http://www.abc.net.au/science/news/h...sh_1438430.htm
Read the whole article, really intresting.
Now it says that a small paper thin cell can generate 1.5v but you need alot to power anything large but since they weigh hardly anything, you could use loads and not add up even close the same weight as Lipos do in same voltage.
If only the capacity was good on them, wouldn't need chargers either. :D