Fabrication of radial porous nickel electrodes with dilated pore structure and experimental research on its hydrogen evolution reaction

Under high current density conditions, the hydrogen evolution reaction (HER) performance in alkaline electrolysis is significantly affected by gas bubbles. To mitigate the negative impact of bubbles on electrode performance and improve bubble transport efficiency, radial porous nickel electrodes (RPNEs) are fabricated using a bidirectional freeze-casting method. Compared to aligned porous nickel electrodes (APNEs), the electrodes in this study feature a radially expanded pore structure, which facilitates the removal of gas bubbles, resulting in superior HER performance. Furthermore, by adjusting the freezing temperature and slurry concentration, a series of RPNEs with varying pore dilation angles and thicknesses are prepared, and their HER performance is evaluated. The results indicate that for thicker electrodes, increasing the pore dilation angle significantly improves HER performance. Notably, when the freezing temperature is -10 degrees C and the electrode thickness is 1100 mu m, the RPNE exhibits optimal performance, with an overpotential of only 212 mV at 300 mA/cm2 and a Tafel slope of 83.92mV/dec, while also demonstrating excellent stability.