A 3D hydrangea-like NiMoO4/rGO/PANI hybrid composite for high performance asymmetric supercapacitor

Development of electrode materials exhibiting exceptional stability and possessing a high specific capacitance is the important task within the realm of supercapacitor research. In this study, a novel micro-architecture of NiMoO4 (NMO) resembling a hydrangea in three dimensions (3D) has been developed. The surface of NMO was modified by anchoring PANI nanoparticles and reduced graphene oxide (rGO) resulting in the formation of a composite material designated as NiMoO4/rGO/PANI (NMORP). The NMORP composite demonstrates a notable increase in specific-capacity, reaching 1150 C g−1 when tested at 1 A g−1. The observed capacity retention percentage of 97.5% after undergoing 5,000 cycles on a notable current density (10 A g−1) provides substantial proof of exceptional cycling performance within the cycling domain. The remarkable outcomes observed can be attributed to the synergistic impact of the structural and componential characteristics of the NMORP composite. The higher cycling stability of the NMORP composite electrode may be ascribed to the 2D-2D coupling phenomenon occurring at the interface of reduced graphene oxide (rGO) and NMO nanosheets, together with the stable 3-D design reminiscent of hydrangea flowers. Furthermore, the NMORP composite, characterized by a pore structure ranging from 10 to 20 nm and higher conductivity, demonstrates enhanced capabilities regarding the transfer of charge and diffusion of ions. In addition, the NMORP//AC supercapacitor shows a remarkable energy density of 82.43 Wh kg−1 at 850 W kg−1 power density. Furthermore, it shows exceptional cycling performance, retaining 94.5% of its capacity with 10 A g−1 current density upon the completion of 10,000 cycles. The fabrication of a composite material, referred to as NMORP, presents a viable approach to address the challenges associated with the inadequate electrochemical durability and sluggish electron/ion transfer exhibited by NMO composite when utilized as an electrode in asymmetric supercapacitors (device).