Constructing a Hierarchical LiMn0.8Fe0.2PO4/C Cathode via Comodification of Li3PO4 and Graphite for High-Performance Lithium-Ion Batteries

The construction of an ionic/electronic conducting network is crucial for achieving satisfactory electrochemical performances of LiMnPO4 materials because of their low conductivity and the dissolution of Mn2+. Herein, a hierarchical LiMn0.8Fe0.2PO4/C composite comodified with Li3PO4 and graphite is synthesized via a facile solid-state method combined with freeze drying. The ionic conductor Li3PO4 in situ generated can improve the lithium-ion conductivity and inhibit the reaction of Mn ions with electrolytes. An electronic conducting network is formed through the secondary coating graphite and the residual carbon in situ created within the grain boundaries of LiMnPO4 nanocrystallites. Taking advantage of the synergy effect, the Li3PO4 and graphite comodified LiMn0.8Fe0.2PO4/C material yields an initial discharge capacity of 150 mA h g–1at 0.1 C, a high-rate reversible capacity of 136 mA h g–1at 5 C, and a long-term capacity retention of 91.6% after 500 cycles at 2 C. The design strategy provides a significant inspiration for the development of high-performance cathode materials with practical application.