LiZn/LiAlO2/Li2O-Derived Chemical Confinement Enabling Hierarchical and Oriented Li Plating/Stripping

Abstract

ZnO with good lithiophilicity has widely been employed to modify the lithiophobic substrates and facilitate uniform lithium (Li) deposition. The overpotential of ZnO-derived Li anode during cycling depends on the lithiophilicity of both LiZn and Li₂O products upon lithiation of ZnO. However, the striking differences in the lithiophilicity between Li₂O and LiZn would result in a high overpotential during cycling. In this research, the Al₂O₃/nZnO (n ≥ 1) hybrid layers were precisely fabricated by atomic layer deposition (ALD) to regulate the lithiophilicity of ZnO phase and Li₂O/LiZn configuration—determining the actual Li loading amount and Li plating/stripping processes. Theoretically, the Li adsorption energy (E_a) values of LiZn and Li₂O in the LiZn/Li₂O configuration are separately predicted as −2.789 and −3.447 eV. In comparison, the E_a values of LiZn, LiAlO_2, and Li₂O in the LiZn/LiAlO₂/Li₂O configuration upon lithiation of Al₂O₃/8ZnO layer are calculated as −2.899, −3.089, and −3.208 eV, respectively. Importantly, a novel introduction of LiAlO₂ into the LiZn/Li₂O configuration could enable the hierarchical Li plating/stripping and reduce the overpotentials during cycling. Consequently, the Al₂O₃/8ZnO-derived hybrid Li-metal anode could exhibit electrochemical performances superior to these of ZnO-derived Li anode in both symmetrical and full cells paired with a LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622) cathode.