Impact of dual-layer solid-electrolyte interphase inhomogeneities on early-stage defect formation in Si electrodes
Chunguang Chen, Tao Zhou, Dmitri L. Danilov, Lu Gao, Svenja Benning, Nino Schön, Samuel Tardif, Hugh Simons, Florian Hausen, Tobias U. Schülli, Rüdiger‐A. Eichel, Peter H. L. Notten
Abstract
Abstract While intensive efforts have been devoted to studying the nature of the solid-electrolyte interphase (SEI), little attention has been paid to understanding its role in the mechanical failures of electrodes. Here we unveil the impact of SEI inhomogeneities on early-stage defect formation in Si electrodes. Buried under the SEI, these early-stage defects are inaccessible by most surface-probing techniques. With operando full field diffraction X-ray microscopy, we observe the formation of these defects in real time and connect their origin to a heterogeneous degree of lithiation. This heterogeneous lithiation is further correlated to inhomogeneities in topography and lithium-ion mobility in both the inner- and outer-SEI, thanks to a combination of operando atomic force microscopy, electrochemical strain microscopy and sputter-etched X-ray photoelectron spectroscopy. Our multi-modal study bridges observations across the multi-level interfaces (Si/Li x Si/inner-SEI/outer-SEI), thus offering novel insights into the impact of SEI homogeneities on the structural stability of Si-based lithium-ion batteries.