The Role of Reduced Graphite Oxide in Transition Metal Oxide Nanocomposites Used as Li Anode Material: An Operando Study on CoFe2O4/rGO
| Autor: | Stefan Zander, Lorenz Kienle, Stefan Permien, Sylvio Indris, Andy Fiedler, Wolfgang Bensch, Stephen Doyle, Björn Richter, Gero Neubüser |
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| Rok vydání: | 2016 |
| Předmět: |
X-ray absorption spectroscopy
Chemistry Organic Chemistry Inorganic chemistry Oxide Nanoparticle Graphite oxide Monoxide 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Catalysis 0104 chemical sciences Anode chemistry.chemical_compound Transition metal Cyclic voltammetry 0210 nano-technology |
| Zdroj: | Chemistry - A European Journal. 22:16929-16938 |
| ISSN: | 0947-6539 |
| Popis: | A composite consisting of CoFe2O4 spinel nanoparticles and reduced graphite oxide (rGO) is studied as an anode material during Li uptake and release by applying synchrotron operando X-ray diffraction (XRD) and operando X-ray absorption spectroscopy (XAS), yielding a comprehensive picture of the reaction mechanisms. In the early stages of Li uptake, a monoxide is formed as an intermediate phase containing Fe2+ and Co2+ ions; this observation is in contrast to reaction pathways proposed in the literature. In the fully discharged state, metallic Co and Fe nanoparticles are embedded in an amorphous Li2O matrix. During charge, metallic Co and Fe are oxidized simultaneously to Co2+ and Fe3+, respectively, thus enabling a high and stable capacity to be achieved. Here, evidence is presented that the rGO acts as a support for the nanoparticles and prevents the particles from contact loss. The operando investigations are complemented by TEM, Raman spectroscopy, galvanostatic cycling, and cyclic voltammetry. |
| Databáze: | OpenAIRE |
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