Degradation mechanism of cathode materials in Germany -Lithium - Ion Battery Equipment
So far, electric vehicles have not made breakthroughs because they have been hindered by factors such as insufficient range, which are expected to be alleviated by batteries with higher capacity. Professor Helmut Ehrenberg, Director of the Institute for Applied Materials-Energy Storage Systems (IAM-ESS), said: "We are developing such high-energy systems and, in our view, based on an understanding of the electrochemical processes of batteries, combined with innovative use of new materials, It is expected to increase the storage capacity of lithium batteries by 30%."(Lithium - Ion Battery Equipment)
The difference between high-energy lithium battery technology and traditional battery technology lies in the difference in cathode materials. Layered oxides composed of different proportions of nickel, manganese and cobalt are no longer used. The energy storage capacity per unit volume/mass of the cathode material. However, so far, the use of such materials has encountered a problem.
For example, high-energy cathode materials degrade during the process of inserting and extracting lithium ions in a battery, an essential function of the battery. After a press time, the layered oxide becomes a crystalline structure with particularly poor electrochemical performance. It was found that the average charge-discharge voltage of lithium batteries decreased at the beginning, thus hindering the development of high-energy lithium batteries.
At present, no one fully understands the exact degradation mechanism. A team of KIT researchers and collaborators describe the mechanism: "Based on a detailed study of high-energy cathode materials, we found that the cathode material does not degrade directly, but rather through the formation of a lithium-bearing rock salt structure that is hard to notice. Indirect degradation." In addition, oxygen plays an important role in the reaction. "In addition to such results, the study reveals that the behavior of battery technology is not necessarily directly caused by degradation. This is what the researchers discovered during the synthesis of cathode materials."
KIT's findings are an important milestone that will advance the development of high-energy lithium-ion batteries for electric vehicles. The researchers employed novel testing methods to minimize the degradation of the layered oxides and began developing suitable new batteries.