Electrochemical hydrogen storage in EPD made porous Ni-CNT electrode

•The hydrogen storage capacity of purified CNTs and Ni-CNTs, is investigated.•Several factors such as current magnitude and annealing effect are studied.•Ni-CNTs have a maximum discharge capacity compared to other electrodes.•Annealing operation leads to more strength of CNTs on the surface.

The hydrogen storage capacity of multi-wall carbon nanotubes (MWCNTs), purified and doped with nano-Nickel particles, is investigated using chronopotentiometry. Several factors such as current magnitude, effect of the number of charge and discharge cycles as well as annealing effect are studied. The X-ray Diffraction (XRD) results indicate that pickling method removes most of the catalysts. Carbon nanotubes (CNTs) are put on nickel foam of nano scale porosities by Electrophoretic deposition (EPD) method. Scanning Electron Microscopy (SEM) technique shows the surface of nickel foam plate. Deposition of nickel particles on CNTs is conducted by electroplating. In order to measure the hydrogen storage capacity, electrodes of CNT and Ni-CNT are used as working electrodes in the three-electrode system. Different results of charge and discharge for various currents in different electrodes show that Ni-CNTs have a maximum discharge capacity (3520 mAh/gr) compared to other electrodes in the optimum current of 2 mA. By increasing the number of cycles in constant current, the capacity is increased to reach a constant amount. Annealing operation leads to more strength of CNTs on the surface.