【作者】 张华香；

【导师】 童庆松；

【作者基本信息】 福建师范大学 ， 物理化学， 2004， 硕士

【摘要】 Li_1+xV₃O₈具有比能量高，锂嵌入量大等优点，是一种非常有发展前途的锂离子电池的正极材料。但其电化学性能受合成工艺影响大，且循环寿命不佳。为此，本文采用三种固相烧结法合成了Li_1+xV₃O₈。第一种固相烧结法是在480至680℃利用直接固相烧结法制样；第二种固相烧结法是用微波辐照合成样品；第三种固相烧结法是在第二种固相烧结法的基础上进一步掺杂TiO₂制备的掺杂样品。通过XRD、FTIR、TEM等研究了样品的电化学性能与合成条件的关系。 研究表明：直接固相烧结法得到的样品呈现棒状结构。480℃样品的第一循环的放电容量为218mAh／g，在40个循环的充放电中放电容量衰减率为27％。680℃样品的第一循环的放电容量为128mAh／g，在40个循环的充放电中放电容量衰减率为3％。微波烧结法得到的样品呈现圆球状结构，粒径在150-300nm范围内。微波处理导致样品的XRD衍射线有明显的宽化现象。微波烧结样的第一循环的放电容量为210mAh／g，第40循环的放电容量为202mAh／g，循环性能较其它烧结样更为优秀，且存放性能也更好。掺杂TiO₂的Li_1+xV₃O₈微波烧结样进一步改善了电化学性能。测试了样品的一些光谱性能。更多还原

【Abstract】 Li1+xV3O8 is regarded as a promising cathode material in Li ions battery, for its high capacity and special electrochemical performance. Past studies show that the electrochemical performance of Li1+xV3O8 remarkably depends on synthesis methods . In this paper three kinds of solid phase sintering methods were employed to synthesize Li1+xV3O8 samples, in which the first included the solid phase sintering process in the temperature range 480 to 680C ;the second included the microwave sintering process ; the third included the simultaneity doped process on the basis of second microwave sintering method .The connection between electrochemical performance and synthesis conditions studied by the modern experimental techniques , such as XRD, FT-IR, TEM, Cyclic voltammetry , charge-discharge experiment, storage experiment etc.Experiments indicate that the samples synthesized by pure solid phase sintering method hold stick-shape. The discharge capacity of 480C sample is 218mAh/g at the first cycle and the declined rate of discharge capacity is 27% in 40 cycles. The discharge capacity of 680C sample is 128mAh/g at the first cycle , nevertheless its declined rate is only 3%.The sample synthesized by the microwave sintering has a kind of sphere-shape with a particle sizes about 150-300nm. XRD diffraction peaks of samples of microwave sintering is obviously expanded . The discharge capacity of sample synthesized by microwave sintering have 210mAh/g discharge capacity at first cycle , while have 202mAh/g capacity after 40 cycles, which show better cycle and stored performance than other samples. TiO2 doped further improved the electrochemical performance . Several special spectrum characters are measured .更多还原