Origin of High Interfacial Resistances in Solid‐State Batteries: Interdiffusion and Amorphous Film Formation in Li 0.33 La 0.57 TiO 3 /LiMn 2 O 4 Half Cells
Origin of High Interfacial Resistances in Solid‐State Batteries: Interdiffusion and Amorphous Film Formation in Li 0.33 La 0.57 TiO 3 /LiMn 2 O 4 Half Cells
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DOI：
10.1002/celc.201901068
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发表时间：
2019-09
期刊：
影响因子：
4
通讯作者：
Pengyu Xu;W. Rheinheimer;S. Shuvo;Z. Qi;Orli Levit;Haiyan Wang;Y. Ein‐Eli;L. Stanciu
中科院分区：
文献类型：
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作者：
Pengyu Xu;W. Rheinheimer;S. Shuvo;Z. Qi;Orli Levit;Haiyan Wang;Y. Ein‐Eli;L. Stanciu
电解质和电极之间的大界面电阻对全固态电池的应用构成了重大障碍。界面相（界面）的形成已被确定为这种高电阻的最重要来源之一。因此，研究界面形成机制，并研究其对离子电导率的影响，可能会发现设计高性能全固态电池的途径。在这项工作中，我们通过放电等离子烧结（SPS）以及传统烧结的共烧结实验研究了钙钛矿电解质Li0.33La0.57TiO3（LLTO）和尖晶石阴极LiMn2O4（LMO）对中的界面形成。尽管加工方法对电极/电解质接触有影响，但界面的形成是不可避免的。在 LLTO/LMO 界面，我们观察到由相互扩散形成的界面以及类似肤色的非晶层。我们使用 HRTEM 直接表征肤色层形态。分析 TEM 和 SEM 用于揭示界面和互扩散层的元素组成。此外，我们使用阻抗谱来测量 LLTO/LMO 界面的电性能，并发现相互扩散引起的界面的界面电阻比单个相大 40 倍，而非晶层在阻抗中不可见。
The large interfacial resistance between electrolyte and electrodes poses a significant roadblock for the application of all‐solid‐state batteries. The formation of interfacial phases (interphases) has been identified as one of the most significant sources for such high resistance. Therefore, studying the mechanism of interphase formation, along with investigating its effect on ionic conductivity, could lead to the discovery of avenues towards designing high‐performance all‐solid‐state batteries. In this work, we studied the interphase formation in the perovskite electrolyte Li0.33La0.57TiO3(LLTO) and spinel cathode LiMn2O4(LMO) pair by co‐sintering experiments via spark plasma sintering (SPS), as well as conventional sintering. Although the processing method has an influence on the electrode/electrolyte contact, the formation of an interphase could not be avoided. At the LLTO/ LMO interface, we observed both an interphase formed by interdiffusion, as well as a complexion‐like amorphous layer. We directly characterized the complexion layer morphology by using HRTEM. Analytical TEM and SEM were used to reveal the elemental composition of the interphase and the interdiffusion layer. Furthermore, we used impedance spectroscopy to measure the electrical properties of the LLTO/LMO interphase and identified the interfacial resistance from the interdiffusion induced interphase to be larger than the individual phases by a factor of 40, whereas the amorphous layer was not visible in the impedance.