Atomic/Molecular Layer-Deposited Laminated Li₂O-Lithicone Interfaces Enabling High-Performance Silicon Anodes

Silicon-based materials are of long-standinginterest as the anodesfor next-generation lithium-ion batteries, yet their low initial Coulombicefficiency and poor interfacial stability are lethal limitations.In this work, we used atomic layer deposition (ALD) and molecularlayer deposition (MLD) techniques to fabricate a lithium-containinglaminated Li2O-lithicone hybrid film (similar to 5nm) on a silicon electrode. The laminated film provides an additionalsurface Li source around silicon cores, which can partially reimbursethe Li loss during battery cycling. Characterization of interfacialcomponents shows that such a laminated Li2O-lithiconeinterface undergoes gentle element changes and participates in a hybridsolid electrolyte interphase with Li2CO3, Li2O, Li x POF y , and LiF species. Finite element model analysis and morphologycharacterization demonstrate that the laminated structure design canhelp relieve the interfacial stress and thus retain the integrityand reactivity of the silicon composite anode during cycling. Moreover,the lithium-based laminated film leads to a fast Li+ migrationkinetics on the surface of the electrode as revealed by the galvanostaticintermittent titration technique and density functional theory calculation.Benefiting from the above merits, a silicon anode with a 91.2% initialCoulombic efficiency, a rate performance of 1460 mA h g(-1) at 2 A g(-1), and a reversible capacity over 646mA h g(-1) after 850 cycles was achieved. This workexemplifies the advantages of lithium-based hybrid films preciselyengineered by ALD/MLD techniques for improving performances of advancedsilicon anode batteries and deepens understandings on the mechanismof interfacial stability and reaction kinetics.