Performance of printable supercapacitors in an RF energy harvesting circuit

Suvi Lehtimäki, Miao Li, Jarno Salomaa, Juho Pörhönen, Antti Kalanti, Sampo Tuukkanen, Petri Heljo, Kari Halonen, Donald Lupo

    Research output: Contribution to journalArticleScientificpeer-review

    60 Citations (Scopus)
    473 Downloads (Pure)

    Abstract

    We report the fabrication of a supercapacitor on a plastic substrate with mass-production-compatible methods and its characterisation using galvanostatic and voltammetric methods. The supercapacitor is prepared in ambient conditions using activated carbon and an aqueous, non-acidic electrolyte. The obtained capacitances are 0.45 F and 0.21 F for device sizes of 4 cm(2) and 2 cm(2), respectively. Additionally, we demonstrate the utilisation of the supercapacitor in an autonomous energy harvesting and storage system. The RF energy harvester comprises a printed loop antenna and a half-wave organic diode rectifier operating at 13.56 MHz frequency. The harvested energy is stored in two supercapacitors connected in series to increase the maximum operating voltage. In order to power a device such as a sensor or a small indicator display, voltage regulation is needed. A voltage regulator, implemented as an application specific integrated circuit (ASIC), was designed for this purpose, and fabricated commercially. We demonstrate the ability of the harvester storage unit to power the regulator for hours with a constant regulator output voltage and power. The effect of supercapacitor charging time on the actual supercapacitor charging state is also discussed, as a slower charging rate is found to have a significant effect on the output of the supercapacitor. (C) 2014 Elsevier Ltd. All rights reserved.

    Translated title of the contributionPerformance of printable supercapacitors in an RF energy harvesting circuit
    Original languageEnglish
    Pages (from-to)42-46
    Number of pages5
    JournalInternational Journal of Electrical Power and Energy Systems
    Volume58
    DOIs
    Publication statusPublished - Jun 2014
    Publication typeA1 Journal article-refereed

    Keywords

    • Supercapacitor
    • Ultracapacitor
    • Electric double layer capacitor
    • Energy harvesting
    • Autonomous power source
    • CAPACITORS

    Publication forum classification

    • Publication forum level 1

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