Nanoscale Investigation of Solid Electrolyte Interphase Inhibition on Li-Ion Battery MnO Electrodes via Atomic Layer Deposition of Al₂O₃

Application of a functional surface coating on Li-ion battery electrodes can potentially result in a significant enhancement of the lifespan of the battery cell. In particular, atomic layer deposition (ALD), which can create highly conformal ultrathin oxide films on many different electrodes has been shown to increase the cyclability in these systems. In this study, we explore the impact of such films on the formation of the solid electrolyte interphase (SEI), which may explain why these films show improvements in the cycling performance. Specifically, we characterize, using in situ scanning ion conductance microscopy and other ex situ surface characterization techniques, the SEI formed on ALD Al₂O₃ coated and uncoated MnO electrodes. We ascertain that ∼9 Å is the minimum thickness of ALD Al₂O₃ that will inhibit thick SEI formation. Furthermore, we show that the ALD surface coating is robust and prevents SEI formation for at least 100 cycles. Lastly, we investigated the differences between our in situ and ex situ measurements to help determine what artifacts can result that are due to post-processing for ex situ studies