This was sort of inevitable. Their strengths do compliment each other and the combination and miniaturization may provide a viable product. Both technologies on their own have struggled to move forward.
It is still all about size and this is a clear strategy to get there. Sooner that later it will happen. We are already most of the way home with a wide range of protocols.
In the meantime we wait and make do..
New device combines the advantages of batteries and supercapacitors