The boffins at MIT are hard at it. This time they are trying to fabricate a turbine on silicon. The turbine would have 1 mm features.
After a decade of work, the first millimeter size turbine engine developed by researchers at MIT should become operational by the end of this summer.
The article talks about the history of turbine engines and wraps with this:
Q: What sort of performance should we expect from the engine?
A: The best metric is energy per unit weight, about 120-150 w-hr/kg for current commercial Li-ion rechargeable batteries. We expect that 500-700 whr/kg can be accomplished in the near term, rising to 1200-1500 whr/kg in the longer term (for the engine and its fuel supply).
Coming soon to a cell phone near you - a gas turbine.