The lithium ion battery performance depends on the structure and properties of material inside the battery, the cathode material has a more direct significance. Therefore, the cathode materials for lithium ion batteries must meet the requirements of the basic performance of lithium ion battery, these properties are reflected in the following aspects:
1, high voltage: cathode material to have a high redox potential, to maintain the lithium battery electromotive force can get a higher output voltage, usually, the nominal voltage of lithium battery requirements of 3.7V;
2, high capacity: capacity is the core advantage of lithium ion batteries, work, there must be a sufficient number of lithium ions in the cathode material embedded and embedded in order to maintain high capacity;
3, long life: in the lithium ion intercalation / de embedding, the cathode material structure can not occur or small change, to ensure that the battery for a long time, give the battery life characteristics;
4, stable platform: in the process of charge and discharge, the positive redox potential changes should be as minimal as possible, so that the battery will not change significantly, so that the battery in a complete working process of stable performance, steady discharge level;
5, large current charging and discharging: to ensure that the lithium battery charge and discharge of large current is the premise of the cathode material has good conductivity;
6, fast charging and discharging: lithium ion in the cathode material has a larger diffusion coefficient, in different current charging and discharging conditions can maintain the speed;
7, security: in addition to lithium ion battery in the positive and negative movement, the cathode material will not react with other lithium battery components.
According to the above characteristics, the cathode material is the basis of decision of lithium battery applications, portable lithium batteries used in most LiCoO2 as cathode, because of its better safety performance, while the lithium iron phosphate batteries because the discharge capacity has reached the theoretical capacity of about 95%, which is more suitable for large scale lithium ion battery.