I think the technology exists (at least somewhere on this planet) but it's being held back to extract as much money as possible in the meantime on current technology. I have no direct evidence of this of course but when you think of what kinds of things humans can accomplish when they put their minds and copious amounts of funding toward it, you'd have to believe it's out there, even if only in a lab somewhere or in some military only role held in secret. This is going completely off topic (and I know I'll going all conspiracy theory and tin-foil hatter on ya) but consider the "non-battery tech" X-10 drone for example http://www.liveleak.com/view?i... and https://en.wikipedia.org/wiki/... That sucker was swirling around the skies in 1953! It went over Mach 2 too. Re-read the year again and it will sink in. You don't just magically design and build something like that in a few years either. Stuff like that takes at LEAST 10 years to plan, build and test. Wikipedia says preliminary design was completed in 1951 and first flight was in 1953. So where are we now...approximately 1943 when they were drawing it up? Think about other technologies of that time frame...then it becomes more almost unicorn and Apple'ish magical! You could say similar things about German technologies of WW2. Like it's so far out there compared to earlier times and other countries offerings as to be mind blowing! Anyhow, back on topic...I'd be really surprised if 10x longer next-gen batteries have not existed for quite some time. DARPA funds crazy things like this all the time and they send people all over the world regularly to sit in on the latest University breakthroughs. If they don't have it, then no one has it - publicly at least.