Lithium batteries are divided into lithium ion batteries and lithium ion batteries. Cell phones and laptops use lithium ion batteries, which are commonly known as lithium ion batteries. The real lithium ion batteries are rarely used in daily electronic products due to their high risk.

　　Lithium-ion battery is a kind of rechargeable battery, which mainly relies on the movement of lithium ions between the positive and negative electrodes to work. During the charging and discharging process, Li+ intercalates and deintercalates back and forth between the two electrodes: when recharging the battery, Li+ deintercalates from the positive electrode and inserts into the negative electrode through the electrolyte, the negative electrode is in a lithium-rich state; the opposite is true during discharge. Generally, batteries that use materials containing lithium as electrodes are representative of modern high-performance batteries.

　　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 (the positive electrode is usually represented by insertion or deintercalation, and the negative electrode is represented by insertion or deintercalation). In the process of charging and discharging, 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 inserted into 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.

　　Generally, the charging current of lithium ion batteries is set between 0.2C and 1C. The higher the current, the faster the charging and the greater the heat generated by the battery. Moreover, charging with an excessive current will result in insufficient capacity because the electrochemical reaction inside the battery takes time. Just like pouring beer, pouring too fast will produce foam, but dissatisfaction.