last time i check liquid fuel has 50x the energy density of battery. so to get to /4, you would need a 12x increase. >since one of the reasons liquid fuel can

last time i check liquid fuel has 50x the energy density of battery. so to get to /4, you would need a 12x increase. >since one of the reasons liquid fuel can store so much energy in such a compact and lightweight form is that it doesn't require storage of one of the primary reactants (oxygen). the main reason is the covalent bond is stronger. using air will only double the energy density for fuel( 1x fuel instead of /2 fuel /2 oxygen.)