A Cobalt‐ and Manganese‐Free High‐Nickel Layered Oxide Cathode for Long‐Life, Safer Lithium‐Ion Batteries

Abstract

AbstractHigh‐nickel LiNi1−x−yMnxCoyO2 and LiNi1−x−yCoxAlyO2 cathodes are receiving growing attention due to the burgeoning demands on high‐energy‐density lithium‐ion batteries. The presence of both cobalt and manganese in them, however, triggers multiple issues, including high cost, high toxicity, rapid surface deterioration, and severe transition‐metal dissolution. Herein, a Co‐ and Mn‐free ultrahigh‐nickel LiNi0.93Al0.05Ti0.01Mg0.01O2 (NATM) cathode that exhibits 82% capacity retention over 800 deep cycles in full cells, outperforming two representative high‐Ni cathodes LiNi0.94Co0.06O2 (NC, 52%) and LiNi0.90Mn0.05Co0.05O2 (NMC, 60%) is presented. It is demonstrated that a titanium‐enriched surface along with aluminum and magnesium as the stabilizing ions in NATM not only ameliorates unwanted side reactions with the electrolyte and structural disintegrity, but also mitigates transition‐metal dissolution and active lithium loss on the graphite anode. As a result, the graphite anode paired with NATM displays an ultrathin (≈8 nm), monolayer anode‐electrolyte interphase architecture after extensive cycling. Furthermore, NATM displays considerably enhanced thermal stability with an elevated exothermic temperature (213 °C for NATM vs 180 and 190 °C for NC and NMC, respectively) and remarkably reduced heat release. This work sheds light on rational compositional design to adopt ultrahigh‐Ni cathodes in lithium‐based batteries with low cost, long service life, and improved thermal stability.