高性能磷酸钒锂正极材料的合成

he VO2 nanorods were prepared with V2O5 by hydrothermal method. Polypyrrole was coated on the surface of VO2 through in-situ polymerization. The VO2 particles coated with polypyrrole were mixed with NH4H2(PO4)3 and Li2CO3 in ethyl alcohol according to the stoichiometry of Li3V2(PO4)3 to synthesize the cathode material Li3V2(PO4)3/C. Polypyrrole coated on the surface of VO2 nanorods was carbonized in the process of calcination to inhibit the growth of Li3V2(PO4)3 grains. A battery was assembled with Li3V2(PO4)3/C (cathode) and lithium metal (anode) to test the electrochemical performance of cathode material. The constant current charge/discharge cycling performance was measured in the potential range of 3.0-4.3 V. The discharge capacities were 130, 125, 123 and 115 mAh g-1 at the rates of 0.2, 1.0, 2.0 and 5.0 C, respectively. And the discharge specific capacity was 121 mAh g-1 after 600 cycles at 1.0 C, meaning the discharge specific capacity retention rate was as high as 96 %. The grain refinement enhances the electrochemical performance of Li3V2(PO4)3/C.