Hierarchically Designed Ag@Ce₆Mo₁₀O₃₉ Marigold Flower-Like Architectures: An Efficient Electrode Material for Hybrid Supercapacitors

We facilely prepared silver nanoparticle-decorated Ce₆Mo₁₀O₃₉ marigold flower-like structures (Ag NPs@CM MFs) for use as an effective positive material in hybrid supercapacitors (HSCs). With the aid of ethylenediaminetetraacetic acid (EDTA) as a chelating agent, self-assembled CM MFs were synthesized by a single-step hydrothermal method. When the electrochemical properties were tested in an aqueous alkaline electrolyte, the synthesized CM MFs with 0.15 g of EDTA exhibited a relatively high charge storage property (55.3 μA h/cm² at 2 mA/cm²) with a battery-type redox behavior. The high capacity performance is mainly because of the large surface area of the CM MFs, and the hierarchically connected nanoflakes provide wide open wells for rapid accessibility of electrolyte ions and enable fast transportation of electrons. A further improvement in electrochemical performance was achieved (62 μA h/cm² at 2 mA/cm²) by decorating Ag NPs on the surface of the CM MFs (i.e., Ag NPs@CM MFs), which is attributed to the increased electric conductivity. Considering the synergistic effect and the high electrochemical activity, Ag NPs@CM MFs were further employed as an effective positive electrode for the fabrication of pouch-type HSC with porous carbon (negative electrode) in an alkaline electrolyte. The HSC exhibited a high cell potential (1.5 V) with maximum energy and power densities of 0.0183 mW h/cm² and 10.237 mW/cm², respectively. The potency of HSC in practical applications was also demonstrated by energizing red and yellow light-emitting diodes as well as a three-point pattern torch light.