It should be relatively straightforward to imagine — we already have that in gasoline-powered internal combustion engines.

The Watt-hours per kilogram of good Lithium Ion batteries is around 250-280 Wh/Kg; for Lithium Iron Phosphate it's about 180 Wh/kg, and for Sodium-Ion about 170 Wh/Kg.

The raw energy in gasoline is about 12,300 Wh/Kg but automobile internal combustion engines get only about 20-30% efficiency yielding about 2500-3600 Wh/Kg. For aviation piston engines it is a bit better at 25-30$ so 3000-3600 Wh/kg.

So, the batteries, instead of being 10-12X the weight of the gasoline for the same net driving/flying range, could weigh about the same as the gasoline. So, a typical car with maybe a 16 gallon tank and 30 miles per gallon fills up with 128 pounds (58 kg) of gasoline to get 480 miles of range. The Li-Ion battery for that range would weigh something like 1300 Lbs (590 kg). That is a substantial additional weight for a car that could be 2800-3800 Lbs in ICE configuration, so 35-45% added weight (a bit less because of savings on the ICE engine, etc). This requires everything else to also be heavier, from the structural frame, the suspension system, and even the wheels and tires (which is also unsprung weight, further impairing performance).

With a 130Lb/60kg battery instead, and saving the weight of the ICE engine and fuel system, the overall car design could go much more lightweight, regaining a lot of performance and range, all while gaining the huge torque of electric motors.

In aviation, a battery systems of that weight would enable all-electric aviation to go from small performance niches to the default for general aviation.

So yes, it would be a HUGE benefit to achieve 10X energy density batteries, and we do have reference points for people to imagine it.

> With a 130Lb/60kg battery instead, and saving the weight of the ICE engine and fuel system, the overall car design could go much more lightweight, regaining a lot of performance and range, all while gaining the huge torque of electric motors.

I think you're underselling it, even. A typical like-for-like modern EV is only marginally heavier than the ICE equivalent. If we were able to drop the weight of the battery by a thousand pounds, cars would be lighter than they have been in decades while retaining all the modern safety and convenience features we've come to expect. And if density improved along with weight, we could make EVs with the same form factor as today but with over a thousand miles of range. Not that we need that, but it is just as a tiny example of how mind boggling the game change would be.

As it is I've only recently internalized the notion that the most powerful electric tools are battery powered (what can I say, I grew up when rechargeable batteries were NiCad and they basically sucked). And it will just get better and better as time goes on.

An EV doesn't need to have 480 miles of range. Nobody is driving that distance daily. 98% of trips are under 50 miles. Only 0.8% of the trips are over 100 miles!

Also, EVs use regenerative braking. That should help a little bit.

EVs should be built with 100 - 150 mile range. All families with 2 cars can immediately switch one of their cars to a daily driver EV and the other vehicle is a minivan. There are lots and lots of people for whom an EV works perfectly well and if they need to go longer, US has a robust rental car industry. What would help is to let people charge anywhere they park. All workplaces should offer free charging, and companies can negotiate to get paid for charging their employees cars. The price of electricity goes negative because of lack of demand, and this is something that they can offer to the grid, demand as a service.