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Summer 2012 Blog - Akshay Shrivastava

Akshay Shri​vastava is spending twelve weeks at the National University of Singapore.

Day 1: 9:00 AM: Dressed in our Monday best, we enter our Professor’s office for the first time. He shakes our hands, smiles, offers us seats. Not bad so far.

Day 1: 11:00 AM: I will admit that my brain is a bit scattered. I’m darting back and forth between his sketches on post-it notes: cyclic voltammetry graphs, anode compositions, half-cell reactions. I have a bit of reading ahead of me.

Day 4: 10:00 AM: Concepts are connecting, pictures are becoming clearer. Srirama, one of the graduate students, draws a voltage vs. time graph for a half-cell under constant current – it looks like a downward slope with a long plateau. What does that mean? According to that paper I read last night, that’s where the conversion reaction occurs – that’s what we’re trying to maximize. And what about that awkward gap between the charge and discharge endpoints? That’s capacity loss – that’s what we’re trying to minimize. And suddenly, it starts to make sense: maybe this is why we don’t all drive electric cars yet. Even in the best cells we have today, capacity retention is too poor, cycling degrades the anodes. These are the kinds of things we need to fix.

Day 7: 1:00 PM: Fabricating a half-cell is a painstaking process – sinter the metal oxides in the oven, wait a day, take them out, make a slurry, wait a day, coat the slurry on the substrate, wait a day, punch out holes in the substrate, put them in the glove box, layer some additional materials, clamp it all up in a neat metal box. And yet out of this collection of mundane tasks, something completely novel emerges. Nobody has tried an RuO2 anode on a sodium-ion cell before. We’re the first ones to do it. And that’s when it hits me – this is actual science.

Day 10: 3:00 PM: Our meeting with the professor concludes. Finally, I have my project. Metal oxide anodes undergoing conversion reaction on sodium-ion half-cells (a phrase which made absolutely no sense to me a week ago) – that would be my next three months. But why should that take three months? Sounds like I can get that done next week.

Day 12: 2:00 PM: Ok, I’m not going to get it done next week. Or the week after that. Or the one after that. I realized now why papers take months to publish – it’s not just about slapping a new anode on a cell and seeing what works. It’s about varying the voltage windows, changing the electrolyte compositions, using binder-heat treatment, analyzing the materials with TEM and XRD and Raman spectroscopy. This…could take a while.

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