One major advantage that hydrogen has over batteries is that you are not carrying the full weight of the reactants around with you. You carry the hydrogen (which gets consumed throughout the flight) but you don’t need to carry the oxygen as it is in the air through which you fly. A battery must carry all reactants throughout the flight and what’s more, will weigh just as much on landing.
Over a decade ago I was lectured on the exciting possibility of storing hydrogen in a “carbon sponge” which went some way to alleviating the fears of explosion of hydrogen tanks in a car accident. I haven’t since heard much on this technology!