Maybe it will not be batteries...

Several teams are working hard on supercapacitors, currently a distant second when it comes to energy density, and a higher cost system.

Super capacitors provide close to unlimited charge and discharge cycles and very fast charging (lab works says you could charge a Model 3 in under 5 minutes or faster).

One research group has found a potential low cost set of materials for super capacitors, potentially cutting costs by a factor of 20 or more.

A second group has found what may require changes to Kirchoff's Law to account for their lab discoveries. A leap that if it proves out may also have an impact on many other areas of physics.

Basic research is just that, sometimes it becomes commercially viable and sometimes not.

In likely a decade we will know if either of these lab finds are viable (along with a dozen or more lab teams working on Super Capacitors) or not.

Super Capacitors in 2040 or 2050 may have 5-10 times the energy density that batteries will have, may be cheaper, and may have a life that batteries don't.

OR NOT.

Time and R&D investment will determine when and what we eventually see, or not.

But Super Capacitors are worth keeping an eye on.