Battery technology currently is just a bit too heavy for airplanes. There are some electrics flying but their range is good for only short missions. Fuel cell technology is also emerging as a possible alternative in other transport areas such as heavy trucks. Lots of stuff gets more efficient when you don't have to drive pistons up and down.

As to safety, I think all fuel supplies have risk. Gasoline, propane, LI batteries, you name it, it's always a disaster when it goes wrong.