Silver–Silver Chloride Reference Electrode: Construction and Performance in Nitrogen-Containing Organic Solvent

Reference electrodes (REs) are essential for electrochemical studies ranging from fundamental measurements to electrosynthesis. Among them, the silver/silver chloride (Ag(s)/AgCl(s)) electrode is widely used due to its simple fabrication and excellent stability in aqueous systems. However, its construction, long-term performance, and shelf life in nitrogen-containing organic solvents, such as dimethylformamide (DMF), have only been sporadically reported and lack systematic analytical characterization, limiting broader practical adoption. Herein, we report a low-cost (∼$5 per electrode), easy-to-fabricate, and stable Ag(s)/AgCl(s) RE for electrochemical measurements in nitrogen-containing organic solvents and provide a systematic evaluation of its performance under relevant electrochemical operating conditions. Specifically, the electrochemical stability of the Ag(s)/AgCl(s) RE in DMF was methodically evaluated as a function of chloride concentration and source, AgCl growth method and duration, and the AgCl-to-Cl- ratio. Under optimized conditions, the RE operates without uncomplexed chloride (Ag(s)/AgCl(s)/AgCl2–(org), AgCl(org)) and exhibits excellent stability in several nitrogen-containing solvents, including DMF, dimethylacetamide (DMA), aniline (AN), and acetonitrile (ACN). The electrode also exhibited minimal potential oscillation (±0.6 mV) over 24 h of uninterrupted cyclic voltammetry (CV), a potential drift of 4 mV during state-of-charge measurements after passing 69 C of charge during ferrocene electrolysis and maintained stable performance over a 21 day shelf life.