Synthesis and Characterization of Graphene/Binary Metal Molybdate (Graphene/Zn1−xNixMoO4) Nanocomposite for Supercapacitors

Abstract

A novel graphene/binary metal molybdate (Zn1‐xNixMoO4) is synthesized via a facile and simple microwave synthesis route (x = 0.0, 0.2, 0.4, 0.6, 0.8). Electrochemical studies are performed for all the samples to study their charge storage mechanism and frequency dependence in a three‐electrode set up with 2m KOH electrolyte solution. Among the samples, Zn0.6Ni0.4MoO4 shows better electrochemical performance which is combined with graphene so as to obtain graphene/Zn1‐xNixMoO4 (x = 0.4) nanocomposite. XRD and Raman analyses have confirmed formation of complexation of graphene/binary metal molybdate nanocomposite. TEM morphological profile illustrates little aggregation and interconnected layers of graphene interspersed with rice‐like grains of binary metal molybdate. Graphene/Zn1‐xNixMoO4 (x = 0.4) exhibits good energy density and power density of 62.3 Wh kg−1 and 448.5 W kg−1 respectively with a specific capacitance of 555.5 F g−1 at 1 A g−1. The electrode material with good cyclic stability of 85% even after 5000 charge/discharge cycles may be explored as a novel option for supercapacitors.