Enhanced Surface Chemical and Structural Stability of Ni-Rich Cathode Materials by Synchronous Lithium-Ion Conductor Coating for Lithium-Ion Batteries

Ni-rich cathode materials LiNi x Co y Mn 1– x – y O 2 ( x ≥ 0.6) have attracted much attention due to their high capacity and low cost. However, they usually suffer from rapid capacity decay and short cycle life due to their surface/interface instability, accompanied by the high Ni content. In this work, with the Ni 0.9 Co 0.05 Mn 0.05 (OH) 2 precursor serving as a coating target, a Li-ion conductor Li 2 SiO 3 layer was uniformly coated on Ni-rich cathode material LiNi 0.9 Co 0.05 Mn 0.05 O 2 by a precoating and syn-lithiation method. The uniform Li 2 SiO 3 coating layer not only improves the Li-ion diffusion kinetics of the electrode but also reduces mechanical microstrain and stabilizes the surface chemistry and structure with a strong Si–O covalent bond. These results will provide further in-depth understanding on the surface chemistry and structure stabilization mechanisms of Ni-rich cathode materials and help to develop high-capacity cathode materials for next-generation high-energy-density Li-ion batteries.