Synthesis And Electrochemical Characteristics Of Vanadium Anode Materials For Lithium Ion Batteries

The lithium- ion battery has become the main battery in energy storage due to a number of advantages such as high capacity, low cost, and long life. The electrode materials have crucial significance in the research on lithium- ion batteries because these determine the performance of the lithium- ion battery. The vanadium based anode material is a hot research topic since it has a low voltage platform, a high capacity, high safety, and high energy density.Lithium vanadate(Li3VO4) has a working platform voltage around 0.5 V, with a theoretical specific capacity of 394 m Ah/g, and has high cycle and rate performance. However it possesses a high initial irreversible capacity and further research is required. This report is on Li3VO4 as an anode material which was prepared by sol- gel and shows results on the crystal structure, morp hology and electro-chemical properties of Li3VO4 using different solution p H, different calcination temperature, and different calcination times. The results show that the electrochemical performance of Li3VO4 is highest when the solution p H=4.5, the calcination temperature is 600℃ and the calcination time is 12 h. C harge-discharge rates of 0.1C, 0.2 C and 0.5 C, showed the first discharge capacity was 472 m Ah/g, 384 m Ah/g and 389 m Ah/g respectively and after 50 cycles, the charge-discharge capacity is 288 m Ah/g, 322 m Ah/g, and 232 m Ah/g respectively. When the charge-discharge rate is 0.1 C the charge-discharge platform of the Li3VO4 is 1.3 V and 0.7 V. O verall this material showed a good cycle performance and high stability with good prospects for use as an anode material.An alternative lithium vanadate anode material is lithium copper vanadate(Li Cu VO4) which has the same working platform voltage as Li3VO4 and also a high cycle and rate performance but with a much higher theoretical specific capacity. However it suffers the same high initial irreversible capacity as Li3VO4 so it requires further research. The Li Cu VO4 anode material was prepared by solid-phase method and the effect of calcination temperature and calcination time on the crystal structure, morphology and electrochemical properties is reported. The results obtained showed that a calcination temperature of 550℃and a calcination time of 16 h gave the best electrochemical performance. When the charge-discharge rate is 50 m A/g, 200 m A/g and 500 m A/g, the first discharge capacity are 808 m Ah/g, 749 m Ah/g and 787 m Ah/g respectively and after 50 cycles the charge-discharge capacities are 406 m Ah/g, 387 m Ah/g and 376 m Ah/g respectively. These values are close to the most recent published results.