I was reading one of my favorite magazines, MIT Technology Review, and ran across a great article about 3D printed batteries.  You can read more about the technical details there, but what it could allow is for the printing of complete sealed electronics with no need for additional power and use of wireless inductive charging.  Applications could include medical devices, military radiation protected electronics, underwater use or microelectronics.  This could also allow for batteries to form all the void space in an electronic perfectly, maximizing ergonomics, size and cost.  In the past 3D printing for prototypes usually meant putting a circuit board into a printed casing, but soon we may print everything…batteries included.