The performance of the lithium-ion battery cathode material directly affects the performance of the lithium-ion battery, and its cost also directly determines the cost of the battery. At present, the positive electrode materials that have been successfully developed and applied mainly include lithium cobalt oxide, lithium iron phosphate, lithium manganate, ternary materials nickel cobalt lithium manganate (NCM) and nickel cobalt lithium aluminate (NCA).
The basic requirements of lithium-ion batteries for cathode materials:
1. The potential of the material itself is high, which can form a large potential difference with the negative electrode material, thereby realizing a battery design with high energy density; at the same time, the insertion and extraction of charged ions have little effect on the electrode potential, so the charging and discharging process will not Excessive voltage fluctuations occur without adversely affecting other electrical systems within the system.
2. The material has a high lithium content, and the intercalation and deintercalation of lithium-ion batteries are reversible. This is the premise of high capacity. Some cathode materials have high theoretical capacity, but half of the lithium ions lose their activity after the first intercalation. Such materials cannot be used commercially.
3. the diffusion coefficient of lithium ions is large, the movement speed of lithium ions in the material is faster, and the intercalation and deintercalation capabilities are strong. It is a factor that affects the internal resistance of the battery cell and is also a factor that affects the power characteristics.
4. The specific surface area of the material is large, and there are many lithium intercalation sites. The specific surface area is large, and the intercalation channel of lithium ions is relatively short, so it is easier to intercalate and deintercalate. Although the channel is shallow, the lithium insertion site should be sufficient.
5. The compatibility and thermal stability with the electrolyte are good, which is for safety considerations.
6. The materials are easy to obtain and the processing performance is good. The material has low cost, is easy to process into an electrode, and has a stable electrode structure, which provides favorable conditions for the popularization and application of the positive electrode material of the lithium ion battery.