Sakti is building a solid-state lithium battery (sans ion) they say will have a power density of 1100 Watt hours per liter and will cost $100 per Kwh or less.
This is no ordinary claim. If they can deliver, it's an inflection point.
The power density is very good. It's more than double lithium-ion batteries, so your mobile devices will get even smaller. (Of course I'd like them to stay the same size and last for days, but for some reason phone manufacturers don't seem to ever provide that option).
But the price is the big deal. Tesla is building its gigafactory in the hopes of using economies of scale to drive lithium-ion costs to $200/Kwh or a little less. Sakti's battery would be half that number. Moreover, there's comparison with internal combustion engines, which Brad Plumer wrote about at the Washington Post.
Check out this infographic, which is so incredibly helpful at showing the dynamic relationship between battery costs and gasoline costs:
In gasoline cars, both the engine and the fuel are expensive, but the cost of the gas tank is an afterthought. In electric cars, the electricity and the engine are relatively cheap (your kitchen appliances have the same kind of engine, just smaller) but the batteries are expensive. So the cost of the battery determines how competitive the electric car is compared to internal combustion engines.
But look that that chart. It doesn't even go to $100/Kwh. Back in 2012 when the article was written, a battery cost that low was too absurd to contemplate. But you can follow the angle of the line in your imagination, and you can see that gas would have to be under $1.50/gallon to compete with Sakti's battery technology. If Sakti fails, Elon Musk's gigafactory should make electric cars just about even with internal combustion engines. But if Sakti succeeds, electric cars will be decisively cheaper.
Sakti claims to be within a year or two of commercialization, and they're apparently close enough that Sir James Dyson has invested $15 million in them so that he can power his growing tools and appliance empire. Car companies like GM have put money in too. Fingers crossed.