John Frederic Daniell (1790-1845), British chemist and meteorologist, invented the Daniell Cell in 1836—the first battery that was a reliable and lasting source of direct-current electricity. A major problem with the voltaic pile, the first electric battery invented by Volta, was that it could not provide currents for a sustained period of time. Daniell's experiments led to the insertion of a barrier between copper and zinc plates in the cell, which, by stopping hydrogen from forming, solved the problem of polarization and created the first battery to produce a constant electrical current over a long period of time. Among Daniell's other inventions was a new type of dew-point hygrometer to measure humidity, and a pyrometer to measure the heat in a furnace.
John Frederic Daniell (King's College, London)