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Al³⁺双掺杂改性的固体电解质Li_6.28-xAl_0.24La₃Zr₂O_12-xF_x(LALZOF),并通过调节Al₂O₃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Al³⁺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-xAl_0.24La₃Zr₂O_12-xF_x (LALZOF),a solid electrolyte modified with F^- and Al³⁺,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 Al₂O₃ and LiF.It is indicated through SEM,PSD,and XRD analysis that F^- and Al³⁺ 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.

吉闫(1995-),男,博士生,研究方向为固体电解质材料,garnetji@163.com;陈召勇(1974-),男,博士,教授,博士生导师,研究方向为先进电池与材料,通讯联系人,chenzhaoyongcioc@126.com。