Projet de thèse en 2MGE : Matériaux, Mécanique, Génie civil, Electrochimie
Sous la direction de Manuel Marechal.
Thèses en préparation à Grenoble Alpes , dans le cadre de École doctorale Ingénierie - matériaux mécanique énergétique environnement procédés production (Grenoble) , en partenariat avec Systèmes Moléculaires et Nano Matériaux pour l'Énergie et la Santé (laboratoire) depuis le 01-10-2018 .
Solid Polymer Electrolytes (SPEs) with high ionic conductivity and appropriate mechanical properties are envisioned as alternatives to liquid electrolytes for a safer generation of high performance electrochemical energy storage devices. Towards this goal, intensive research efforts onto new generations of SPEs have flourished worldwide since the first suggestion in the late 70s by Dr. M. Armand and co-workers. Yet, simultaneously achieving a full control of mechanical properties towards the desired level together with fast ionic transport still remains to date a red-brick wall; preventing the advent of a competitive SPE-based solution for electrochemical energy devices. Within the different material strategies developed to date, such as PEO-based homo and block copolymer anionic or cationic salts, single-ion polymer electrolytes (SIPEs) and polymeric ionic liquids (PILs) to name a few, SIPEs hold promises owing to their tunable by design material aspect (allowing the encoding of specific morphologies and physicochemical properties inherited from their precisely defined macromolecular architectures) coupled with its single ion (e.g. lithium for secondary lithium-ion battery or hydronium for fuel cell) transport capability. Using a series of single-ion precise copolymer electrolytes (SIPRECE) within which ionic functions will be precisely positioned onto a polymeric backbone ensuring the appropriate properties of ion conduction and multiscale organization, we will perform in depth structure/property correlation studies to evaluate the performances of this new type of SPEs. Multi-scale variable-temperature and relative humidity (when appropriate) WAXS/SAXS characterizations will be performed to determine the hierarchical self-organization of SIPRECE model systems across nanomesomicroscopic length scales. In-plane and through-plane ionic conductivity studies will be also conducted on a customized platform combining Electrochemical Impedance Spectroscopy (EIS), Polarized Optical Microscopy (POM), without or with electric field alignment, with the goal to assess the presence or absence of grain boundaries onto the measured ionic conductivity levels of non vs. fully-aligned SIPRECE model systems.
Self-Organized Single-ion precise electrolytes towards efficient directional ionic transmport
Precisely Functionalized Polymer ElectrolytesPFPEs, (all covalent vs supramolecular polyethylenes (PE)-based or supramolecular PFPEs) are new classes of materials displaying protic or ionic transport, which offer great promise for applications in low-cost, future energy-device applications. We aim to perform in situ studied polymer thin films with (w) and without (w/o) the application of an ac-electric field when confined into the micrometer gap (ca. 5-10 m) defined by electrodes. This ac-field is a means to overcome the disorder present in melt-processed films, through alignment of the polymer chains. While it is well-established that multiscale (dis)order dramatically impacts the efficiency of proton/ion transport through and across state of the art (e.g. Nafion® & PEO/Li salts[4-6]) conducting membranes, a clear structure/property correlation within the advanced and recently synthesized single-ion precisely functionalized polymers remains elusive till date.