The two electrodes are linked by a chemical mix, and the heat gradient triggers reactions in the chemicals that push electrons around an external circuit. (newscientist.com)
At one electrode, fuel molecules are broken apart and stripped of negatively charged electrons, which pass through an external circuit to a second electrode. (sciencemag.org)
The electrons quickly jump to a network of titanium dioxide particles, which ferries them to an electrode that is connected to an external circuit, allowing them to power lights, toasters, or other electrical equipment. (sciencemag.org)