Scanning Electrochemical Microscopy Meets Optical Microscopy: Probing the Local Paths of Charge Transfer Operando in Booster-Microparticles for Flow Batteries
Jerzy J. Jasielec
University of Turku (Finland) and AGH-UST (Krakow, Poland)
The behaviour of individual Solid Booster (SB) microparticles is explored at both global and local scales combining scanning electrochemical microscopy (SECM) combined with finite element method (FEM) modelling, for electrochemical interrogation of a microparticle, and optical microscopy monitoring to obtain a higher resolution dynamic image of the local electrochemistry within this particle. Computer-aided SECM analysis enables quantifying the charge transfer as well as its dynamics during the oxidation/reduction cycles by a redox mediator in solution. These conditions allow mimicking the charge storage processes in these particles when they are used as SB in redox flow batteries. At the same time, optical imaging with sub-particle resolution allows the mapping of local conversion rates and state-of-charge within individual CuHCF particles. The presented method can facilitate the screening for the new SB materials and the characterisation of the potential candidates.