“I’ve been very fortunate to work with extremely smart people from other places — graduate students to Nobel Prize nominees — from whom I learned so much,” said Balasubramanian. “It’s important having a diversity of interactions. New things always come out of it. I’m always open to that.”

Expanding battery expertise at ORNL

Today, his job at ORNL allows Balasubramanian to focus full time on energy storage challenges. For example, a key goal for electric vehicle batteries is replacing the nickel and rare cobalt that serve as active materials within the positive electrode. The U.S. relies on foreign sources for these critical elements. Balasubramanian and his team are seeking ways to overcome performance challenges associated with more abundant metals like manganese and iron.

Achieving these improvements can help the U.S. meet clean energy goals with wider integration of wind and solar energy, as well as expanded electric vehicle charging capacity. “People have been working on this a long time, but there has been a renewed emphasis because of supply chain issues,” Balasubramanian said. “We have to get this going in the next 10 years, because if you have to go renewable, you have to have battery storage.”

He has planned visits to synchrotrons like Argonne’s — now as a user — where X-ray beams can help characterize new combinations of metals. He is also excited at the prospect of using the beamline at ORNL’s neutron sources, the Spallation Neutron Source and the High Flux Isotope Reactor, which bombard materials with neutrons to reveal internal details. SNS and HFIR are DOE Office of Science user facilities.

“I knew there was an opportunity to bring user facility science to a battery program at a larger scale,” Balasubramanian said. “My intention is to develop a significant advanced characterization team, an expertise that wasn’t in the group before, to complement the great work that’s already being done here.”

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