钙钛矿型锂离子固体电解质Li_(2x−y)Sr_(1−x)Ti_(1−y)Nb_(y)O_(3)的性能  

Performance of perovskite-type Li-ion solid electrolyte Li_(2x−y)Sr_(1−x)Ti_(1−y)Nb_(y)O_(3)

作　　者：卢佳垚 厉英 倪培远 唐甜甜 LU Jia-yao;LI Ying;NI Pei-yuan;TANG Tian-tian(School of Metallurgy,Northeastern University,Shenyang 110819,China;Key Laboratory for Metallurgical Sensor Materials and Technology(Liaoning Province),Shenyang 110819,China)

机构地区：[1]东北大学冶金学院,沈阳1108192 [2]辽宁省冶金传感器材料及技术重点实验室,沈阳110819

出　　处：《工程科学学报》2021年第8期1024-1031,共8页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(51834004,51774076,51704062)。

摘　　要：采用高温固相法成功制备了Li_(2x−y)Sr_(1−x)Ti_(1−y)Nb_(y)O_(3)(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y≤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.Li_(0.35)Sr_(0.475)Ti_(0.3)Nb_(0.7)O_(3)锂离子固体电解质有着高离子电导率,为3.62×10^(−5) S·cm^(−1),其电子电导率为2.55×10^(−9) S·cm^(−1),活化能仅为0.29 eV.使用以Li_(0.35)Sr_(0.475)Ti_(0.3)Nb_(0.7)O_(3)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 mA·h·g^(−1),容量保持率为90.72%.All-solid-state lithium batteries are recognized as the next-generation energy storage batteries due to their high energy density and high security,to which researchers have paid more attention.All-solid-state lithium batteries are composed of solid materials,and the Li-ion solid electrolytes do not contain flammable and explosive organic solvents,which can enhance the safety of the battery.As important components,Li-ion solid electrolytes are widely studied in all-solid-state lithium batteries,which currently include Li-superionic solid electrolyte(LISICON),Na-superionic solid electrolyte(NASICON),garnet-type solid electrolyte,perovskite-type solid electrolyte,sulfide-type solid electrolyte,and polymer solid electrolyte.Li-ion solid electrolytes generally have the advantages of high Li-ion conductivity,low electronic conductivity,wide operating temperatures,wide electrochemical windows,and inhibition of lithium dendrite growth.Among the solid electrolytes,the perovskite-type solid electrolytes have a wide tolerance factor that allows most elements to dope into the ABO3 structure.Additionally,the perovskite-type Li-ion solid electrolytes are summarized into two types:(1)the three-component Li3xLa2/3−xTiO3(LLTO,0<x<1/6)and(2)the four-component(Li,Sr)(A,B)O3(A=Zr,Hf,Ti,Sn;B=Nb,Ta).In this paper,the four-component Li_(2x−y)Sr_(1−x)Ti_(1−y)Nb_(y)O_(3)(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 method.X-ray diffraction(XRD),scanning electron microscopy,alternating current impedance,and potentiostatic polarization methods were adopted to study the crystal structure,micromorphology,ion conductivity,and electronic conductivity,respectively.XRD analysis show the synthesized samples exhibit a cubic perovskite structure when y≤0.70 with almost no impurity phase formed.Li_(0.35)Sr_(0.475)Ti_(0.3)Nb_(0.7)O_(3)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℃,and activatio

关 键 词：钙钛矿 锂离子固体电解质 交流阻抗 电子电导率 锂电池 

分 类 号：TM911[电气工程—电力电子与电力传动]