The working principle of lithium ion battery

Lithium-ion batteries use carbon materials as the negative electrode and lithium-containing compounds as the positive electrode. There is no metal lithium, only lithium ions, which is a lithium-ion battery. Lithium ion battery refers to the general term for batteries with lithium ion intercalation compound as the cathode material. The charging and discharging process of lithium ion batteries is the process of intercalation and deintercalation of lithium ions. In the process of intercalation and deintercalation of lithium ions, it is accompanied by the intercalation and deintercalation of electrons equivalent to lithium ions (usually the positive electrode is represented by insertion or deintercalation, and the negative electrode is represented by insertion or deintercalation). During the charging and discharging process, lithium ions are intercalated/deintercalated and intercalated/deintercalated back and forth between the positive and negative electrodes, which is vividly called the "rocking chair battery".

When the battery is charged, lithium ions are generated on the positive electrode of the battery, and the generated lithium ions move to the negative electrode through the electrolyte. The carbon as the negative electrode has a layered structure. It has many micropores. The lithium ions reaching the negative electrode are embedded in the micropores of the carbon layer. The more lithium ions are inserted, the higher the charging capacity. Similarly, when the battery is discharged (that is, the process we use the battery), the lithium ions embedded in the carbon layer of the negative electrode are released and move back to the positive electrode. The more lithium ions returned to the positive electrode, the higher the discharge capacity.