Breakthrough Solid State Battery - 900 Wh/L Samsung

At 3:40 - "they achieved a 50% increase in battery energy density"
At 5:39 - "they used a matrix of silver instead of silica to hold the lithium ion, increasing the density of lithium."

https://youtu.be/TAFk-CebHWA

Batteries still have nowhere near the energy density of gasoline, although the gap between the two narrows when you consider that combustion engines are much less efficient than electric motors at using that energy.