The Cathode Material Of Liv <sub> 3 </ Sub> O <sub> 8 </ Sub> Synthesis And Properties

As a new generation green non-pollution battery, Lithium-ion batteries are important power sources for portable electronics, such as laptop computers, cellular phones and camcorders. In addition, they are also considered as the promising candidates for using in the electric vehicles in the future. The cathode material is known to exert a major influence on the performance of Li-ion batteries. Layered-type lithium trivanadate Li_1+XV₃O₈ is among the best promising cathode materials for Li-ion batteries, due to the low cost, large specific capacity, high discharge rate and long cycle life. The methods used to prepare the Li_1+XV₃O₈ strongly influenced its electrochemical properties, Such as specific capacity, rate capability and cycling efficiency. In this paper, LiV₃O₈ was synthesized by different methods.The main work of the paper was as follows:(1) lithium trivanadate LiV₃O₈ was synthesized by low temperature quasi solid-state method, the structure and electrochemical properties of the material were studied by XRD and electrochemical measurements respectively. The results show that the sample sintered at 530℃for 24h has good electrochemical properties. The first discharge capacity of which is 228.6mAh·g-1, and maintains a discharge capacity of 181.2 mAh·g-1 after 30 cycles at 0.1 C rate and the voltage range over 3.6V¹.8V.A low cost, simple and effective route to synthesized LiV₃O₈ is provided.(2) Layered-type lithium trivanadate LiV₃O₈ was synthesized by citric acid sol-gel method with NH4VO3 and LiAc·H2O as raw reagents. The effect of sintering temperature and time on the structure, morphology and electrochemical property was investigated. The investigation of XRD , SEM and the determination of the electrochemical properties show the sample obtained under the optimum synthesis conditions has perfect layered-type structure and good electreochemical properties, with the initial discharge capacity of 251.2mAh·g-1 and 201.3mAh·g-1 in the 30th cycle.(3) Li-ion batteries cathode materials LiV₃O₈ was prepared at low temperature by sol-gel process with NH4VO3 and LiAc·H2O as initial reagents, The synthesis routewas based on a very strong complexing agent (EDTA).The electrochemical preoperties of samples prepared at different conditions were compared. The sample sintered at 550℃for 15h has excellent electrochemical properties with the first discharge of 251.7mAh·g-1, and the discharge capacity of the 30th was 219.7 mAh·g-1.(4) LiV₃O₈ was synthesized by sol-gel method with V2O5, LiOH and H2O2 as raw materials. The investigation results of XRD , SEM and the electrochemical measurement show the samples sintered at 530℃for 15h has the first discharge capacity of 261.0mAh·g-1,and maintains a discharge capacity of 205.1mAh·g-1 after 25 cycles. The influence of the preparing conditions including sintering temperature and time on crystal structure and electrochemical performance were investigated.