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Vanadium-doped LiFePO4/Cused as a cathode for a lithium ion battery has been successfully synthesized.In this work, LiFePO4 was synthesized from LiOH, NH4H2PO4,and FeSO4.7H2O at a stoichiometric amount. Vanadium was added in theform of H4NO3V at concentration variations and 3 wt.%carbon black. The characterization includes thermal analysis, X-raydiffraction, electron microscopy, and electrical impedance spectroscopy. Thethermal analysis results showed that the LiFePO4 formationtemperature is 653.8?700.0°C. The X-raydiffraction results showed an olivine structure with an orthorhombic spacegroup, whereas the electron microscopy results showed that LiFePO4/Chas a round shape with an agglomerated microstructure. Electrical impedancetest results showed values of 158 Ω and 59 Ω for the as-synthesizedLiFePO4/C and the 5 wt.% vanadium-dopedLiFePO4/C, respectively. Cyclic performance test results at 1 Cshowed capacities of 24.0 mAh/g and 31.2 mAh/g for the as-synthesized LiFePO4/Cand the 5 wt.% vanadium-doped LiFePO4/C,respectively. Charge and discharge test results showed charge and dischargecapacities of 27.6 mAh/g and 40.2 mAh/g for the as-synthesized LiFePO4/Candthe5 wt.%vanadium-doped LiFePO4, respectively. This result is promisingin terms of increasing the performance of a lithium ion battery. |
