Decoration of NiO on hierarchical porous carbon spheres as advanced electrodes for supercapacitor applications

Recently, the application of nickel oxide (NiO) is restricted by the poor electrical conductivity and cycling stability. Herein, a versatile method is developed to synthesize NiO hybridized porous poly(p-phenylenediamine) carbon spheres (NiO@PPCSs) as the electrode of supercapacitors. The NiO@PPCSs electrode exhibits a high specific capacitance (up to 580 F g⁻¹ at 1 A g⁻¹) and durable cycle stability (over 90% retention rate after 8000 cycles at 5 A g⁻¹). The excellent electrochemical properties of the NiO@PPCSs is attributed to the hybridization of NiO providing reversible redox reaction between Ni²⁺ and Ni³⁺as well as the hierarchical porous structure for fast ion diffusion. Graphical abstract: [Figure not available: see fulltext.]