Improvement of crystal structure and electrical performance of NASICON-type NaTi_(2)(PO_(4))_(3) solid electrolyte by doping Cr^(3+) ions  

Cr^(3+)离子掺杂改善NASICON型NaTi_(2)(PO_(4))_(3)固态电解质的晶体结构与导电性能

作　　者：Cheng-jian WEN Zhi-wei LUO Xin-yu LIU Ju-xia TONG Pan HE An-xian LU 温成健;罗志伟;刘新宇;童菊霞;何盼;卢安贤(中南大学材料科学与工程学院,长沙410083)

机构地区：[1]School of Materials Science and Engineering,Central South University,Changsha 410083,China

出　　处：《Transactions of Nonferrous Metals Society of China》2024年第12期4020-4031,共12页中国有色金属学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.51972344);the Natural Science Foundation of Hunan Province,China(No.2018JJ3646).

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。

关 键 词：NaTi_(2)(PO_(4))_(3) solid electrolyte crystal structure ionic conductivity Cr-doping 

分 类 号：TM912[电气工程—电力电子与电力传动] O646[理学—物理化学]