LiF掺杂对LiNi0.9Mn0.1O2正极材料组织及性能的影响

Effects of Separator on Properties of Lithium Ion Batteries

本文利用共沉淀-高温固相的方法,制备了含有不同LiF掺杂量的LiNi0.9Mn0.1O2正极材料,通过X射线衍射仪(XRD)和扫描电子显微镜(SEM)对其相结构和形貌进行观察。结果显示,适量的Li F掺杂可以改善LiNi0.9Mn0.1O2正极材料的放电比容量、低温性能以及降低材料在不同放电深度下的阻值,当掺杂量为0.5%时,具有最佳性能。LiF的掺杂不会改变LiNi0.9Mn0.1O2正极材料的相结构,但是会影响正极材料的晶胞体积,当LiF掺杂量为0.5%时,其晶胞体积最小(101.71?3),此时材料的阳离子混排程度较低。此外,不同LiF掺杂量的LiNi0.9Mn0.1O2正极材料呈类球形形貌分布,当LiF掺杂量为0.5%时,正极材料粒度分布更均匀。这两者的综合影响,是适量的LiF掺杂改善LiNi0.9Mn0.1O2正极材料性能的原因。

LiNi0.9Mn0.1O2 cathode materials with different LiF contents were prepared by coprecipitation-high temperature solid phase method.The phase structure and morphology of materials were observed by X-ray diffraction (XRD) and scanning electron microscopy (SEM).The results showed that the proper amount of LiF doping in LiNi0.9Mn0.1O2 cathode material can improve the discharge specific capacity,low temperature performance and resistance at different discharge depths.When the content of LiF was 0.5%,it has the best performance.Further,LiF doping did not change the phase structure of LiNi0.9Mn0.1O2 cathode material,but affected the cell volume.When the content of LiF was 0.5%,the cell volume was the smallest (101.71?3),the value of c/a and I(003)/I(104) reached the maximum,and the degree of cation mixing was lower.The morphology of LiNi0.9Mn0.1O2 cathode materials with different LiF contents were spherical,and the particle size distribution of cathode materials was more uniform when the doping amount of LiF was 0.5%.The comprehensive effect of these two factors was the main reason that the proper amount of LiF doping improves the performance of LiNi0.9Mn0.1O2 cathode material.