Nanopipette Reference Electrodes with Facile Fabrication and Enhanced Stability

Reference electrodes are essential for meaningful electrochemical measurements but face significant challenges in miniaturization and long-term stable potential. Conventional commercial reference electrodes, which rely on ion migration across porous frits, suffer from electrolyte leakage, potential drift, and limited scalability to micro dimensions. Quasi-reference electrodes lack a thermodynamically defined interface, exhibiting polarization-sensitive potentials that drift with experimental conditions, compromising their reliability for rigorous quantitative analysis. Therefore, a miniaturized reference electrode capable of stable potential output is critical for techniques like scanning electrochemical cell microscopy (SECCM), where accuracy and spatial resolution depend on electrode robustness. Herein, we report a facile and reproducible strategy to fabricate a nanopipette reference electrode (NPRE) leveraging nanoscale ion transport. This architecture replaces conventional glass bodies and fritted junctions with a monolithic pulled capillary structure, integrating a nanoscale terminal pore that inherently minimizes electrolyte leakage. The NPRE demonstrates excellent potential stability (>24 h) in both aqueous and organic media, underscoring its robustness across distinct chemical environments. Successful integration of NPRE with SECCM enables precise nanoscale electrochemical measurements, effectively overcoming the inherent limitations of conventional systems and providing an ideal platform for high-resolution studies in complex physiological or materials environments.