Core-shell structured lithium manganese iron phosphate cathode material with “manganese-rich core and iron-rich shell” and preparation method thereof

Abstract

The present invention relates to a manganese-rich core-iron-rich shell core-shell structured lithium manganese iron phosphate cathode material and a preparation method thereof, belonging to the technical field of lithium-ion battery cathode materials. The manganese-rich core-iron-rich shell core-shell structured lithium manganese iron phosphate cathode material comprises a manganese-rich LiMnxFe1-xPO4 inner core, an iron-rich LiMnyFe1-yPO4 layer coating the inner core from inside to outside, and a carbon coating layer; wherein x=0.5-0.9, y=0.1-0.4. The manganese-rich core-iron-rich shell core-shell structured lithium manganese iron phosphate cathode material prepared by the present invention provides high capacity and high working voltage through the manganese-rich component as the inner core. The iron-rich outer shell inhibits dissolution of manganese, enhances structural stability of the material, and improves electronic conductivity, thereby improving cycling performance and rate performance of the battery. Furthermore, carbon coating as an effective modification method further improves conductivity of the material, playing an important role in enhancing electrochemical performance of the manganese-rich core-shell structured cathode material.

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