BIBLIOS

Document type
Conference papers

Document subtype
Poster without full or short paper

Title
Extending the voltage window of aqueous electrolytes for supercapacitors

Participants in the publication
J Baptista (Author)
J Sagu (Author)
U Wijayantha (Author)
K Lobato (Author)
Dep. Engenharia Geográfica, Geofísica e Energia
IDL

Summary
Currently, the main drawback of supercapacitors is their low energy density, which is mostly limited by the break-down voltage of the electrolyte. Commercial devices typically use organic solvents, which can withstand up to 2.7 V, but are toxic and expensive. Aqueous electrolytes would be a cheaper and environmentally friendly alternative, as long as its electrochemically stable potential window (ΔV ≈ 1 V) could be extended. A possible way to achieve this is by electrodepositing a passivating coating on the surface of the carbon-based electrode. For the passivation to be successful, it should be pinhole-free and thick enough to prevent electron transfer between the electrode and the electrolyte (>2 nm) while simultaneously thin enough (<30 nm) to preserve the electrode’s high surface area, indispensable for a high capacitance. Polymer A has been identified as a suitable candidate for this insulating layer. This work aims at establishing the relationship between the thickness (and the coulombic efficiency) of the electropolymerized coating and the scan rate during the electrodeposition.


Event
ISEECAP2019 - International Symposium on Enhanced Electrochemical Capacitors

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