Synthesis and Electrochemical Properties of NiFe-Se/rGO Nanocomposites

Background: Renewable energies are in great demand because of the shortage of traditional fossil energy and the associated environmental problems. Ni and Se-based materials are recently studied for energy storage and conversion owing to their reasonable conductivities and enriched redox activities as well as abundance. However, their electrochemical performance is still unsatisfactory for practical applications. Objective: To enhance the capacitance storage of Ni-Se materials by modification of their physiochemical properties with Fe. Methods: A two-step method was carried out to prepare FeNi-Se loaded reduced graphene oxide (FeNi-Se/rGO). In the first step, metal salts and graphene oxide (GO) were mixed under the basic condition and autoclaved to obtain hydroxide intermediates. As a second step, selenization process was carried out to acquire FeNi-Se/rGO composites. Results: X-ray diffraction measurements (XRD), nitrogen adsorption at 77K, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were carried out to study the structures, porosities and the morphologies of the composites. Electrochemical measurements revealed that FeNi-Se/rGO notably enhanced capacitance than the NiSe/G composite. This enhanced performance was mainly attributed to the positive synergistic effects of Fe and Ni in the composites, which not only had an influence on the conductivity of the composite but also enhanced redox reactions at different current densities. Conclusion: NiFe-Se/rGO nanocomposites were synthesized in a facile way. The samples were characterized physicochemically and electrochemically. NiFeSe/rGO giving much higher capacitance storage than the NiSe/rGO explained that the nanocomposites could be an electrode material for energy storage device applications.