Formation mechanism of electrodeposited Sb/Sb2O3 micro-composites. (10th January 2021) - Voigt, K.
Highlights: Sb/Sb2 O3 formation is an interplay between Sb ECD and precipitation of Sb2 O3. Local pH shifts causing the precipitation of Sb2 O3 are monitored for the first time. Critical deposition conditions and the Sb nucleation mechanism are determined. ECD rate, pH shift and Sb2 O3 layer are responsible Sb/Sb2 O3 composite properties. A model for the formation mechanism of Sb/Sb2 O3 composites is proposed. Abstract: Antimony (Sb) and antimony oxide have (Sb2 O3 ) gained attention in research and industry in recent years because of their potential use in secondary batteries and as materials for sensor applications. As shown in recent studies, Sb/Sb2 O3 composites with a variety of nanostructures and compositions can be manufactured by a straightforward electrochemical deposition process. In the present work the formation mechanism of Sb/Sb2 O3 composites is investigated by means of electrochemical and chemical methods combined with electron microscopy and X-ray diffraction. A local pH shift, caused by the electrodeposition of Sb and leading to the co-deposition of Sb2 O3, is verified experimentally for the first time. The Sb nucleation mechanism is investigated by fast transient measurements. The formation of Sb2 O3 is examined by titration with KOH. Based on the results, a nucleation and growth model is proposed that explains the development of different Sb/Sb2 O3 structures and compositions depending on the applied electrochemical process parameters.