In Dakotah's article there is a good recap of how Sakti3 was formed and how Sastry's upbringing helped her become such a driven individual. Instead of simply improving on lithium-ion batteries like many other startups, Sastry and her company took a different approach. They wanted to design a battery from the ground up based on meticulous calculations and simulations. Departing as well from much of the academic research that often doesn't have commercial promise, her company focused "very hard on equipment that was scalable, because the bottom line is these battery cells need to be affordable."
While specific details about the company's battery technology is not yet available, we do know it is making solid-state batteries based on lithium-ion technology, replacing the liquid electrolyte with a layer of non-flammable material. Solid state batteries tend to allow thousands of charge-discharge cycles and withstand higher temperatures. Because of the increased robustness of these types of batteries, cooling devices and associated materials don't need to be engineered into EV packs, thus increasing their effective energy density while reducing cost.
Sakti3 will be sending out prototypes of the batteries this year (no doubt GM will be getting their hands on some), and scaling up to production levels in the next few years.
[Source: Huffington Post and Technology Review]