Improved Electrochemical Performance of LiMn0.6Fe0.4PO4 via Chitosan-Derived Nitrogen-Doped Carbon Coating

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.