Effect of Surface Chemical Bonding States on Lithium Intercalation Properties of Surface‐Modified Lithium Cobalt Oxide

Understanding interfacial reactions between surface‐modified lithium intercalation cathodes and organic electrolytes facilitates the design of highly functional cathodes for lithium‐ion batteries. Here, the chemical bonding state between a LiCoO 2 cathode and a ZrO 2− x surface layer is controlled by pulsed arc plasma deposition using different ion energies. The lithium intercalation properties and interfacial structure changes are subsequently analyzed. The Zr−O−Co‐modified surface formed by interaction between ZrO 2− x and LiCoO 2 provides superior cycle stability under high‐voltage operation (2.8–4.5 V). X‐ray photoemission spectroscopy clarifies that the Zr−O−Co surface forms highly adhesive ZrO x F y as a cathode electrolyte interphase (CEI). The chemical bonding state at the ZrO 2− x /LiCoO 2 interface affects the reactivity of ZrO 2− x with electrolyte species as well as the architecture of the CEI, which may determine the cell performances of lithium intercalation cathodes.