Why only hydrogen is regarded as fuel of future and not other elements?

Question

I have basic idea of working of hydrogen fuel cell but why just hydrogen? Isn’t there any better or maybe cheaper alternative?
(I know it’s bit complex for but I would appreciate your answers)

In: 346

Answer 1

Per weight, H2 gas has the single highest chemical potential energy possible. (or more ELI5, it can do a lot of stuff while not weighing a lot)
Burning hydrogen releases a lot of energy, and Hydrogen (having no neutrons and very few protons) is also incredibly light.

Also, burning H2 with O2 just makes Water. No other nasty byproducts.