Co-ZIF derived porous NiCo-LDH nanosheets/N doped carbon foam for high-performance supercapacitor

Abstract

The three-dimensional (3D) interconnected structure is desirable for high-performance supercapacitor since it can provide more exposed electroactive sites as well as accelerate the electron and ion transfer. Herein, nitrogen doped carbon foams with good hydrophilicity and mechanical property are first prepared from cheap melamine foams via the heat-treatment at low temperature in the air, which can serve as an ideal substrate for growing nickel cobalt layered double hydroxide nanosheets (NiCo-LDH) derived from cobalt zeolitic imidazole frameworks (Co-ZIF). The as-prepared NiCo-LDH/N doped carbon foam (NiCo-LDH/NCF) exhibits high specific capacity of 756 C g−1 at a current density of 0.5 A g−1, and still retains the specific capacity of 414 C g−1 at a current density of 20 A g−1, indicating the excellent rate capability. Furthermore, the assembled NiCo-LDH@NCF//activated carbon asymmetrical supercapacitor device achieves a high energy density of 41.5 Wh kg−1 at a power density of 750 W kg−1, and an excellent cyclic stability of 80.4% retention over 10000 cycles. The remarkable capacitive performance of NiCo-LDH@NCF is assigned to the self-supporting 3D interconnected architecture of NCF that makes the uniform distribution of NiCo-LDH nanosheets and also provides the rapid channels for electron and ion transfer. The results indicate that NiCo-LDH@NCF will be a promising candidate for high-performance supercapacitors.