Through detailed analysis, how to select the cathode material for lithium ion batteries?

Lithium-ion batteries are capable of secondary charging during use and belong to a secondary rechargeable battery. The main working principle is the repeated movement of lithium ions between positive and negative poles, regardless of the shape of the battery. Its main components are electrolytes, positive plates, negative plates and diaphragm. At present, the international production of lithium-ion batteries is mainly concentrated in China, Japan and South Korea. The main lithium ion application markets are mobile phones and computers. With the continuous development of lithium-ion batteries, the application field is gradually expanding, and its use of positive polar materials has changed from monolithic to diversified. These include: olivine type ferrous phosphate lithium, layered cobalt acid lithium, spinel type manganese acid, etc., to achieve the coexistence of a variety of materials.

It can be seen from the development of technology that more new types of positive materials will be produced in the future development. For the power cell's positive electrode material, it has strict requirements in terms of cost, safety performance, circulation capacity, and energy density. In the field of Applied materials, due to the high cost and low safety of lithium cobalt acid, it is usually applicable to ordinary consumer batteries in specific applications and it is difficult to meet the requirements of power batteries. The other materials listed above have been fully utilized in the current power cells.

Lithium-ion battery cathode material

1,Lithium cobalt acid, as a positive electrode material, was used the earliest, and it is still the mainstream positive electrode material in consumer electronics products. Compared with other positive materials, lithium cobalt acid can be seen that the voltage in the process of operation is relatively high, the voltage operation is relatively stable when charging or discharging, and it can meet the requirements of high current, has strong cyclic performance, and has high conductivity. Materials and batteries and other processes are relatively stable. However, it also has many disadvantages. For example, resources are scarce, prices are higher, cobalt contains toxicity, and it has certain risks when used, and it can have adverse effects on the environment. In particular, its security can not be effectively guaranteed, which will become an important factor that restricts its extensive development. Among the studies carried out on it, metal cations such as Al 3 +, Mg2 +, and Ni2 + are the most widely doped, and with the continuous advancement of scientific research, At present, metal cation doping forms such as Al 3 + and Mg2 + have been put into use. In the preparation of lithium cobalt acid, two methods are mainly included, namely solid phase synthesis and liquid phase synthesis. What is commonly used in industry is the high-temperature solid phase synthesis method. It mainly uses lithium salts, such as Li2CO3 or LiOH, and cobalt salts, such as CoCO3, to fuse at a ratio of 1:1. It is formed by calcination at a high temperature of 600 °C to 900 °C. At present, the application of lithium cobalt acid materials in the market is mainly in the secondary battery market, and it is also the best choice for small high-density lithium ion battery materials.

2,The ternary cathode material has a relatively significant ternary synergistic effect. Compared with lithium cobalt oxide, it can be seen that it has great advantages in thermal stability, and the production cost is relatively low, and it can become the best substitute material for lithium cobalt oxide. . However, its density is low and the cycle performance needs to be improved. In this regard, adjustment can be made using an improved synthesis process, ion doping, and the like. Ternary materials are mainly used in cylindrical lithium-ion batteries such as steel shells and aluminum shells, but their application in soft pack batteries is greatly limited due to the influence of expansion factors. In the future application, its development direction mainly has two aspects: First, toward the high manganese direction, mainly in the development of small portable devices such as Bluetooth and mobile phones. Secondly, in the direction of high nickel, it is mainly applied in fields where electric energy bicycles, electric vehicles and the like have high demand for energy density.

3,Lithium ferric phosphate has good cycling performance and thermal stability in charging and discharging. It has strong safety guarantees during use, and the material is green and environmentally friendly and will not cause serious damage to the environment. At the same time, the price is also relatively low. China's battery industry is considered to be the best material for large-scale battery module production. The main application areas at present are: electric vehicles, portable mobile charging power sources, etc.. In the future, it will develop in the direction of energy storage power sources and portable power sources.

4, Lithium manganese oxide has strong safety and anti-overload in application. Due to the abundant manganese resources in China, the price is relatively low, the pollution to the environment is small, non-toxic and harmless, and the industrial preparation operation is relatively simple. However, during the charging or discharge process, due to the instability of the spinel structure, the Jahn-Teller effect is easily produced, and the dissolution of manganese at high temperatures makes it easy to reduce the battery capacity, so its application is also greatly limited. At present, the application scope of Lithium manganese oxide is mainly small batteries, such as mobile phones, digital products, etc.. In terms of power cells, lithium iron phosphate can be replaced with each other, thus creating strong competition. Its development direction will be high energy, high density, low cost trend.

Lithium-ion battery products have shown a vigorous development. With the development of science and technology, smart phones, computers and other products have been widely used. This will make the demand for lithium-ion batteries greater and bring greater development opportunities for them. At the same time, vehicle-mounted lithium ions and energy storage power supplies have gradually been developed, providing new growth points for lithium ion batteries. Therefore, in the future development, it is necessary to strengthen the research on this aspect, so that the role of lithium-ion batteries will play a greater role, which will also lead to the continuous replacement of its battery materials.

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