Pressurization of all-solid-state lithium-ion batteries is expected to increase the efficiency of ion transport between solid electrolyte particles. Here, we show the practicality of considering internal stress distribution to explain the ion transport behavior inside a composite electrode containing a sulfide solid electrolyte. Considering internal stress distribution allows for an accurate evaluation in microscale, and phenomenon stemming from nanoscale features is explained. To independently analyze the effect of ohmic overpotential on ion transport, undesired electrochemical reactions are eliminated by replacing active materials in a composite electrode by zirconia. The ionic conductivity of the zirconia composite at different pressures is measured and its three-dimensional structure is visualized by X-ray computed tomography. Graphics processing unit-based large-scale voxel finite element method stress analysis and an electric field numerical calculation are conducted to analyze the effect of stress distribution on the ion transport characteristics of the composite electrode. Experimentally, the ionic conductivity of the zirconia composite decreases drastically as the volume fraction of zirconia increases. The degree to which the ionic conductivity decreases exceeds that expected when considering the volume fraction and tortuosity of zirconia. When stress distribution is also considered, the discrepancy between experimental and numerical results decreases greatly.

全固态锂离子电池的加压有望提高固体电解质颗粒之间离子传输的效率。在这里，我们展示了考虑内部应力分布来解释包含硫化物固体电解质的复合电极内部离子传输行为的实用性。考虑内部应力分布可以在微米级进行精确评估，并解释了由纳米级特征引起的现象。为了独立分析欧姆超电势对离子迁移的影响，通过用氧化锆代替复合电极中的活性材料，消除了不希望的电化学反应。测量了氧化锆复合材料在不同压力下的离子电导率，并通过X射线计算机断层扫描显像了其三维结构。进行了基于图形处理单元的大型体素有限元方法应力分析和电场数值计算，以分析应力分布对复合电极离子迁移特性的影响。实验上，随着氧化锆体积分数的增加，氧化锆复合材料的离子电导率急剧下降。当考虑氧化锆的体积分数和曲折度时，离子电导率降低的程度超过了预期。当还考虑应力分布时，实验结果与数值结果之间的差异大大减小。