Sinteza i strukturne značajka spinelnih nanomaterijala tipa AMn2O4(A = Co, Zn, Ni, Cd, Cu)

doctoral thesis

• Title (english): Synthesis and structural features of spinel-type nanomaterials AMn2O4(A = Co, Zn, Ni, Cd, Cu)
• Author: Mirjana Bijelić
• Mentor: Jasminka Popović (mentor); MBZ: 268735
• Committee member: Vladimir Stilinović (predsjednik povjerenstva)
• Committee member: Marijana Jurić (član povjerenstva); MBZ: 245015
• Committee member: Dubravka Matković-Čalogović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2016-02-26, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

Izvršena su strukturna istraživanja uzoraka AMn2O4 (A= Co, Zn, Ni, Cd, Cu) s ciljem određivanja utjecaja uvjeta sinteze na specifične značajke spinelnih struktura. Nađeno je da svi uzorci spinelne strukture pri čemu CoMn2O4, ZnMn2O4 i CdMn2O4 kristaliziraju u tetragonskom, a NiMn2O4 i CuMn2O4 u kubnom sustavu. Parametri inverzije za CoMn2O4 i CdMn2O4 rastu s porastom temperature termičke obrade (25500 oC). Parametar inverzije ZnMn2O4 povećava se s porastom temperature do 300 oC nakon čega se inverzija smanjuje. Struktura NiMn2O4 ne ovisi o temperaturi termičke obrade. Spoj CuMn2O4 nije moguće prirediti bez prisutstva nečistoća neovisno o temperaturi termičke obrade. Provedena su i elektrokemijska mjerenja; ustanovljeno je da najbolje ponašanje pokazuje CoMn2O4. Porast temperature termičke obrade uzrokovao je i rast čestica. Uzorak s najvećom veličinom čestica koji pokazuje najviši specifični kapaciteta, najbolje elektrokemijsko ponašanje te izrazito visoku održivost kapaciteta od 104 % nakon 1000 ciklusa punjenja i pražnjenja.

Abstract (english)

Structural studies on AMn2O4 (A = Co, Zn, Ni, Cd, Cu) have been performed in order to determine the influence of the synthesis conditions on the specific features of spinel structure, primarily on the inversion parameter. It was found that all samples belong to the spinel structure type; CoMn2O4, ZnMn2O4 and CdMn2O4 are tetragonal while NiMn2O4 and CuMn2O4 crystallize in the cubic system. The inversion parameter of CoMn2O4 and CdMn2O4 increases with increasing temperature (25500 C) while inversion in ZnMn2O4 increases with increase of temperature up to 300 C and decreases afterwards. Structure of NiMn2O4 does not depend on the heat treatment. Phase purity for CuMn2O4 was not achieved regardless of the temperature of the heat treatment. Electrochemical measurements were carried out for all samples; CoMn2O4 showed the best electrochemical performance. The increase in heat treatment caused pronounced particle growth. The sample with the largest particle size showed the highest specific capacity, best electrochemical cycling and extremely high capacity retention (104 % after 1000 cycles).

• Keywords: inverzija; litijske ionske baterije; spineli; rentgenska strukturna analiza
• Keywords (english): inversion; litium-ion battery; spinels; X-ray powder diffraction
• Language: croatian
• URN:NBN: urn:nbn:hr:217:037745
• Study programme: Title: Doctoral study in chemistry; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija (doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija)
• Type of resource: Text
• Extent: 134 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-02-02 15:24:44