A Low Temperature Self‐Assembled ZrO2 Layer as a Surface Modification for High Energy Density Ni‐Rich Cathode Materials in a Lithium‐Ion Battery

Ni‐rich layered oxide cathodes are an immediately applicable alternative for meeting the high energy density demand of lithium‐ion batteries. The most significant hurdle of Ni‐rich layered cathode materials is their poor cyclability because of their increasing surface resistance due to their electrochemically reactive surfaces causing side reactions and the occurrence of Li/Ni cation mixing. Surface coating has been extensively studied for safeguarding particles, thereby leading to increases in electrochemical performance; however, the synthesis conditions must be carefully controlled due to the fragile surface of a Ni‐rich layered cathode. Herein, an effective coating method with self‐assembled ZrO 2 (SA–ZrO 2 ) on the surface of a Ni‐rich layered cathode material, LiNi 0.82 Co 0.09 Mn 0.09 O 2 (NCM82), through a low‐temperature self‐combustion reaction is proposed. SA–ZrO 2 is built by a combustion reaction of Zr(SO 4 ) 2 ·4H 2 O and thioacetamide to improve the surface stability of the cathode. In addition, a very small content of SO x is retained from the precursor, which promotes high lithium diffusion on the surface. Systematic analyses by X‐ray photoelectron spectroscopy and transmission electron microscopy demonstrate that this highly homogeneous ZrO 2 coating layer, which is prepared at a low temperature of 500 °C, largely enhances the electrochemical performance in the half‐cell and full‐cell.