Nanostructured Co‐Free Layered Oxide Cathode that Affords Fast‐Charging Lithium‐Ion Batteries for Electric Vehicles

Abstract

AbstractThe development of Co‐free Li[NixMn1−x]O2 cathodes for lithium‐ion batteries (LIBs) that can supersede Co‐containing Li[NixCoyMn1−x−y]O2 and Li[NixCoyAl1−x−y]O2 cathodes is considered a priority as Co is associated with price volatility, environmental concerns, and human rights violations. However, the complete removal of Co from cathodes for LIBs is difficult because Co‐free cathodes suffer from structural instability and inferior capacity. In this study, a morphology‐engineering approach is used to develop a Co‐free Li[Ni0.9Mn0.1]O2 cathode with a Ni‐rich core–Mn‐rich shell structure to overcome the limitations of Co‐free Li[NixMn1−x]O2 cathodes. The engineered morphology of the Co‐free Li[Ni0.9Mn0.1]O2 cathode particles effectively dissipates internal strain caused by state‐of‐charge heterogeneity and fracture toughening the cathode. Owing to the effective dissipation of internal strain and chemical protection provided by the Mn‐rich shell, the Co‐free cathode demonstrates excellent long‐term cycling stability; it retains 78.5% of its initial capacity after 2000 cycles at 1 C charge and 0.8 C discharge rates, and retains an unprecedented 79.5% after 1000 cycles under fast‐charging conditions (3 C charge and 1 C discharge). The proposed Co‐free layered oxide cathode represents a next‐generation cathode that affords fast‐charging and durable LIBs, which are more cost effective than LIBs featuring commercial Co‐containing cathodes.