Core-shell structured Ni3S2 nanorods grown on interconnected Ni-graphene foam for symmetric supercapacitors

We report the synthesis of mesoporous Ni3S2 nanorod arrays on three-dimensional Ni-graphene foams by a facile hydrothermal method for ultrahigh performance supercapacitors. The graphene foam facilitates unique morphological evolution during the hydrothermal process, from a mesoporous, monolithic structure to nanorod arrays of Ni3S2 with a hollow core-solid shell structure and to entirely solid nanorod arrays of Ni3S2. The Ni3S2 composite electrode delivers a remarkable specific capacitance of 1900 F g(-1) at a current density of 1 A g(-1), as well as promising cyclic stability with a high capacitance of 940 F g(-1) after 2000 cycles at 10 A g(-1) and 96% retention of its initial capacitance after the 2001st cycle at 5 A g(-1). The symmetric supercapacitor prepared using the Ni3S2 electrodes under an optimum condition operates in a wide potential window of 0-1.6 V and offers a specific capacitance of 190.5 F g(-1) at 4.5 mA cm(-2) along with a maximum energy density of 67.7Wh kg(-1). The promising electrochemical performance along with the facile synthesis strategy offers a new insight into developing high performance supercapacitors for emerging energy storage applications. (C) 2018 Elsevier Ltd. All rights reserved.