I would assume something to do with power usage, perhaps it's just increased it's efficiency per watt or even just a die shrink? Or it could be a software thing, perhaps it has new instructions allowing it to do some things faster natively.
I doubt it's a new battery, perhaps a Li-Poly?
Could be they've just started using higher quality gates, as they do in the new i-series of Intel processors with the hafnium-based high-k dielectrics.
It is wholly possible but such technology is most likely patented by Intel.
Since the new efficient gates were first introduced on the 45n architecture and the New Orion Chips were designed to be 45n
The Proccessor that will be used in the SII is Exynos4210
Doesn't specify what archtecture it will be using.
Even so the battery life would be terrible at 2.0Ghz look at LG Optimus.
I had made a claim before that 1Ghz will be a sweetspot for a while and I will stick to it, even though the SII is 1.2Ghz I don't see this number rising untill there is better battery management, efficiency can only take you so far.