Apple actually did this on the iPhones once. It was a PR disaster when someone found out charging past 100% did something.

If you do that, it skews all of your figures for "kwh per kg" and "kwh per m3". I'd suggest that those are far more important figures of merit for design of electric aircraft and vehicles.

You may have meant this ironically/sarcastically, but it is entirely true. I'm a very happy owner of a fast-charging EV6. For longevity, slow overnight charging almost always just goes to 80%. I only need about 25% of the pack for my daily commute, and lithium battery degradation is dominated by time at high state-of-charge and temperature.

For road trips, the battery charges up to 80% capacity in about 18 minutes on a fast charger (with some caveats when its cold). Charging rate rapidly falls off with increasing state-of-charge, so you're almost always better off just hitting the road at that point. But since you don't actually discharge all the way down to zero, the fast charge cycle realistically only takes 12-15 minutes. The only times that I've taken it to 100% (125%!) were immediately prior to a road trip segment on the overnight slow charger, or for a quarterly balancing charge.

That's all with today's technology on a commercially available product. So this technology can only offer an incremental decrease in weight and/or increase in range.

Damn researchers being honest.

Actually I'd be fine with that marketing if all claims on battery life and autonomy were based on what they call 100% (i.e., the actual 80%).

First commercially viable lithium metal solid state battery charges to 100% in just 15 minutes!*

*using base 9

could also say it charges to tesla 3 capacity in under 5 minutes