Comprehensive Study of Zr-Doped Ni-Rich Cathode Materials Upon Lithiation and Co-Precipitation Synthesis Steps

• DOI: 10.1021/acsami.4c05058
• Publication Date: 2024-05-20T23:50:03Z
• Authors: Mattia Colalongo; Basit Ali; Isaac Martens; Marta Mirolo; Ekaterina Laakso; Cesare Atzori; Giorgia Confalonieri; Peter Kus; Anna Kobets; Xiangze Kong; Tobias Schulli; Jakub Drnec; Timo Kankaanpää; Tanja Kallio
• Keywords: NMC811; EXAFS; synchrotron radiation; Zr doping; HR-XRD; NMC811; Zr doping; EXAFS; synchrotron radiation; HR-XRD

Ni-rich layered oxides LiNi1-x-yMnxCoyO2 (NMC811, x = 0.1 and y = 0.1) are considered promising cathode materials in lithium-ion batteries (LiBs) due to their high energy density. However, those suffer a severe capacity loss upon cycling at high delithiated states. The loss of performance over time can be retarded by Zr doping. Herein, a small amount of Zr is added to NMC811 material via two alternative pathways: during the formation of the transition metal (TM) hydroxide precursor at the co-precipitation step (0.1%-Zr-cp) and during the lithiation at the solid-state synthesis step (0.1%-Zr-ss). In this work, the crystallographic Zr uptake in both 0.1%-Zr-ss and 0.1%-Zr-cp is determined and quantified through synchrotron X-ray diffraction and X-ray absorption spectroscopy. We prove that the inclusion of Zr in the TM site for 0.1%-Zr-cp leads to an improvement of both specific capacity (156 vs 149 mAh/g) and capacity retention (85 vs 82%) upon 100 cycles compared to 0.1%-Zr-ss where the Zr does not diffuse into the active material and forms only an extra phase separated from the NMC811 particles.