Single-step fabrication of fibrous Si/Sn composite nanowire anodes by high-pressure He plasma sputtering for high-capacity Li-ion batteries

Abstract

To realize high-capacity Si anodes for next-generation Li-ion batteries, Si/Sn nanowires were fabricated in a single-step procedure using He plasma sputtering at a high pressure of 100–500 mTorr without substrate heating. The Si/Sn nanowires consisted of an amorphous Si core and a crystalline Sn shell. Si/Sn composite nanowire films formed a spider-web-like network structure, a rod-like structure, or an aggregated structure of nanowires and nanoparticles depending on the conditions used in the plasma process. Anodes prepared with Si/Sn nanowire films with the spider-web-like network structure and the aggregated structure of nanowires and nanoparticles showed a high Li-storage capacity of 1219 and 977 mAh/g, respectively, for the initial 54 cycles at a C-rate of 0.01, and a capacity of 644 and 580 mAh/g, respectively, after 135 cycles at a C-rate of 0.1. The developed plasma sputtering process enabled us to form a binder-free high-capacity Si/Sn-nanowire anode via a simple single-step procedure.

Covalent-assisted seeding of Si nanoparticles into a dual-matrix design toward advanced Si-based Li-ion batteries

“…In addition, the Sn and SiOC dual-active matrix is expected to reduce electrode impedance through the combined electrical conductivity of metallic Sn and the ionic conductivity of the Li x Sn phase. 72,76–82…”

“…In addition, electrically conductive Sn, together with ionically conductive lithiated Sn phases (Li x Sn), form a solid mixed conducting matrix for Si, enhancing Li-ion transport into Si. 79,81,82 Synergistic effects between Si particles and the Sn/SiOC framework, as well as the robust structural integration and the Li-ion/electron mixed conducting pathways, are the key factors for the SiSn@SiOC electrode to achieve superior overall electrochemical performance. Synergistic effects between this ionically and electrically conducting matrix and its embedded Si play an important role in improving charge-transport capability.…”