AnodeThe anode (negative electrode) is usually made of graphite. Graphite is carbon in layers, and lithium is stored between the layers.
CathodeThe cathode is the positive electrode, usually a lithium metal oxide. Lithium cobalt oxide is a common one.
SeparatorA thin sheet with tiny pores, between the two electrodes. It keeps them apart, and lithium ions pass through its pores.
ElectrolyteThe electrolyte carries lithium ions between the two electrodes. It is usually a lithium salt dissolved in a liquid.
Lithium ionsWhile discharging, lithium ions travel anode to cathode. They cross the electrolyte and pass through the separator.
ElectronsWhile discharging, electrons flow through the wire to the cathode. Only the ions go through the electrolyte.
Copper current collectorA thin copper foil that the anode is coated on. It carries electrons between the anode and the wire.
Aluminum current collectorA thin aluminum foil that the cathode is coated on. It carries electrons between the wire and the cathode.
External circuitThe wire outside the cell, here lighting a lamp. The electrons moving along it are the electric current.
Charging 3
ChargerThe charger is an outside power source. It pushes electrons from the cathode side back to the anode side.
Lithium ionsWhile charging, lithium ions move back to the anode. They are stored between its layers until the cell is used.
ElectronsWhile charging, electrons flow through the wire to the anode. The charger drives them.
How this list was compiled: Every name and fact checked on 2026-10-01, a name kept only where two independent sources use it. (1) Wikipedia, text only: Anode, https://en.wikipedia.org/wiki/Anode (in battery engineering the electrodes of a rechargeable battery are named for their roles on discharge, so anode means the negative terminal), and Lithium-ion battery, https://en.wikipedia.org/wiki/Lithium-ion_battery (the negative electrode is usually graphite and the positive typically a metal oxide or phosphate, lithium cobalt oxide in handheld electronics; the electrolyte is a lithium salt in an organic solvent; during discharge the anode is the negative electrode and lithium ions move through the electrolyte and separator to the positive electrode while electrons move through the external circuit; during charging an external power source forces electrons and ions back; foil current collectors, aluminum for the cathode and copper for the anode; the charger applies the charging current; a small battery is a single cell). (2) University of Washington Clean Energy Institute, Lithium-Ion Battery, https://www.cei.washington.edu/research/energy-storage/lithium-ion-battery/ (during discharge lithium ions move from the anode through the electrolyte to the cathode, passing a micro-permeable separator; lithium cobalt oxide cathode and graphite anode in phones and laptops; ions are stored between the layers of graphite). (3) UL Research Institutes, What Are Lithium-Ion Batteries?, https://ul.org/research/electrochemical-safety/getting-started-electrochemical-safety/what-are-lithium-ion (anode: negative electrode; cathode: positive electrode; electrolyte; current collectors: conductive foils at each electrode; separator: a porous film that separates the electrodes and lets lithium ions through; the anode gives up lithium ions to the cathode on discharge and the cathode releases them back to the anode on charge, while electrons move in the external circuit; a battery is one or more cells). (4) An educational battery site kept by a maker of battery test equipment, BU-204, https://batteryuniversity.com/article/bu-204-how-do-lithium-batteries-work (a metal oxide cathode coated onto an aluminum current collector, a carbon or graphite anode on a copper current collector, plus a separator and an electrolyte of lithium salt in an organic solvent; a discharging battery's anode is negative). (5) US Department of Energy, Office of Science, DOE Explains...Batteries, https://www.energy.gov/science/doe-explainsbatteries (anode, cathode, electrolyte, the external circuit; electrons move through the circuit while ions move through the electrolyte, either way in a rechargeable battery). (6) Explain that Stuff, How lithium-ion batteries work, https://www.explainthatstuff.com/how-lithium-ion-batteries-work.html (on charge the ions and the electrons both end at the negative graphite electrode, the electrons by the outer circuit; on discharge both go to the positive electrode; electrons do not flow through the electrolyte). (7) Chemistry LibreTexts, Rechargeable Batteries, https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Supplemental_Modules_%28Analytical_Chemistry%29/Electrochemistry/Exemplars/Rechargeable_Batteries (its figure of a rechargeable cell being charged names the charger drawn above the cell; read for that name only). Licence: own work
The drawing: Drawn for this site on 2026-10-01 from plain geometry; nothing traced. Licence: own work
How it works
A lithium-ion cell is the rechargeable cell inside phones and laptops. The first drawing shows it discharging and the second charging. Tap a part to read what it does.
Read the full guide
Inside the cell
Two electrodes face each other: a graphite anode and a cathode made of a lithium metal oxide. Each is coated on a metal foil, its current collector: copper for the anode, aluminum for the cathode. Between them is the electrolyte, with a porous separator down the middle.
Discharging, then charging
While the cell is in use, lithium ions leave the anode, cross the electrolyte and enter the cathode. Electrons go to the cathode too, by the outside wire, here through a lamp. A charger pushes the electrons back, and the lithium ions move back to the anode too.
Ions and electrons always head for the same electrode: the cathode on discharge, the anode on charge.
The quiz takes negative electrode for anode and positive electrode for cathode.
Questions and answers
What are the parts of a lithium-ion cell?
An anode, a cathode, a separator between them, an electrolyte that carries the lithium ions, and two current collectors: a copper foil behind the anode and an aluminum foil behind the cathode.
How does a lithium-ion cell work?
On discharge, lithium ions move from the anode through the electrolyte to the cathode, while electrons flow from anode to cathode through the outside circuit and power the device. Charging sends both back to the anode.
Is the anode positive or negative in a lithium-ion cell?
Negative. The graphite electrode is called the anode and the lithium metal oxide electrode, which is positive, the cathode. The names follow what happens while the cell discharges.
What does the separator do in a lithium-ion cell?
It is a thin porous sheet that keeps the anode and the cathode apart. Lithium ions pass through its pores, so the cell still works.
What is the difference between a lithium-ion cell and a battery?
A cell is one unit: two electrodes, a separator and electrolyte. A lithium-ion battery is one cell, or several cells joined together.