Tesla teaser med et bilde til sin battery day.

A reverse Google search on the image shows that it is similar to silicon nanowires, a nanostructure that has been used to create batteries with higher performance though it has yet to be commercialized.

One of the main companies developing the technology is Amprius:

“Developed on a patented technology platform that includes a 100% silicon nanowire anode, Amprius Technologies batteries provide significantly more energy and power with less weight and volume than any other lithium-ion battery technology. Amprius Technologies batteries provide up to 50% higher energy density than standard lithium ion batteries with carbon anodes”

Interestingly, Amprius is based right next to Tesla’s 901 Page Ave. building in Fremont, California
Her er artikkel.
https://electrek.co/2020/08/24/tesla-teases-nanowire-technology-battery-day/