Hierarchical NiMoO4@Co3V2O8 Hybrid Nanorod/Nanosphere Clusters as Advanced Electrodes for High-performance Electrochemical Energy Storage
Herein, a synergistic strategy to construct hierarchical NiMoO4@Co3V2O8 (noted as NMO@CVO) hybrid nanorod/nanosphere clusters is proposed for the first time, and Co3V2O8 nanospheres (noted as CVO) are uniformly immobilized on the surface of the NiMoO4 nanorods (noted as NMO) via a facile two-step hydrothermal method. Due to the surface recombination effect between NMO and CVO, the as-prepared NMO@CVO effectively avoid the aggregation of CVO nanosphere clusters. the unique hybrid architecture can make the utmost of a large interfacial area and abundant active sites for storing charge, which is greatly beneficial for the rapid diffusion of electrolyte ions and fast electron transport. The optimized NMO@CVO-8 composite nanostructure displays a battery-like behavior with maximum specific capacity of 357 C g −1, excellent rate capability (77.8% retention at current density increased by 10 times) and remarkable cycling stability. In addition, an aqueous asymmetric energy storage device is assembled based on the NMO@CVO-8 hybrid nanorod/nanosphere clusters and activated carbon. The device shows an ultrahigh energy density of 48.5 Wh kg -1 at a power density of 839.1 W kg -1, good rate capability (20.9 Wh kg -1 even at 7833.7 W kg -1) as well as excellent cycling stability (83.5% capacitance retention after 5000 cycles). More notably, two charged devices in series can light up a red light emitting diodes (LEDs) for 20 min, demonstrating its potential in future energy storage applications. This work not only indicates that the hierarchical NiMoO4@Co3V2O8-8 hybrid nanorod/nanosphere clusters is a promising energy storage material in future practical applications, but also provides a rational strategy to fabricate novel nanostructure materials for high-performance energy storage.