What are the advantages of boehmite? The application of boehmite in lithium battery separators

- Mar 19, 2021-

What are the advantages of boehmite? Application of boehmite in lithium battery separator. As we all know, the demand in the three major areas of consumer batteries, power batteries and lithium energy storage is increasing. Therefore, driven by market demand, one of the key materials in lithium batteries-the lithium battery diaphragm industry has also been increasing. Recently, the editor found that many battery companies and research institutions have begun to pay attention to the application of boehmite in lithium battery separators. So what are the advantages of Mushi in lithium battery separators?



  What is boehmite



Boehmite (γ-AlOOH) is the main component of bauxite. It is an important chemical raw material with a unique crystal structure. It is widely used in many fields such as catalysts and carriers, paper fillers, inorganic flame retardants, etc. In particular, it can be used as a precursor to prepare aluminum oxide, which is widely used in the fields of ceramics, electronics, adsorption and catalysis, and has broad application prospects. At present, the preparation of inorganic nanomaterials with specific morphology has become a research hotspot in the field of materials science. Especially low-dimensional nanomaterials have received more and more attention due to their special physical and chemical properties and broad application value.



In 1927, De La Palant analyzed the bauxite ore of Lebaud in the Provence region and confirmed this point, and named the ore formed by γ-AlOOH as boehmite. In recent years, the global boehmite production has shown an increasing trend. In 2012, the global boehmite production was 275,000 tons, the consumption was 263,000 tons, and the industry market scale exceeded 500 million US dollars. The European and American markets are the most important consumption regions for boehmite in the world. In 2012, the two together accounted for 62.3% of the total global consumption. The Asia-Pacific market is dominated by China and Japan. Australia, Russia and other countries, which are the main producing areas, are mainly export-oriented products due to insufficient domestic consumption. They are important boehmite supply markets in the world.


Application of boehmite in lithium battery separator


Boehmite coating can significantly improve the thermal stability of the separator under the premise of a lower coating thickness, enhance the safety of lithium batteries, improve the rate performance and cycle performance of the battery, and at the same time have a thinner coating thickness It helps to increase the volume energy density and weight energy density of lithium-ion batteries. Alumina is more widely used in diaphragms. However, it is worth noting that the hardness of alumina is relatively large, so in the cutting and coating process, the wear on the machine is large, and the cost is higher than that of boehmite. Boehmite has the characteristics of high heat resistance temperature, good compatibility with organics, and low hardness, which can reduce mechanical wear and cost advantages.


Advantages of boehmite in lithium battery separators


Advantage 1: When the current is too large, it can block the current. The PP/PE lithium battery separator is a through hole. When the current is too large, it is easy to cause perforation, which will cause the lithium battery to burn or explode. High-purity alumina or boehmite is used as the coating material and adhesive. When used together, coating on the surface of PP/PE material can play a role in adjusting pores. This is because high-purity alumina and boehmite have a plate-like crystal structure. When the current is too large, the material heats up, and the plate-like crystal structure becomes The high-purity alumina or boehmite coating material will expand in volume, which will close the current conducting holes on the lithium battery separator, thereby blocking the current. When the temperature drops, the volume of the material will shrink. The current conducting hole on the diaphragm will be reopened. The special physical and chemical properties of the material can greatly improve the safety performance of the lithium battery, thereby making it possible for high-power lithium batteries to charge and discharge safely and reliably.


Advantage 2: High-purity alumina or boehmite materials also have very good thermal conductivity. If the battery temperature is too high, this material can conduct heat well, thus solving the problem of poor thermal conductivity of PP/PE materials.



Advantage 3: High-purity alumina or boehmite materials also have excellent flame retardancy. This is because high-purity alumina or boehmite materials themselves are very good flame retardants, even if the temperature is too high, it can reach zero combustion. At the boundary point, the good flame retardant properties of the material will prevent large-scale combustion or even explosion.


Comparison of boehmite and alumina


At present, alumina is more widely used in diaphragms. However, it is worth noting that the hardness of alumina is relatively large, so in the cutting and coating process, the wear on the machine is large, and the cost is higher than that of boehmite. Boehmite has the characteristics of high heat resistance temperature, good compatibility with organics, and low hardness, which can reduce mechanical wear and cost advantages.


At present, the price of my country's boehmite industry tends to be stable. In the next few years, due to the influence of market competitiveness and the impact of rising prices of raw materials and labor costs, the price of my country's boehmite industry will maintain an upward trend. Under the temptation of this, it is no wonder that various battery companies are unable to sit still, and it is no wonder that some friends have said that "the trend of replacing alumina with boehmite is unstoppable".