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.