Evaluation of electrochemical hydrogen storage capability of graphene oxide multi-layer coating

Abstract

Due to its unique physical and chemical properties, graphene oxide (GO) has excellent potential in energy-saving applications, especially in hydrogen storage materials such as bulk and layer coatings. A three-layer GO/Ni/GO coating was applied successfully on the Ni-foam through the hybrid coating process. GO was firstly synthesized by modified Hummers' method and then deposited on Ni-Foam using an electrophoretic deposition (EPD) method at 40, 60, and 80 V at various times (1 and 2 h). Furthermore, Ni-layer was applied on the first applied to GO layer using a Ni-electroplating bath at 3 V for 3 min. For evaluation of the electrochemical hydrogen storage performance, cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) were carried out in 1 M NaOH solution at room temperature. Obtained results showed a significant improvement in the amount of adsorbed hydrogen. The hydrogen storage capacity was increased from 88 to 741 F. g−1, and load transfer resistance decreased from 260 to 35 Ω for uncoated and coated porous substrates, respectively, which is due to the achieved high specific area. Based on the hydrogen storage capacity, the optimum EPD method is 60 V and 2 h.