Interface-mediated fast ionic conductivity in nanocomposite solid-state electrolytes

Description du projet

Les bases de l’avenir des électrolytes à l’état solide

Les batteries modernes, les piles à combustible et d’autres dispositifs électrochimiques s’appuient fortement sur la conduction des ions dans les électrolytes solides (SSE pour «solid-state electrolytes»), mais sont depuis longtemps limités par leur faible conductivité intrinsèque. Cette situation suscite l’intérêt des chercheurs qui entendent relever le défi de parvenir à une meilleure conductivité des SSE. Bien que les travaux réalisés aient montré que les non-conducteurs peuvent considérablement influencer la conductivité des SSE, les efforts déployés pour l’améliorer sont restés vains jusqu’à présent. Le projet Interfacial Ionics, financé par le CER, vise à étudier et à comprendre les mécanismes fondamentaux à l’origine de la conductivité ionique de l’interface, ce qui permettra de développer des SSE sur mesure à l’aide de mélanges d’oxydes. Le projet analysera des SSE nanocomposites modèles avec des oxydes et recourra à différentes techniques de sondage pour analyser la composition des interfaces et d’autres facteurs clés.

Objectif

Ion conduction in solid-state electrolytes (SSEs) is the bedrock of several electrochemical devices like batteries and fuel cells which are vital to our modern society. High conductivity is crucial for such applications, and increasing the intrinsically low conductivity of SSEs has been of enormous technological interest. The discovery that the conductivity of SSEs can increase or decrease by orders of magnitude at their interface with a non-conductor (e.g. oxides) has led to much interest in the use of interface engineering to rationally design SSEs with improved conductivity and overall performance in electrochemical devices. This has so far not been successful because the underlying mechanisms that lead to the profound changes in conductivity at interfaces are not yet well understood due to the complex composition of such interfaces, and the fact that several properties of the two components concomitantly influence this effect.

Building on my preliminary results, I aim to unravel the fundamental mechanisms of interface ion conductivity by preparing model nanocomposite SSEs (SSE + oxides) that will allow me to disentangle the different parameters that contribute to this effect. The interface physics/chemistry responsible for interface ion transport will be precisely tuned via surface and compositional modification of the oxides. I will combine advanced surface-sensitive probe techniques, including XPS, X-ray Raman Scattering, HR-TEM/EDX, and NMR to study the interface compositions. This will enable me to establish for the first time how the properties of SSE-oxide mixtures influence their interface reactions, conductivity, and performance in applications. Such fundamental insights will enable the design of novel SSEs with tailor-made properties for a variety of electrochemical applications. My extensive expertise and track record in nanocomposite materials, SSEs, and advanced materials characterization, place me in the perfect position to lead this project.