NEIL · Nanoscale Electrochemistry in Ionic Liquids

Nanoscale Electrochemistry in Ionic Liquids

Recent years have seen the emergence of a diverse range of electrochemical technologies (devices) capable of reliably generating (e.g., solar cells), converting (e.g., fuel cells) and storing (e.g., batteries) energy from renewable sources. These devices are comprised of one or more electrochemical cells, which, in their simplest form, are made up of two electronic conductors (electrodes) separated by an ionic conductor (electrolyte). One particularly important class of electrode are “electrocatalysts”, which are materials that promote or “catalyse” a number of technologically important electrochemical reactions (water splitting, fuel oxidation etc.). Electrocatalysts are crucial in the operation of many salient electrochemical technologies, where they lower the energy barriers associated with electrochemical transformation, maximising overall device efficiency. The characteristics of the electrodes (e.g., electrocatalysts) and electrolyte are critically important as they ultimately dictate properties of the electrochemical device, including the lifetime, performance and safety. It follows that in order to “rationally” design new materials that are cheaper, safer and/or more efficient in these applications, one must understand the functional properties of said materials in minute detail. In this project, we present a new tool that makes use of a special probe (known as a “scanning probe”) to measure the functional properties of (electrode) materials, which can be related to microscopic structure in order to guide the development of more effective renewable energy technologies (i.e., devices). In essence, we have developed and implemented a suite of “scanning probe” techniques to measure functional (electrochemical) information with unprecedented spatial-resolution, which, when taken with complementary information on microscopic structure, allowed the features that comprise a “functional” or “active” electrode (i.e., the “active sites”) to be unambiguously revealed. We effectively showed that this novel approach to relating “structure” and “function” (i.e., activity) is generally applicable to any type of electrode material by applying it to study a number of promising electrocatalysts, including metal nanoparticles, molybdenum disulfide and pentlandite. In addition, we adapted the “scanning probe” technology to explore the use of novel electrolytes in these applications, notably ionic liquids, which possess a number of favourable properties including high conductivity and non-flammability.

Data: CORDIS, © European Union