Rechargeable battery
OverviewCharging and dischargingApplicationsActive componentsTypesAlternativesFurther reading
During charging, the positive active material is oxidized, releasing electrons, and the negative material is reduced, absorbing electrons. These electrons constitute the current flow in the external circuit. The electrolyte may serve as a simple buffer for internal ion flow between the electrodes, as in lithium-ion and nickel-cadmium cells, or it may be an active participant in the electrochemical reaction, as in lead–acid