Submitted by bj on May 27, 2017
Enovix Corp claim their three-dimensional silicon Li-Ion cell architecture has capacity of 695 Wh/L as opposed to about 460 Wh/L for conventional cells, a 50% improvement.
They also claim their design solves thermal runaway.
spectrum ieee org/semiconductors/design/how-to-build-a-safer-more-energydense-lithiumion-battery
I hope they've sent Elon a working example.