The Complex Role of Aluminium Contamination in Nickel‐Rich Layered Oxide Cathodes for Lithium‐Ion Batteries

A major challenge for lithium-ion batteries based on nickel-rich layered oxide cathodes is capacity fading. While chemo-mechanical degradation and/or structural transformation are widely considered responsible degradation, a comprehensive understanding of this process still not complete. For the stable performance these cathode materials, aluminium (Al) plays crucial role, only as current collector but also substitutional element transition metals in and protective coating (as Al2O3). However, excess Al can be detrimental due to both its redox inactive nature insulating Al2O3. In work, we report an analysis content two different types manganese cobalt materials after battery cycling. Our results indicate significant thickening Al-containing phases surface NMC811 electrode. Similar observed from commercial (a mixture NMC532 LiMn2O4) that were analysed before use at end life, where found increase significantly surfaces grain boundaries. Considering effects cathodes, our observation increased via cycling believed bring new perspective ongoing discussions regarding fading phenomenon part their complex mechanisms.