Construction of orderly self-growing nanosheet arrays on nickel foam by introducing novel carbon composite materials for high-performance supercapacitors

Abstract In this work, multiwalled carbon nanotube–graphene oxide nanoribbon@graphitic carbon nitride/Ni–Co layered double hydroxide/nickel foam (MWCNTs-GONRs@g-C3N4/Ni–Co-LDH/NF), named as MW-CN-LDH, is synthesized by a single-step microwave-assisted method using MWCNTs-GONRs@g-C3N4 as a novel carbon composite material. This synthesis strategy produces an electrode by self-growing nanosheet arrays on a nickel foam. It avoids the use of adhesives and reduces electrode impedance. Consequently, the MW-CN-LDH electrode exhibits high specific capacitance (2532.80 F∙g−1 at 1 A∙g−1) and exceptional performance (75.81% capacitance retention at 20 A∙g−1). Moreover, density functional theory (DFT) calculations reveal the material’s excellent conductivity and strong affinity to OH−, providing theoretical support to the experiment. The analysis results are consistent with test data. When used as an asymmetric supercapacitor, MW-CN-LDH//AC (active carbon) delivers high capacitance (193.36 F∙g−1) and long cycle life (91.92% capacitance retention after 10 000 cycles). Moreover, the maximum energy density (i.e., 77.61 Wh∙kg−1 at 0.85 kW∙kg−1 power density) is attained. This synthetic approach is a promising strategy for rapidly synthesizing high-performance supercapacitors, thus facilitating the extensive application of supercapacitors in the future.