Shape Dependence on the Electrochemistry of Uncoated Magnetite Motifs
Shape Dependence on the Electrochemistry of Uncoated Magnetite Motifs
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DOI：
10.1149/1945-7111/ac8626
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发表时间：
2022-08
影响因子：
3.9
通讯作者：
Kenna L. Salvatore;Mallory N. Vila;S. Mcguire;Nathaniel Hurley;Citlalli Rojas Huerta;E. Takeuchi;K. Takeuchi;A. Marschilok;Stanislaus S. Wong
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作者：
Kenna L. Salvatore;Mallory N. Vila;S. Mcguire;Nathaniel Hurley;Citlalli Rojas Huerta;E. Takeuchi;K. Takeuchi;A. Marschilok;Stanislaus S. Wong
通过采用包括水热法和微波辅助法等多种合成方案，所制备的磁铁矿的形貌得以可靠地改变，以此探究晶面变化对所测电化学过程的影响。具体而言，直径约100至200纳米的磁铁矿结构单元，被制备成正方体、球体、八面体和片状等不同形状，从而能够根据具体几何形状，优先暴露（111）、（220）或（100）晶面。我们特意在不使用含碳表面活性剂的情况下制备这些样品，并利用X射线衍射（XRD）和扫描电子显微镜（SEM）对其进行表征，以增强它们的内在电化学性能。在此，我们对具有3种不同晶面的特定改性形状形貌进行直接电化学比较，并研究它们作为锂离子电池电极材料的影响。我们的整体数据表明，在不同电流密度下展现出最大可释放容量的形状，包含了表面能最高的晶面，例如本研究中暴露的（220）晶面。不同形貌的晶面特性凸显出（220）＞（111）＞（100）的电化学趋势；此外，还发现所制备样品的团聚程度和多分散性也起着关键作用。
Using a variety of synthetic protocols including hydrothermal and microwave-assisted methods, the morphology of as-prepared magnetite has been reliably altered as a means of probing the effect of facet variations upon the resulting electrochemical processes measured. In particular, motifs of magnetite, measuring ∼100 to 200 nm in diameter, were variously prepared in the form of cubes, spheres, octahedra, and plates, thereby affording the opportunity to preferentially expose either (111), (220), or (100) planes, depending on the geometry in question. We deliberately prepared these samples, characterized using XRD and SEM, in the absence of a carbonaceous surfactant to enhance their intrinsic electrochemical function. Herein, we present a direct electrochemical comparison of specifically modified shape morphologies possessing 3 different facets and their impact as electrode materials for Li-ion batteries. Our overall data suggest that the shapes exhibiting the largest deliverable capacities at various current densities incorporated the highest surface energy facets, such as exposed (220) planes in this study. The faceted nature of different morphologies highlighted a trend in electrochemistry of (220) > (111) > (100); moreover, the degree of aggregation and polydispersity in prepared samples were found to play key roles as well.