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How do batteries convert chemical energy into electrical energy?
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battery
Cutaway view of an alkaline–manganese dioxide power cell.
Batteries convert chemical energy into electrical energy through electrochemical reactions that occur at two separate electrodes: the anode (negative plate) and the cathode (positive plate).12
These electrodes are immersed in or separated by an electrolyte, a substance that permits the movement of ions between them. The process functions as follows:23
- Oxidation: At the anode, a chemical reaction occurs where the material gives up electrons.3
- Reduction: Simultaneously, at the cathode, a chemical reaction occurs where the material accepts electrons.3
- Electron Flow: Because these reactions are physically separated, the electrons released at the anode are forced to travel through an external circuit to reach the cathode, creating an electric current.143
- Internal Balance: The electrolyte allows ions to move through the cell's interior, balancing the charge and completing the circuit.3
This flow of electrons continues as long as the chemical reactants are available to sustain the electromotive force. Once the chemical energy is exhausted, the battery can no longer produce electricity.42