Electrochemistry, from batteries to brains | MIT Information


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

“It might appear to be we’ve been contributing to totally different applied sciences,” says Yildiz, MIT’s Breene M. Kerr (1951) Professor within the Division of Nuclear Science and Engineering (NSE) and the Division of Supplies Science and Engineering, who was not too long ago named a fellow of the American Bodily Society. “It’s true. However basically, it’s the identical phenomena that we’re after in all these.” That’s, the conduct 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 plenty of enjoyable time by the ocean, and likewise tinkered together with her dad on restore and development tasks at dwelling. She loved learning and attended a science-focused highschool, the place she vividly recollects a selected two-year undertaking. Town sat on a polluted bay, and her biology instructor related her and a pal with a college professor who received them engaged on methods to wash the water utilizing algae. “We had plenty of enjoyable within the lab with restricted provides, accumulating samples from the bay, and oxygenating them within the lab with algae,” she says. They wrote a report for the municipality. She’s not in biology, however “it made me conscious of the analysis course of and the significance of the surroundings,” she says, “that also stays.”

Earlier than getting into college, Yildiz determined to review nuclear power engineering, as a result of it sounded fascinating, though she didn’t but know the sphere’s significance for mitigating world warming. She ended up having fun with the mixture of math, physics, and engineering. Turkey didn’t have a lot of a nuclear power program, so she ventured to MIT for her PhD in nuclear engineering, learning synthetic intelligence for the protected operation of nuclear energy crops. She appreciated making use of pc science to nuclear techniques, however got here to appreciate she most well-liked the bodily sciences over algorithms.

Yildiz stayed at MIT for a postdoctoral fellowship, between the nuclear engineering and mechanical engineering departments, learning electrochemistry in gasoline cells. “My postdoc advisors on the time had been, I feel, taking a threat by hiring me, as a result of I actually didn’t know something” about electrochemistry, she says. “It was a particularly useful and defining expertise for me — eye-opening — and allowed me to maneuver within the path of electrochemistry and supplies.” She then headed in one other new path, at Argonne Nationwide 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 in the US and overseas. In a typical experiment, she and her group may first create a cloth that might 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 numerous 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 establish 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’ve constructed over a few years,” she says, “from having recognized the issue to figuring out the explanations for that drawback, then to proposing some options for that drawback.”

Strong 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 capacity to move electrons and oxygen ions. However these atoms, additionally referred to as dopants, typically precipitate on the floor of the fabric, lowering each its stability and its efficiency. Yildiz’s group uncovered the rationale: The negatively charged dopants migrate towards positively charged oxygen vacancies close to the crystal’s floor. They then engineered an answer. Eradicating a few of the extra oxygen vacancies by oxidizing the floor with one other ingredient, hafnium, prevented the motion of strontium to the floor, preserving the gasoline cell functioning longer and extra effectively.

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

In her current work, she considers analog, brain-guided computing. Most computer systems we use day by day are digital, flipping electrical switches on and off, however the mind operates with many orders of magnitude extra power effectivity, partly as a result of it shops and processes data in the identical location, and does so by various the native electrical properties on a continuum. Yildiz is utilizing small ions to fluctuate the resistance of a given materials repeatedly, 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, specifically 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 Division of Electrical Engineering and Laptop Science, and Michale Charge and Ila Fiete from the Division of Mind and Cognitive Sciences. Their staff is investigating totally different ions, supplies, and gadget 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}.

On reflection, Yildiz says, the leap from her formal coaching on nuclear engineering into electrochemistry and supplies was an enormous one. “I work on a analysis drawback, as a result of it sparks my curiosity, I’m very motivated and excited to work on it and it makes me pleased. I by no means suppose whether or not this drawback is simple or troublesome when I’m engaged on it. I actually simply need to do it, it doesn’t matter what. Once I look again now, I discover this leap was not trivial.” She provides, “However now I additionally see that we do that in our school work on a regular basis. We establish new questions that aren’t essentially in our direct experience. And we study, contribute, and evolve.”

Describing her return to MIT, after an “thrilling and gratifying” time at Argonne, Yildiz says she most well-liked the mental flexibility of getting her personal tutorial lab — in addition to the prospect to show and mentor her college students and postdocs. “We get to work with younger college students who’re energetic, motivated, good, hardworking,” she says. “Fortunately, they don’t know what’s troublesome. Like I didn’t.”