1. Delicate Structural Control of Si–SiOx–C Composite via High-Speed Spray Pyrolysis for Li-Ion Battery Anodes
- Author
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Hye-jin Kim, Sunghun Choi, Dae Soo Jung, Seung Jong Lee, Tae Hoon Hwang, Erhan Deniz, Jang Wook Choi, and Sung Hyeon Park
- Subjects
initial Coulombic efficiency ,Materials science ,Silicon ,Composite number ,chemistry.chemical_element ,Nanoparticle ,Bioengineering ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Cycle life ,Catalysis ,chemistry.chemical_compound ,General Materials Science ,Aqueous solution ,Mechanical Engineering ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,silicon monoxide ,0104 chemical sciences ,chemistry ,Chemical engineering ,Sodium hydroxide ,pulverization ,spray pyrolysis ,0210 nano-technology ,Carbon ,Faraday efficiency - Abstract
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-SiOx 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 [SiO4]4-. During the dynamic course of spray pyrolysis, [SiO4]4- transforms to SiOx 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-SiOx composite, in which Si nanodomains are homogeneously embedded in the SiOx matrix with carbon surface layer, is generated by a one-pot process with a residence time of only 3.5 s in a flow reactor. The optimal composite structure in terms of Si domain size and Si-to-O ratio exhibited excellent electrochemical performance, such as reversible capacity of 1561.9 mAh g-1 at 0.06C rate and ICE of 80.2% and 87.9% capacity retention after 100 cycles at 1C rate. J.W.C. acknowledges the financial support by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (NRF-2015R1A2A1A05001737). This work was also made possible by NPRP Grant No. NPRP 7-301-2-126 from the Qatar National Research Fund (a member of Qatar Foundation). Scopus
- Published
- 2017