This seems pretty exciting. I do see a lot of articles about some revolutionary new battery technology, but not on Android Police; their quality of content is usually pretty good.
A doubling of capacity would significantly reduce the size and weight (and hopefully the cost, eventually) of the battery packs in EVs. Same deal with phones, although in those cases it's more about having a phone that can reliably last more than a day.
I've read about SolidEnergy's innovation in a few other electronics news outlets.
Would be lovely to see that go to market. There are currently quite a few smartphones with 4k to 5k mAh Li-ion batteries, and the promise is from 360 h and up on stand-by. That time cuts drastically if you ever use it for anything. With the new kind of battery, hopefully, this will be alleviated. This, let alone electric car improvement, which is fantastic.
One thing to note is that it's not an "improvement on Li-ion batteries": it's its own sort of battery with lithium as the main component. One can see the difference if one scrolls down the article, where they present the outline of what the comparable batteries - various generations of Li-ion and Li-metal (the kind SolidEnergy makes).