We have used atomic layer deposition (ALD) to create highly controlled, thin ceramic type coatings as an artificial solid electrolyte interphases (SEIs) to protect these anode surfaces by preventing dendrite formation and electrolyte decomposition. The ultrathin Al2O3 protective coating on Na stabilizes the Na-electrolyte interface and extends its cycle life under high current density (i.e., high power) cycling conditions. We have also developed a hybrid (elastomer + ceramic-type) protective coating on Li metal by combining ALD ceramic (LiPON) and electrochemical deposition of a polymeric elastomer. The hybrid layer achieves high Li conductivity while suppressing corrosion and due to electrolyte breakdown. The elastomer component provides mechanical flexibility to accommodate volume change both may play roles in the observed mitigation of dendrite growth at high current density.
These results demonstrate promise for achieving high energy density anodes with significantly enhanced chemical stability, electrochemical cyclability, and dendrite protection as needed for a viable beyond Li or Na ion battery technology.