What is spinel manganese-based cathode material?
Manganese materials are rich in resources, low in price and environmentally friendly, and have been widely used in dry batteries. In addition, lithium-ion batteries using spinel-type manganese-based cathode materials are safer and can use inexpensive protection circuits. The manganese-based cathode materials used in lithium-ion batteries are mainly divided into two categories. The first category is used in portable electronic devices, such as mobile phones. Although the current market share is low, spinel lithium manganate has become a choice of cell phone battery materials due to its good safety and the availability of cheaper protective plates. In addition, the mixed use of LiNiχCo1-χO2-LiMn2O4 can effectively inhibit the precipitation of manganese on the negative electrode at high temperature, thereby improving its high temperature cycle performance.
LiCoO2 has high energy density and has become the main cathode material for lithium-ion batteries for mobile phones. However, diamond resources are scarce and prices fluctuate greatly, which to a certain extent promotes the mixed use of drill-based materials and manganese-based materials with spinel structure. This hybrid material has the same energy density as traditional materials. Since 2004, this hybrid battery has entered the market. It is expected that the share of this type of battery will continue to expand in the future.
The second type of spinel manganese-based cathode material is used in large-size lithium-ion batteries, such as EV and HEV power supplies. This application field requires batteries with high energy, high safety and low cost, so it is more suitable to use manganese-based cathode materials. In terms of energy density, it surpasses the cheaper iron-based cathode material (LiFePO4). In the field of hybrid electric vehicle power supply, this material has been used in the market for 3 years. In recent years, spinel-type manganese oxide has been used as the main cathode material for lithium-ion batteries and has a good market application in power-assisted bicycles and electric motorcycles. In addition, after erbium-lithium, iron-lithium material (LiFePO4) as the expected positive electrode material has been extensively studied worldwide, but it has not been practically applied due to its poor conductivity and complex synthesis method.
For positive electrode materials, metal ions and lithium ions that undergo oxidation-reduction reactions are indispensable for lithium removal during the charging process. A higher content of metal ions and lithium ions can better increase the capacity of the positive electrode material. The lower the molecular weight of the material, the higher the mass specific energy. Therefore, lower oxygen ions per unit charge mass and low-cost materials are more suitable for lithium ions. That is to say, lithium manganese oxide is the best for lithium ion batteries. Cathode material.
Some research reports pointed out that spinel LiMn2O4, spinel Li2Mn2O4, orthorhombic LiMnO2, layered LiMnO2, O2 Li0.7MnO2, and Li0.33MnO2 are all of this type. Manganese-based cathode material. Li0.33 MnO2 is a high-capacity 3V-type cathode material developed by researchers. Israel Tadiran Company has commercialized AAA-type batteries made of this cathode material and metal lithium anode.
This battery has a special safety mechanism. Tetrahydrofuran plays a dual role in it. One is to act as a solvent in the electrolyte containing polymerization inhibitor amine, and the other is to act as a polymerized monomer when the temperature rises to an emergency. The active material Li0.33 MnO2 lithium manganese composite oxide (CDMO) was developed and commercialized by Sanyo. The button battery using this material is used as a memory backup battery because of its safety. In addition, spinel Li2Mn2O4, layered LiMnO2 and Li0.7MnO2 are generally prepared by chemical reduction or ion exchange using more expensive chemical reagents, so the manufacturing cost is very high and there is no cost advantage.
In short, the candidate materials for manganese-based cathode materials for lithium-ion batteries will be spinel Li2Mn2O4, orthorhombic LiMnO2, and layered manganese-based materials, such as LiMnχNiyCo1-x-yO2 and LiMnχNi1-χO2 type materials. Both can be prepared by simple solid-phase synthesis. There is a saying that although orthorhombic LiMnO2 can exhibit a capacity of 200mA • h/g or higher in the 3~4V region, its cycle performance is poor, because its crystal structure changes during the first charge and discharge. A spinel structure is formed, and this spinel structure will be maintained during subsequent charge and discharge reactions. According to another report, there is an orthorhombic manganese-based material that has excellent cycling performance in the 3~4V region.
Layered Ni-Mn-based cathode materials have been put on the market in the form of single or mixed cathode materials , the spinel manganese-based materials will be explained below, and this compound is also single or mixed with layered nickel or cobalt-based materials. Put the form on the market.
Layered Ni-Mn-based cathode materials have been put on the market in the form of single or mixed cathode materials, and this compound is also put on the market in the form of single or mixed with layered nickel or cobalt-based materials.
Charge and discharge curves of LiCoO2 and LiNiO2.
Current status of cathode material.
You can learn more about Lithium ion batteries material.
