Electrochemical reaction, any process either caused or accompanied by the passage of an electric current and involving in most cases the transfer of electrons between two substances—one a solid and the other a liquid. In electrochemical reaction electrons flow from one chemical substance to another, driven by an oxidation-reduction (redox) reaction. A redox reaction occurs when electrons are transferred from a material that is oxidized to one that is being reduced.
Electrochemical cells have two conductive electrodes, called the anode and the cathode. The anode is defined as the electrode where oxidation occurs. The cathode is the electrode where reduction takes place.
Low cost and non–toxic materials.
Cannot be recycled, can leak (weak acid electrolyte reacts with zinc)
Unstable voltage and current (as the battery ‘runs down’) and low power