Low-diameter/defect carbon nanotubes formed on nickel foam derived from nickel-cobalt Prussian blue analogs for high-performance supercapacitor

Abstract

Carbon nanotubes (CNTs) with high specific surface area, low internal resistance, high structural stability, and abundant active sites are ideal electrode materials. In this work, regulating nickel-cobalt Prussian blue analogs (Ni-Co PBA) nucleation on nickel foam (NF) guides CNTs morphological evolution, achieving in-situ growth of low-diameter/defect CNTs on NF. Ni-Co PBA is anchored on NF through deposition and chemical bonding mechanisms. Chemical vapor deposition (CVD) is employed to synthesize CNTs on the NF surface. The framework structure of Ni-Co PBA not only effectively prevents transition metal ion agglomeration, but pyrolytic Ni-Co nanoparticles also catalyze this growth. Selenization converts the nanoparticles encapsulated within CNTs into metal selenides, yielding the product [email protected]. The fabricated [email protected] electrode exhibits a specific capacitance of 1592.3 F g⁻¹ at current density of 1 A g⁻¹. The assembled [email protected]//AC achieves a maximum energy density of 48.6 Wh kg⁻¹ at power density of 800 W kg⁻¹; it also maintains 81.7% of initial specific capacitance after 10,000 cycles at a current density of 10 A g⁻¹. Importantly, this work provides inspiration for the preparation of low-diameter/defect CNTs and their application in high-performance supercapacitor energy storage.