The working principle of lithium batteries, there are several types of lithium batteries? With the increasing demand for electronic products, the demand for lithium batteries is getting higher and higher. The basic principle of lithium batteries is the so-called "rocking chair theory". ". The discharge and discharge of a lithium battery is not a transfer of electrons in a conventional manner, but an energy change occurs by the passage of lithium ions in the crystal of the layered substance.
How lithium batteries work
The charging and discharging process of a lithium ion battery is a process in which Li+ is embedded and deintercalated in a positive and negative electrode material accompanied by energy absorption and release. Lithium-ion battery is charged: Li+ is deintercalated from the positive electrode material, reaches the negative electrode through the electrolyte, and is absorbed into the negative electrode material to form a higher energy embedded compound. Lithium-ion battery discharge:
Li+ deintercalates from the negative electrode material and releases electrons. Li+ reaches the positive electrode through the electrolyte, and absorbs electrons and then inserts into the positive electrode material to form a relatively stable intercalation compound.
The positive and negative materials of lithium ion batteries are mixed conductors of ions and electrons embedded in compounds, and electrons can only move in the positive and negative materials. The charging and discharging process requires lithium ions and electrons to work together. This requires the lithium ion electrode material to have good conductivity and ion diffusion capacity to ensure that electrons are quickly conducted to the external circuit through the electrode tab during discharge, and lithium ions are in the negative electrode. After the material is deintercalated, it rapidly diffuses into the electrolyte; the lithium ions in the electrolyte are transported to the positive electrode material by the carrier, and combined with electrons to form an intercalation compound.
A battery in which a lithium battery is a lithium metal or a lithium alloy as a negative electrode material and a nonaqueous electrolyte solution is used, and its working principle is a redox reaction of Li + MnO 2 = LiMnO 2 . Due to the very active chemical properties of lithium metal, it has not been widely used for a long time, but now with the rapid development of science and technology, lithium batteries have gradually become mainstream.
The working principle of lithium-ion battery refers to its charging and discharging principle. 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.
By the same token, when the battery is discharged, 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 lithium battery capacity refers to the discharge capacity. Lithium-ion batteries are an ideal reversible battery. During the discharge and discharge, lithium ions are turned in and out of the positive and negative electrodes of the battery, and are shaken between the positive and negative electrodes like a rocking chair. Therefore, the image of the lithium ion battery is called a rocking chair battery.
How many types of lithium batteries are there?
Lithium batteries are usually divided into two categories:
Lithium metal battery: A lithium metal battery is generally a battery using manganese dioxide as a positive electrode material, metallic lithium or an alloy metal thereof as a negative electrode material, and a nonaqueous electrolyte solution.
Lithium-ion battery: A lithium-ion battery is generally a battery using a lithium alloy metal oxide as a positive electrode material, graphite as a negative electrode material, and a non-aqueous electrolyte.
Generally, the most commonly used power batteries are lithium iron phosphate batteries, lithium manganate batteries, lithium cobalt oxide batteries, and ternary lithium batteries.
Manganese lithium battery
Advantages: low price; good low temperature performance, more than 90% efficiency at minus 20 degrees of discharge; good safety performance.
Disadvantages: poor high temperature performance; low cycle life (generally normal service life is about 300 to 400 times); low specific capacity (112); poor rate discharge.
2. Three-dimensional lithium battery
Advantages: The price is the most expensive of the three materials; the capacity is high (150. can save volume); the cycle life is good (600 to 700 times); the rate is good.
Disadvantages: Safety performance is the worst of the three (especially with steel shells); at present, the Chinese battery industry is still not mature enough to use the material.
3. Iron lithium battery
Advantages: price; capacity (130); high cycle life (about 1500 times); high temperature performance; good rate discharge
Disadvantages: the price is not cheap; low temperature performance is not good; in the electric car can fully reflect its superior performance (can be fully charged in 6 minutes, can discharge 20 times)
4. Lithium cobaltate battery
Usually used in 3C products, the safety is very poor, not suitable for power batteries.
In theory, the lithium battery we need should be high in energy density, high in bulk density, good in safety, high in temperature and low temperature, long in cycle life, non-toxic and harmless, high-power charge and discharge, and all advantages are integrated and low cost. However, there is no such battery at present, so there is a trade-off between the advantages and disadvantages of different types of batteries.
