This type of battery has an unusually highenergydensity, which means the units can be smaller and thus lighter for a given amount of power than traditional batteries.
Instead of being stored in batteries, the electricity made by solar panels can be used to split water into oxygen and hydrogen molecules, the latter of which can be used as a fuel with highenergydensity.
We're resigned to the fact that the constantly increasing power demands of modern gadgets will always outstrip slow increases in the energydensity of batteries: however, highenergydensity is not the only factor that goes into making a good battery.
Hydrocarbons, helium, hydrogen, and volatiles in the solar system are important for human exploration and habitation because they will provide essential high-energy, high-density fuels and feedstock for off-world manufactured goods and materials for construction.