Size induced structural changes in maricite-NaFePO4: an in-depth study by experiment and simulations.
Size induced structural changes in maricite-NaFePO4: an in-depth study by experiment and simulations.
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马云石-NaFePO4 尺寸引起的结构变化：通过实验和模拟进行的深入研究
DOI：
10.1039/c9cp03838h
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Sevi Murugavel
中科院分区：
文献类型：
--
作者：
M. Sharma;P. Kaghazchi;Sevi Murugavel
基于最丰富的元素（例如钠和铁）的可再充电电池在开发用于大规模能量存储装置的成本有效的钠离子电池方面具有巨大的潜力。我们报告，第一次，通过X射线衍射，X射线吸收光谱和理论模拟的maricite-NaFePO 4的晶粒尺寸依赖的结构调查。Rietveld精修分析的X-射线衍射数据表明，在晶胞参数的减少导致体积收缩后，在微晶尺寸的减少。此外，X射线吸收光谱上的原子多重态模拟明确地提供了过渡金属离子的位置对称性的变化。高分辨率的氧K边光谱揭示了一个实质性的变化的成键特性与晶粒尺寸的减少，这是在单位晶胞参数的变化的maricite-NaFePO 4的根本原因。同时，我们进行了第一性原理密度泛函理论（DFT）的计算与不同的钠离子空位浓度的钠铁云母-NaFePO 4。所获得的结构参数与实验观察的介观结构的maricite-NaFePO 4非常一致。相对于微晶尺寸的体积变化与压缩应变有关，从而导致电子扩散率的改善。纳米晶水铝石-NaFePO 4具有更好的动力学性能，将为其作为钠离子电池正极材料开辟一条新的途径。
Rechargeable batteries based on the most abundant elements, such as sodium and iron, have a great potential in the development of cost effective sodium ion batteries for large scale energy storage devices. We report, for the first time, crystallite size dependent structural investigations on maricite-NaFePO4 through X-ray diffraction, X-ray absorption spectroscopy and theoretical simulations. Rietveld refinement analysis on the X-ray diffraction data reveals that a decrease in the unit cell parameters leads to volume contraction upon reduction in the crystallite size. Further, the atomic multiplet simulations on X-ray absorption spectra provide unequivocally a change in the site symmetry of transition metal ions. The high resolution oxygen K-edge spectra reveal a substantial change in the bonding character with the reduction of crystallite size, which is the fundamental cause for the change in the unit cell parameters of maricite-NaFePO4. In parallel, we performed first-principles density functional theory (DFT) calculations on maricite-NaFePO4 with different sodium ion vacancy concentrations. The obtained structural parameters are in excellent agreement with the experimental observations on the mesostructured maricite-NaFePO4. The volumetric changes with respect to crystallite size are related to the compressive strain, resulting in the improvement in the electronic diffusivity. The nano-crystalline maricite-NaFePO4 with improved kinetics will open a new avenue for its usage as a cathode material in sodium ion batteries.
影响因子：
16.6
作者：
Wang, Yonggang;Wang, Yarong;Zhou, Haoshen
通讯作者：
Zhou, Haoshen
LiFePO4 中粒径相关的限制和晶格应变效应。
DOI：
--
发表时间：
2013
期刊：
Physical Chemistry, Chemical Physics - PCCP
影响因子：
--
作者：
R. Shahid;S. Murugavel
通讯作者：
S. Murugavel
Co3中间自旋态P2-NaxCoO2晶体电场
DOI：
--
发表时间：
2013
期刊：
影响因子：
--
作者：
G. Shu;F. Chou
通讯作者：
F. Chou