Comment by jim90

I guess that would be the case if the battery was 100% lithium. But they are not (and cannot be) If I remember correctly the issue with increasing density in lithium batteries is their propensity to catch fire + explode (due to dendrites forming between lithium plates)

So a better battery tech might have a material that can store less electrons per m3 within the "active" material - but it can contain 30% more.