Concentration-Gradient Structural LiFe 0.5 Mn 0.5 PO 4 /C Prepared via Co-precipitation Reaction for Advanced Lithium-Ion Batteries.

The intrinsically low electronic conductivity and slow ion diffusion kinetics limit further development of olivine LiFe x Mn 1-x PO 4 cathode materials. In this paper, with the aim of improving the performance of such materials and alleviating the Jahn-Taller effect of Mn 3+ ion, a bimetallic oxalate precursor with gradient distribution of elemental concentration followed with an efficient process is applied to synthesize LiFe 0.5 Mn 0.5 PO 4 nanocomposite. The results shown that with certain structural modulation of the precursor, the discharge capacity of synthesized LiFe 0.5 Mn 0.5 PO 4 increased from 149 mAh g -1 to 156 mAh g -1 at 0.1 C, the cycling capacity was also remarkably improved. the Fe 0.5 Mn 0.5 C 2 O 4  ⋅ 2H 2 O-1 precursor with gradient distribution of elemental concentration effectively restricts the reaction between electrode material and electrolyte, thereby alleviates the dissolution of Mn 3+ ion, reduces the decay of capacity and improves the stability of the material.