Because the chemical properties of lithium metal are very active, the processing, storage and use of lithium metal have very high environmental requirements, so the production of lithium batteries must be carried out under special environmental conditions. Due to the many advantages of lithium batteries, lithium batteries are widely used in electronic instruments, digital and home appliances. However, most lithium batteries are secondary batteries, and there are also disposable batteries. A few secondary batteries have poor life and safety.

　　Later, Japan's Sony Corporation invented a lithium battery with carbon material as the negative electrode and lithium-containing compound as the positive electrode. During the charging and discharging process, there is no metal lithium, only lithium ions. This 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. 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 return to the positive electrode, the higher the discharge capacity. What we usually call battery capacity refers to the discharge capacity. During the charging and discharging process of Li-iond, lithium ions are in a state of movement from positive electrode to negative electrode to positive electrode. Li-ionBatteries is like a rocking chair. The two ends of the rocking chair are the two poles of the battery, and the lithium ion runs back and forth in the rocking chair like an athlete. So Li-ionBatteries are also called rocking chair batteries.

　　With the widespread use of digital products such as mobile phones, notebook computers and other products, lithium-ion batteries have been widely used in such products with excellent performance, and have gradually developed into other product applications in recent years. In 1998, Tianjin Power Research Institute began commercial production of lithium-ion batteries. Traditionally, people refer to lithium-ion batteries as lithium batteries. Now lithium-ion batteries have become the mainstream.