The said oxidation-reduction phenomenon cause most of the batteries to have a major defect: the chemical reaction generates material sediments which keeps the batteries from functioning lastingly. To get round this problem, the french physicist Antoine Becquerel is the first to imagine in 1829 the separation of the two metals in distinct liquids. The zinc is isolated in an ox intestine, with an acid liquid.
John Frederic Daniell improves this system in 1836, by replacing the ox intestine by a soil vase. However, the Daniell battery principle lies in the separation of the metals and of their liquids. This separation causes a differentiated pressure. Therefore, the battery must remain still so as to avoid a mixing of the liquids.
