摘要:
采用高温固相法成功制备了Li2x-ySr1-xTi1-yNbyO3（x=3y/4，y=0.25，0.5，0.6，0.7，0.75，0.8）锂离子固体电解质，并通过X射线衍射（XRD）、扫描电子显微镜（SEM）、交流阻抗图谱、恒电位极化等分别研究了各个组分的晶体结构、微观形貌、离子电导率和电子电导率。XRD显示当≤ 0.70时，材料为立方钙钛矿型结构，几乎没有杂质相生成。SEM表明随着掺杂含量的增加材料的晶粒尺寸逐渐增大。Li0.35Sr0.475Ti0.3Nb0.7O3锂离子固体电解质有着高离子电导率，为3.62×10-5 S·cm-1，电子电导率为2.55×10-9 S·cm-1，活化能仅为0.29 eV。使用以Li0.35Sr0.475Ti0.3Nb0.7O3为隔膜的LiFePO4/Li半电池经过100圈循环后，放电比容量仍有93.9 mAh·g-1，容量保持率为90.72 %。
Abstract:
Li2x-ySr1-xTi1-yNbyO3 (x=3y/4, y=0.25, 0.5, 0.6, 0.7, 0.75, 0.8) solid electrolytes were prepared by conventional solid-state reaction process. X-ray diffraction (XRD), Scanning electron microscopy (SEM), Alternating current impedance, and Potentiostatic polarization method were adopted to study the crystal structure, micromorphology, ion conductivity, and electronic conductivity, respectively. X-ray diffraction analysis showed cubic perovskite-structred were synthesised when y≤ 0.70, almost no impurity phase was formed. Li0.35Sr0.475Ti0.3Nb0.7O3 exhibits the highest ion conductivity of 3.62×10-5 S·cm-1, electronic conductivity of 2.55×10-9 S·cm–1 at 20 °C, and activation energy of only 0.29 eV. LiFePO4/Li battery was fabricated using Li0.35Sr0.475Ti0.3Nb0.7O3 as a separator, a capacity of 93.9 mAh·g-1, and retention capacity of 90.72 % after 100 cycles.
点击查看大图
下载:
