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master's thesis
Comparison of supercapacitive properties of different active carbons
Zagreb, Split: University of Zagreb, Faculty of Chemical Engineering and Technology, 2022. urn:nbn:hr:149:349647
Nwodika, Chekwube Ginika
University of Zagreb
Faculty of Chemical Engineering and Technology
University of Split
Faculty of Chemistry and Technology

Institutional repository: Repository of Faculty of Chemical Engineering and Technology University of Zagreb

Cite this document

Nwodika, C. G. (2022). Comparison of supercapacitive properties of different active carbons (Master's thesis). Zagreb: University of Zagreb, Faculty of Chemical Engineering and Technology; Split: University of Split, Faculty of Chemistry and Technology. Retrieved from https://urn.nsk.hr/urn:nbn:hr:149:349647

Nwodika, Chekwube Ginika. "Comparison of supercapacitive properties of different active carbons." Master's thesis, University of Zagreb, Faculty of Chemical Engineering and Technology; University of Split, Faculty of Chemistry and Technology, 2022. https://urn.nsk.hr/urn:nbn:hr:149:349647

Nwodika, Chekwube Ginika. "Comparison of supercapacitive properties of different active carbons." Master's thesis, University of Zagreb, Faculty of Chemical Engineering and Technology; University of Split, Faculty of Chemistry and Technology, 2022. https://urn.nsk.hr/urn:nbn:hr:149:349647

Nwodika, C. G. (2022). 'Comparison of supercapacitive properties of different active carbons', Master's thesis, University of Zagreb, Faculty of Chemical Engineering and Technology; University of Split, Faculty of Chemistry and Technology, accessed 01 April 2025, https://urn.nsk.hr/urn:nbn:hr:149:349647

Nwodika CG. Comparison of supercapacitive properties of different active carbons [Master's thesis]. Zagreb: University of Zagreb, Faculty of Chemical Engineering and Technology; Split: University of Split, Faculty of Chemistry and Technology; 2022 [cited 2025 April 01] Available at: https://urn.nsk.hr/urn:nbn:hr:149:349647

C. G. Nwodika, "Comparison of supercapacitive properties of different active carbons", Master's thesis, University of Zagreb, Faculty of Chemical Engineering and Technology, Zagreb; University of Split, Faculty of Chemistry and Technology, Split, 2022. Available at: https://urn.nsk.hr/urn:nbn:hr:149:349647

