Electrode Performance of Newly Developed Ni-W-S Deposited Alloy for Alkaline Water Electrolysis

Abstract

Ni-W-S coatings were fabricated by electroplating. The bath denoted as “Ni-W-S No.1” was derived from a neutral pH bath for Ni-W alloy plating. Furthermore, sulfosalicylic acid was added as a stress reducer in order to prevent surface cracks. In the solution denoted as “Ni-W-S No.2” contains sodium tungstate, as a source of tungsten, sodium citrate. Plating solution denoted as “Ni-S” is same bath with Ni-W-S No.2 without sodium tungstate. Ni-W-S electrodes showed significantly excellent characteristics as a cathode for alkaline water electrolysis. Specifically, the Ni-W-S electrode in which sulfosalicylic acid was added as a stress reducer exhibited an excellent performance comparing to conventional Ni-S and Ni cathode. In order to obtain the performances of thus obtained electrode for alkaline water electrolysis, an electrode surface morphology was observed by SEM and the film composition was evaluated by EDX. In order to specify the crystal structure, XRD was employed. Furthermore, in order to evaluate the durability performance as a cathode for water electrolysis, sequential changes in electrode performance was investigated periodically using LSV while performing long-term electrolysis test for 48 hours. Furthermore the prevention of sulfur dissolution during cathodic polarization was monitored.