Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
ACS Appl Mater Interfaces. 2013 Apr 10;5(7):2745-51. doi: 10.1021/am4004073. Epub 2013 Mar 22.
We report a facile colloidal route to prepare octahedral-shaped cuprite (Cu2O) nanocrystals (NCs) of ∼40 nm in size that exploits a new reduction pathway, i.e., the controlled reduction of a cupric ion by acetylacetonate directly to cuprite. Detailed structural, morphological, and chemical analyses were carried on the cuprite NCs. We also tested their electrochemical lithiation, using a combination of techniques (cyclic voltammetry, galvanostatic, and impedance spectroscopy), in view of their potential application as anodes for Li ion batteries. Along with these characterizations, the morphological, structural, and chemical analyses (via high-resolution electron microscopy, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy) of the cycled Cu2O NCs (in the lithiated stage, after ∼50 cycles) demonstrate their partial conversion upon cycling. At this stage, most of the NCs had lost their octahedral shape and had evolved into multidomain particles and were eventually fragmented. Overall, the shape changes (upon cycling) did not appear to be concerted for all the NCs in the sample, suggesting that different subsets of NCs were characterized by different lithiation kinetics. We emphasize that a profound understanding of the lithiation reaction with NCs defined by a specific crystal habit is still essential to optimize nanoscale conversion reactions.
我们报告了一种简便的胶体路线，可制备尺寸约为 40nm 的八面体形状的氧化亚铜（Cu2O）纳米晶体（NCs），该方法利用了一种新的还原途径，即乙酰丙酮酸盐对铜离子的受控还原直接生成氧化亚铜。我们对氧化亚铜 NCs 进行了详细的结构、形态和化学分析。还考虑到它们作为锂离子电池阳极的潜在应用，使用了一系列技术（循环伏安法、恒电流和阻抗谱）对其电化学嵌锂性能进行了测试。除了这些特性之外，循环后的氧化亚铜 NCs（在嵌锂阶段，经过约 50 次循环后）的形态、结构和化学分析（通过高分辨率电子显微镜、电子能量损失光谱和 X 射线光电子能谱）表明，它们在循环过程中发生了部分转化。此时，大多数 NC 已经失去了八面体形状，演变成多畴颗粒，最终发生了碎裂。总体而言，（在循环过程中）NCs 的形状变化似乎并不是所有 NCs 同时发生的，这表明不同子集的 NCs具有不同的嵌锂动力学。我们强调，深入了解具有特定晶体习性的 NCs 的嵌锂反应仍然对于优化纳米级转化反应至关重要。
