Lithium manganese iron phosphate (LiMnxFe1-xPO4) is a new type of phosphate lithium-ion battery cathode material formed by doping a certain proportion of manganese (Mn) on the basis of lithium iron phosphate (LiFePO4). Through the doping of manganese element, on the one hand, the advantageous characteristics of iron and manganese can be effectively combined, and on the other hand, manganese and iron are both located in the fourth periodic subgroup and adjacent to the periodic table, and have similar ions Radius and some chemical properties, so doping will not significantly affect the original structure.
At present, in the field of power batteries, the mainstream application materials are olivine-structured lithium iron phosphate and layered ternary nickel-cobalt-manganese material (NCM). Its performance has advantages and disadvantages compared to both.
Compared with lithium iron phosphate, the advantages and disadvantages of lithium iron manganese phosphate:
Advantages: The characteristics of high voltage of manganese make lithium manganese iron phosphate have a higher voltage platform, which also leads to a higher energy density at the same specific capacity, and the energy density is 10% higher than that of lithium iron phosphate under the same conditions. -20%.
Disadvantage: The introduction of manganese significantly reduces the electrical conductivity of the material. At the same time, a higher voltage platform also means higher requirements for electrolytes, and there are relatively few types of electrolytes that meet the discharge characteristics.
Compared with ternary NCM materials, the advantages and disadvantages of lithium iron manganese phosphate:
Advantages: Compared with the layered structure of ternary NCM materials, lithium iron manganese phosphate has the same olivine structure as lithium iron phosphate, and the structure is more stable during charging and discharging. Structural collapse occurs, so it is safer and less expensive.
Disadvantages: Compared with high-efficiency ternary materials, the specific capacity and energy density of lithium iron manganese phosphate are still very low, and the gap in electrical conductivity is even greater. This has also led to more applications of lithium iron manganese phosphate in small power fields such as electric two-wheelers with relatively low performance requirements.