Energy Institute Faculty Profile: Bart Bartlett

Friday, June 10, 2016
Author: 
Nick Soberal, Summer Science Communication Fellow

About Bart Bartlett’s Research

Professor Bartlett is an Associate Professor of Chemistry and serves as Associate Director at the Energy Institute, working in inorganic material synthesis. Bartlett’s research focuses on two main areas of renewable energy: investigating artificial photosynthesis for the purpose of solar conversion, and newer, more efficient batteries. The solar conversion team uses their knowledge of inorganic materials for the purpose of investigating catalysts able to perform the complex series of biochemical reactions that leaves use to convert water into oxygen. Bartlett’s team is investigating ways to implement Magnesium, which is more abundant and more energy dense than Lithium, in rechargeable batteries.

When asked what prompted him to pursue a career in chemistry, Bart Bartlett answered that he had always been fascinated with figuring out how things work.

“I liked taking things apart. I wasn’t very good at putting things back together; that’s why I’m a scientist, not an engineer,” he joked.

Bartlett spoke of his early fascination with science and how his self-proclaimed stubbornness started him on a lifelong pathway that would lead him to be an Associate Professor of Chemistry at the College of Literature, Science, and the Arts. As a teenager, when he heard his fellow students groaning about their struggles with high school chemistry, Bartlett found his curiosity piqued.

“I actually went to the St. Louis Public Library, grabbed a chemistry book, and read it over the summer. Not only did I sort of ‘get it,’ but I realized I sort of liked it as well.”

He found that the underlying principles of the science, the logic and reasoning, were what he liked most about it in the beginning. Later, he discovered another vital component of a successful research career.

“I think what took me a while to learn about the job, that wasn’t inherent in high school, was how people-oriented doing science is. It’s not some white lab coat crazy-hair guy in a basement with boiling solutions, but instead it’s really a community of scholars that work together.”

This collaborative philosophy is a big part of Bartlett’s lab. Their weekly group meetings are a time for both groups to bounce ideas off each other, make plans, and solve problems. For the battery research team, each week’s conversations add up to one goal: making rechargeable lithium batteries obsolete.

As a resource, lithium is nowhere near as abundant as magnesium is. It has also demonstrated dendrite formation (deposits on the electrodes), effectively short-circuiting the battery, when subjected to charging. Add to this the lower energy density relative to magnesium, and magnesium becomes an attractive alternative.

At present, the main challenges to reliable magnesium batteries are incompatibility between magnesium and the traditional electrolyte salts utilized in lithium-ion batteries, and the much slower kinetics associated with magnesium ions.

Typically, lithium-ion batteries contain a liquid electrolyte consisting of lithium salts in organic solvents, or a more solid polymer gel electrolyte. The current design allows diffusion of lithium ions across the electrolyte from one electrode to the other during the processes of charging and discharging. With magnesium, reactivity between the magnesium electrodes and the traditional electrolytes would render the battery useless following formation of a blocking layer at the interface of the two.

Dr. Bartlett’s lab has hypothesized that redesigning the battery from scratch could lead to a design that utilizes magnesium instead of lithium in rechargeable batteries.

“We’ve actually turned to some computational modeling to help us figure out, well, what are the right design principles for salts in solution that will be really chemically-stable over a large voltage range?”

The other problem is the electrode design. Magnesium, being a heavier element, is more energy-dense than lithium, but that also makes it move more slowly. This means that getting the electrons to move and power the device is harder because the magnesium ions resist movement.

“There’s still the fact that the same electrodes you use for lithium are largely oxide-based...but magnesium moves really slowly. It’s really strongly electrostatically attracted to the lattice.”

The challenge then becomes finding materials to which magnesium binds less strongly.

“If we know that it’s because oxides form strong electrostatic interactions, what ions can we use to break up those interactions? That’s what we’re trying to do now in the lab, is figure out what sort of structures and elements don’t bind as strongly to magnesium, so that the faster I can get the magnesium in and out, the faster we can move electrons.”

As if that isn’t cool enough already, the other side of Professor Bartlett’s lab group is working on a way to synthesize catalysts that recreate the oxygen evolution reaction seen in photosynthesis.

“The reason you have to give plants sunlight is that it takes the sunlight as the driving force for turning water into oxygen,” Bartlett explained. “That’s a slow process and we’d like to understand better what chemical catalysts we can prepare, ideally ones that last much longer than the machinery of the leaf, so that we can think about making solar fuel.”

A potential goal here is to produce hydrogen. Hydrogen, when combusted with oxygen, produces water and releases energy. Running this reaction in reverse would turn water into oxygen and hydrogen.

There are still some challenges to be seen with this process as well; for example, if the goal is to produce hydrogen, where do you store it? Moreover, the process of turning over water to produce oxygen is an extremely slow and inefficient process.

But these are long term concerns. For Dr. Bartlett, the process of furthering understanding for both the field of chemistry and for his students comes first. When asked what was the most exciting part of his work, he responded “For me, as a professor, the most exciting part is actually seeing when the students recognize that it’s working.”

Bartlett explained that, after working in a field for so long, looking at the data and seeing a result can sometimes not elicit the same excitement that it would have when he first started in research. To him, the best part is seeing his students experience it, knowing that they found the results and seeing the product of their own hard work.

 
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