Characterization of Raney Nickel electrodes for alkaline water electrolysis at high current densities

In this work Raney Nickel electrodes produced by electrodeposition in a Watt's bath were compared to plasma-sprayed electrodes and bare nickel electrodes. Scanning electron microscopy (SEM) images of the electrodeposited material show a rough structure, resembling a “pebble beach” with electrochemical active surface area (ECSA) of around 1000 cm 2 /cm 2 . The Raney Nickel electrodes show a high activity in hydrogen evolution and a direct correlation between the activity and the ECSA was found. Yet, the activity increase in the oxygen evolution reaction (OER) is much less pronounced with no clear relation with ECSA. The materials also show good catalytic performance at elevated temperatures and current densities up to 9 A cm −2 . However, longer term tests show a clear loss of activity, which is also apparent from SEM images that show loss of electrode material from the substrate. • Electrodeposited Raney Nickel has a rough surface with visible pores. • Raney Nickel showed strong activity improvement in the HER compared to bare nickel. • Raney Nickel exhibited minimal improvement in the OER reaction compared to bare Ni. • Raney Nickel maintained good activity at current densities up to 9 A at 75 °C. • Long-term testing revealed material loss over time.