Synthesis of Oxide Nanowires by Solution-based Processing and Their Electrochemical Performance for Energy Storage Applications

Abstract

One-dimensional (1-D) transition metal oxide nanostructures have attracted considerable interest because of their unique physical properties, including optical, magnetic, and electronic characteristics. In this presentation, three 1-D transition metal oxide nanostructures will be introduced such as LiMn2O4, LiNi0.5Mn1.5O4, and ZnMn2O4 with tailored morphologies and properties. The higher electrochemical performances of these nanostructures are due to the favorable morphology. Ultra-thin spinel LiMn2O4 nanowires were synthesized using a facile, easy to scale up two step process, hydrothermal and solid-state reaction. Galvanostatic battery testing showed that the material delivers 100 and 78 mAh/g at very high rate (60C and 150C, respectively) in large potential window with very good capacity retention and outstanding structural stability. The high voltage LiNi0.5Mn1.5O4 nanorods (150 nm in diameter) were also prepared with the same method. The material showed reversible capacity higher than 100 mAh/g at 4.7 V when charged at 1C and discharged at 10C using an electrolyte with improved electrochemical stability (i.e. Li[C2F2]3PF3 in EC/DMC). One-dimensional ZnMn2O4 nanowire is prepared and investigated for anode material. Formation of Mn3O4 and ZnO phases are identified from ex-situ TEM studies after initial discharge-charge cycle, which indicates that ZnMn2O4 phase converts to nanocomposite of Mn3O4 and ZnO phases immediately after the electrochemical conversion reaction.