500 W/kg in the future? Good. In comparison to fuel (ca. 12'000 W/kg), these future batteries will be 4 % as powerful in the future as fuel is today... So, for 1 kg of fuel, you'd still need 25 kg of these future batteries. Hoping for better efficiency of electrical systems, it maybe 15 or 10 kg... So this very bad weight factor of ten or twenty is and will be a huge challenge. Please do further research!!!

So if I have a 300-mile battery pack, 600 charge cycles would be somewhere upward of 150,000 miles. Seems plausible.

Indeed dan.
Further, when you take into account that unlike a battery, fuel load is decreasing in mass between full and as the fuel is used up, you can effectively double that weight factor disadvantage.

@catweazle. Sure, you are right. In particular for commercial aircrafts. But we never should underestimate potential of anybody or any technology. but if scientists celebrate a battery of 4 % of the power to existing technology/fuel (that even is favourouble for a lower landing weight) we are very far away from any eVtOL application or fully substitution as it is not competitive with fuel. And by the way, I even have read about 500 W/kg some years ago, on this blog, when this site still had the old name...

@Dan & @Weazle, technically true, but you’re evaluating the two “fuels” too narrowly.

Batteries don’t have to reach anywhere near the energy density of ICE fuels to be successful.

Once the fuel in an ICE vehicle is used up, the supply chain must replenish it. Whereas, with a battery, energy in the form of electricity is far more efficiently “transported” to the “refueling” location. Unlike ICE fuel, that refueling location can easily be the owners home or workplace. Furthermore, electricity can be “manufactured” anywhere by anyone using solar or wind, completely eliminating the need to transport it.

So the real measure of success for EV’s will be when they reach distance and purchase price parity with ICE vehicles. Already EVs have dramatically lower maintenance and “fuel” costs vs ICE vehicles.

So they want to use Lithium metal, huh? I wonder how the various fire departments will react to a vehicle fire. Spray water on a Lithium fire and watch what happens!

We need a better source; Lithium is a rare element coming mostly from China, so it's limited in more ways than one.
There are all kinds of new battery technologies coming out that need our attention.

Cars need to be made lighter and with a lower coefficient of air resistance to take better advantage of the batteries.

Currently a plane that requires to land again shortly after take-off has to circle for ages to burn off fuel or dump it in order to get down to a safe landing weight and speed.
Can't jettison those expensive heavy batteries.

@Dan and @Catweazle you’re right, though outside of the field of transportation/electric vehicles there are battery uses where ICE are less practical.

As for lithium fires, industrial availability and recycling, there are lots of research projects addressing these issues and many seem promising, especially if your standards are not based around electrical vehicles.