材料科学
晶界
离子电导率
陶瓷
相(物质)
电导率
兴奋剂
电解质
离子半径
离子
微观结构
粒度
分析化学(期刊)
四方晶系
化学工程
复合材料
矿物学
物理化学
化学
光电子学
工程类
有机化学
色谱法
电极
作者
Libin Zhuang,Xiao Huang,Yang Lu,Jiawen Tang,Yongjian Zhou,Xin Ao,Yan Yang,Bingbing Tian
标识
DOI:10.1016/j.ceramint.2021.04.295
摘要
Cubic phase garnet-type Li7La3Zr2O12 (LLZO) is a promising solid electrolyte for highly safe Li-ion batteries. Al-doped LLZO (Al-LLZO) has been widely studied due to the low cost of Al2O3. The reported ionic conductivities were variable due to the complicated Al3+-Li+ substitution and LixAlOy segregation in Al-LLZO ceramics. This work prepared Li7−3xAlxLa3Zr2O12 (x = 0.00~0.40) ceramics via a conventional solid-state reaction method. The AC impedance and corresponding distribution of relaxation times (DRT) were analyzed combined with phase transformation, cross-sectional microstructure evolution, and grain boundary element mapping results for these Al-LLZO ceramics to understand the various ionic transportation levels in LLZO with different Al-doping amounts. The low conductivity in low Al-doped (0.12~0.28) LLZO originates from the slow Li+ ion migration (1.4~0.25 μs) in the cubic-tetragonal mixed phase. On the other hand, LiAlO2 and LaAlO3 segregation occur at the grain boundaries of high Al-doped (0.40) LLZO, resulting in a gradual Li+ ion jump (6.5 μs) over grain boundaries and low ionic conductivity. The Li6.04Al0.32La3Zr2O12 ceramic delivers the optimum Li+ ion conductivity of 1.7 × 10−4 S cm−1 at 25 °C.
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