Skip to content
ContentLora

    Tip: press / anywhere to search.

    Explainer

    How lithium-ion batteries work

    A lithium-ion battery stores energy by moving lithium ions from a cathode into a graphite anode while charging and back again while discharging, with electrons taking the outside path through the device.[1][2] It offers some of the highest energy densities of any commercial battery, and it dominates electric cars and grid storage.[3][4]

    Editor reviewedUpdated Batteries and energy storageEnergy and climateScience

    The parts of a cell

    Every lithium-ion cell has two electrodes. The anode is usually made of graphite. The cathode is a metal oxide or phosphate that contains lithium.[5][6] Between them sits a liquid electrolyte, which carries the ions, and a thin separator with tiny pores that lithium ions can pass through.[2][7]

    The classic cell pairs a graphite anode with a layered oxide cathode such as lithium cobalt oxide. Other common cathodes include lithium manganese oxide and lithium iron phosphate.[6] Both electrodes are intercalation hosts: lithium ions slot between the graphene layers of graphite or into the cathode lattice without breaking the structure.[5][8] A micro-permeable separator lets ions cross between the electrodes.[7]

    Charging and discharging

    When you charge a battery, the charger pushes lithium ions out of the cathode and into the graphite anode. When you use the battery, the ions travel back to the cathode through the electrolyte. Their electrons travel the long way round, through your phone or car motor, and that flow of electrons is the electric current.[1][2] Because the ions rock back and forth between the two sides, this is sometimes called a “rocking-chair” battery.[1]

    During charge, lithium leaves the cathode lattice and forms lithiated graphite (LiC6) at the anode. On discharge the ions return.[1] At the anode, lithium is oxidised and gives up its electron to the external circuit. The ion crosses the electrolyte and recombines with an electron at the cathode.[2] Cell voltage comes from the potential gap between the electrodes. Lithium cobalt oxide works above 4.0 volts, and carbon anodes intercalate lithium at about 0.5 volts against lithium metal.[9][8]

    Why lithium-ion won

    Lithium-ion cells reach up to about 330 watt-hours per kilogram, among the highest energy densities of any commercial battery technology.[3] Prices fell about 90% between 2010 and 2023, and lithium-ion now dominates both electric vehicles and new grid storage.[10][4] In 2025 the average pack cost 108 dollars per kilowatt-hour.[11]

    A short history

    In the 1970s researchers showed that titanium disulfide could hold lithium ions in its layers, and a 2.5-volt cell followed in 1976.[12] Around 1980 lithium cobalt oxide raised working voltage above 4 volts.[9] In 1985 a carbon (petroleum coke) anode replaced reactive lithium metal and became the first commercial intercalation anode.[8] The 2019 Nobel Prize in Chemistry went to John B. Goodenough, M. Stanley Whittingham and Akira Yoshino for the development of lithium-ion batteries.[13]

    Limits and what comes next

    Lithium batteries can fail when thin threads of lithium metal, called dendrites, grow on the anode.[14] Researchers are working on solid-state-batteries, which swap the liquid electrolyte for a solid one and promise more energy and better safety.[15] Others are working on sodium-ion-batteries, which use abundant sodium.[16]

    Dendrites stand in the way of combining high energy density with long cycle life, for example in lithium-sulfur designs.[14] Solid electrolytes could enable lithium-metal anodes, but each family has its own hurdle: dendrites in sulfides, interfacial resistance in oxides and low conductivity in polymers.[17] Sodium-ion keeps the same intercalation principle with a more abundant ion, and CATL’s mass-production cells reach up to 175 Wh/kg.[18]

    Questions readers ask

    What actually moves inside a lithium-ion battery?

    Lithium ions. While charging they move from the cathode into the graphite anode, and while discharging they move back through the electrolyte to the cathode.[1][2]

    What does the separator do?

    It sits between the anode and the cathode and is micro-permeable, so lithium ions can pass through it.[7]

    Why do lithium batteries sometimes fail?

    A common failure mode is the growth of dendrites, root-like filaments of lithium metal on the anode.[14]

    How much energy can a lithium-ion cell hold?

