That is, they produce a stream of electrons (electricity) by forcing two bits of charged material, say nickel and cadmium, to exchange electrons.

FORBES: Running in place

When a suitable kick is applied, however, a stream of hot electrons does indeed flow from the metal to the superconductor, and the laws of physics are boringly preserved.

ECONOMIST: Microrefrigeration

Strip the electrons off a stream of xenon gas atoms so that they become charged (ions).

BBC: Satellites have an electric future