Improved Electrochemical Performance of LiMn_0.6Fe_0.4PO₄ via Chitosan‐Derived Nitrogen‐Doped Carbon Coating

Abstract

The olivine‐type compound LiMnxFe1‐XPO4 (LMFP) combines the advantageous characteristics of LiFePO4 and LiMnPO4, including high energy density, extended cycle life, eco‐friendliness, and cost‐effectiveness. However, its application is limited by certain challenges such as low electronic conductivity and stability issues related to the Jahn‐Teller effect induced by Mn3+, which hinder its scalability. Here, we introduce an innovative approach by applying nitrogen‐doped carbon layers, derived from chitosan as both a carbon and nitrogen sources, to encapsulate LMFP. This encapsulation significantly improves LMFP's electrochemical performance compared to those using sucrose‐derived carbon coatings. The LMFP cathode with nitrogen‐doped carbon coating exhibits a specific capacity of 156.8 mAh/g at 0.1 C, achieved a first‐cycle Coulombic efficiency of 96.8 %, and maintained a capacity retention rate of 94.6 % after 200 cycles at 1 C. This new method of employing chitosan for producing nitrogen‐doped carbon coatings holds great promise for enhancing the usability of LMFP in broader applications.