An innovative ZnO[sbnd]NbN composite cathodic electrode with large interfacial contact area for high performance supercapacitor

Nanostructure engineering and compositional optimization are crucial for enhancing the performance of supercapacitors positive electrode materials. ZnO is a promising supercapacitor electrode material; however, its slow kinetics and instability limit its performance. Herein, we synthesized ZnO and NbN using hydrothermal techniques and cost-effectively produced NbN-ZnO nanocomposites to address these issues. ZnO nanoparticles were incorporated into NbN sheets, resulting in a hybrid structure with a large specific surface area that improves electrolyte contact and ion diffusion. At 1 A g⁻¹, the composite material had a substantially greater specific capacitance (582 F g⁻¹) than pure ZnO (175 F g⁻¹). The NbN-ZnO//MnO₂ asymmetric supercapacitor (ASC) has a specific capacitance of 214 F g⁻¹ at 1 A g⁻¹ and a maximum energy density of 76 Wh kg⁻¹. It retains 92.11 % of its specific capacitance after 10,000 cycles at 10 A g⁻¹, indicating high performance and cycling stability. These findings show that using the NbN-ZnO composite nanostructure as a negative electrode in an asymmetric arrangement can produce more efficient energy storage solutions for practical applications.