AlF3 coating improves cycle and voltage decay of Li-rich manganese oxides

Li-rich manganese-based cathode materials are known as one of the most promising cathode materials for next-generation lithium batteries due to their high theoretical specific capacity. However, there are problems such as low specific capacity, poor rate performance, and fast decay rate during cycling. In this paper, spherical lithium-rich manganese-based cathode material Li1.2Mn0.54Ni0.13Co0.13O2 was prepared by co-precipitation method, and aluminum fluoride (AlF3) was prepared by high temperature solid state reaction, so that AlF3 was uniformly coated on lithium-rich manganese-based cathode. The results show that AlF3 is uniformly coated on the surface of the spherical Li1.2Mn0.54Ni0.13Co0.13O2 material with a thickness of about 5 similar to 7 nm, and the material maintains the original layered structure without changing. The charge-discharge cycle test was carried out in the voltage range of 2.0 similar to 4.8 V, and the specific capacity of the Li-rich manganese-based cathode material coated with AlF3 was significantly improved, reaching 283.3 mAh/g (Under the same preparation method and test conditions, this value is in the forefront of the 260-290 mAh/g that can be achieved by most of the current coating methods). The AlF3 coating with the best retention performance is 4 wt% and still has a retention rate of 84.4% after 200 charge-discharge cycles. During the charging and discharging process, AlF3 can maintain the stability of the main cathode material and inhibit the next transformation, thereby ensuring the high specific capacity and cycle stability of the material.

Automated summary

In this paper, a spherical lithium-rich manganese-based cathode material Li1.2Mn0.54Ni0.13Co0.13O2 was prepared by co-precipitation method, and aluminum fluoride (AlF3) was uniformly coated on the surface of the material. The AlF3 coating significantly improved the specific capacity of the cathode material, reaching 283.3 mAh/g, and showed a retention rate of 84.4% after 200 charge-discharge cycles. AlF3 can maintain the stability of the cathode material and inhibit unwanted transformations, ensuring high specific capacity and cycle stability.