A lithium-ion conductive polymeric coating enables high-performance silicon anodes

Although lithium-ion batteries (LIBs) have dominated portable electronics, they are still not desirable for transportation. In this regard, new electrode chemistries have been undergoing intensive investigation. To this end, silicon (Si) is very promising as an anode, ascribed to its exceptionally high capacity and cost effectiveness. However, its practical application has been severely hindered by substantial volume changes during cycling. To tackle these issues, in this work, we applied a novel lithium-containing cross-linked polymer coating over Si electrodes conformally, which was deposited via a molecular layer deposition (MLD) process using lithium tert-butoxide (LTB) and glycerol (GL) as precursors. This MLD coating has been demonstrated in our group's previous studies to provide excellent protective effects on Li metal electrodes. Building on this, our study shows that the resulting polymeric LiGL-coated Si electrodes deliver a reversible capacity of ∼838 mAh g^-1 after 100 cycles at 0.1C. We found that the LiGL coating was highly ion-conductive and served as an artificial solid electrolyte interphase (SEI), which protected Si electrodes from undesirable reactions, accommodated their volume changes, and improved their mechanical integrity. As a result, this study presents a new route for addressing the issues of Si electrodes while MLD offers new solutions to battery issues.