Origin of High Interfacial Resistance in Solid‐State Batteries: LLTO/LCO Half‐Cells**
Origin of High Interfacial Resistance in Solid‐State Batteries: LLTO/LCO Half‐Cells**
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DOI：
10.1002/celc.202100189
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发表时间：
2021-04
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影响因子：
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通讯作者：
Pengyu Xu;W. Rheinheimer;A. Mishra;S. Shuvo;Z. Qi;Haiyan Wang;A. Dongare;L. Stanciu
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文献类型：
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作者：
Pengyu Xu;W. Rheinheimer;A. Mishra;S. Shuvo;Z. Qi;Haiyan Wang;A. Dongare;L. Stanciu
阴极和电解质之间的界面是固态电池（SSB）中大界面电阻的重要来源。放电等离子烧结 (SPS) 可以一步致密化电解质和电极，从而改善 SSB 中的界面接触并显着缩短加工时间。在这项工作中，我们提出了一种通过 SPS 制备阴极（LiCoO2，LCO）/电解质（Li0.33La0.57TiO3，LLTO）半电池的两步连接工艺。通过 SEM/STEM 在界面处观察到 Ti4+/Co3+ 之间的相互扩散，导致在 LLTO 中形成 Li−Ti−La−Co−O 和 Li−Ti−Co−O 相，在 LCO 中形成 Li−Co−Ti−O 相。进行计算建模以验证 Li−Ti−Co−O 相具有 LiTi2O4 主晶格。在界面电特性的研究中，发现该相互扩散层的电阻为 105Ω，比单个 LLTO 相的电阻高 40 倍。相互扩散层的形成被认为是 LLTO/LCO 半电池中高界面电阻的根源。
The interface between cathode and electrolyte is a significant source of large interfacial resistance in solid‐state batteries (SSBs). Spark plasma sintering (SPS) allows densifying electrolyte and electrodes in one step, which can improve the interfacial contact in SSBs and significantly shorten the processing time. In this work, we proposed a two‐step joining process to prepare cathode (LiCoO2, LCO)/electrolyte (Li0.33La0.57TiO3, LLTO) half cells via SPS. Interdiffusion between Ti4+/Co3+was observed at the interface by SEM/STEM, resulting in the formation of the Li−Ti−La−Co−O and Li−Ti−Co−O phases in LLTO and the Li−Co−Ti−O phase in LCO. Computational modeling was performed to verify that the Li−Ti−Co−O phase has a LiTi2O4host lattice. In a study of interfacial electrical properties, the resistance of this interdiffusion layer was found to be 105Ω, which is 40 times higher than the resistance of the individual LLTO phase. The formation of an interdiffusion layer is identified as the origin of the high interface resistance in the LLTO/LCO half‐cell.