You could cram a lot more energy in a lithium-ion battery anode if you replaced the graphite in the anode with silicon. Silicon has about 10 times as much storage capacity.
But silicon bloats during charging, and that can break a battery’s innards. Graphite hardly swells at all because during charging it slips incoming lithium ions between its one-atom-thick layers. That process, called intercalation, involves no chemical change whatever. But it’s different with silicon: Silicon and lithium combine to form lithium silicide, a bulky alloy.
A lot of companies are trying to sidestep the problem by fine-tuning the microstructure of silicon sheets or particles, typically by building things from the bottom up. We’ve written about a few of them, including Sila Nanotechnologies, Enovix, and XNRGI.
Now comes Advano, a startup in New Orleans, that champions a top-down approach. The point is to produce silicon particles that are perhaps not so fine-tuned, but still good enough, and to produce the little dots in huge quantities.