Li-Ions Transport Promoting and Highly Stable Solid–Electrolyte Interface on Si in Multilayer Si/C through Thickness Control

Lithium-ion batteries (LIBs) have been considered as promising electrochemical energy storage devices due to the high volumetric, gravimetric capacity and high power density. The charge/discharge rate and power output of LIBs largely depend on the transport property of lithium-ions (Li-ions). The Li-ions diffusion coefficient and diffusion length are the critical factors influencing the charge/discharge rate of LIBs. In this work, we present that silicon–carbon (Si–C) interfaces in an amorphous Si/C multilayer electrode promote the transport of Li-ions along the direction not only perpendicular to but also parallel to the Si–C interfaces after electrode cracking. The electrode, stacked with 5 nm amorphous carbon and 10 nm amorphous Si, has the most stable solid–electrolyte interface (SEI) formed at the cracks, even when the Si is in direct contact with the electrolyte. It exhibits highly stable cycle performance and a high retained specific capacity. Electron microscopy characterization shows that the str...