Studij elektrokemijskih reakcija na granici faza Ca/acetonitril

master's thesis

• Title (english): The study of electrochemical reactions on the Ca/acetonitrile interface
• Author: Livia Grgurić
• 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: 2024-09-13, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Kalcijeve baterije se smatraju jednom od privlačnih zamjena za Li-ion baterije, zbog obilja kalcija u Zemljinoj kori i standarnog redukcijskog potencijala koji je usporediv s tim od litija. No, za realizaciju kalcijeve baterije koja u potpunosti radi potrebno je identificirati i razviti prikladne elektrode i elektrolit. Najveći izazov predstavlja uspostavljanje reverzibilne depozicije i otapanje metalne anode od kalcija. Dodatno, u velikom broju elektrolita dolazi do inhibicije kalcija zbog čega je od izrazito važno odabrati formulaciju elektrolita koja neće dovesti do inhibicije kalcija. U okviru ovog rada provedena su elektrokemijska ispitivanja kalcijeve elektrode u Ca(TFSI)2/ACN elektrolitu kako bi se istražio utjecaj Ca(TFSI)2/ACN elektrolita na elektrokemijsko ponašanje kalcijeve elektrode i na reverzibilnost reakcija otapanja i depozicije. Ispitivanje kalcijeve anode u Ca(TFSI)2/ACN elektrolitu provedeno je sljedećim tehnikama: naponom otvorenog kruga, cikličkom voltametrijom te elektrokemijskom impedancijskom spektroskopijom. Mjerenjem napona otvorenog kruga utvrđeno je da je kalcij u Ca(TFSI)2/ACN elektrolitu podložan koroziji pri čemu se elektroda prekriva inhibirajućim slojem. Inhibirajući sloj usporava katodnu depoziciju kalcija zbog male permeabilosti kalcijev iona kroz njega. Katodna depozicija kalcija je vidljiva na cikličkim voltamogramima u prvom ciklusu promjene potencijala, ali se kod sljedećih ciklusa elektroda potpuno inhibira. Anodno otapanje kalcija iz otopine Ca(TFSI)2/ACN ide neometano unatoč nastalom inhibirajućim sloj. Moguće je da otapanje kalcija razgrađuje nastali sloj i na taj način omogućuje daljnje otapanje.

Abstract (english)

An attractive substitute for Li-ion batteries are calcium batteries due to the abundance of calcium in the Earth's crust and the standard reduction potential of calcium that is comparable to that of lithium. However, to fully realize a working secondary calcium battery, identification and development of suitable electrodes and electrolyte is needed. The biggest challenge is how to establish reversible plating and stripping of calcium at the metal-anodeinterface. Calcium inhibition occurs in a large number of electrolytes, therefore, it is extremely important to choose an electrolyte formulation that will not lead to calcium inhibition. Within this work, electrochemical tests of calcium electrode in Ca(TFSI)2/ACN electrolyte were carried out in order to investigate the influence of Ca(TFSI)2/ACN electrolyte on the electrochemical behavior of the calcium electrode and on the reversibility of plating and stripping reactions. Testing of the calcium anode in Ca(TFSI)2/ACN electrolyte was performed using the following techniques: open circuit voltage, cyclic voltammetry and electrochemical impedance spectroscopy. By measuring the open circuit voltage, it was determined that calcium in the Ca(TFSI)2/ACN electrolyte is subject to corrosion, where the electrode is covered with an inhibiting layer. The inhibiting layer slows down the cathodic deposition of calcium due to the low permeability of calcium ions through it. Cathodic deposition of calcium is visible on cyclic voltammograms in the first cycle of potential change, but the electrode is completely inhibited in subsequent cycles. The anodic dissolution of calcium from the Ca(TFSI)2/ACN solution proceeds unhindered despite the formation of an inhibiting layer. It is possible that the dissolution of calcium breaks down the resulting layer and thus enables further dissolution.

• Keywords: kalcij; acetonitril; ciklička voltametrija; elektrokemijska impedancijska spektroskopija; napon otvorenog kruga
• Keywords (english): calcium; acetonitrile; cyclic voltammetry; electrochemical impedance spectroscopy; open circuit voltage
• Language: croatian
• URN:NBN: urn:nbn:hr:149:681613
• Study programme: Title: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Advanced materials and technologies; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra primijenjene kemije (sveučilišni/a magistar/magistra primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-09-24 12:56:35