A Uniform Conductive Carbon Coating of Nitrogen‐Doped Carbon Improves the Electrochemical Performance of LiMn_0.7Fe_0.3PO₄ Cathode Material for Lithium‐ion Batteries

Abstract

Abstract The practical application of LiMn 1−x Fe x PO 4 as a cathode material is hindered considerably by its poor electronic conductivity and slow lithium‐ion diffusion. In the present study, a uniform nitrogen‐doped carbon coating on LiMn 0.7 Fe 0.3 PO 4 (LiMn 0.7 Fe 0.3 PO 4 @NC) was achieved using ethylene diamine tetraacetic acid (EDTA) as a chelating agent and carbon source. The nitrogen‐doped carbon layer enhanced the electronic conductivity and ionic diffusion of the LiMn 0.7 Fe 0.3 PO 4 cathode. Furthermore, the uniform carbon layer prevented metal ion dissolution and stabilized the crystal structure. The resulting LiMn 0.7 Fe 0.3 PO 4 @NC‐2 sample demonstrated superior performance with a specific capacity of 152.5 mAh g −1 at 0.1 C and preserved 93.7 % of this capacity over 200 cycles at 1 C. Meanwhile, the LiMn 0.7 Fe 0.3 PO 4 @NC‐2 sample demonstrated a high Li + diffusion coefficient (3.98×10 −11 cm 2 s −1 ) and electrical conductivity (1.47×10 −2 S cm −1 ). This study presents a novel approach to designing high‐performance cathode materials using a cost‐effective and straightforward process.