Facile synthesis of NiS hierarchical hollow cubes via Ni formate frameworks for high performance supercapacitors

Uniform NiS hierarchical hollow cubes Were facilely fabricated by an anion exchange reaction of low-cost Ni formate framework precursor ([CH3NH3][Ni(HCOO)(3)]) with S2-. The hierarchical hollow structure formed due to the Kirkendall effect and Ostwald ripening. When evaluated as electrode materials for supercapacitors, NiS hierarchical hollow cubes exhibited high specific capacitance (874.5 F g(-1) at 1 A g(-1)) and good cycling stability (retention of 90.2% after 3000 cycles). Moreover, the as-fabricated asymmetric supercapacitor had an enhanced energy density of 34.9 Wh kg(-1) at a power density of 387.5 W kg(-1). (C) 2017 Elsevier B.V. All rights reserved.