I would expect any certification of this solution will at least involve taking the plane up to some high altitude airport, start one engine, pressurize the cabin to get the air flowing, short circuit the battery and wait 180 minutes or whatever ETOPS time is required and see what happens.
I would also advocate placing some kind of animals in the cabin to see if the exposure to fumes within that time frame will not prove hazardous - though I do hope there is some more humane way of assessing this particular risk.
The whole experiment could of course be filmed and then published on the web - actually seeing it work will convince people it can be trusted.