Yes potatoes can go in the slow cooker and they will cook just fine.
When I'm making beans I like to add a whole potato to the slow cooker and it cooks right in with the beans.
Then it just gets mushed up in the beans.
You can also bake potatoes in the slow cooker by adding a bit of water to the bottom of the slow cooker and wrapping the potatoes in some tin foil or aluminum foil and cook them on high.
The water helps to keep the baked potatoes moist and they will cook within 8 hours.
You can also cut up potatoes and put the cut up potatoes into the slow cooker with your other ingredients or cook them alone.