Facile preparation of mesoporous NiCo2S4 microaggregates constructed by nanoparticles via puffing NiCo2O4 cubes for high performance asymmetric supercapacitors

Mesoporous NiCo2S4 materials with high specific surface area and suitable mesopores display excellent supercapacitor performance due to rich electroactive sites and short diffusion paths. Here, the mesoporous NiCo2S4 microaggregates composed of nanoparticles are first successfully prepared by a simple anion exchange method to puff NiCo2O4 cubes. The NiCo2S4 microaggregates possess rich mesoporous structure with high surface area of 63.79m(2)g(-1) and suitable pore size distribution centered at 6.1 nm. The NiCo2S4 microaggregates deliver high specific capacity of 249 mAh g(-1) (at 1 A g(-1)) and good rate capability of 56.2% capacity retention from 1 to 20 A g(-1). The fabricated NiCo2S4//AC ACS exhibits a prominent energy density of 47.9Wh kg(-1) at a power density of 783 W kg(-1) and immensely distinguished cycling stability (98.8% retention of the initial capacitance after 4000 cycles). These remarkable performances can corroborate superiority of the mesoporous structure for improving supercapacitor electrode properties. (C) 2019 Elsevier B.V. All rights reserved.