Synthesis and properties of xLiFePO4•yLi3V2 (PO4)3/carbon microsphere composites as Li-ion battery cathodes

Composite xLiFePO(4) (LF)center dot yLi(3)V(2) (PO4)(3) (VP) carbon microspheres (CMSs) (LFVPC) with different (x:y) molar ratios were investigated for lithium-ion batteries (LIBs), synthesized using a hydrothermal and carbon reduction method. The microstructures and properties of the LFVPC composites were characterized via scanning electron microscopy, transmission electron microscopy, and X-ray diffraction methods, respectively. The electrochemical behavior of the samples was analyzed by carrying out galvanostatic charge/discharge tests, electrochemical impedance spectroscopy, and cyclic voltammetry. The results show that the LFVPC composites have two phase structures with element doping. LFVPC-2 (molar ratio of 5:1), which was sintered at 650 degrees C for 18 h, exhibits a lower electrochemical resistance, weaker polarization, significantly improved reversibility and cycling life, and superior capacity retention of 97.1% after 25 cycles at 1 C and exhibits a high capacity of 114.1 (+/- 1.4) mAh g(-1), even at 5 C.