Electrons are more energy dense than hydrogen unfortunately you need a heavy battery to store and use them properly. However hydrogen needs high pressure tanks

Electrons are more energy dense than hydrogen unfortunately you need a heavy battery to store and use them properly. However hydrogen needs high pressure tanks and fuels cells to store and use it properly so there is basically no energy density advantage right now in a car, both fuel cells and batteries are increasing in energy density due to R&D not sure which will win out it the end. My current opinion is batteries are simpler in every way and have good enough energy density. All the current cars also need a lithium buffer battery because the fuel cell can not put out enough burst power nor do regenerative braking.