Novel precursor of Mn(PO₃(OH))·3H₂O for synthesizing LiMn_0.5Fe_0.5PO₄ cathode material

A brand new method for synthesizing Mn(PO₃(OH))·3H ₂O is attained in this paper. During this process, pure flake-like Mn(PO₃(OH))·3H₂O precipitate is prepared using C₂H₅OH as initiator. Besides that, LiMn _0.5Fe_0.5PO₄/C is successfully synthesized from the Mn(PO₃(OH))·3H₂O precursor at 650°C for the first time. Thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) are applied in the characterization of the Mn(PO₃(OH))·3H₂O precursor and LiMn _0.5Fe_0.5PO₄/C. High-resolution transmission electron microscopy (HRTEM) is also used to investigate the morphology of LiMn_0.5Fe_0.5PO₄/C. X-ray photoelectron spectroscopy (XPS) and galvanostatic charge and discharge test are employed to characterize the Mn(PO₃(OH))·3H₂O precursor and LiMn_0.5Fe_0.5PO₄ material, respectively. The as-prepared LiMn_0.5Fe_0.5PO₄/C material exhibited a reversible capacity of 131 mAh g^-1 at 0.05 C. It can be confirmed that the incorporation of Fe into LiMnPO₄ can significantly improve the electrochemical properties for improving the conductivity of the material and facilitating the Li⁺ diffusion. In addition, a capacity of 120 mAh g^-1 is still delivered at 0.05 C rate with a capacity retention of about 91% after 25 cycles, and reversible capacity can reach 105 mAh g^-1 at 1 C.