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

•NiS hierarchical hollow cubes have been facilely fabricated by an anion exchange reaction.•Uniform-sized Ni formate frameworks precursor [CH3NH3][Ni(HCOO)3] was easily prepared at room temperature.•NiS hierarchical hollow cubes exhibited high specific capacitance and good cycling stability.

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.

Graphical abstractUniform 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−. 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.Download high-res image (62KB)Download full-size image