Dual-Function\nZnO-Li<sub>3</sub>TaO<sub>4</sub> Surface\nModification of Single-Crystalline Ni-Rich Cathodes for All-Solid-State\nBatteries

Herein, we introduce a ZnO–Li<sub>3</sub>TaO<sub>4</sub> composite coating designed to stabilize single-crystalline\nLiNi<sub>0.95</sub>Co<sub>0.03</sub>Mn<sub>0.015</sub>Al<sub>0.005</sub>O<sub>2</sub> (sNCMA) in ASSBs with Li<sub>6</sub>PS<sub>5</sub>Cl.\nThis\ndual-function coating establishes a Ta-rich surface layer and Zn-doped\nnear-surface regions, as verified by detailed analyses, including\natom probe tomography and transmission electron microscopy. The ZnO-Li<sub>3</sub>TaO<sub>4</sub> coating markedly enhances both interfacial\nand structural stabilities, showcasing an exceptional performance\nin sNCMA|Li<sub>6</sub>PS<sub>5</sub>Cl|(Li–In) cells at 30\n°C (initial discharge capacity of 196 mA h g<sup>–1</sup> with 82.7% capacity retention after 1000 cycles), exceeding the\nperformance of both uncoated or only Li<sub>3</sub>TaO<sub>4</sub>-coated sNCMA (only 82.5 or 84.2%, respectively, after 200 cycles).\nThe protective role of ZnO-Li<sub>3</sub>TaO<sub>4</sub> is corroborated\nby electrochemical impedance spectroscopy and ex situ X-ray photoelectron\nspectroscopy. Finally, density functional theory calculations and\ncomparative tests with oxidatively inert Li<sub>2</sub>ZrCl<sub>6</sub> catholytes elucidate the enhanced performance mechanism, specifically,\nthe suppression of Ni<sup>2+</sup> migration by Zn doping, emphasizing\nthe importance of cathode structural stability in all-solid-state\nbatteries.