Eh, there's still a lot of interesting things going on in batteries. The new frontier is nano-materials, though. This is where shit can get wild and into real "unobtanium" type properties. Self repairing materials. Materials that can change properties depending on conditions. Molecular robots. A lot of work is being done around carbon, but there is still a wide open range of possibilities.

Oop. And ceramics. That's been a lot of the last 50 years. I keep saying batteries, but there's an increasing amount of money going into conductors and energy storage. But, ceramics have been hot for awhile.