It's not very often scientists get to say they have found a new way to generate electricity, but that's exactly what researchers at MIT have done. An Inhabit.com article and PhysOrg.com article describe the discovery of thermopower. MIT chemical engineer Michael Strano and mechanical engineering student Wonjoon Choi and their team produced thermopower waves by coating a carbon nanotube with a fuel and igniting the fuel.
The thermal pulse propagated through the carbon carried electrons along with it, thus generating electricity. The energy output of the system is reported to be a hundred times greater that what you would get from a lithium ion battery of the same weight. You can read more about the discovery and how thermopower is believed to work in the March 7 edition of Nature Materials.