“The findings…demonstrate a new way of separating hydrogen and oxygen gas from seawater via electricity. Existing water-splitting methods rely on highly purified water, which is a precious resource and costly to produce…But now that the basic recipe is figured out for electrolysis with seawater, the new method will open doors for increasing the availability of hydrogen fuel powered by solar or wind energy.
In the future, the technology could be used for purposes beyond generating energy. Since the process also produces breathable oxygen, divers or submarines could bring devices into the ocean and generate oxygen down below without having to surface for air.”
—Erin Garcia de Jesus, “Stanford researchers create hydrogen fuel from seawater.” Stanford News Service. March 18, 2019.
Besides being able to make air in places with water, such as Mars, it strikes me as an obvious way to store energy.