So, what happens to the water by product? Will we have to buy hydrogen canisters to recharge the cell?
Hmmm....
You have hydrogen delivered to your house right now. It just happens to be bonded with oxygen. Electrolysis isn't particularly efficient, but neither are current options for recharging batteries.
I am guessing that plugging into an electrical source will "crack" the water via electrolysis into hydrogen and oxygen, thereby again having a fuel source for the fuel cell. The process can be repeated many times.
I have experimented with fuel cells that do this. They can generate electricity, and inputting electricity generates the hydrogen and oxygen. But mine are inefficient. Apple may be onto something big.