The high impedance of the solid electrolyte (SE)|cathode active material (CAM) interface often limits the charge transfer in oxide-based solid-state battery (SSB) cells. Lowering the interfacial impedance by maximizing the contact between SE and CAM is usually attempted by co-sintering the materials at elevated temperatures. In this work Li_6.25Al_0.25La₃Zr₂O₁₂ (LLZO) and LiNi_0.6Co_0.2Mn_0.2O₂ (NCM) composite cathodes co-sintered at different temperatures were investigated by employing various transmission electron microscopy (TEM) techniques to study the influence of the sintering temperature on the material’s integrity. High-resolution TEM images of the layered NCM phase ($R\overline{3}m$) degraded to a NiO (rock salt)-like structure ($Fm\overline{3}m$), as well as the formation of a LaNiO₃-like transition phase between LLZO and NCM grains in direct contact, are presented for samples co-sintered at a temperature as low as 500°C. This is significantly lower than previously reported and questions the viability of an LLZO-NCM composite cathode.

固体电解质（SE）|阴极活性材料（CAM）界面的高阻抗通常限制氧化物固态电池（SSB）电池中的电荷转移。通常通过在高温下共烧结材料来尝试最大化 SE 和 CAM 之间的接触来降低界面阻抗。在这项工作中，采用各种透射电子显微镜研究了在不同温度下共烧结的Li _6.25 Al _0.25 La ₃ Zr ₂ O ₁₂ (LLZO)和LiNi _0.6 Co _0.2 Mn _0.2 O _{2 (NCM)复合阴极。}(TEM) 技术研究烧结温度对材料完整性的影响。层状 NCM 相的高分辨率 TEM 图像（$右\stackrel{￣}{3}米$）降解为 NiO（岩盐）样结构（$F米\stackrel{￣}{3}米$），以及直接接触的 LLZO 和 NCM 晶粒之间形成 LaNiO ₃类过渡相，展示了在低至 500°C 温度下共烧结的样品。这明显低于之前报道的水平，并对 LLZO-NCM 复合阴极的可行性提出了质疑。