What are the requirements for positive electrode materials of lithium batteries?

First, the potential of the material itself is high, so that a large potential difference can be formed between the material and the negative electrode material, resulting in a high energy density cell design; At the same time, the insertion and removal of charged ions have little impact on the electrode potential, so there will be no excessive voltage fluctuation during the charge and discharge process, and no adverse impact on other electrical devices in the system.

Second, 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 insertion. Such materials cannot be put into commercial use.

Third, the diffusion coefficient of lithium ions is large, the movement of lithium ions in the material is faster, and the ability of intercalation and deintercalation is strong. It is a factor that affects the internal resistance of the cell and also the power characteristics.

Fourth, the material has a large specific surface area and a large number of lithium intercalation sites. If the surface area is large and the intercalation channel of lithium ions is relatively short, the intercalation and deintercalation are easier. While the channel is shallow, the lithium intercalation position should be sufficient.

Fifth, it has good compatibility and thermal stability with electrolyte, which is due to safety considerations.

Sixth, the material is easy to obtain and has good processing performance. Low cost, easy processing of materials into electrodes, and stable electrode structure are favorable conditions for the promotion and application of positive electrode materials for lithium-ion batteries.