F-Al双掺杂改性Li_(6.28-x)Al_(0.24)La_(3)Zr_(2)O_(12-x)F_(x)及其性能研究

F-Al doped modification of Li_(6.28-x)Al_(0.24)La_(3)Zr_(2)O_(12-x)F_(x)and study on its performance

为提高锂镧锆氧(LLZO)固体电解质的离子电导率和致密度,实现低成本的LLZO陶瓷制备,采用传统固相法制备了F^(-)和Al^(3+)双掺杂改性的固体电解质Li_(6.28-x)Al_(0.24)La_(3)Zr_(2)O_(12-x)F_(x)(LALZOF),并通过调节Al_(2)O_(3)和LiF的添加量以优化LALZOF陶瓷的离子电导率和致密度。SEM、PSD和XRD分析结果表明,F^(-)和Al^(3+)掺杂进入LALZOF中并稳定了立方相,且F^(-)可以降低LALZOF的粉体粒径尺寸。在高温烧结后,SEM、EDS、EIS和致密度测试结果表明,F^(-)对LALZOF陶瓷晶粒的发育具有促进作用,可以增加陶瓷的致密度,并提高锂离子电导率,且F^(-)均匀的掺入在LALZOF晶粒内;在F^(-)掺杂量为0.2 mol时具有最佳性能,致密度为86.28%,总离子电导率为4.30×10^(-4)S/cm。

In order to improve the ionic conductivity and relative density of lithium lanthanum zirconium oxide(LLZO)solid electrolyte,and achieve low-cost production of LLZO ceramics,Li_(6.28-x)Al_(0.24)La_(3)Zr_(2)O_(12-x)F_(x)(LALZOF),a solid electrolyte modified with F^(-)and Al^(3+),is synthesized through using a traditional solid phase method.The ionic conductivity and relative density of LALZOF ceramics are optimized by adjusting the adding amount of Al_(2)O_(3)and LiF.It is indicated through SEM,PSD,and XRD analysis that F^(-)and Al^(3+)has been doped into LALZOF and stabilize the cubic phase,and F^(-)can reduce the particle size of LALZOF powder.After high-temperature sintering,it is shown by SEM,EDS,EIS,and relative density tests that the addition of F^(-)can promote the growth of LALZOF ceramics grain,which can enhance densification of the ceramics and improve the ionic conductivity of lithium.Moreover,F^(-)is uniformly doped into LALZOF grains.As F^(-)doping amount is 0.2 mol,LALZOF has the optimal performance,with a density of 86.28%and a total ionic conductivity of 4.30×10^(-4) S·cm^(-1).