摘要
A series of Cr^(3+)-substituted Na_(1+x)Ti_(2−x)Cr_(x)P_(3)O_(12)(x=0.1,0.2,0.3,0.4,0.5,molar fraction)solid electrolytes were prepared by the solid-phase reaction method.The effects of Cr^(3+)ions on the phase composition,microstructure,and electrochemical ion conductivity of Na-based conductors were studied using X-ray powder diffraction,field emission scanning electron microscopy,and AC impedance measurement.The results show that the main crystal phase of NaTi_(2)(PO_(4))_(3) is formed in the solid electrolytes.The substitution of Ti4+sites by 15 at.%Cr^(3+)ions contributes to the enhancement of electrical conductivity,which is attributed to the combined effect of suppressing the formation of impurity phases,broadening ion channels,and improving the bonding degree of grains.Na_(1.3)Ti_(1.7)Cr_(0.3)P_(3)O_(12) electrolyte can obtain the best ionic conductivity of 6.13×10^(−6)S/cm at room temperature,which is 8 times that of the undoped NaTi_(2)(PO_(4))_(3) electrolyte.
采用固相反应法制备一系列Cr^(3+)离子取代的Na_(1+x)Ti_(2−x)Cr_(x)P_(3)O_(12)(x=0.1,0.2,0.3,0.4,0.5,摩尔分数)固态电解质。通过X射线粉末衍射、场发射扫描电子显微镜和交流阻抗测试,研究Cr^(3+)离子对钠基导体的相组成、显微组织和电化学离子电导率的影响。结果表明,在固体电解质中生成NaTi_(2)(PO_(4))_(3)的主晶相,15%(摩尔分数)的Cr^(3+)离子取代Ti4+位有助于抑制杂相的形成及拓宽离子通道,并通过改善晶粒的粘结程度共同促进电导率的增强。Na_(1.3)Ti_(1.7)Cr_(0.3)P_(3)O_(12)电解质在室温下可获得6.13×10^(−6) S/cm最佳离子电导率,是未掺杂NaTi_(2)(PO_(4))_(3)电解质的8倍。
基金
supported by the National Natural Science Foundation of China(No.51972344)
the Natural Science Foundation of Hunan Province,China(No.2018JJ3646).
