Coupled artificial mixed conductor interfaces boosts excess Li-storage capability and ultra-long cycle durability in Si composite

Abstract

It is a critical challenge for silicon to achieve fast lithium storage for the intrinsic sluggish kinetics in spite of an attractive theoretic capacity up to 4200 mAh g−1. In this study, mixed conductor double layers composed of heterogeneous SnO: carbon and Si: carbon interfaces are conceived and configured successfully on the surface of silicon to construct SnO/C@Si composite. Amazing excess Li-storage on interface combined with bulk storage is thus strategically obtained by the coupled job-sharing modes in the artificial interfaces. Outstanding surfacial pseudocapacitive effect, which is hardly mentioned in the modification of silicon electrode materials, is demonstrated in the constructed SnO/C@Si composite. The approach demonstrates that constructing artificial interfaces with coupled job-sharing mode opens a feasible way for alloy-type materials to meet the requirement of fast kinetics and capacity enhancement.