Introducing Co Nanoshells onto Ni-Rich Cathode Materials for High-Rate Long-Life Li-Ion Batteries

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