Electrochemistry, from batteries to brains | MIT News



Bilge Yildiz’s analysis impacts a variety of applied sciences. The members of her lab examine gasoline cells, which convert hydrogen and oxygen into electrical energy (and water). They examine electrolyzers, which go the opposite manner, utilizing electrical energy to transform water into hydrogen and oxygen. They examine batteries. They examine corrosion. They even examine computer systems that try to mimic the way in which the mind processes info in studying. What brings all this collectively in her lab is the electrochemistry of ionic-electronic oxides and their interfaces.

“It may seem like we’ve been contributing to different technologies,” says Yildiz, MIT’s Breene M. Kerr (1951) Professor within the Department of Nuclear Science and Engineering (NSE) and the Department of Materials Science and Engineering, who was just lately named a fellow of the American Physical Society. “It’s true. But fundamentally, it’s the same phenomena that we’re after in all these.” That is, the habits of ions — charged atoms — in supplies, notably on surfaces and interfaces.

Yildiz’s consolation crossing scientific borders might come from her trek to the place she is — or vice versa. She grew up within the seaside metropolis of Izmir, Turkey, the daughter of two math academics. She spent a variety of enjoyable time by the ocean, and likewise tinkered together with her dad on restore and development tasks at dwelling. She loved finding out and attended a science-focused highschool, the place she vividly remembers a specific two-year challenge. The metropolis sat on a polluted bay, and her biology instructor linked her and a buddy with a college professor who acquired them engaged on methods to wash the water utilizing algae. “We had a lot of fun in the lab with limited supplies, collecting samples from the bay, and oxygenating them in the lab with algae,” she says. They wrote a report for the municipality. She’s now not in biology, however “it made me aware of the research process and the importance of the environment,” she says, “that still stays.”

Before getting into college, Yildiz determined to review nuclear vitality engineering, as a result of it sounded attention-grabbing, though she didn’t but know the sphere’s significance for mitigating international warming. She ended up having fun with the mixture of math, physics, and engineering. Turkey didn’t have a lot of a nuclear vitality program, so she ventured to MIT for her PhD in nuclear engineering, finding out synthetic intelligence for the secure operation of nuclear energy crops. She preferred making use of pc science to nuclear methods, however got here to appreciate she most popular the bodily sciences over algorithms.

Yildiz stayed at MIT for a postdoctoral fellowship, between the nuclear engineering and mechanical engineering departments, finding out electrochemistry in gasoline cells. “My postdoc advisors at the time were, I think, taking a risk by hiring me, because I really didn’t know anything” about electrochemistry, she says. “It was an extremely helpful and defining experience for me — eye-opening — and allowed me to move in the direction of electrochemistry and materials.” She then headed in one other new course, at Argonne National Laboratory in Illinois, studying about X-ray spectroscopy, blasting supplies with highly effective synchrotron X-rays to probe their construction and chemistry.

At MIT, to the place Yildiz returned in 2007, she nonetheless makes use of Argonne’s devices, in addition to different synchrotrons within the United States and overseas. In a typical experiment, she and her group may first create a cloth that could possibly be used, for instance, in a gasoline cell. They’ll then use X-rays in her lab or at synchrotrons to characterize its floor beneath varied operational situations. They’ll construct computational fashions on the atomic or electron stage to assist interpret the outcomes, and to information the subsequent experiment. In gasoline cells, this work allowed to determine and circumvent a floor degradation drawback. Connecting the dots between floor chemistry and efficiency permits her to foretell higher materials surfaces to extend the effectivity and sturdiness of gasoline cells and batteries. “These are findings that we have built over many years,” she says, “from having identified the problem to identifying the reasons for that problem, then to proposing some solutions for that problem.”

Solid oxide gasoline cells use supplies referred to as perovskite oxides to catalyze reactions with oxygen. Substitutions — as an example, strontium atoms — added to the crystal improve its potential to move electrons and oxygen ions. But these atoms, additionally referred to as dopants, usually precipitate on the floor of the fabric, decreasing each its stability and its efficiency. Yildiz’s group uncovered the explanation: The negatively charged dopants migrate towards positively charged oxygen vacancies close to the crystal’s floor. They then engineered an answer. Removing a number of the extra oxygen vacancies by oxidizing the floor with one other factor, hafnium, prevented the motion of strontium to the floor, holding the gasoline cell functioning longer and extra effectively.

“The coupling of mechanics to chemistry has also been a very exciting theme in our research,” she says. She has investigated the results of pressure on supplies’ ion transport and floor catalytic exercise properties. She’s discovered that sure forms of elastic pressure can facilitate diffusion of ions in addition to floor reactivity. Accelerating ion transport and floor reactions improves the efficiency of stable oxide gasoline cells and batteries.

In her latest work, she considers analog, brain-guided computing. Most computer systems we use every day are digital, flipping electrical switches on and off, however the mind operates with many orders of magnitude extra vitality effectivity, partially as a result of it shops and processes info in the identical location, and does so by various the native electrical properties on a continuum. Yildiz is utilizing small ions to range the resistance of a given materials constantly, as ions enter or exit the fabric. She controls the ions electrochemically, just like a course of within the mind. In impact, she’s replicating some performance of organic synapses, particularly the strengthening and weakening of synapses, by creating tiny, energy-efficient batteries.

She is collaborating with colleagues throughout the Institute — Ju Li from NSE, Jesus del Alamo from the Department of Electrical Engineering and Computer Science, and Michale Fee and Ila Fiete from the Department of Brain and Cognitive Sciences. Their group is investigating totally different ions, supplies, and system geometries, and is working with the MIT Quest for Intelligence to translate studying guidelines from mind research to the design of brain-guided machine intelligence {hardware}.

In retrospect, Yildiz says, the leap from her formal coaching on nuclear engineering into electrochemistry and supplies was an enormous one. “I work on a research problem, because it sparks my curiosity, I am very motivated and excited to work on it and it makes me happy. I never think whether this problem is easy or difficult when I am working on it. I really just want to do it, no matter what. When I look back now, I notice this leap was not trivial.” She provides, “But now I also see that we do this in our faculty work all the time. We identify new questions that are not necessarily in our direct expertise. And we learn, contribute, and evolve.”

Describing her return to MIT, after an “exciting and gratifying” time at Argonne, Yildiz says she most popular the mental flexibility of getting her personal educational lab — in addition to the possibility to show and mentor her college students and postdocs. “We get to work with young students who are energetic, motivated, smart, hardworking,” she says. “Luckily, they don’t know what’s difficult. Like I didn’t.”

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