Green Phytic Acid-Assisted Synthesis of LiMn1-xFexPO4/C Cathodes for High-Performance Lithium-Ion Batteries

Abstract

As a promising cathode material, olivine-structured LiMnPO4 holds enormous potential for lithium-ion batteries. Herein, we demonstrate a green biomass-derived phytic-acid-assisted method to synthesize a series of LiMn1−xFexPO4/C composites. The effect of Fe doping on the crystal structure and morphology of LiMnPO4 particles is investigated. It is revealed that the optimal Fe doping amount of x = 0.2 enables a substantial enhancement of interfacial charge transfer ability and Li+ ion diffusion kinetics. Consequently, a large reversible capacity output of 146 mAh g−1 at 0.05 C and a high rate capacity of 77 mAh g−1 at 2 C were acquired by the as-optimized LiMn0.8Fe0.2PO4/C cathode. Moreover, the LiMn0.8Fe0.2PO4/C delivered a specific capacity of 68 mAh g−1 at 2 C after 500 cycles, with a capacity retention of 88.4%. This work will unveil a green synthesis route for advancing phosphate cathode materials toward practical implementation.