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 LiCoO2 cathode and a ZrO2-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 ZrO2-x and LiCoO2 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 ZrOxFy as a cathode electrolyte interphase (CEI). The chemical bonding state at the ZrO2-x/ LiCoO2 interface affects the reactivity of ZrO2-x with electrolyte species as well as the architecture of the CEI, which may determine the cell performances of lithium intercalation cathodes.