Lithium-ion-battery
During the charging cycle the electrolyte carries positively charged lithium ions from the lithium-rich cathode to the anode through the separator. This movement of lithium ions creates free electrons in the cathode that flow via the cathode current collector and an external circuit to the current collector at the anode. In this case, the external circuit is the battery charger that provides electric energy to charge the cell. The separator, which physically separates the anode and cathode, regulates the flow of ions from one electrode to the other and blocks the flow of electrons directly between the electrodes thus preventing short-circuiting of the battery. When the battery is fully charged, the anode is laden with lithium. During discharge the flow of lithium ions and electrons is reversed such that the lithium ions flow from the anode back to the cathode via the separator and the electrons flow through the device being powered (e.g. cell phone, computer, etc.) to the cathode. This cycle is repeated for the life of the battery.