[s0rce]

Its just academic research papers that get brief press coverage. Its very hard to actually commercialize these and compete (performance and economics) with the incumbent technologies. Some stuff makes it in specialized applications (satellites, earbuds, etc).

[hinkley]

You could also find your way into automotive and never achieve more than 40% of the battery market. What works in cars and flashlights is different, and by the time you got automotive penetration, grid storage would also be at volume, sucking up as much production as vehicles, and without having to worry about power density and max charge rate.