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Electrodes are electrical conductors used to make contact with non-metallic parts of an electrical circuit such as semiconductors, electrolytes,vacuum or air.Electrodes are an important part of batteries and can consist of a variety of materials depending on the type of battery.Electrophoresis, invented by Johan Wilcke, was an early version of an electrode used to study static electricity.
Anode and cathode in electrochemical cells
Electrodes are an essential part of any battery.The first electrochemical cell was designed by Alessandro Volta and was aptly named the voltaic cell.The battery consisted of a stack of copper and zinc electrodes separated by paper discs soaked in salt water.It's not very practical due to the fluctuating voltage provided by the voltage battery.The first practical battery was invented in 1839 and named the Daniell battery after John Frederic Daniell.It still uses a zinc-copper electrode combination. Since then,many more batteries have been developed using various materials (see list of batteries).The basis of all this is still the use of two electrodes, an anode and a cathode.
Anode 
"Anode" was coined by William Whewell at Faraday's request, and is derived from the Greek ἄνο (ano), "upward" and ὁδός (hodós), "a way".The anode is the electrode at which electrical current enters the non-metallic battery from the electrical circuit of the electrochemical cell (battery).The electrons then flow to the other side of the battery.Note the difference between the flow of electricity and the flow of electrons,this is due to the fact that the flow of electricity was discovered before the discovery of electrons.Benjamin Franklin suspected that the current went from positive to negative.Electrons flow from the anode, and regular current flows to the anode.From both it can be concluded that the charge of the anode is negative.Electrons entering the anode come from an oxidation reaction occurring next to the.
Cathode
A cathode is the opposite of an anode in many ways.The name (also coined by William Whewell) comes from the Greek words κìτω (kato), "downward" and ὁδός (hodós), "a way".It is the positive pole, meaning electrons flow from the circuit through the cathode to the non-metallic part of the electrochemical cell.At the cathode,the reduction reaction takes place and electrons arrive from the wire connected to the cathode and are absorbed by the oxidizing agent.
Primary cell
Primary batteries are batteries designed to be used once and then discarded.This is because the electrochemical reactions that occur at the electrodes in the battery are irreversible.An example of a primary battery is the disposable alkaline batteries used in flashlights. Consists of a zinc anode and a manganese oxide cathode where ZnO is formed.
