Facile synthesis of a novel Fe3O4-rGO-MoO3 ternary nano-composite for high-performance hybrid energy storage applications.

Supercapacitors (SCs) have been considered as inspiring energy storage devices due to the long cycle lifetime and high power densities. However, their energy density is limited due to the low capacitance of cathode materials and inferior cycling stability at practically useable potential windows >1.2 V. In this paper, we demonstrate the synthesis of a novel ternary Fe 3 O 4 -rGO-MoO 3 nano-composite (FGM) with nanoparticles-like morphology (NPs) by utilizing the fast and facile microwave hydrothermal process. The optimized composition of FGM nanocomposite is characterized by the XPS, EDS, Raman, SEM, TEM and HRTEM techniques. The FGM-NPs supported on the carbon cloth (FGM@CC) electrode is used to investigate the electrochemical charge storage properties in basic potassium hydroxide (KOH) electrolyte. The charge-storage properties of the FGM@CC electrode were studied by the CV, GCD and EIS techniques. The obtained results of FGM@CC electrode in aqueous electrolyte showed excellent electrochemical performance as compared with single metal oxides: maximum specific capacitance of 1666.50 F g−1 (FGM@CC), 1075.26 F g−1 (Fe 3 O 4 NPs) and 952.38 F g−1 (MoO 3 NPs) at a current density of 2.5 A g−1. The capacitance retention was 95.01% (FGM@CC), 94.1% (Fe 3 O 4 NPs) and 92.5% (MoO 3 NPs) after 5000 cycles. Further, the charge storage mechanism is analyzed in the light of power's law and systematical investigated the capacitive and diffusion controlled based stored charge in FGM@CC electrode. Thus FGM nano-composite showed best performance as the cathode material for the next generation flexible supercapacitors. The FGM@CC electrode showed excellent electrochemical performance with as high as C sp of 1666.50 F g−1 at 2.5 A g−1. The FGM@CC electrode possesses 55% of stored energy from surface capacitive storage process and 45% from diffusion controlled process. Image 1 • A ternary Fe3O4-rGO-MoO3 nano-composite is synthesized through a facile microwave strategy. • FGM supported on carbon cloth electrode (FGM@CC) exhibits exceptional high charge storage performance. • FGM@CC electrode reached at high potential window of 1.2 V in aqueous electrolyte. • FGM@CC electrode shows excellent cycling stability >95%. [ABSTRACT FROM AUTHOR]