Impact of Ni–Mn–Co–Al-Based Cathode Material Composition on the Sintering with Garnet Solid Electrolytes for All-Solid-State Batteries

A systematic and comprehensive study of the thermal stability of the cathode active materials LiNi1/3Mn1/3Co1/3O2 (NMC111), LiNi0.6Mn0.2Co0.2O2 (NMC622), LiNi0.8Mn0.1Co0.1O2 (NMC811), and LiNi0.8Co0.15Al0.05O2 (NCA) in combination with the garnet solid electrolyte Li6.45La3Zr1.6Ta0.4Al0.05O12 was performed, and the respective thermal stability limits in air were assessed. Compared to prior studies on such material mixtures, additional Zr-containing secondary phases were detected, which had not been taken into consideration in a previously published work. Here, these phases were successfully identified for the first time by a combination of X-ray diffraction, Raman spectroscopy, and microstructural analysis