Delicate Structural Control of Si–SiOx–C Composite via High-Speed Spray Pyrolysis for Li-Ion Battery Anodes

Despite the high theoretical capacity, silicon (Si) anodes in lithium-ion batteries have difficulty in meeting the commercial standards in various aspects. In particular, the huge volume change of Si makes it very challenging to simultaneously achieve high initial Coulombic efficiency (ICE) and long-term cycle life. Herein, we report spray pyrolysis to prepare Si–SiO x composite using an aqueous precursor solution containing Si nanoparticles, citric acid, and sodium hydroxide (NaOH). In the precursor solution, Si nanoparticles are etched by NaOH with the production of [SiO 4 ] 4– . During the dynamic course of spray pyrolysis, [SiO 4 ] 4– transforms to SiO x matrix and citric acid decomposes to carbon surface layer with the assistance of NaOH that serves as a decomposition catalyst. As a result, a Si–SiO x composite, in which Si nanodomains are homogeneously embedded in the SiO x matrix …