The synthesis of oriented metal oxide nanodots on graphene oxide (GO) sheets using a surfactant-directed assembly strategy was recently reported by Professor Liqiang Mai and co-workers in Materials Horizons. This technique presents a versatile and general method for the synthesis of carbon-confined metal oxide nanodots, as well as a way to significantly enhance the energy storage properties of metal oxide nanocomposites.
Tin dioxide (SnO2) is a promising candidate electrode material for high performance lithium-ion batteries, due to its high theoretical capacity. However, the large volume expansion caused by lithium intercalation into SnO2 (up to 300%) results in poor cycling stability. In this article, metal-ligand bonds were used to immobilise SnO2 nanodot precursors onto a functionalised GO surface. The nanodots were complexed with organic ligands and subsequently carbonised to form nanocrystalline carbon-confined metal oxide nanodots (C@SnO2@Gr). Nanocrystallinity was achieved through the mismatched coordination of the organic ligands, as the distortion prevented aggregation of the precursor and crystal growth across larger areas.
When tested in a lithium-ion battery, the C@SnO2@Gr nanodots were found to have exceptional cycling stability and capacity over 1200 cycles in comparison to similar carbonised SnO2 nanocomposites. The material also demonstrated excellent rate capabilities, facilitated by its high surface area.
This paper highlights a promising method for the general synthesis of metal oxide nanodots, including SnO2, Cr2O3, Fe3O4, and Al2O3. Furthermore, this method could be used to enhance the lithium storage capabilities of metal oxide materials for future energy storage applications.
Markus Müllner is a member of the Community Board for Materials Horizons and an academic at The University of Sydney. Markus and Honours student Olivia McRae are interested in nanostructuring electrode materials to advance performance of lithium ion batteries. https://www.polymernanostructures.com/