A Uniform Conductive Carbon Coating of Nitrogen-Doped Carbon Improves the Electrochemical Performance of LiMn0.7Fe0.3PO4 Cathode Material for Lithium-ion Batteries

The practical application of LiMn1-xFexPO4 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 LiMn0.7Fe0.3PO4 (LiMn0.7Fe0.3PO4@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 LiMn0.7Fe0.3PO4 cathode. Furthermore, the uniform carbon layer prevented metal ion dissolution and stabilized the crystal structure. The resulting LiMn0.7Fe0.3PO4@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 LiMn0.7Fe0.3PO4@NC-2 sample demonstrated a high Li+ diffusion coefficient (3.98x10(-11) cm(2) s(-1)) and electrical conductivity (1.47x10(-2) S cm(-1)). This study presents a novel approach to designing high-performance cathode materials using a cost-effective and straightforward process.