V2O5 Nano‐Electrodes with High Power and Energy Densities for Thin Film Li‐Ion Batteries |
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Authors: | Yanyi Liu Michael Clark Qifeng Zhang Danmei Yu Dawei Liu Jun Liu Guozhong Cao |
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Affiliation: | 1. Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, USA;2. Department of Physics and Astronomy, University of British Columbia, Vancouver V6T 1Z1, Canada;3. College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, P.R. China;4. Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O.Box 999, Richland, WA 99352, USA |
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Abstract: | Nanostructured V2O5 thin films have been prepared by means of cathodic deposition from an aqueous solution made from V2O5 and H2O2 directly on fluorine‐doped tin oxide coated (FTO) glasses followed by annealing at 500°C in air, and studied as film electrodes for lithium ion batteries. XPS results show that the as‐deposited films contained 15% V4+, however after annealing all the vanadium is oxidized to V5+. The crystallinity, surface morphology, and microstructures of the films have been investigated by means of XRD, SEM, and AFM. The V2O5 thin film electrodes show excellent electrochemical properties as cathodes for lithium ion intercalation: a high initial discharge capacity of 402 mA h g?1 and 240 mA h g?1 is retained after over 200 cycles with a discharging rate of 200 mA g?1 (1.3 C). The specific energy density is calculated as 900 W h kg?1 for the 1st cycle and 723 W h kg?1 for the 180th cycle when the films are tested at 200 mA g?1 (1.3 C). When discharge/charge is carried out at a high current density of 10.5 A g?1 (70 C), the thin film electrodes retain a good discharge capacity of 120 mA h g?1, and the specific power density is over 28 kW kg?1. |
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Keywords: | lithium‐ion batteries electrodes nanostructures thin films vanadium oxide |
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