Lithium iron phosphate (LiFePO4) has an olivine structure, which is a slightly twisted hexagonal close-packed, and its space group is Pmnb type.

　　LiFePO4 consists of FeO6 octahedrons and PO4 tetrahedrons forming a spatial framework. P occupies tetrahedral positions, while Fe and Li are filled in the octahedral voids. Fe occupies co-angular octahedral positions and Li occupies co-sided octahedral positions. . In the lattice, one FeO6 octahedron is coedges with two FeO6 octahedrons and one PO4 tetrahedron, while the PO4 tetrahedron is coedges with one FeO6 octahedron and two LiO6 octahedrons. Due to the close arrangement of oxygen atoms in the nearly hexagonal packing, lithium ions can only be deintercalated on a two-dimensional plane, and therefore have a relatively high theoretical density (3.6g/cm3). In this structure, the voltage of Fe2+/Fe3+ to metal lithium is 3.4V, and the theoretical specific capacity of the material is 170mA·h/g. A strong P-O-M covalent bond is formed in the material, which greatly stabilizes the crystal structure of the material, resulting in high thermal stability of the material.

　　Wang et al. made a detailed analysis of the electrochemical performance of LiFePO4. Figure 2.2 is the cyclic load voltammogram of LiFePO4. Two peaks are formed in the CV diagram. During anode scanning, Li+ is removed from the LixFePO4 structure and forms oxidation at 3.52V. Peak; when scanning from 4.0 to 3.0, Li+ is inserted into the LixFePO4 structure, and the corresponding reduction peak is formed at 3.32V; the redox peak in the CV curve indicates that a reversible lithium ion intercalation and deintercalation reaction occurs on the LiFePO4 electrode.