Revealing Seed-mediated Structural Evolution of Copper-Silicide Nanostructures: Generating Structured Current Collectors for Rechargeable Batteries.

Metal silicide thin films and nanostructures typically employed in electronics have recently gained significant attention in battery technology, where they are used as active or inactive materials. However, unlike thin films, the science behind the evolution of silicide nanostructures, especially 1-D Nanowires (NWs), is a key missing aspect. Cu x Si y nanostructures synthesized by solvent vapor growth technique (SVG) are studied as a model system to gain insights into metal silicide formation. The temperature-dependent phase evolution of Cu x Si y structures proceeds from Cu>Cu 0.83 Si 0.17 >Cu 5 Si>Cu 15 Si 4 . The role of Cu diffusion kinetics on the morphological progression of Cu silicides is studied, revealing that the growth of 1D metal silicide NWs proceeds through an in-situ formed, Cu seed-mediated, self-catalytic process. The different Cu x Si y morphologies synthesized were utilized as structured current collectors (CC) for K-ion battery anodes. Sb deposited by thermal evaporation upon Cu 15 Si 4 tripod NWs and cube architectures exhibited reversible alloying capacities of 477.3 and 477.6 mAh/g at a C/5 rate. Furthermore, Sb deposited Cu 15 Si 4 tripod NWs anode tested in Li-ion and Na-ion batteries demonstrated reversible capacities of ∼518 mAh/g and 495 mAh/g. This article is protected by copyright. All rights reserved.