1. Battery presentation

Under the right conditions, a spontaneous redox reaction can generate an electric current. To do this, the overall reaction is broken down into two simultaneous, spatially distinct partial reactions, one of which captures electrons, the other of which releases them. These electrons, whose circulation requires a closed circuit, are exchanged between the two reaction sites via an external circuit element, while a charge transfer takes place in ionic form within the system between the electrodes, the sites of each reaction. To achieve this, the electrodes are immersed in a suitable medium - usually liquid, sometimes solid - known as the electrolyte. This is dissociated into ions and has zero electronic conductivity (so as not to short-circuit the electrodes). Thus, the electric current is of an electronic nature in the external part of the circuit and of an ionic nature within the generator,...