Mitigating Planar Gliding in Single‐Crystal Nickel‐Rich Cathodes through Multifunctional Composite Surface Engineering

Abstract

AbstractNickel‐rich layered oxides are a class of promising cathodes for high‐energy‐density lithium‐ion batteries (LIBs). However, their structural instability derived from crystallographic planar gliding and microcracking under high voltages has significantly hindered their practical applications. Herein, resurfacing engineering for single‐crystalline LiNi0.83Co0.07Mn0.1O2 (SNCM) cathode is undertaken. A passivation shell, comprising a surface fast ion conductor Li1.25Al0.25Ti1.5O4 (LATO) layer and a near‐surface confined cation hybridization region, is established through co‐infiltrating Al and Ti into SNCM, which can profoundly improve structural stability. Compelling evidences  show that high‐conductivity LATO‐overcoat facilitates Li+ conduction and resists electrolyte attack. The introduction of strong Al─O bonds and resurfacing regions stabilize bulk and near‐surface lattice oxygen respectively during cycling, thus hindering the formation of oxygen vacancies and the occurrence of detrimental phase transformations, ultimately suppressing the crystallographic planar gliding and nanocracking. Subsequently, the modified SNCM drastically outperforms the baseline SNCM, exhibiting an ultrahigh 88.9% retention rate of original capacity at 1.0C after 400 cycles, and a discharge capacity of 146.8 mAh g−1 with a 92.6% capacity retention rate after 200 cycles at 5.0C within a voltage window of 2.7–4.3 V. The promising performance demonstrated by the multifunctional surface coating highlights a new way to stabilize Ni‐rich cathodes for LIBs.