Comparative Electrochemical Charge Storage Properties of Bulk and Nanoscale Vanadium Oxide Electrodes
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Vanadium oxide nanostructures have been widely researched as a cathode material for Li-ion batteries due to their layered structure and shorter Li+ diffusion path lengths, compared to the bulk material. Some oxides exhibit charge storage due to capacitive charge compensation, and many materials with cation insertion regions and rich surface chemistry have complex responses to lithiation. Herein, detailed analysis by cyclic voltammetry was used to distinguish the charge stored due to lithium intercalation processes from extrinsic capacitive effects for micron-scale bulk V2O5 and synthesized nano-scale vanadium oxide polycrystalline nanorods (poly-NRs), designed to exhibit multivalent surface oxidation states. The results demonstrate that at fast scan rates (up to 500 mV/s), the contributions due to diffusion-controlled intercalation processes for micron-scale V2O5 and nanoscale V2O3 are found to dominate irrespective of size and multivalent surface chemistry. At slow potential scan rates, a greater portion of the redox events are capacitive in nature for the polycrystalline nanorods. Low dimensional vanadium oxide structures of V2O5 or V2O3, with greater surface area do not automatically increase their (redox) pseudocapacitive behaviour significantly at any scan rate, even with multivalent surface oxidation states.
KeywordsSpecific Capacity Vanadium Oxide Intercalation Process Diffusion Path Length Capacitive Effect
This publication has emanated from research conducted with the financial support of the Charles Parsons Initiative and Science Foundation Ireland (SFI) under Grant No. 06/CP/E007. Part of this work was conducted under the framework of the INSPIRE programme, funded by the Irish Government’s Programme for Research in Third Level Institutions, Cycle 4, National Development Plan 2007–2013. We acknowledge support from Science Foundation Ireland under a Technology Innovation and Development Award no. 13/TIDA/E2761. This research has received funding from the Seventh Framework Programme FP7/2007-2013 (Project STABLE) under grant agreement no. 314508. This publication has also emanated from research supported in part by a research grant from SFI under Grant 14/IA/2581.
- 32.Marschilok AC, Davis SM, Leising RA (2001) Silver vanadium oxides and related battery applications. Coord Chem Rev 219:283–310Google Scholar
- 33.Miller JR, Simon P (2008) Electrochemical capacitors for energy management. Sci Mag 321:651–652Google Scholar
- 35.Huang C, Grant PS (2013) One-step spray processing of high power all-solid-state supercapacitors. Sci Rep 3:2393Google Scholar
- 48.Mendialdua J, Casanova R, Barbaux Y (1995) XPS studies of V2O5, V6O13, VO2 and V2O3. J Electron Spectrosc Relat Phenom 71:249–261Google Scholar