Hydrothermal Synthesis of CoSb2O4: In Situ Powder X-ray Diffraction, Crystal Structure, and Electrochemical Properties

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• 作者：Peter N?rby ; Martin Roelsgaard ; Martin S?ndergaard ; Bo B. Iversen
• 刊名：Crystal Growth & Design
• 出版年：2016
• 出版时间：February 3, 2016
• 年：2016
• 卷：16
• 期：2
• 页码：834-841
• 全文大小：537K
• ISSN：1528-7505

文摘

MSb₂O₄ constitutes a relatively unexplored class of multinary oxides that is traditionally synthesized by high-temperature solid-state methods. Here, we report a facile synthesis of CoSb₂O₄ under hydrothermal conditions (T = 135–300 °C, 256 bar). Using in situ synchrotron powder X-ray diffraction (PXRD), the formation and growth of CoSb₂O₄ nanoparticles are followed in real time using different precursor stoichiometries. Phase-pure CoSb₂O₄ can be formed at 135 °C, although the formation mechanism changes with precursor stoichiometry. The crystallite size can be fine-tuned between 14 and 17.5 nm under nonstoichiometric conditions, but crystallites twice as large are found in the stoichiometric case. An activation energy of 65(12) kJ/mol is obtained for the crystallization from a nonstoichiometric precursor. Modeling of atomic displacement parameters obtained from Rietveld refinement of multi-temperature high-resolution synchrotron PXRD data gives a Debye temperature of 331(11) K. The thermal expansion coefficients for the material was found to be α_a = 6.2(1) × 10^–6 K^–1 and α_c = 3.1(4) × 10^–6 K^–1. Electrochemical measurement shows that CoSb₂O₄ displays a large irreversible capacity (1131 mAh/g) on the first cycle in Li-ion half-cells and that the capacity decreases significantly in the following cycles.