Voltaic (galvanic) cells are widely used as convenient energy sources whose primary virtue is portability. Voltaic cells are the chemical basis of many portable batteries.

Voltaic cells work by utilizing a spontaneous redox reaction. The cell forces the reaction to take place through an external pathway rather than directly between reactants.

Because redox reactions are the transfer of electrons, when voltaic cells force the reaction to occur through an external pathway, it creates a flow of electrons from one point to another (electricity). The point from which the electrons come is the anode. Anodes are the negative electrode on the battery because electrons are negatively charged, and the anode is the part of the cell where the electron flow originates. The cathode is the positive electrode of the battery. Here, electrons react to oxidize some species.

The voltaic cell is able to produce electricity by using species which natually tend to donate and receive electrons. Thus, the species that spontaneously gives up electrons is reduced and the species that spontaneously gains electrons is oxidized, driving the reaction foward.

A voltaic cell can also be called a galvanic cell, a galvanic battery, or a voltaic battery.