Permien Stefan, Indris Sylvio, Neubüser Gero, Fiedler Andy, Kienle Lorenz, Zander Stefan, Doyle Stephen, Richter Björn, Bensch Wolfgang
Institute of Inorganic Chemistry, University of Kiel, Max-Eyth-Strasse 2, 24118, Kiel, Germany.
Institute for Applied Materials - Energy Storage Systems, Karlsruhe Institute of Technology, P.O. Box 3640, 76021, Karlsruhe, Germany.
Chemistry. 2016 Nov 14;22(47):16929-16938. doi: 10.1002/chem.201603160. Epub 2016 Oct 10.
A composite consisting of CoFe O 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 Fe and Co 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 Li O matrix. During charge, metallic Co and Fe are oxidized simultaneously to Co and Fe , 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.
通过应用同步辐射原位X射线衍射（XRD）和原位X射线吸收光谱（XAS），研究了由CoFeO尖晶石纳米颗粒和还原氧化石墨烯（rGO）组成的复合材料在锂嵌入和脱出过程中的阳极材料性能，从而全面了解了反应机理。在锂嵌入的早期阶段，形成了一种含有铁和钴离子的中间相一氧化碳；这一观察结果与文献中提出的反应途径相反。在完全放电状态下，金属钴和铁纳米颗粒嵌入非晶态LiO基质中。在充电过程中，金属钴和铁分别同时被氧化为Co和Fe，从而实现了高容量和稳定容量。这里有证据表明，rGO作为纳米颗粒的支撑体，防止颗粒失去接触。原位研究通过透射电子显微镜（TEM）、拉曼光谱、恒电流循环和循环伏安法得到补充。
