If you have electricity then you can generate oxygen… first you desalinate sea water, and then distill it. (Fuel cells need distilled water or you break them). Once it is distilled the process of electrolysis seperates the Hydrogen from the Oxygen. Scrubbers are needed to remove the carbon dioxide from the air as it doesn’t matter how much oxygen is in the air when you get above something like 15-25% carbon dioxide it becomes toxic.

As for the ISS, they have something completely different and revolutionary, I don’t know what it is but it’s deeply classified in the US military files, I must conclude that they have something new that is on the new Seawolf boats, as most of the other systems are declassified

Was my understanding that the CO2 scrubbers and air system on board the ISS was designed by the US and the Russians. The US modules had US scrubbers and the Russian modules had Russian systems… for quite some time in 2002 the US systems had failed and the Russian scrubbers were used to keep the station habitable.

ie

Mission Control also followed up on repair work on the Carbon Dioxide Removal Assembly by Korzun and Whitson. The pair had replaced one of two absorbent beds for the system last week. On Tuesday, flight controllers attempted to activate the replacement bed, which contains Zeolite crystals to absorb the excess carbon dioxide breathed out by the crew. But the replacement bed showed signs of leakage similar to that seen from the original bed, but at a lower rate. Life support systems engineers on the ground suspect there may be another leak elsewhere in the CDRA that was not corrected by the bed replacement, but are still studying the data and considering further options. They verified that the system can still function properly with just one bed in operation. In the meantime, scrubbers in the station’s Russian segment continue to provide all of the carbon dioxide removal required by the Expedition 5 crew and visiting taxi crews.

(ref http://www.astronautix.com/details/int52672.htm )