Template-free and large-scale synthesis of hierarchical dandelion-like NiCo2O4 microspheres for high-performance supercapacitors

Abstract In this work, dandelion-like NiCo 2 O 4 mesoporous microspheres were uniformly assembled from slim nanowires via a large-scale and template-free method. The Brunauer–Emmett–Teller (BET) surface area of NiCo 2 O 4 microspheres was determined to be about 35.2 m 2 g −1 with dominant pore diameter of 10.9 nm and narrow size distribution of 8–20 nm. Furthermore, the electrochemical properties of NiCo 2 O 4 microspheres were evaluated by cycle voltammetric (CV) and galvanostatic charge–discharge (GCD) measurements. The results demonstrated that the NiCo 2 O 4 microspheres exhibited high specific capacitance (372 F g −1 at 1 A g −1 ), good rate capability, and excellent cycling stability (88.3% retention after 2000 cycles). In principle, this synthetic approach could be extended for the fabrication of other microstructure materials for promising electrode candidates in energy storage devices.