CO₂-based atomic/molecular layer deposition of lithium ethylene carbonate thin films

When a conventional lithium-ion battery (LIB) is cycled, a solid electrolyte interphase (SEI) forms on the surface of a negative electrode, passivating it but also depleting the capacity of the battery. Most commercial LIBs utilize a carbonate-based electrolyte, which at least temporarily leads to the formation of lithium alkyl carbonates (ROCO₂Li) as the main organic SEI component. Here, we pioneer the use of atomic/molecular layer deposition (ALD/MLD) for the fabrication of lithium ethyl glycoxide (LiEG) and lithium ethylene carbonate (LiEGCO) thin films, to mimic the lithium alkyl carbonate component of the SEI. For the in situ growth of LiEGCO, we employ for the first time CO₂ as an ALD/MLD precursor. The films are characterized using XRR, GIXRD, FTIR, AFM and SEM.