Scanning Electrochemical Cell Microscopy (SECCM) with Hydrogel Probes: A Theoretical and Experimental Investigation

Scanning Electrochemical Cell Microscopy (SECCM) has emerged as a powerful tool in electrochemical research due to its ability to measure morphology and electrochemical information simultaneously at the nano- or microscale. However, traditional SECCM using liquid probes suffers from issues, such as evaporation, solution residue, and droplet deformation. This study introduced a hydrogel-based SECCM probe and comprehensively explored its superiority over liquid probes through both theoretical and experimental approaches. Finite element simulations demonstrated that hydrogel probes significantly reduce the contact area with samples and minimize the retraction distance. These effects are attributed to the restriction of the solution flow by the hydrogel's 3D network structures. SECCM experimental results further confirmed the superior stability and efficiency of the hydrogel probes in imaging applications. In addition, the hydrogel probe was successfully applied to characterize Au/ITO interfaces, enabling the concurrent acquisition of localized morphological and electrochemical information, thereby demonstrating its feasibility for standard SECCM measurements. These findings provide a valuable reference for the emerging field of hydrogel probes in SECCM research and development.