How to evaluate cathode materials for lithium batteries？

The performance of lithium-ion batteries is mainly determined by the structure and properties of the materials used inside the battery. These battery internal materials include anode electrode materials, electrolytes, battery separators, and cathode electrode materials. Among them, the selection and quality of positive and negative materials directly determine the performance and price of lithium-ion batteries. Therefore, the research on cheap and high-performance positive and negative electrode materials has always been the focus of the development of the lithium-ion battery industry. The negative electrode material is generally made of carbon material, and the current development is relatively mature. The development of cathode materials has become an important factor restricting the further improvement of lithium-ion battery performance and the further reduction of price. In the current commercial production of lithium-ion batteries, the cost of cathode materials accounts for about 40% of the cost of the entire battery, and the reduction in the price of cathode materials directly determines the reduction in the price of lithium-ion batteries. This is especially true for lithium-ion power batteries. For example, a small lithium-ion battery for a mobile phone requires only about 5 grams of positive electrode material, while a lithium-ion power battery for driving a bus may require up to 500 kilograms of positive electrode material.

To measure the quality of lithium-ion battery cathode materials, it can be roughly evaluated from the following aspects:

(1) The positive electrode material should have a higher redox potential, so that the battery has a higher output voltage;

(2) Lithium ions can be reversibly intercalated and deintercalated in a large amount in the positive electrode material, so that the battery has a high capacity;(3) During the lithium ion intercalation/deintercalation process, the structure of the positive electrode material should not change or change as little as possible to ensure good cycle performance of the battery;

(4) The redox potential of the positive electrode should change as little as possible during the intercalation/deintercalation of lithium ions, so that the voltage of the battery will not change significantly, so as to ensure the smooth charging and discharging of the battery;

(5) The positive electrode material should have high electrical conductivity, so that the battery can be charged and discharged with a large current;

(6) The positive electrode does not chemically react with the electrolyte, etc.;

(7) Lithium ions should have a large diffusion coefficient in the electrode material, which is convenient for fast charging and discharging of the battery;

(8) The price is cheap and no pollution to the environment.