    Up to about 330 watt-hours per kilogram, among the highest of any commercial battery technology.[3]

    Sources

    Each numbered claim is a statement we checked against the sources listed with it. Status shows how well established it is.

    1. [1]

      During charging, lithium ions move out of the cathode lattice to the anode to form lithiated graphite; during discharging they move back, a reversible shuttle often called the rocking-chair mechanism. confirmedas of 2026-10-10

    2. [2]

      During discharge, lithium atoms in the anode give up their electrons, and the lithium ions travel through the electrolyte to the cathode, where they recombine with electrons. confirmedas of 2026-10-10

    3. [3]

      Lithium-ion batteries have some of the highest energy densities of any commercial battery technology, as high as 330 watt-hours per kilogram. confirmedas of 2026-10-10

    4. [4]

      Lithium-ion batteries dominate both electric-vehicle and stationary storage applications. confirmedas of 2024-04-25

    5. [5]

      Graphite anodes store lithium ions by intercalation, in which the ions slot in between the two-dimensional graphene layers that make up graphite. confirmedas of 2026-10-10

    6. [6]

      Besides lithium cobalt oxide, common lithium-ion cathode materials include lithium manganese oxide and lithium iron phosphate. confirmedas of 2026-10-10

    7. [7]

      Lithium ions pass through a micro-permeable separator placed between the anode and the cathode. confirmedas of 2026-10-10

    8. [8]

      In 1985 petroleum coke was shown to reversibly intercalate lithium ions at low potential, becoming the first commercial intercalation anode and a safer alternative to lithium metal. confirmedas of 2026-10-10

    9. [9]

      Lithium cobalt oxide, identified around 1980, reversibly takes in and releases lithium ions at potentials above 4.0 volts, enabling higher-energy cells. confirmedas of 2026-10-10

    10. [10]

      Lithium-ion battery prices fell about 90%, from roughly 1,400 US dollars per kilowatt-hour in 2010 to less than 140 dollars in 2023. confirmedas of 2024-04-25

    11. [11]

      BloombergNEF's 2025 survey found average lithium-ion battery pack prices fell 8% from 2024 to a record low of 108 US dollars per kilowatt-hour. confirmedas of 2025-12-09

    12. [12]

      Titanium disulfide, studied in the 1970s, can intercalate lithium ions and was used in a 2.5-volt cell demonstrated in 1976. confirmedas of 2026-10-10

    13. [13]

      The 2019 Nobel Prize in Chemistry was awarded to John B. Goodenough, M. Stanley Whittingham and Akira Yoshino for the development of lithium-ion batteries. confirmedas of 2019-10-10

    14. [14]

      Lithium-based batteries often fail because root-like dendrites of lithium metal grow on the anode, which stands in the way of combining high energy density with long cycle life in advanced designs such as lithium-sulfur. confirmedas of 2026-10-10

    15. [15]

      All-solid-state lithium batteries promise higher energy density and better safety than batteries with liquid electrolytes, partly because the solid electrolyte can act as a physical barrier to dendrites. confirmedas of 2024-04-01

    16. [16]

      CATL cites abundant raw materials and cold-weather performance as sodium-ion advantages. confirmedas of 2026-02-05

    17. [17]

      Each solid electrolyte family has a hurdle - sulfides suffer dendrite formation and a limited electrochemical window, oxides have interfacial resistance with lithium metal, and polymers have limited ionic conductivity. confirmedas of 2024-04-01

    18. [18]

      CATL's Naxtra sodium-ion battery reaches up to 175 Wh/kg, which CATL calls the benchmark for mass production, and gives a pure-electric range above 400 km. confirmedas of 2026-02-05

    Revision history (1)
    1. Page created.

    Created Oct 10, 2026. Last reviewed by an editor on Oct 10, 2026. Next scheduled review: Jan 10, 2027.

    Cite this page

    "How lithium-ion batteries work." ContentLora, updated Oct 10, 2026. https://contentlora.com/explain/how-lithium-ion-batteries-work

    Spotted an error? Suggest a correction or emailcorrections@contentlora.com.

    Keep exploring

    ☰ Contents