Ultramicroelectrode fabrication guidelines for multifunctional scanning electrochemical microscopy

We report a scalable and versatile protocol for fabricating high-performance metal disk ultramicroelectrodes (UMEs) with precisely controlled geometries for multifunctional scanning electrochemical microscopy (SECM). By integrating a thick-wall nanopipette template with tip forging, our approach achieves precise control over probe morphology, yielding dual-disk electrodes (DDE) with RG values of <1.1 and interelectrode gaps of 5-10 μm. This reproducible method boasts a success rate of >95% across large batches. We demonstrate the practical utility of these probes through simultaneous O₂ and pH monitoring during water oxidation catalysis and in situ mapping of lithium-ion flux during lithium plating. Our findings establish a reliable platform for the production of sensitive, multifunctional SECM probes, significantly advancing the quantitative investigation of complex interfacial chemical processes in electrocatalysis and energy storage.