LiNbO 3 Coatings on NCM622: Structure and Performance Insights

Abstract For enhancing the electrochemical performance of solid‐state batteries (SSBs), protective coatings are applied on the cathode active material (CAM) to mitigate the degradation of the cathode/electrolyte interface. A comprehensive understanding of the structural properties of these coatings is crucial for further optimization. This study investigates the effect of LiNbO 3 ‐related coatings on LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) CAM, focusing on the relationship between coating structure and electrochemical performance in battery cells. Therefore, three samples calcinated at 550, 350 and, 80 °C temperature are analyzed with scanning transmission electron microscopy (STEM), energy dispersive X‐ray spectroscopy (EDS), and scanning precession electron diffraction (SPED) in combination with a pair distribution function (PDF) analysis. The results reveal that only an amorphous LiNbO 3 coating with a calcination temperature of 350 °C significantly improves the electrochemical performance of the CAM. In contrast, at higher calcination temperatures the coating crystallizes, while at lower calcination temperatures the coating becomes a mixed niobium oxide phase, both of which correlate with reduced battery performance.