Nanostructuring Nickel–Zinc–Boron/Graphitic Carbon Nitride as the Positive Electrode and BiVO<sub>4</sub>-Immobilized Nitrogen-Doped Defective Carbon as the Negative Electrode for Asymmetric Capacitors
Diab Khalafallah, Xiaoyu Li, Mingjia Zhi, Zhanglian Hong
Abstract
Rationally designed compounds with exceptional surface functionalities are greatly necessary for efficient energy-storage technologies. Herein an aqueous battery-type hybrid supercapacitor device is fabricated based on amorphous nickel–zinc–boron/graphitic carbon nitride (Ni–Zn–B/g-C3N4) nanosheet network structures as the cathode and a bismuth vanadate-anchored carbon nanotube matrix with nitrogen dopants and defect sites (BiVO4/NC) as the anode. Interconnected nanosheet-assembled Ni–Zn–B/g-C3N4 porous networks are developed via a scalable liquid-phase reduction method, while the BiVO4/NC nanocomposite frameworks are prepared by a simple chemical precipitation route and annealing treatment. Because of the unique compositional and structural features as well as enhanced electrochemical properties, the as-assembled Ni–Zn–B/g-C3N4//BiVO4/NC aqueous alkaline device with a large working potential of 1.6 V exhibits a remarkable energy-storage capability with a high energy density of 78.4 Wh kg–1 and a power density of 907.7 W kg–1 together with a good cyclic performance (85.3% retention after 8000 cycles). Considering the intriguing results and reasonable design of the cathode and anode materials, this work provides a significant prospect for designing a high-performance energy-storage system. The intrinsically enhanced electrochemical performances of heterostructured Ni–Zn–B/g-C3N4 and BiVO4/NC demonstrate their potential utilization in energy-storage systems.