Mobile ions are in the core of some of the most important technologies that will revolutionize our society in the next decades, particularly in the field of energy and communications. As a matter of example, fuel cells and electrolyzers, batteries or neuromorphic transistors are often based on ion migration and related redox reactions. Nevertheless, despite its major importance, a proper understanding of the ion movement, especially at the interface and nanoscale levels, is still missing. Developing new tools to direct visualize ion diffusion at this scale is a major challenge for new disciplines such as Nanoionics or Iontronics to take off.
We recently developed a disruptive methodology for direct observation of ion diffusion with subnanometric resolution. This new approach combines advanced nanoscopic analysis using Atom Probe Tomography with conventional ion tracing by isotope exchange. This novel tool allowed us imaging and quantifying the diffusion of mobile ions while correlating them with other chemical species. Both papers in Advanced Materials and Nature Communications were released this year for presenting the methodology by applying it to enhanced interfaces of mixed ionic-electronic conductors with application in a collection of devices in the field of energy and information technologies.