Scanning Electrochemical Microscopy Meets Optical Microscopy: Probing the Local Paths of Charge Transfer Operando in Booster‐Microparticles for Flow Batteries

• DOI: 10.1002/smll.202309607
• Publication Date: 2024-05-17T07:55:54Z
• Authors: Mahdi Moghaddam; Louis Godeffroy; Jerzy J. Jasielec; Nikolaos Kostopoulos; Jean‐Marc Noël; Jean‐Yves Piquemal; Jean‐François Lem...; Pekka Peljo; Frédéric Kanoufi
• Keywords: Scanning Electrochemical Microscopy; Microparticle; Particle (ecology)

Abstract Understanding the oxidation/reduction dynamics of secondary microparticles formed from agglomerated nanoscale primary particles is crucial for advancing electrochemical energy storage technologies. In this study, behavior individual copper hexacyanoferrate (CuHCF) explored at both global and local scales combining scanning microscopy (SECM), interrogation a single, but global‐scale microparticle, optical monitoring to obtain higher resolution dynamic image electrochemistry within same particle. Chronoamperometric experiments unveil multistep process with varying dynamics. On one hand, SECM analysis enables quantifying charge transfer as well its single microparticle level during cycles by redox mediator in solution. These conditions allow mimicking processes these when they are used solid boosters flow batteries. other imaging sub‐particle allows mapping conversion rates state‐of‐charge CuHCF particles. maps reveal that regions different material loadings exhibit capacities rates. The findings highlight significance porous nanostructures provide valuable insights designing more efficient materials.