NSF Grant-Funded Microscope to Aid Students in Researching Tiny Materials
Electron Microscope to Enhance Research, Collaborations, and Educational Needs in New England
“ This is an instrument that most of the big companies have, so I want to put this instrument in the course materials. ”
Assistant Professor of Chemistry Niya Sa’s expertise is in designing rechargeable battery materials, which is beyond the current lithium ion technology. Sa is the lead principal investigator of a $426,000 National Science Foundation-Major Research Instrumentation Program (NSF-MRI) grant, which she and her co-PI, Associate Professor of Chemistry Michelle Foster, have used to purchase a field emissions scanning electron microscope. It’ll arrive in the Integrated Sciences Complex this spring.
“It will have elemental analysis and an EBSD (electron backscatter diffraction) detector function to probe and analyze materials at a very small scale. The resolution could be down to 0.8 nanometers. … Its best resolution probably allows us to see things a million times smaller than our hair,” Sa said. “This grant helps us to get a very advanced instrument to see materials at a very small scale.”
And it’s critical for her research.
“Once we cycle battery materials, it decays, it degrades. All those degradations affect the lifetime of the battery. We can’t identify the materials by sight or regular microscope. This high-resolution electronic microscope will help us to identify the issues,” Sa said.
The new microscope will include a transfer chamber under inert atmosphere so Sa will be able to transfer materials from the Glove Box, a sealed container that she uses to do all her battery research, into the microscope without exposing the materials into air.
“Right now rechargeable batteries in laptops, cell phones, and cars use carbon as anode material, with a maximum capacity of roughly 300 milliamps hour per gram. Silicon material’s maximum capacity is roughly 10 times higher than graphite. However, the problem of silicon is it cracks out during battery operation, meaning if you use silicon material in your battery, you can only use it maybe for a few times, then it will die.
“Right now we’re trying to see what we can do to form a layer, like a glue, that would glue them together and at the same time make them conductive. … We can’t see the [silicon materials] interface with our eyes, so we have to have this kind of advanced technique to help us identify, to probe what happened at the silicon and electrolyte interface with the development of the new electrolyte.”
Sa describes this cracking out like what happens when you bake a cake.
“The dough goes to the oven. If the temperature goes up, the cake cracks out. That’s exactly what’s going on with silicon material because of volume expansion. Once it cracks out, the particles are not connecting with each other, they are detached and not conductive, and that is why the battery dies. So we want to heal those cracks,” Sa said.
Other professors and students will also get to use the new tool.
“I do think it’s very important to expose students with advanced instruments,” Sa said. “This is an instrument that most of the big companies have, so I want to put this instrument in the course materials so both undergraduate students and graduate students can get a chance to operate it.”
Sa is in her second year at UMass Boston.
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