Cobalt Oxide Nanomaterials by Vapor-Phase Synthesis for Fast and Reversible Lithium Storage

The design and assembly of suitable nanosystems are key issues in the development of smaller and more efficient lithium batteries. To this regard, cobalt oxides possess very favorable properties for use as negative electrode materials. In this work, we describe a convenient synthesis route to cobalt oxide nanomaterials (both single- and mixed-phase CoO and Co3O4) supported on Ti. The systems are grown by chemical vapor deposition starting from an innovative second-generation molecular source, Co(hfa)2·TMEDA (hfa ) 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate, TMEDA ) N,N,N′,N′-tetramethylethylenediamine). Controlled variations of the substrate temperature and O2 pressure in the reaction atmosphere enabled tailoring both the phase composition and the system morphology. The electrochemical properties of the obtained nanosystems were evaluated by galvanostatic measurements and impedance spectroscopy. The results showed excellent cycling performances and very high specific capacity values, offering attractive perspectives for the use of the present systems as advanced anode materials in Li-ion batteries.