Garnet Electrolytes for Solid State Batteries: Visualization of Moisture-Induced Chemical Degradation and Revealing Its Impact on the Li-Ion Dynamics
Garnet Electrolytes for Solid State Batteries: Visualization of Moisture-Induced Chemical Degradation and Revealing Its Impact on the Li-Ion Dynamics
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DOI：
10.1021/acs.chemmater.8b00486
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发表时间：
2018-06-12
影响因子：
8.6
通讯作者：
Aguadero, Ainara
中科院分区：
文献类型：
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作者：
Brugge, Rowena H.;Hekselman, A. K. Ola;Aguadero, Ainara
在这项工作中，我们揭示了水分引起的化学降解和质子-锂交换对锂离子动力学在体和晶界，并在界面处与锂金属在高锂导电石榴石电解质的影响。提供了通过深度分辨二次离子质谱法测量的化学变化与电解质的运输性质的变化之间的直接相关性。为了探测交换对石榴石结构内锂动力学的内在影响，与二次腐蚀产物贡献隔离，首先使用受控气氛处理来产生无质子的Li6.55Ga0.15La3Zr2O12（Ga0.15-LLZO），然后在100 ℃下在H2O浴中进行降解步骤，导致在表面去除LiOH二次相。质子交换区域进行了分析，通过聚焦离子束二次离子质谱（FIB-SIMS），并发现延伸到1.35 μ m的Ga 0.1.5-LLZO石榴石丸30分钟后，在水中。在对称的电池与锂金属电极的阻抗分析表明，在晶界比在晶粒和一个显着的不利影响的锂转移动力学在锂金属/石榴石界面相关的质子化石榴石中的锂迁移率的3倍减少更大的反应。这一结果表明，锂的电荷转移和扩散动力学在含质子的石榴石电解质的恶化，这些系统在商业电池设备的优化和集成具有根本性的影响。
In this work, we reveal the impact of moisture-induced chemical degradation and proton-lithium exchange on the Li-ion dynamics in the bulk and the grain boundaries and at the interface with lithium metal in highly Li-conducting garnet electrolytes. A direct correlation between chemical changes as measured by depth-resolved secondary ion mass spectrometry and the change in transport properties of the electrolyte is provided. In order to probe the intrinsic effect of the exchange on the lithium kinetics within the garnet structure, isolated from secondary corrosion product contributions, controlled-atmosphere processing was first used to produce proton-free Li6.55Ga0.15La3Zr2O12 (Ga0.15-LLZO), followed by degradation steps in a H2O bath at 100 degrees C, leading to the removal of LiOH secondary phases at the surface. The proton-exchanged region was analyzed by focused ion beam secondary ion mass spectrometry (FIB-SIMS) and found to extend as far as 1.35 mu m into the Ga0.1.5-LLZO garnet pellet after 30 min in H2O. Impedance analysis in symmetrical cells with Li metal electrodes indicated a greater reactivity in grain boundaries than in grains and a significantly detrimental effect on the Li transfer kinetics in the Li metal/garnet interface correlated to a 3-fold decrease in the Li mobility in the protonated garnet. This result indicates that the deterioration of Li charge transfer and diffusion kinetics in proton-containing garnet electrolytes have fundamental implications for the optimization and integration of these systems in commercial battery devices.