<Tr> <Td> </Td> <Td> This article relies largely or entirely on a single source . Relevant discussion may be found on the talk page . Please help improve this article by introducing citations to additional sources . (May 2016) </Td> </Tr> <P> An electrochemical cell is a device capable of either generating electrical energy from chemical reactions or facilitating chemical reactions through the introduction of electrical energy . A common example of an electrochemical cell is a standard 1.5 - volt cell meant for consumer use . This type of device is known as a single galvanic cell . A battery consists of one or more cells, connected in either parallel or series pattern . </P> <P> An electrochemical cell consists of two half - cells . Each half - cell consists of an electrode and an electrolyte . The two half - cells may use the same electrolyte, or they may use different electrolytes . The chemical reactions in the cell may involve the electrolyte, the electrodes, or an external substance (as in fuel cells that may use hydrogen gas as a reactant). In a full electrochemical cell, species from one half - cell lose electrons (oxidation) to their electrode while species from the other half - cell gain electrons (reduction) from their electrode . </P> <P> A salt bridge (e.g., filter paper soaked in KNO NaCl, or some other electrolyte) is often employed to provide ionic contact between two half - cells with different electrolytes, yet prevent the solutions from mixing and causing unwanted side reactions . An alternative to a salt bridge is to allow direct contact (and mixing) between the two half - cells, for example in simple electrolysis of water . </P>

Where does reduction take place in an electrochemical cell