Synthesis and Electrochemical Properties of Fe-Doped LiMnPO Nanocomposite Prepared by a Hydrothermal Process in a High-Pressure Reactor

LiMn 1 - x Fe x PO 4 powders with varied Fe concentrations (x=0, 0.2, 0.3, 0.4) were prepared in a high-pressure reactor by a hydrothermal process. The effect of the Fe dopant concentration on the crystal structure, morphology, surface area and electrochemical properties were studied. LiMn 1-x Fe x PO 4 with a higher Fe concentration presented better cyclic performance, and the capacity retention of a LiMn 0.60 Fe 0.40 PO 4 electrode after 20 cycles was 97.2% at 25°C with an initial capacity of 145 mAh/g at a 0.1C rate. LiMn 0.60 Fe 0.40 PO 4 also delivered discharge capacities of 151 mAh/g and 109.3 mAh/g at rates of 0.05C and 5C, respectively. Because the total charge/discharge capacity of LiMn 1-x Fe x PO 4 was enhanced as the Fe concentration increased while the average discharge voltage was reduced, a high specific energy value of 513 Wh/kg was achieved in the LiMn 0.70 Fe 0.30 PO 4 material.