Inorganic ionic conductors for electrochemical devices

Bioelectricity is the electrical phenomenon of living processes, underlining the essential role of ionic transport in the functioning of our organism. Concerted membrane ionic effects thus help explain the electric eel's ability to send strong electric discharges. Apart from this, ionic conductors are also the common denominator of all electrochemical systems ; they ensure the transport of ions from the positive to the negative electrode while blocking the passage of electrons. They can be liquid, polymeric or even   . Ceramics conductive by _O2-^{, H+}, ^Li+ or even ^Na+ ions are currently being extensively studied to enhance fuel cell performance and even facilitate the development of " all-solid " batteries. The latter, with their safety benefits, have attracted a great deal of interest from industry. In this context, it is important to understand the fundamental aspects of ionic conduction in order to design and develop new ionic ceramics. This lecture has responded to this need by i) describing the panorama of research in this field and ii) highlighting recent advances, notably the discovery of the _Li7Ge12S24 phase, which has a conductivity at room temperature close to, or even greater than, that of a liquid electrolyte. As a result, Toyota has made the development of " all-solid " batteries its next hobbyhorse.