Fascinating technology

A lasting and precious heritage | MIT News

Betar Gallant, associate professor at MIT and career development chair in mechanical engineering for the class of 1922, grew up in a curious and independent family. His mother held several jobs over the years, including urban planning and geospatial. His father, although formally trained in English, read textbooks of all kinds cover to cover, taught many technical fields himself, including engineering, and worked there successfully. When Gallant was very young, she and her father did science experiments in the basement.

It was only as a teenager that she says she was drawn to science. Her father, who had fallen ill five years prior, died when Gallant was 16, and while grieving, “when I missed him the most”, she began to watch what had captivated her father.

“I started to become more interested in the things he had spent his life working on in order to feel closer to him in his absence,” Gallant said. “I spent a couple long months one summer going through some of the stuff he had been working on and found myself reading physics textbooks. That was enough and I was hooked.

The love for finding and understanding solutions independently, which she apparently inherited from her parents, eventually led her to the professional love of her life: electrochemistry.

As an undergraduate student at MIT, Gallant completed an Undergraduate Research Opportunity Program project with Professor Yang Shao-Horn’s research group that progressed from her sophomore year to her graduate thesis. ‘studies. This was Gallant’s first formal exposure to electrochemistry.

“When I met Yang, she showed me very quickly how challenging and rewarding electrochemistry can be, and there was real conviction and enthusiasm in the way she and her group members talked about the research,” says Gallant. “It was totally eye-opening, and I’m lucky she was a (relatively rare) electrochemist in a mechanical engineering department, otherwise I probably wouldn’t have gone that route.”

Gallant earned three degrees at MIT (’08, SM ’10, and PhD ’13). Before joining the MIT faculty in 2016, she was a Kavli Nanoscience Institute Prize Postdoctoral Fellow at Caltech in the Chemistry and Chemical Engineering Division.

His passion for electrochemistry is huge. “Electrons are simply dazzling – they power much of our everyday world and are key to a renewable future,” she says, explaining that despite electrons’ incredible potential, lone electrons cannot be stored and products on demand, because “nature does not allow excessive amounts of charge imbalances to accumulate.

Electrons can, however, be stored on molecules, in bonds, and in metallic ions or non-metallic centers capable of losing and gaining electrons – as long as positive charge transfers occur to accommodate the electrons.

“This is where the chemistry comes into its own,” says Gallant. “What kinds of molecules or materials can behave in this way? How to store as much load as possible while minimizing weight and volume? »

Gallant points out that early battery developers using lithium and ions built technology that “arguably has shaped our modern world more than any other.

“If you look at some of the early papers, the concepts of how a lithium-ion battery or a lithium metal anode works were sketched out by hand – they had been inferred to be true, even before the field has the tools to prove all the mechanisms were actually happening – yet, even now, these ideas still turn out to be right!”

According to Gallant, “It’s because if you really understand the basic principles of electrochemistry, you can begin to understand how systems will behave. Once you can do that, you can really start designing better materials and devices.

Truly her father’s daughter, Gallant emphasizes independent finding of solutions.

“At the end of the day, it’s a race to have the best mental models,” she says. “A large lab and lots of funding and staff to run it is very nice, but the most valuable tools in the toolbox are strong mental models and a way of thinking about electrochemistry, which is actually very personalized according to the researcher.”

She says one project with immediate impact coming out of her Gallant Energy and Carbon Conversion Lab involves primary (non-rechargeable) battery work that she and her team are working to bring to market. This involves injecting new electrochemically active electrolytes into the main high-energy batteries as they are assembled. Replacing a conventional electrolyte with the new chemistry decreases the battery’s normally idle weight and dramatically increases energy, Gallant says. An important application of these batteries would be in medical devices such as pacemakers.

“If you can extend lifespan, you’re talking about longer times between invasive replacement surgeries, which really affects the patient’s quality of life,” she says.

Gallant’s team is also leading efforts to enable higher-energy rechargeable lithium-ion batteries for electric vehicles. The key to a gradual change in energy, and therefore range, is to use a lithium metal anode instead of graphite. However, lithium metal is highly reactive with all battery electrolytes, and its interface must be stabilized in a way that researchers still elude. Gallant’s team is developing design guidelines for such interfaces and for next-generation electrolytes to form and maintain these interfaces. Gallant says that applying the technology for this purpose and bringing it to market would be “a bit longer term, but I think this change from lithium anodes will happen, and it’s only a matter of time.”

About six years ago, when Gallant founded her lab, she and her team began introducing carbon dioxide into batteries to experiment with the electrochemical conversion of greenhouse gases. She says they realized that batteries don’t present the best practical technology for mitigating CO2, but their experimentation has opened up new avenues for carbon capture and conversion. “This work got us thinking creatively, and we started to realize that there is tremendous potential for manipulating CO2 reactions by carefully designing the electrochemical environment. This led his team to the idea of ​​performing electrochemical transformations on CO2 of a captured state bound to a capture sorbent, replacing the energy-intensive regeneration step of current capture processes and streamlining the process.

“Now we see other researchers working on this too and taking this idea in exciting directions – it’s a very challenging and very rich topic,” she says.

Gallant has won awards including an MIT Bose Fellowship, the Army Research Office Young Investigator Award, the Scialog Fellowship in Energy Storage and in Negative Emissions Science, a CAREER Award from the National Science Foundation, the Ruth and Joel Spira Award for Distinguished Teaching at MIT, the Electrochemical Society (ECS) Battery Division Early Career Award, and an ECS-Toyota Young Investigator Award.

These days, Gallant makes some of her best thoughts while brainstorming with members of her research group and with her husband, who is also an academic. She says being a professor at MIT means she has “a queue of things to think about,” but sometimes she gets an epiphany.

“My brain is overloaded because I can’t think of everything instantly; ideas must align! So there’s a lot going on in the background all the time,” she says. “I don’t know how it works, but sometimes I go for a walk or do something else, and an idea pops up. These are the most fun.