Performance of sealed lithium battery -Lithium - Ion Battery Equipment

New Performance Technology of Closed Lithium Battery -Lithium - Ion Battery Equipment

New chemical methods are expected to overcome the defects of lithium air batteries.

At the same weight, lithium air battery (lithium air battery) can provide more power, so it is widely used in electric vehicles and other mobile electronic devices. However, lithium air batteries have many disadvantages: high heat generation (a large amount of chemical energy is converted into heat energy and not provided to the equipment), short life, expensive and complex manufacturing process (charging and discharging air into the battery requires expensive equipment and is very troublesome).

Recently, Li Ju, a professor of nuclear engineering at MIT, Zhu Zhi, a postdoctoral fellow, and five other authors working at MIT, Argonne National Laboratory and Peking University published an article in the journal Nature Energy, reporting a new technology called "nano lithium cathode", which can be used to manufacture sealed lithium batteries with performance similar to lithium air batteries to overcome the above problems.

Li Ju said that one of the weaknesses of lithium air batteries is that the charging and discharging voltages are different. The discharging voltage is 1.2 volts lower than the charging voltage. Therefore, the energy lost in the form of thermal energy during each charging process is as high as 30%. "If you charge too fast, your lithium battery may really burn up."(Lithium - Ion Battery Equipment)

Shut up the gas

When the traditional lithium air battery is discharged, the oxygen in the air is used to react with the lithium in the battery. During charging, the oxygen in lithium oxide is released into the atmosphere.

The new nano lithium cathode battery also takes advantage of the role of oxygen and lithium. The difference is that when discharging, oxygen will not be released in the form of gas, but will be enclosed in the solid. Specifically, oxygen is enclosed in three solid compounds in three redox states - Li2O, Li2O2 and LiO2, which are wrapped in cobalt dioxide glass.

The advantage of this is that the nano lithium cathode battery reduces the voltage difference during charging and discharging by five times - from 1.2 V to 0.24 V, so only 8% of the energy is lost in the form of thermal energy during charging. This means that the car battery can be charged at a faster speed without fear of overheating and fire.

The second disadvantage of lithium air battery is that the oxygen released in the form of gas will damage the ion channel in the battery, thus reducing the life of lithium battery.

The new technology uses cobalt dioxide glass to wrap lithium and oxygen in nanoscale space, which scientists call nano lithium. In this way, the transformation of LiO2, Li2O2, and Li2O will not change the macro structure of the material. In addition, since lithium nanoparticles are very unstable, cobalt dioxide glass with nano channels can just stabilize them. Cobalt dioxide also acts as a catalyst in charge discharge.

Li Ju said that the traditional lithium air battery is actually just a lithium oxygen battery, because the water vapor and carbon dioxide in the air will have a side reaction with lithium, so the lithium air battery must be equipped with a huge auxiliary system to remove water vapor and carbon dioxide, which is a very difficult step. The new solid lithium battery has no such problem.

Equipped with overcharge prevention function

The new solid lithium battery also has an overcharge prevention function, because the chemical reaction in the battery will self adjust through negative feedback. When the battery is fully charged, the reaction will automatically stop. If the traditional battery is overcharged, it will cause irreversible damage to the battery, even explosion. But the solid lithium battery was charged continuously for 15 days in the experiment, and the charge capacity was 100 times of the battery capacity, but the battery was undamaged.

In the charge and discharge experiment, the solid lithium battery has been charged and discharged 120 times, and the capacity loss is only 2%, which means that it is much longer than the life of the traditional lithium air battery. As the solid lithium battery does not need an auxiliary air purification system, it can be conveniently applied to electric vehicles, or even grid level energy storage stations.

As the solid oxygen cathode is much lighter than the cathode of the lithium ion battery, the new solid lithium battery can store twice as much power as the lithium ion battery of the same weight. With the improvement of technology, the power of the new battery can be doubled.



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