Compressing neon gas won't do much, aside storing energy as compressed fluid.
My point was the traditional fuels (incl. the edible ones) use more material/weight than their own. So it is very likely they'll be more efficient. The batteries require a reversible action by just applying current - this is quite the climb compared to most chemical reactions.
We have not done much since the li-ion inception, using FePO4 instead of cobalt is more sensible from an economic point of view but the energy density is even lower.
My point was the traditional fuels (incl. the edible ones) use more material/weight than their own. So it is very likely they'll be more efficient. The batteries require a reversible action by just applying current - this is quite the climb compared to most chemical reactions.
We have not done much since the li-ion inception, using FePO4 instead of cobalt is more sensible from an economic point of view but the energy density is even lower.