The technical term for this is "water splitting" and there are about 20000 papers published on the topic per year. So at least the ones providing money to acade

The technical term for this is "water splitting" and there are about 20000 papers published on the topic per year. So at least the ones providing money to academia are convinced that it is a problem worth solving. FWIW, the professor I knew working in this field and also owning a startup in the field recently switched from a hydrogen powered car to battery power. However as others noted, hydrogen is great to be converted to liquid fuel, because you won't be flying transatlantic on battery power any time soon.