Why must a battery’s electrodes be kept separated?

In a battery, the electrodes must be kept separated to ensure that chemical reactions occur in distinct locations, which allows the device to generate a controlled electromotive force rather than simply releasing heat through a direct, uncontrolled mixture of chemicals.1

When the reactive chemicals are kept apart, the energy released by their interaction is harnessed through an external circuit, creating a voltaic cell capable of supplying electric power. If the electrodes were to mix directly, the energy would be dissipated as heat, rendering the battery ineffective for powering electronic devices. In many battery designs, a separator is used to maintain this physical distance while still allowing for the necessary flow of ions to complete the internal circuit.12