阴阳离子复合掺杂型Li_(1+x)Mn_(2-x)O_(4-y)F_y的合成机理研究

Study of the reaction mechanism of anion-cation compound substitution Li_(1+x)Mn_(2-x)O_(4-y)F_y

以LiNO3、LiF和醋酸锰为原料,采用柠檬酸络合法,通过控制原材料配比,在750℃下,制备出尖晶石型系列Li1+xMn2-xO4-yFy电极材料。运用等离子体发射光谱法和电位分析法相结合的分析手段测定材料的实际组成,通过分析试样的IR和XRD谱图参数、氟和锂掺杂量与锰的平均氧化数以及材料晶胞常数的变化关系,研究了氟的掺杂取代机理,并得出掺杂的氟取代λMnO2骨架中氧的结论;结合合成材料前驱体的TGA DTA谱图,阐述了Li1+xMn2-xO4-yFy的形成过程。

Lithium nitrate, lithium fluoride and manganous acetate were used as raw materials, controlled n(Li)∶n(Mn) , a series of spinel Li_(1+x)Mn_(2-x)O_(4-y)F_y were prepared by citric acid complex method at 750℃. The actual composition of samples was determined by ICP-AES and potentiometry, the mechanism of the F doping was investigated by analyzed the parameter of IR and XRD, the relation of the amount of fluoride and lithium doped, the valence of manganese and material cell parameters. The results showed that oxygen was replaced by fluorine in the λ-MnO_2 framework and the reaction mechanism of the doped material was proposed on the base of the results of TGA-DTA.