Facile preparation of NiO nanoparticles anchored on N/P-codoped 3D carbon nanofibers network for high-performance asymmetric supercapacitors

Highlights: • The facile method for "in-situ" preparation of CNF/NiO composites is proposed. • CNF/NiO possesses 3D hierarchical porous network structure for supplying rapid, efficient channels for ion diffusion. • NiO nanoparticles uniformly anchored on CNF network supply stable capacitance. • CNF/NiO applied to supercapacitors shows high cyclic stability and a maximum energy density of 30.2 Wh kg⁻¹. -- Abstract: The 3D porous carbon materials/transition metal oxide composite is considered to be a potential candidate for supercapacitors owing to the synergy effect of excellent pore structure, electrical conductivity and high pseudocapacitance. However, its complicated preparation and uncontrollable stability are still challenges. In this paper, we propose a facile method for "in-situ" preparing a novel kind of the NiO nanoparticles anchored on N/P-codoped carbon nanofibers network (CNF/NiO) composite. The CNF/NiO composite exhibits a 3D hierarchical porous network and high specific surface area, which supply efficient channels for the transmission of electrons/ions, and ample place for sufficient reaction between active substance and electrolyte. In addition, the NiO nanoparticles anchored on carbon nanofibers network can provide stable and excellent pseudocapacitance. When applied for supercapacitors, the CNF/NiO-based electrode can achieve the capacitance value of 674 F g⁻¹ and 98.6% capacitance preservation after 5000 cycles in a three-electrode system. Moreover, the asymmetric supercapacitors based on CNF/NiO composite obtain a superior capacitance value of 86 F g⁻¹ in a wide voltage of 1.6 V, and the maximum energy and power density reach 30.2 Wh kg⁻¹ and 8.1 kW kg⁻¹, respectively. The process has the advantages of simple operation, environmental friendliness, and possible mass production. It also provides prospects for designing and developing next-generation electrode materials for energy conversion devices.