Why lithium sulfur / lithium air battery does not have the power battery application prospects

It is generally accepted in the industry that the immediate term objective of lithium battery technology is to achieve 300wh / kg through a high-nickel NMC cathode and a silicon carbon anode. The medium-term (2025) target is based on a lithium-rich manganese-based / high capacity Si-C anode, to achieve 400wh / kg; forward is the development of lithium sulfur, lithium air battery, to achieve the specific energy than 500wh / kg.
Lithium air coin cell case
Figure 1:  Lithium air coin cell case
The long-term goal, lithium sulfur and lithium air battery theoretical value far exceeds 500wh / kg (lithium sulfur 2600wh / kg, lithium air 11000wh / kg), but its feasibility needs to be considered.
As a product, lithium air battery has four fatal flaws:
The first is the control of moisture. Lithium-ion battery is an open system, which is not the same as lithium-ion batteries, lithium-air use of oxygen in the air, while the air contains water, lithium will react with water. It is a difficult problem to solve both by oxygen permeation and waterproofing.
Second, catalytic reduction of oxygen. The reaction speed of oxygen is very slow. To improve the reactivity of oxygen, an efficient catalyst must be used. Nowadays the catalysts are all precious metals.
Third, is the lithium metal anode rechargeable.
Lithium Chips
Figure 2: Lithium Chips
Fourth, is the re-decomposition of the discharge product. Lithium-ion battery discharge product is lithium oxide, the solid lithium oxide re-catalyzed decomposition of oxygen and lithium, how difficult.
Look at the lithium-sulfur battery, the first is the electrode cycle performance is poor. On the one hand, dissolved lithium polysulfide diffuses to the negative electrode and then oxidizes at the positive electrode, resulting in a shuttle effect resulting in low coulombic efficiency and high self-discharge; on the other hand, dissolved lithium polysulfide also has a positive charge on the positive electrode surface during charging Deposition, resulting in the electrode surface due to blockage and inactivation, therefore, the electrode cycle performance is poor.
The second problem is the rechargeable of lithium metal anode, which is also a problem that is difficult to solve in a short time.
The third problem is the lithium-sulfur battery volume energy density is relatively low, may be only equal to lithium iron phosphate batteries. Because sulfur is an insulator , if you want to makes it conductive, allowing it to react and disperse it, a large amount of high surface area carbon must be used, resulting in a very small density of sulfur / carbon composites. In addition, the sulfur reaction is first dissolved and redeposited, so there must be a large number of liquid phase transmission channels on the electrode.
And now most of the lithium-sulfur battery, the sulfur electrode can not be pressed, the porosity is particularly high, so the volume energy density is very low.
TOB NEW ENERGY which has 15 years experience in lithium battery industry. We supply full kinds of lithium battery making equipment and material, we have ability to build lithium battery production line for our clients. We have cooperated with many famous company, such as Apple, Sumsang, 3M, SKC etc.
Welcome to join us!
Contact: Mr.Runner(Sales & Engineer )
Email: tob.runner@tobmachine.com
Whatsapp: +86 15980946320
Skype: tob.runner@tobmachine.com
Wechat: TOB-009

评论