Hydrothermal synthesis of LiMn0.79Fe0.2Mg0.01PO4/C composite cathode materials using different Li3PO4 precursors

Doping and particle size controlling are two important approaches to improve the electrochemical performance of LiMn x Fe 1−x PO 4 cathode materials . By employing a straightforward hydrothermal method and utilizing cost-effective lithium phosphate (Li 3 PO 4 ) as the precursor, we successfully synthesized high Mn-content LiMn 0.79 Fe 0.2 Mg 0.01 PO 4 /C composites. The results reveal that the minute amount of Mg substantially enhances the electrochemical performance. In the subsequent mechanism study using Li 3 PO 4 precursors with different particle size, we found that the nucleation process, dependent on specific surface area and diffusion rate, is likely to play a critical role for the size and morphology of formed LiMn 0.79 Fe 0.2 Mg 0.01 PO 4 . LiMn 0.79 Fe 0.2 Mg 0.01 PO 4 /C (LMFP-1), synthesized from initially smaller-sized and less agglomerated Li 3 PO 4 (LPO-1), exhibited the most diminutive average particle size coupled with the highest specific surface area, which further facilitated electrolyte interfacial interaction and promoted Li + diffusion kinetics. At 1C, LMFP-1 displayed a specific capacity of 110.7 mAh g −1 , with 97.07% capacity retention after 200 cycles. This study provides pivotal insights for the synthesis of high-performance LiMn x Fe 1−x PO 4 materials.