American Chemical Society, ACS Applied Materials and Interfaces, 7(5), p. 2745-2751, 2013
DOI: 10.1021/am4004073
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We report a facile colloidal route to prepare octahedral shaped cuprite (Cu2O) nanocrystals (NCs) of ~50 nm in size that exploits a new reduction pathway, i.e. the controlled reduction of cupric ion by acetylacetonate directly to cuprite. Detailed structural, morphological and chemical analyses were carried on the 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 post-mortem 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 multi-domain particles and eventually disintegrated. Overall, the shape changes (upon disintegration after 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 should emphasize that a complete understanding on the lithiation process on NCs defined by a specific crystal habit is still essential in order to optimize nanoscale conversion reactions.