Hierarchical NiCo2S4 Nanotube@NiCo2S4 Nanosheet Arrays on Ni Foam for High-Performance Supercapacitors

Hierarchical NiCo2S4 nanotube@NiCo2S4 nanosheet arrays on Ni foam have been successfully synthesized. Owing to the unique hierarchical structure, enhanced capacitive performance can be attained. A specific capacitance up to 4.38Fcm(-2) is attained at 5mAcm(-2), which is much higher than the specific capacitance values of NiCo2O4 nanosheet arrays, NiCo2S4 nanosheet arrays and NiCo2S4 nanotube arrays on Ni foam. The hierarchical NiCo2S4 nanostructure shows superior cycling stability; after 5000cycles, the specific capacitance still maintains 3.5Fcm(-2). In addition, through the morphology and crystal structure measurement after cycling stability test, it is found that the NiCo2S4 electroactive materials are gradually corroded; however, the NiCo2S4 phase can still be well-maintained. Our results show that hierarchical NiCo2S4 nanostructures are suitable electroactive materials for high performance supercapacitors.