The material of the positive electrode of the lithium battery is manganese dioxide or thionyl chloride, and the negative electrode is lithium. For example, button batteries used in cameras in the past were lithium batteries. After battery assembly is completed, the battery is powered and does not need to be charged. This type of battery can also be charged, but its cycle performance is not good during the charge and discharge cycle, resulting in the formation of lithium dendrites. an internal short circuit in the battery, so generally this kind of battery Battery charging is prohibited.
Later, the Japanese company Sony Corporation invented a lithium battery with carbon as the negative electrode and lithium-containing compounds as the positive electrode. During the charging and discharging process, there is no metallic lithium, only lithium ions. Easta lithium-ion battery.
Lithium-ion batteries are developed from lithium batteries. The main component of the positive electrode is LiCoO2 and the main component of the negative electrode is C.
Positive reaction during charging: LiCoO2 → Li1-xCoO2 + xLi+ +?xe-
Negative reaction: C + xLi+ + xe- ?→ CLix
Battery Overall reaction: LiCoO2 + C→ Li1-xCoO2 + CLix The opposite reaction of the above reaction occurs during discharge.
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 used as a negative electrode has a layered structure with numerous micropores. The lithium ions that reach the negative electrode are integrated into the micropores of the carbon layer. The more lithium ions, the higher the charging capacity. Likewise, when the batrie is discharged (that is, the process in which we use the battery), the lithium ions embedded in the carbon layer of the negative electrode are released and return to the positive electrode. The more lithium ions returned to the positive electrode, the higher the discharge capacity.
Lithium batteries use metallic lithium as an electrode and use electron transfer to generate current. Because they are prone to dendrites and cause explosions, they are no longer used. Lithium batteries are primary batteries.
Lithium-ion batteries use lithium ion transfer to complete charging and discharging, and mainly use lithium-doped metal oxides as electrodes. Lithium-ion batteries are rechargeable secondary batteries.
1. Primary lithium battery
Also called primary lithium battery. It can be dischargedoperated continuously or intermittently. Once the energy is exhausted, it can no longer be used, and it is widely used in low-power electronic products, such as cameras. Primary lithium batteries have a very low self-discharge and can be stored for 3 years. The effect will be better if stored in refrigerated conditions. It is a good idea to store primary lithium batteries in a low temperature location. Note: Primary lithium batteries are different from lithium-ion batteries, cannot be charged, and charging is very dangerous!
2. Lithium-ion battery
Also called secondary lithium battery. It can be stored for more than six months at 20°C because its self-discharge rate is very low and most of its capacity can be restored.
Lithium batteries have a self-discharge phenomenon. If the battery voltage is stableIf left below 3.6V for a long time, the battery will overdischarge and damage the internal structure of the battery, thereby reducing the battery capacity. life. Therefore, lithium batteries stored for a long time need to be recharged every 3-6 months. Once, charge to a voltage of 3.8~3.9V (the best storage voltage of lithium batteries is d 'about 3.85 V) and keep the depth of discharge between 40% and 60%. It is not recommended to fully charge it. Batteries should be stored in a dry environment between 4°C and 35°C or in moisture-proof packaging. Keep away from heat sources and do not expose to direct sunlight.
Lithium batteries have a wide application temperature range. They can still be used outdoors during the northern winter, but their capacity will be significantly reduced if they return to temperatureambient, capacity can be restored.