Concentration-Gradient Structural LiFe0.5Mn0.5PO4/C Prepared via Co-precipitation Reaction for Advanced Lithium-Ion Batteries

Abstract

The intrinsically low electronic conductivity and slow ion diffusion kinetics limit further development of olivine LiFe_xMn_1-xPO₄ cathode materials. In this paper, with the aim of improving the performance of such materials and alleviating the Jahn-Taller effect of Mn³⁺ ion, a bimetallic oxalate precursor with gradient distribution of elemental concentration followed with an efficient process is applied to synthesize LiFe_0.5Mn_0.5PO₄ nanocomposite. The results shown that with certain structural modulation of the precursor, the discharge capacity of synthesized LiFe_0.5Mn_0.5PO₄ increased from 149 mAh g^-1 to 156 mAh g^-1 at 0.1 C, the cycling capacity was also remarkably improved. the Fe_0.5Mn_0.5C₂O₄ ⋅ 2H₂O-1 precursor with gradient distribution of elemental concentration effectively restricts the reaction between electrode material and electrolyte, thereby alleviates the dissolution of Mn³⁺ ion, reduces the decay of capacity and improves the stability of the material.

Keywords: Fe0.5Mn0.5C2O4 ⋅ 2H2O; LiFe0.5Mn0.5PO4 nanocomposite; Lithium ion battery; concentration gradient.