> Isn't H2 energy density much better than Li-Ion batteries?
By weight, hydrogen and oxygen creates 20x more chemical energy per kilogram than lithium-ion batteries [1]. (It's comparable to gasoline and air.) By volume, uncompressed, it has far less. Once compressed, we have to take into account the weight of the containment tanks, the weight of the fuel cell and the energy lost in converting hydrogen to electricity, an output batteries directly provide, a combination which negates that specific energy advantage.
By weight, hydrogen and oxygen creates 20x more chemical energy per kilogram than lithium-ion batteries [1]. (It's comparable to gasoline and air.) By volume, uncompressed, it has far less. Once compressed, we have to take into account the weight of the containment tanks, the weight of the fuel cell and the energy lost in converting hydrogen to electricity, an output batteries directly provide, a combination which negates that specific energy advantage.
[1] https://en.wikipedia.org/wiki/Energy_density_Extended_Refere...