Long-Lasting Ni-Rich NCMA Cathodes via Simultaneous Microstructural Refinement and Surface Modification

Abstract

Li[Ni1-x-y-zCoxMnyAlz]O2 (NCMA) cathodes have attracted public attention owing to their improved durability by leveraging the advantages of NCM and NCA cathodes. As the Ni content approaches 90%, however, it is challenging to realize high-energy Ni-rich NCMA cathodes without sacrificing durability. Herein, we improve the cycling stability of a Ni-rich Li[Ni0.93Co0.03Mn0.03Al0.01]O2 (NCMA93) cathode using a combination strategy involving microstructural refinement and surface modification. The F-coating-induced protective layer of the F coated, Sb-doped NCMA93 cathode combined with its engineered microstructure enables the formation of a robust cathode-electrolyte interphase (CEI) layer on the cathode surface, which suppresses surface degradation to afford a long battery life. However, the F coating alone does not significantly improve the cycling stability of cathode because it suffers severe microcracking during cycling owing to its suboptimal microstructure. To realize a cathode with a long lifespan, a robust CEI layer should be generated and maintained on the cathode without severe microcracking.