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.

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−. 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−1.62