Synthesis and electrochemical properties of Fe-doped LiMnPO4 nanocomposite prepared by a hydrothermal process in a high-pressure reactor

Abstract

LiMn1-xFexPO4 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. LiMn1-xFexPO4 with a higher Fe concentration presented better cyclic performance, and the capacity retention of a LiMn0.60Fe0.40PO4 electrode after 20 cycles was 97.2% at 25°C with an initial capacity of 145 mAh/g at a 0.1C rate. LiMn0.60Fe0.40PO4 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 LiMn1-xFexPO4 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 LiMn0.70Fe0.30PO4 material.