Energy harvesting and storage with ceramic piezoelectric transducers coupled with an ionic liquid-based supercapacitor

• Published in: Journal of energy storage 2023-04, Vol.60, p.106660, Article 106660
• Main Authors: Selleri, Giacomo, Poli, Federico, Neri, Riccardo, Gasperini, Leonardo, Gualandi, Chiara, Soavi, Francesca, Fabiani, Davide
• Format: Article
• Language: English
• Subjects: Energy harvesting; Piezoelectricity; Self-charging; Supercapacitor; Wearable electronics
• ISSN: 2352-152X
• DOI: 10.1016/j.est.2023.106660

One of the main issues of wearable electronic devices regards their power supply and autonomy. The exploitation of mechanical energy from body motion and vibrations can be realized by using piezoelectric materials coupled with a proper energy storage device. To this aim, Self-Powered Supercapacitors (SPSCs) have been investigated over the last decades, either as internally integrated SPSC (iSPSC), where the piezoelectric element of the device is used as Super Capacitor (SC) separator, or via an external integration (eSPSC), where the piezoelectric unit and the SC are connected by a bridge rectifier. In this paper, an eSPSC power supply is developed by integrating a stuck of commercial ceramic piezoelectric disks and an ionic liquid-based micro-SC. In detail, a stack of 15 commercial lead zirconate titanate (PZT) disks is used as the energy harvesting unit and mechanically stressed by a compressive force of 85 N at 2 Hz. The piezoelectric output successfully charged the 22 mF supercapacitor up to 3.1 V after 2 h of test, achieving a stored energy value equal to 110 mJ. The proposed integrated system outperforms the state-of-the-art SPSC assembled with micro-SC (both iSPSC and eSPSC). The use of the two different units (piezo-energy harvesting unit and micro-SC energy storage unit) allows an independent sizing and tuning of the supercapacitor according to the output current of the piezoelectric unit. [Display omitted] •Piezoelectric ceramic disks were used as energy harvesting source at 2 Hz frequency.•An ionic-liquid based micro-supercapacitor was used as energy storing unit.•The system optimizes the coupling between the piezo unit and the supercapacitor.•The system outperforms the state-of-the-art devices in terms of stored energy.