Novel 3D Si/C/SiOC nanocomposites: Toward electrochemically stable lithium storage in silicon

In this work, we present an easy and environmentally friendly approach to stabilize nanostructured, porous crystalline (Si-tc) and amorphous (Si-sa) silicon synthesized via magnesiothermic reduction. As matrix, fructose-derived carbon, polymer-derived SiOC ceramic or both, carbon and SiOC, are used. By means of X-ray diffraction and Raman spectroscopy it is found that the crystallinity of Si-tc as well as the amorphous character of Sis(a) is preserved in the final composites. Embedding of crystalline silicon into carbon leadS to high initial capacities of similar to 600-650 mAh.g(-1), but only the matrix consisting of carbon and SiOC results iri a stable cycling behaviour over 50 cycles with a final capacity of 575 mAh.g(-1). All composites derived from amorphous Sisa show a stable cycling behaviour; the highest, stable capacity of similar to 500 mAh.g(-1) is observed when silicon is covered with carbon and SiOC. (C) 2016 Elsevier B.V. All rights reserved.