Metadata
TitleComparison of supercapacitive properties of different active carbons
Title (croatian)Usporedba superkapacitivnih svojstava različitih aktivnih ugljika
AuthorChekwube Ginika Nwodika
MentorZoran Mandić (mentor)
Committee memberZoran Mandić (predsjednik povjerenstva)
Committee memberMarin Kovačić (član povjerenstva)
Committee memberMarijana Kraljić Roković (član povjerenstva)
GranterUniversity of Zagreb
Faculty of Chemical Engineering and Technology
Zagreb
GranterUniversity of Split
Faculty of Chemistry and Technology
Split
Defense date and country2022-06-29, Croatia
Scientific / art field,
discipline and subdiscipline		TECHNICAL SCIENCES
Chemical Engineering
Abstract
Five different active carbons obtained by OVIA inovacije d.o.o. were used in making slurries for supercapacitor electrodes to compare their supercapacitive properties based on various electrochemical tests. The tested active carbons were prepared by various mechanical and thermal treatments of the original active carbon produced by the company T.T.T. d.o.o, Croatia. The cyclic voltammetry plots for all materials exhibited capacitive behavior except for the sample additionally activated with KOH... More and annealed at 700°C. Two samples, one pretreated in microwave oven in air and one pretreated in the furnace in the inert atmosphere show a slight indication of additional pseudocapacitive properties. The Nyquist plots of all samples have a high-frequency semicircle originating from kinetic hindrance and a low-frequency capacitive vertical line. The graphs show an increase in the diameter of the semicircle for the original material and the one pretreated in the microwave oven after subjecting these supercapacitors to 30 cycles of charging and discharging indicating interfacial deterioration in these supercapacitors. Charge/discharge tests for all materials exhibited triangular curves at studied current density, indicating the absence of faradic reactions. The supercapacitor fabricated from microwave treated original active carbon yielded the highest specific capacitance Cs determined from both CV and EIS test at 27.31 F g^-1 and 24.46 F g^-1 respectively, while the active carbon pretreated in the furnace recorded the highest specific capacitance from GCD test with a value of 30.27 F g^-1. General comparison of the Cs values from the three tests shows that the values derived from CV and GCD tests are closer in comparison to the values from EIS test. FTIR analysis indicated the presence of oxygen groups that generally influence the electrochemical performance of supercapacitors. The DLS analysis shows that there are two particle sizes in the sample additionally activated with KOH and annealed, and the one pretreated in the microwave oven, while other active materials have single particle size. the original material and the one pretreated in the microwave oven are significantly similar over a range of temperatures in terms of thermal stability. The sample additionally activated with KOH and annealed is the active material with the least desirable properties among studied materials. Less
Abstract (croatian)
Pet različitih aktivnih ugljika dobivenih od tvrtke OVIA inovacije d.o.o. korišteno je u proizvodnji elektroda superkondenzatora za usporedbu njihovih kapacitivnih svojstava. Ispitivani aktivni ugljici pripremljeni su različitim mehaničkim i toplinskim obradama originalnog aktivnog ugljika proizvođača T.T.T. d.o.o, Hrvatska. Ciklički voltamogrami za sve materijale su pokazali kapacitivno ponašanje osim za uzorak koji je dodatno aktiviran s KOH i žaren na 700 °C. Dva uzorka, jedan prethodno... More tretiran u mikrovalnoj pećnici na zraku i jedan prethodno tretiran u peći u inertnoj atmosferi, pokazuju naznake i dodatnih pseudokapacitivnih svojstava. Nyquistovi dijagrami svih uzoraka imaju visokofrekventni polukrug koji je posljedica kinetike elektrokemijskih reakcija i niskofrekventnu kapacitivnu okomitu liniju. Nakon punjenja i pražnjenja ovih materijala kroz 30 sukcesivnih ciklusa, veličina polukruga u impedancijskim dijagramima pokazuje povećanje promjera, što ukazuje na degradaciju materijala na jednoj od granica faza. Ispitivanja punjenja/pražnjenja za sve materijale pokazali su trokutaste krivulje pri ispitivanoj gustoći struje, što ukazuje na odsutnost Faradayskih reakcija. Specifični kapaciteti ovih materijala određeni su tehnikama CV i EIS. Najveći specifični kapacitet dobiven je za originalni aktivni ugljik tretiranog mikrovalovima i iznosi 27,31 F g^-1 odnosno 24,46 F g^-1, dok je aktivni ugljik prethodno tretiran u peći zabilježio najveći specifični kapacitet kod testiranja punjenja i pražnjenja konstantom strujom s vrijednošću od 30,27 F g^-1. Opća usporedba vrijednosti specifičnih kapaciteta od tri različite metodologije pokazuje da su vrijednosti dobivene CV i GCD tehnikama bliže u usporedbi s vrijednostima iz EIS. FTIR analiza pokazala je prisutnost kisikovih skupina koje općenito utječu na elektrokemijsko ponašanje superkondenzatora. DLS analiza pokazuje da postoje dvije veličine čestica u uzorku dodatno aktiviranom KOH-om i žarenom te onom prethodno obrađenom u mikrovalnoj pećnici, dok ostali aktivni materijali imaju jednu veličinu čestica. Izvorni materijal i onaj prethodno obrađen u mikrovalnoj pećnici značajno su slični u rasponu temperatura u smislu toplinske stabilnosti. Uzorak dodatno aktiviran s KOH i žaren je aktivni materijal s najmanje poželjnim svojstvima među ispitivanim materijalima. Less
Keywords
Keywords (croatian)
Languageenglish
URN:NBNurn:nbn:hr:149:349647
Study programmeTitle: Chemical and environmental technology - graduate - university
Study programme type: university
Study level: graduate
Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
Type of resourceText
File originBorn digital
Access conditionsAccess restricted to students and staff of home institution
Terms of useLicence In copyright icon
Created on2023-03-31 13:15:41
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