The microstructure design of electrodes comprising active materials and solid electrolytes (SE) determines the conduction properties of the electrode composites and the overall battery performance of all-solid-state batteries (ASSBs). This correlation, which is generally evaluated using macroscopic parameters based on effective conductivity, can be understood through insights into the microscopic conduction mechanism. Here, we investigate the microscopic electronic conduction properties of LiNi_0.5Co_0.2Mn_0.3O₂ (NCM) cathode composites employed in ASSBs using scanning spreading resistance microscopy (SSRM). The cathode composites with low NCM volume fractions show a bimodal resistance distribution in the NCM domains, leading to capacity deficit due to sparse electronic conductive networks. A simulation of the 3D microstructure generated by machine learning suggests that the resistance component of the composite detected using SSRM is strongly influenced by the electronic contact resistance between the material directly beneath the probe and other materials. Our findings emphasize that high electrochemical utilization of ASSBs requires minimization of the electronic contact resistance between the cathode active materials. The combination of SSRM and 3D generative microstructure simulation enables the evaluation of the electronic contact resistance between particles within inhomogeneous composites, such as ASSB electrodes. This approach provides fundamental guidelines for optimizing microstructure design to achieve high-performance ASSBs.

中文翻译：

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通过扫描扩散电阻显微镜阐明全固态电池正极复合材料的微观传导机制

由活性材料和固体电解质（SE）组成的电极的微观结构设计决定了电极复合材料的导电性能和全固态电池（ASSB）的整体电池性能。这种相关性通常使用基于有效电导率的宏观参数来评估，可以通过深入了解微观传导机制来理解。在这里，我们使用扫描扩散电阻显微镜（SSRM）研究了ASSB中使用的LiNi _0.5 Co _0.2 Mn _0.3 O ₂ (NCM)阴极复合材料的微观电子传导特性。具有低NCM体积分数的阴极复合材料在NCM域中表现出双峰电阻分布，导致由于稀疏的电子导电网络而导致容量不足。对机器学习生成的 3D 微观结构的模拟表明，使用 SSRM 检测到的复合材料的电阻分量很大程度上受到探针正下方的材料与其他材料之间的电子接触电阻的影响。我们的研究结果强调，ASSB 的高电化学利用率需要最大限度地降低阴极活性材料之间的电子接触电阻。 SSRM 和 3D 生成微观结构模拟相结合，可以评估非均质复合材料（例如 ASSB 电极）内颗粒之间的电子接触电阻。这种方法为优化微观结构设计以实现高性能 ASSB 提供了基本指导。