@article{c87eb18250304b30a40f30b2a305d28b,
title = "Electrochemical stability enhancement in reactive magnetron sputtered VN films upon annealing treatment",
abstract = "Vanadium nitride (VN) thin films were produced via direct-current reactive magnetron sputtering technique followed by vacuum annealing. The treatment was carried out at different temperatures for any effect on their electrochemical (EC) stability, up to 10,000 charge-discharge cycles in 0.5 M K2SO4 solution. The film surface chemistry was investigated by using X-ray photoelectron spectroscope (XPS) and cyclic voltammetry (CV) techniques. For the as-deposited film, the oxide layer formed on the VN surface was unstable upon K2SO4 immersion treatment, along with ~23% reduction in the EC capacitance. Vacuum annealing under optimized conditions, however, made the oxide layer stable with almost no capacitance loss upon cycling for up to 10,000 cycles. Annealing treatment of the VN films makes them a potential candidate for long-term use in electrochemical capacitors.",
keywords = "Cyclic voltammetry, Electrochemical capacitor, Vacuum annealing, VN films, XPS",
author = "Amine Achour and Mohammad Islam and Iftikhar Ahmad and Khalid Saeed and Shahram Solaymani",
note = "Funding Information: authors would like to extend their sincere appreciation to the Deanship of Scientific Research at King Saud University for its funding of this research through the Research Group No. RGP-283. Funding Information: Figure 6. Cycling stability of the annealed VN film at 200 mV·s−−11 scan rate, and (b–d) XPS V 2p core level deconvoluted spectra of the annealed VN films: (b) V1 sample, (c) V2 sample, and (d) V3 sample. level deconvoluted spectra of the annealed VN films: (b) V1 sample, (c) V2 sample, and (d) V3 sample. 4. Conclusions 4. Conclusions Nanocrystalline VN films were produced via DC-plasma reactive magnetron sputtering followed Nanocrystalline VN films were produced via D◦C-plasma reactive magnetron sput◦ tering followed by thermal treatment under a vacuum at 400, 600, and 800 °C. For the as-dep2 os4ited and 400 °C annealed VN films, the topmost surface oxide layer was found to degrade upon treatment in K2SO4 electrolyte solution. This was confirmed from XPS analysis besides a ~23% capacitance loss◦in the case of the as-deposited VN film after 10,000 cycles. Vacuum annealing of the VN films at 600 and 800 °C led to an enhancement in electrochemical cycling stability, with an almost 100% capacitance retention, even after 10,000 cycles. Such an improvement in EC properties is speculated to originate from VN film crystallization or a thickness increase in the surface oxide layer, or both. From this finding, VN-based electrode materials may be developed with superior VN cycling stability in electrochemical energy devices. Author Contributions: A.A. and M.I. conceived the idea and designed the experimentation scheme; A.A., K.S., Author Contributions: A.A. and M.I. conceived the idea and designed the experimentation scheme; A.A., K.S., manuscript draft with input from other co-authors. M.I. was responsible for acquisition of funding for this research. and I.A. performed the experiments; M.I. and S.S. carried out data analysis; A.A. and M.I. prepared the original manuscript draft with input from other co-authors. M.I. was responsible for acquisition of funding for this King Saud University for its funding of this research through the Research Group No. RGP-283. Funding Information: Conflicts of Interest: The authors declare no conflict of interest. Funding: The authors would like to extend their sincere appreciation to the Deanship of Scientific Research at King Saud University for its funding of this research through the Research Group No. RGP-283. Publisher Copyright: {\textcopyright} 2019 by the authors. Copyright: Copyright 2019 Elsevier B.V., All rights reserved.",
year = "2019",
month = jan,
day = "1",
doi = "10.3390/COATINGS9020072",
language = "English",
volume = "9",
journal = "Coatings",
issn = "2079-6412",
publisher = "Multidisciplinary Digital Publishing Institute (MDPI)",
number = "2",
}