【摘要】 橄榄石型LiMn1"xFexPO4在不同的条件下通过固相反应法合成,这些条件包括不同的烧结温度(600℃,550℃,500℃),不同的掺铁量x(x=0.1,0.2,0.3,0.4),不同的研磨方式以及是否掺碳。得到样品的结构和形貌通过X射线衍射(XRD)和电子扫描电镜(SEM)来表征,充放电性能通过电化学手段进行测试。XRD结果表明,手工研磨合成的产物含有杂相,而机械球磨条件下合成的产物都形成了纯相。随着掺铁量的增加,衍射峰的强度没有明显的变化,而随着烧结温度的升高,衍射峰强度增大,峰变尖锐,物相趋于完整。SEM结果表明,掺碳能很好的抑制颗粒的生长。电化学测试表明,当掺铁量x=0.3时,采用机械球磨混料,在600℃烧结而成的掺碳橄榄石型LiMn0.7Fe0.3PO4性能最好,获得了高达130mAh·g’1的可逆容量。更多还原

【Abstract】 Olivine LiMn1-xFexPO4 were synthesized by the method of solid-state reaction in different conditions, which include different sintering temperatures(600 ℃,550 ℃,500 ℃),different quantity of iron, different milling methods, and with or without carbon black added in it. Structure, surface morphology and charge-discharge performance of LiMn1-xFexPO4 were characterized by X ray diffraction (XRD), scanning electron microscope (SEM), and electrochemical measurement respectively. Samples mixed by ball-milling are pure olivine LiMn1-xFexPO4, while sample mixed by hand contains impurities. The intensity of the diffraction peak has no obvious change with the increase of the amount of iron. However, the diffraction peak enhances with the increase of temperature, which indicates that the crystal becomes more integrated. SEM results show that the addition of carbon black restrains the growth of LiMn0.7Fe0.3PO4 particles. Carbon-containing LiMn0.7Fe0.3PO4 synthesized at 600 ℃ combining with ball-milling of reagents and precursors displays a best capability by the electrochemical tests. It has a reversible charge-discharge capacity of 130 mAh·g-1.更多还原