A lot of incredible science would be involved. And much much more money and a lot of time.
If we (humanity) could achieve that, that would be really cool.
But: how much solar-, wind- and battery-farms could we built with the same money and in much less time?
Fusion is great, but it will probably not be the solution of the energy demand we currently have. Nevertheless it’s something we should pursue furthermore. But we shouldn’t bet everything on it.
You could just put it in mWh. BAM, bigger number.
3000 mAh * 3.7V = 11.100 mWh Much bigger. Much better.
I hate mAh… it’s absolutely no information how much energy is inside without taking the voltage into account. If you use directly (m)Wh, you directly have the amount of energy the battery can contain.