Electrochemical characterization and influencing factor analysis of the real surface area of lamellar Ni3Si electrode

Abstract

To reflect the real contact state, we characterize the real surface area of lamellar Ni3Si electrodes by the potentiostatic step method, and analyze its influencing factors. The theoretical surface areas of lamellar Ni3Si are calculated through mathematical methods, and reasons for the difference between the real and theoretical surface area are explained. The theoretical surface area of Ni3Si electrode is inversely proportional to lamellar spacing, and proportional to corrosion depth. The increase in lamellar spacing facilitates material exchange, but decreases the lamellae number. Ni3Si electrodes with a lamellar spacing less than 6.4 μm observed a smaller real surface area than theoretical surface area. Variation of real surface area with the corrosion depth reflects the competition between the resident gas and the rough inner surface. When the corrosion depth is 49.6 μm, the real surface area is 3.225 cm2 and is 31% less than its theoretical surface area, which is due to the hindering effect of the resident gas. Whereas, when the corrosion depth is larger than 49.6 μm, the real surface area sharply increases and becomes larger than the theoretical surface area, because the roughness inner-surface of the Ni3Si electrode becomes the dominant factor. The real surface area of lamellar Ni3Si electrode is controllable and can be adjusted by changing the structural parameters. It will undoubtedly play a positive role in the precise control of electrochemical measurements and reactions. Hopefully, this paper can enrich people's cognition of lamellar Ni3Si and provide an exercisable characterization method for porous materials.