The carbon material is used as the negative electrode and the lithium-containing compound is used as the positive electrode. During the charging and discharging process, no metal lithium exists, only lithium ions, which is a lithium ion 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, and it has many micropores. The lithium ions reaching the negative electrode are embedded in the micropores of the carbon layer, and the more lithium ions are embedded, the higher the charging capacity. Similarly, when the battery is discharged (ie, the process we use the battery), the lithium ions embedded in the carbon layer of the negative electrode come out and move back to the positive electrode. The more lithium ions return to the positive electrode, the higher the discharge capacity. What we usually call battery capacity refers to the discharge capacity. During the charge and discharge process of Li-ion, lithium ions are in a state of motion from positive electrode to negative electrode to positive electrode. The Li-ion Batteries are like a rocking chair. The ends of the rocking chair are the two poles of the battery, and the lithium ions run back and forth in the rocking chair like an athlete. So Li-ion Batteries is also called rocking chair battery.