Preparation of lithium ferromanganese phosphate by non-stoichiometric strategy

Li x Fe x Mn 1-x PO 4 exhibits low production costs, environmental friendliness, high energy density, thermal stability, and cycling stability in lithium-ion batteries (LIBs), presenting broad application prospects. Furthermore, studies have shown that adopting a non-stoichiometric ratio strategy can reduce particle size, decrease anti-site defects, and generate a conductive impurity phase on the material surface. This leads to an enhancement in the electrochemical performance of the material, making it an effective approach to achieving high-performance olivine-type cathode materials. In this study, three materials were successfully prepared using the solid-phase method: Li 1.05 Fe 0.5 Mn 0.475 PO 4 /C, Li 1.05 Fe 0.5 Mn 0.5 PO 4 /C, and Li 1.05 Fe 0.475 Mn 0.5 PO 4 /C. The physical properties of the materials were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The electrochemical performance including specific capacity, rate performance, and cycling performance were studied through charge-discharge tests, with Li 1.05 Fe 0.5 Mn 0.475 PO 4 /C exhibiting the best specific capacity at all rates. At rates of 0.1 C, 0.5 C, 1 C, 2 C, and 5 C, its average reversible specific capacities were 143.5, 129.5, 122.1, 112.8, and 97.3 mAh·g −1 , respectively. Furthermore, differences in electrochemical performance of three materials were discussed in detail through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).