Electrochimica Acta, Vol.146, 288-294, 2014
Synthesis and electrochemical properties of xLiMn(0.9)Fe(0.1)PO(4)center dot yLi(3)V(2)(PO4)(3)/C composite cathode materials for lithium-ion batteries
The xLiMn(0.9)Fe(0.1)PO(4)center dot gamma Li3V2(PO4)(3)/C (x:y=1:0, 9:15:1,3:1,1:1 and 0:1) cathode materials are synthesized by a ball-milling and post-calcination method. XRD results reveal that the xLiMn(0.9)Fe(0.1)PO(4)center dot gamma Li3V2(PO4)(3)/C (x,y not equal 0) composites are composed of LiMn0.9Fe0.1PO4 and Li3V2(PO4)(3) phases, and no impurities are detected. In LiMn0.9Fe0.1PO4-Li3V2(PO4)(3) system, most of the manganese, iron and vanadium elements in the raw materials tend to form the two major phases, and only small amounts of V, Mn and Fe as dopants enter into the lattice of LiMn0.9Fe0.1PO4 and Li3V2(PO4)(3). Electrochemical tests show that the xLiMn(0.9)Fe(0.1)PO(4 center dot)gamma Li3V2(PO4)(3)/C (x,y not equal 0) composites exhibit much better performance than the single LiMn0.9Fe0.1PO4/C. Among the samples, 5LiMn(0.9)Fe(0.1)PO(4)center dot Li3V2(PO4)(3)/C shows the best electrochemical performance. The sample delivers the specific capacities of 158.1, 140.7 and 100.2 mAh g(-1) at 0.05, 1 and 4C rates in the potential range of 2.5-4.5 V, and exhibits very long and flat discharge plateau around 4.0 V up to 1 C rate. The sample also shows good cycling performance at various C-rates. (C) 2014 Elsevier Ltd. All rights reserved.
Keywords:lithium-ion battery;cathode material;lithium manganese iron phosphate;lithium vanadium phosphate;composite material