A positively charged lithium atom that shuttles between electrodes during battery charge and discharge.A lithium ion is a positively charged atom of lithium that moves between the anode and cathode of a battery during charging and discharging. In lithium-ion batteries, these ions are the charge carriers that store and release energy. The movement of lithium ions is what allows the battery to power devices, from smartphones to electric vehicles. The efficiency and longevity of a battery depend heavily on how smoothly these ions can travel through the electrolyte and electrode materials.
The concept of lithium-ion batteries was developed in the 1970s and 1980s, with the first commercial lithium-ion battery introduced by Sony in 1991, based on work by John Goodenough, Stanley Whittingham, and Akira Yoshino.
During discharge, lithium ions migrate from the anode through the electrolyte to the cathode, while electrons flow through an external circuit, providing electrical power. During charging, an external voltage drives the ions back to the anode. The electrodes are typically made of materials that can host lithium ions in their crystal structures, such as graphite for the anode and metal oxides for the cathode. The intercalation and deintercalation of lithium ions cause slight structural changes in the electrodes, which can lead to degradation over time.
Lithium-ion batteries power portable electronics, electric vehicles, and grid energy storage systems, and are also used in aerospace and medical devices.
Lithium is the lightest metal and the third lightest element, which makes lithium-ion batteries particularly lightweight and energy-dense compared to other rechargeable battery technologies.













