Older TDK story from 2020.[2]
TDK claims "a next-generation solid-state battery with an energy density of 1,000 Wh/L, approximately 100 times greater than the energy density of TDK’s conventional solid-state battery." Their "conventional solid state battery" is a tiny thing used in meat thermometers, a ceramic device with, like most ceramic devices, good high temperature tolerance.
Lithium-ion batteries are around 250–693 W⋅h/L. So this is maybe 2x existing lithium-ion technology. That's about what everybody else is claiming for next-generation solid state batteries.
Incidentally, gasoline is around 9,500 Wh/L, although only about half of that reaches the driveshaft.
End result: longer cell phone battery life, and an end to "bulging" battery failures.
[1] https://www.tdk.com/en/news_center/press/20240617_01.html