Electrodeposited MoOx films as negative electrode materials for redox supercapacitors

MoOx films composed of agglomerated nanoparticles were synthesized by potentiostatic electrodeposition on stainless steel collectors for charge storage electrodes working in aqueous electrolyte (1M H2SO4) and negative potential window. The agglomerated nanoparticles were amorphous in nature and poss...

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Bibliographic Details
Published in:Electrochimica acta 2017-01, Vol.225, p.19-28
Main Authors: Upadhyay, Kush K., Nguyen, Tuyen, Silva, Teresa M., Carmezim, Maria J., Montemor, M. Fatima
Format: Article
Language:English
Subjects:
Agglomeration
amorphous
Aqueous electrolytes
Charge density
Electrochemical analysis
Electrochemical impedance spectroscopy
Electrode materials
Electrodeposition
Electrodes
MoOx
Nanoparticles
negative electrode
Spectroscopic analysis
Stability
Stainless steel
supercapacitor
Supercapacitors
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Summary:MoOx films composed of agglomerated nanoparticles were synthesized by potentiostatic electrodeposition on stainless steel collectors for charge storage electrodes working in aqueous electrolyte (1M H2SO4) and negative potential window. The agglomerated nanoparticles were amorphous in nature and possess mixed valance state. By optimizing the charge density applied during electrodeposition, the electrodes delivered maximum specific capacity of 228Cg−1 (507Fg−1) at 1Ag−1 for the sample electrodeposited at −0.3Ccm−2. This film showed very good rate capability and retained around 48% of specific capacity at 10Ag−1. The galvanostatic charge discharge cycling stability test showed 87% of initial capacity retained after 900 cycles, suggesting good stability behaviour. Electrochemical impedance spectroscopy (EIS) measurements evidenced lower equivalent series resistance for the sample electrodeposited at −0.3Ccm−2 among the tested samples, revealing its better electrochemical performance. Aging of the electrode with higher specific capacity was also investigated by performing EIS after different cycles; the results revealed an increment on the overall resistance, thus clarifying the capacity degradation.
ISSN:0013-4686
1873-3859
DOI:10.1016/j.electacta.2016.12.106