Vpliv veziv na tiskanje in delovanje litij žveplovih baterij

Perko, Polona (author), Dominko, Robert (mentor), Muck, Deja (comentor)

Namen magistrskega dela je bil izdelati delujoče tiskane litij-žveplove baterije, ki bodo imele za vezivo v katodah uporabljene različne materiale. V teoretičnem delu naloge so predstavljene osnove elektrokemije, lastnosti in delovanje baterij, njihova zgodovina ter osnove delovanja litij-žveplovih baterij. Opisane so tudi osnove o površinski prosti energiji, ki je pri tisku zelo pomembna. V tem poglavju je nekaj besed namenjenih tudi plazmi in obdelavi površin z njo. Predstavljene so osnove reologije, saj ima viskoznost velik vpliv na tiskanje v tehniki sitotiska. Prav tako je v teoretičnem delu predstavljena tehnika sitotiska in pregled dotedanjih raziskav tiskanih baterij. V eksperimentalnem delu je najprej predstavljena izdelava aktivnega materiala za katode v litij-žveplovih baterijah, nato še postopek impregnacije elementarnega žvepla v ogljik. Največji del pa je namenjen raziskavi o vezivih. Predstavljena so veziva karboksimetil celuloza, poliviniliden fluorid in polimerne ionske tekočine. Opisani so tudi postopki priprave suspenzij za tiskanje za vsa tri različna veziva in njihove reološke lastnosti. Predstavljen je tudi postopek uporabe atmosferske plazme za zviševanje površinske proste energije tokovnega nosilca. Opisan je postopek tiskanja in kasnejša izdelava litij-žveplovih baterij. V poglavju Rezultati in razprava so predstavljeni rezultati obdelave površine aluminijeve folije z atmosfersko plazmo, s katero je zvišana površinska prosta energija. Predstavljeni so rezultati tiskanja, SEM posnetki površin in prečnih prerezov, s katerimi so prikazane tudi debeline nanosov in kvaliteta adhezije nanosa na tiskovni material. Sledijo še rezultati reoloških meritev suspenzij za katode in elektrokemijski rezultati, predstavljeni z grafi, ki kažejo delovanje baterij ter krivulje polnjenja in praznjenja.

• Language: Slovenian
• Keywords: litij-žveplova baterija, sitotisk, katoda, plazma, viskoznost
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2017
• PID: 20.500.12556/RUL-92764
• Publication date in RUL: 03.07.2017

Secondary language

• Language: English
• Title: Impact of binders on printing and performance of lithium sulfur batteries

Abstract

Purpose of master thesis is to make functioning printed lithium-sulfur batteries in which we will use three different binders. In the theoretical part of the master's thesis basics of electrochemistry, principle of battery functioning, their history and basics about lithium-sulfur batteries are explained. Some basics of surface free energy are also described. In this section atmospheric plasma is presented as tool for treating surface free energy of substrate – aluminum foil. Theoretical part also presents rheology which is important in screen printing. Screen printing technique is explained as well. The last theoretical part is review of research on printed batteries. Focus of the experimental part is on different binders (carboxymethylcellulose, polyvinylidene fluoride and polymer ionic liquids). The aim was to prepare effective mixtures of cathode materials for lithium-sulfur batteries with those binders. We also present preparation of impregnated sulfur into carbon black as active material for cathodes. Preparation of suspensions and their rheology properties are presented too. Particular importance for the cathode material is contact between active material and aluminum foil since it provides pathway for electrons and therefore influence electrochemistry of the battery. Improved contacts between cathode particles and aluminum foil were achieved by increasing of surface free energy of the aluminum foil with atmospheric plasma. Process of printing cathodes is also presented. As the last part we present procedure of preparation of “coffee bag” batteries. In result section we present our results of increasing surface free energy of current collector with atmospheric plasma. We show the results of printing with SEM photos of surface and cross-sections of printed suspensions. With those photos we can define thickens and adhesion of printed layer. We also present results of rheological measurements of suspensions and in the end there are electrochemical results of batteries performance.

• Keywords: lithium-sulfur battery, screen printing, cathode, plasma, viscosity