Artificial Solid Electrolyte Interphase Developed In Vitro by Tailoring Molecular Layer Deposition of a Li-Ion-Containing Electrolyte on Carbonaceous Anode Materials

Various carbonaceous anode materials have been developed to improve both the rate and capacity characteristics of Li-ion batteries (LIBs), and yet the performances of the anodes depend on the quality of the inevitable and uncontrollable growth of the solid-electrolyte interphase (SEI), resulting from the electrolyte reduction and decomposition during the initial cycles. Here, we propose the fabrication of an artificial SEI (Art-SEI), enabling tuning of specific properties, such as the chemical composition, electrochemical impedance, and thickness of the interfacial film. In this work, a genuine Art-SEI was conformally fabricated via molecular layer deposition (MLD), utilizing as one of the precursors a commercial battery electrolyte itself, with a cross-linker-functionalized film grown on the surface of the carbonaceous anode materials, along with a Li-ion source. This type of air- and moisture-stable Art-SEI possesses enhanced protective characteristics, and it mitigates the irreversible capacity loss associated with the SEI buildup during the formation cycles while substantially improving Li-ion battery cycling performances.