Atto-Ampere Nanoelectrochemistry

We recently introduced a new technique for versatile nano-electrochemical measurements at the atto-Ampere level (3 orders of magnitude below the previous state of the art) based on an up-conversion of the electrochemical current to GHz frequencies.¹For example, this allowed us to image the electrochemical current of non-moving redox molecules at the nanoscale for the first time.<br/>We also showed that the potential of this approach is even more prosperous, since it can be employed for quantitative mapping of the nanoscale impedance spectra as a function electrochemical potential (CV) and frequency (EIS). We developed a closed framework that allows for a rigorous analysis and quantification of the measured complex impedance signal covering a wide frequency domain (DC to GHz) ². A global understanding of the nano-electrochemistry at the nanoscale on these systems is now possible, including the diffusive double layer effects.<br/>Interestingly, we stress that an important feature is that DC and GHz excitations have a different impact on the ions at the solid electrolyte interface (SEI), which provides additional degrees of freedom to understand the nano electrochemical processes. Our work was demonstrated on a model system (ferrocene undecane thiol) that has greatly interested electrochemists and molecular electronics communities ^1,2. Finally we will show exciting new applications on more complex 2-dimensional material systems for energy applications.<br/> <br/>¹ S. Grall et al, Atto-Ampere Nanoelectrochemistry, <i>Small</i> 17, 2101253 (2021) [Cover]<br/>² M. Awadein, et al. 2022, Nanoscale Adv., 2023,5, 659-667