Template sacrificial controlled synthesis of hierarchical nanoporous carbon@NiCo2S4 microspheres for high-performance hybrid supercapacitors

Binary transition metal sulfides are hotly investigated in advanced energy storage devices because of their ultra-high reversible capacity. Nevertheless, the unsatisfied rate capability and cycling stability still hinder their practical application. Herein, hierarchical nanoporous carbon@NiCo 2 S 4 (HNCMs@NCS) composites with core–shell flower-like structures were prepared by in situ growing of NiCo 2 S 4 nanosheets on HNCMs through a hydrothermal-assisted template sacrificial method. Benefiting from a synergistic effect between the NiCo 2 S 4 shell with high specific capacity and the HNCMs with unique porous structure, the synthesized flower-like HNCMs@NCS composites exhibit extraordinary electrochemical performances, including a high capacity of 346.9 mAh·g −1 at 1 A·g −1 , superb rate property with 86.4% initial capacity at 30 A·g −1 and predominant cycle stability with 81.2% capacity retention after 5000 cycles. Furthermore, the resulting HNCMs@NCS cathode was coupled with the chemical-activated HNCMs (AHNCMs) anode to construct a hybrid supercapacitor device. The as-fabricated device exhibits superior energy density (49.9 Wh·kg −1 at 802 W·kg −1 ) and ultra-high power density (24 kW·kg −1 at 29.5 Wh·kg −1 ). This fascinating result further demonstrates the tremendous prospect of the synthesized HNCMs@NCS composites as high-performance supercapacitor electrode materials. Graphical Abstract