A method for forming an Ag/AgCl coated electrode includes providing a polymeric electrode substrate made of Acrylonitrile Butadiene Styrene (ABS). A layer of silver (Ag) is deposited on the polymeric electrode substrate using physical vapor deposition (PVD) to form an Ag coated electrode. The layer of Ag is deposited to a first thickness by sputtering an Ag target onto the polymeric electrode substrate. The Ag coated electrode is then converted to a layer of silver/silver chloride (Ag/AgCl) by dipping it into a conversion solution. The resulting Ag/AgCl coated surface electrode provides improved performance and stability for various applications.