Introducing\nCo Nanoshells onto Ni-Rich Cathode Materials\nfor High-Rate Long-Life Li-Ion Batteries

Conventionally, cobalt (Co) is an essential element in\nLiMO<sub>2</sub> (M = Ni, Co, Mn, Al) cathode materials. However,\nits high\ncost and price fluctuations hinder its full utilization, limiting\nthe average fraction of Co. To address this problem, recent studies\nfocused on maximizing the effects of a limited amount of Co. Herein,\nwe introduce a new approach that fully utilizes Co by forming a Co\nnanoshell on a Ni-rich [Ni<sub>0.90</sub>Co<sub>0.05</sub>Mn<sub>0.05</sub>](OH)<sub>2</sub> precursor via a single coprecipitation process.\nThe Co nanoshell acts as a sintering inhibitor during calcination,\nthereby generating columnar structures that are not observed in the\nbaseline Li[Ni<sub>0.90</sub>Co<sub>0.05</sub>Mn<sub>0.05</sub>]O<sub>2</sub> cathode material. In addition, introducing the Co nanoshell\ncontributes to forming spinel-like structures that facilitate Li<sup>+</sup> (de)intercalation during electrochemical cycling. This study\nnot only provides a new approach that fully utilizes a limited amount\nof Co but also offers a facile and cost-effective method in synthesizing\nhigh-performance cathode materials.