[C2mpyr][FSI]/PEDOT-Cl composites as dual ionic and electronic conductors

Abstract

[EN]Nowadays, it is quite common to see a wide range of investigations related to the development of technological devices that make use of clean energy, with the sole objective of decreasing unhealthy pollution emissions. Some of the most promising ones are related to rechargeable batteries, especially lithium ion batteries (LIBs), due to their high energy storage and cyclability. The electrodes of these kind of batteries still are design based on inorganic materials, such as carbon and polyvinylidene fluoride (PVDF), which in a future can finite and are not very environmental friendly. That is why there is an increased demand for a new kind of materials for electrodes, for example, polymeric materials that can conduct electrons and ions at the same time are a perfect option. These kind of materials improve the capacity of LIBs, making out the best of them. However, this is an area that still has a lot of research to be made, in order to be able to understand well the functionality of these kind of materials when using in organic electrodes.

The aim of this work is to investigate if the mixture of an organic ionic plastic crystal (OIPC) and a conducting polymer results in a composite that can be used as an organic battery electrode. The objective is to do the characterization of the created composites, which helps to understand their properties. For that, first of all, synthesizes of [C2mpyr][FSI] and PEDOT-Cl were done. Afterwards, composites of different weight ratios were prepared mixing both the mentioned materials. Finally, the characterization of the composites was carried out, using techniques like Fourier-transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and 4 point probe. The results of all these analyses demonstrate how the properties of the composites change varying the composition, as well as showing if the obtained results are good enough to be used as electrode materials. The results indicate that the mixture of [C2mpyr][FSI] and PEDOT-Cl is a good approach to obtain dual ionic and electronic conducting materials. However, there is a lot of research to be made yet, in order to be able to study and observe the applications of these new materials in battery electrodes.

[EU]Gaur egun energia garbian oinarritzen diren gailu teknologikoen garapenean dihardute ikerketa talde asko, osasunerako kaltegarriak diren kutsadura emisioak jaisteko helburuarekin, hain zuzen ere. Berriz kargatzeko pilek interes handia piztu dute, zehazki litiozko bateriek (LIBs), beraien energia biltegiratzeko eta zikloak osatzeko kapazitate handiarengatik, beste gauza batzuen artean. Oraindik ere, bateria mota hauen elektrodoak material inorganikoetan oinarritzen dira, esaterako, karbonoan eta polibinilideno fluoruroan (PVDF), baina material hauek etorkizun batean amaitzeko aukerak asko dira, eta hori gutxi balitz, ingurumenarekiko kutsatzaileak dira. Hau guztia dela eta, elektrodoetarako material berriak sortzeko behar handia dago. Esaterako, material berdinean elektroiak eta ioiak garraiatzeko gaitasuna duten polimeroak aukera paregabeak dira aipatutako arazoari aurre egiteko. Material hauek litiozko baterien gaitasuna hobetzen dute, beraien alderdi hoberenak eskura ateraz. Hala eta guztiz ere, oraindik gai honen inguruko ikerketa asko egiteko daude, material mota hauek elektrodo organikoetan nola funtzionatzen duten ulertzeko, besteak beste.

Lan honen helburu nagusia, kristal plastiko organiko ioniko (OIPC) baten eta polimero eroale baten arteko nahasketen inguruan ikertzea da, konposatu mota hauek baterietan elektrodo organiko bezala erabili ote daitezkeen ikusteko asmoz. Helburua sortutako konposatuen karakterizazioa egitea izango da, elektrolito hauen propietateak nolakoak diren ulertzen laguntzeko. Horretarako, lehendabizi, [C2mpyr][FSI] eta PEDOT-Cl-ren sintesiak egin dira. Horren ostean, aipatutako bi materialak nahastuz pisu proportzio desberdineko konposatuak prestatu dira. Azkenik, konposatuen karakterizazioa burutu da, horretarako teknika desberdinak erabiliz: espektroskopia infragorriaren Fourier transformazioa (FTIR), analisi termo grabimetrikoa (TGA), ekortze kalorimetria diferentziala (DSC), ekortze mikroskopia elektronikoa (SEM), inpedantziaren espektroskopia elektrokimikoa (EIS), boltametria ziklikoa eta 4 puntazko proba. Analisi guzti hauen emaitzek konposizioak aldatuz konposatuen propietateak nola aldatzen diren frogatu dute; bai eta, ea lortutako emaitzak elektrodoetan material bezala erabiltzeko onak diren ikusten lagundu ere. Emaitzek erakutsi dutenez, [C2mpyr][FSI]-ren eta PEDOT-Cl-ren arteko nahasketa egitea material eroale ioniko eta elektronikoak lortzeko hurbilketa ona da. Hala eta guztiz ere, ikerketa gehiagoren beharra dago oraindik, material berri hauek baterien elektrodoetan duten aplikazioak ikertzeko eta emaitzak ziurtatzeko.