Uniformly Dispersed ZnFe₂O₄ Nanoparticles on Nitrogen-Modified Graphene for High-Performance Supercapacitor as...

A facile strategy has been adopted for the preparation of ZnFe₂O₄/NRG composite by anchoring ultrasmall ZnFe₂O₄ nanoparticles on nitrogen-doped reduced graphene (denoted as NRG) for high-performance supercapacitor electrode. Remarkably, the growth of ZnFe₂O₄ nanocrystals, the reduction of graphitic oxide and the doping of nitrogen to graphene have been simultaneously achieved in one process. It is found that the NRG employed as substrate can not only control the formation of nano-sized ZnFe₂O₄, but also guarantee the high dispersion without any agglomeration. Benefiting from this novel combination and construction, the hybrid material has large surface area which can provide high exposure of active sites for easy access of electrolyte and fast electron transport. When served as supercapacitor electrode, the ZnFe₂O₄/NRG composite exhibits a favorable specific capacitance of 244 F/g at 0.5 A/g within the potential range from -1 to 0 V, desirable rate stability (retain 131.5 F/g at 10 A/g) and an admirable cycling durability of 83.8% at a scan rate of 100 mV/s after 5000 cycles. When employed as symmetric supercapacitor, the device demonstrates favorable performance. These satisfactory properties of the ZnFe₂O₄/NRG composite can make it be of great promise in the supercapacitor application.