Superkondenzatori pripravljeni od ugljikovih nano-čestica kao elektrodnih materijala

master's thesis

• Title (english): Supercapacitors prepared from carbon nano-particles as active electrode materials
• Author: Petra Ivanković
• Mentor: Zoran Mandić (mentor)
• Committee member: Zoran Mandić (predsjednik povjerenstva)
• Committee member: Marijana Kraljić Roković (član povjerenstva)
• Committee member: Vladimir Dananić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2023-01-27, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Svrha ovog rada bila je pripraviti superkondenzatore od dva različita elektrodna materijala i testirati njihova elektrokemijska svojstva. Uspoređivane su dvije vrste aktivnih ugljika: Norit DLC SUPER 30 i NC (OVIA INOVACIJE). Sastavljena su dva superkondenzatora; jedan s elektrodama od Norita i drugi s elektrodama od NC-a. Superkondenzatori su testirani EIS-om, cikličkom voltametrijom i metodom punjenja/pražnjenja. EIS se provodila pri potencijalu 0 V u rasponu frekvencija od 10 mHz do 100 kHz. Ciklička voltametrija provodila se u dvoelektrodnom sustavu kroz tri ciklusa s brzinom promjene potencijala 20 mV s^-1, a raspon potencijala iznosio je od 0 V do 2 V. Galvanostatsko punjenje/pražnjenje provodilo se i u dvoelektrodnom i u troelektrodnom sustavu kroz 30 ciklusa uz stalnu struju od 20 mA. Na kraju su se opet ponovljeni EIS i ciklička voltametrija pod opisanim uvjetima. Materijali aktivnih ugljika okarakterizirani su FTIR analizom, DLS-om i termogravimetrijom. Rezultati dobiveni EIS-om prikazani su grafički Nyquistovim prikazom. Za NC otpori su gotovo jednaki prije i nakon rada superkondenzatora, dok se kod Norita značajno poveća otpor nakon 30 ciklusa punjenja i pražnjenja. Iz rezultata cikličke voltametrije primjećuje se da kod NC superkondenzatora nakon 30 ciklusa punjenja i pražnjenja dobivena struja postiže gotovo konstantnu vrijednost te bolje kapacitivne karakteristike. To znači da je kod NC superkondenzatora došlo do aktiviranja elektrodne površine i/ili porozne strukture materijala pa je i izmjena iona između pora unutar elektrode i otopine olakšana. To nije bio slučaj kod superkondenzatora s Norit ugljikom. Prema kapacitetima superkondenzatora, izračunatim iz krivulja punjenja i pražnjenja u dvoelektrodnom i troelektrodnom sustavu, može se zaključiti da NC ima veći kapacitet.

Abstract (english)

The purpose of this work was to prepare supercapacitors from two different electrode materials and test their electrochemical properties. Two types of activated carbons were compared; Norit DLC SUPER 30 and NC. Two supercapacitors were assembled, one with Norit electrodes and the other with NC electrodes. The supercapacitors were tested by EIS, cyclic voltammetry and the charge/discharge method. EIS was performed at a potential of 0 V in the frequency range from 10 mHz to 100 kHz. Cyclic voltammetry was carried out in a two-electrode system through three cycles with a potential scan rate of 20 mV s^-1, and the potential range was from 0 V to 2 V. Galvanostatic charging/discharging was carried out both in a two-electrode and in a three-electrode system through 30 cycles with a constant current of 20 mA. At the end, EIS and cyclic voltammetry were repeated under the described conditions. Activated carbon materials were characterized by FTIR analysis, DLS and thermogravimetry. The results obtained by EIS are shown graphically using the Nyquist plot. For NC, the resistances are almost the same before and after the operation of the supercapacitor, while for Norit, the resistance increases significantly after 30 charging and discharging cycles. From the results of cyclic voltammetry, it can be observed that with NC supercapacitors, after 30 cycles of charging and discharging, the obtained current reaches an almost constant value and better capacitance characteristics. This means that with the NC supercapacitor, the electrode surface and/or the porous structure of the material has been activated, so the exchange of ions between the pores inside the electrode and the solution is facilitated. This was not the case with the Norit carbon supercapacitor. According to the supercapacitor capacitance, calculated from the charge and discharge curves in the two-electrode and three-electrode systems, it can be concluded that the NC has a higher capacitance.

• Keywords: superkondenzatori; aktivni ugljik; elektrokemijska impedancijska spektroskopija; ciklička voltametrija; galvanostatsko punjenje/pražnjenje
• Keywords (english): supercapacitors; activated carbon; electrochemical impedance spectroscopy; cyclic voltammetry; galvanostatic charge/discharge
• Language: croatian
• URN:NBN: urn:nbn:hr:149:372089
• Study programme: Title: Chemical Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-02-15 10:49:06