The performance of cathode materials for lithium-ion batteries directly affects the performance of lithium-ion batteries, and its cost also directly determines the cost of the battery. At present, the cathode materials that have been successfully developed and applied include lithium cobaltate, lithium iron phosphate, lithium manganate, lithium nickel-cobalt manganate (NCM) and lithium nickel-cobalt aluminate (NCA), and so on.
The basic requirements of lithium-ion batteries for cathode materials:
First, the material itself has a high potential, so that it can form a large potential difference with the negative electrode material, which brings about the design of the electric core with high energy density; at the same time, the charged ions embedded in and out of the electrode potential has a small impact, so that in the process of charging and discharging, there will be no excessive voltage fluctuations, which will not adversely affect the other electrics in the system.
Second, the material contains high lithium and lithium-ion battery embedded in the embedded reversible. This is the premise of high capacity. Some cathode materials, the theoretical capacity is very high, but half of the lithium ion, the first embedded after the loss of activity. Such a material can not be put into commercial use.
Third, the lithium ion diffusion coefficient is large, the lithium ion moves more rapidly inside the material, and the ability of embedding and de-embedding is strong. It is a factor that affects the internal resistance of the electric core and also affects the power characteristics.
Fourth, the material has a large specific surface area and a large number of embedded lithium positions. Large surface area, lithium ion embedded channel is relatively short, then embedding and de-embedding easier. Shallow channel at the same time, embedded lithium position should be sufficient.
Fifth, good compatibility and thermal stability with the electrolyte, this is for safety reasons.
Sixth, the material is easy to obtain, and good processing performance. Low cost, easy to process materials into electrodes, and stable electrode structure are favorable conditions for the popularization and application of anode materials for lithium-ion batteries.
